CN113833480A - Shield initial tunneling and arrival construction method - Google Patents

Shield initial tunneling and arrival construction method Download PDF

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Publication number
CN113833480A
CN113833480A CN202111148081.6A CN202111148081A CN113833480A CN 113833480 A CN113833480 A CN 113833480A CN 202111148081 A CN202111148081 A CN 202111148081A CN 113833480 A CN113833480 A CN 113833480A
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China
Prior art keywords
shield
grouting
tunneling
tunnel
pipe
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钱峰
李健
罗苗
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Chengdu Construction Ninth Construction Engineering Co ltd
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Chengdu Construction Ninth Construction Engineering Co ltd
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Priority to CN202111148081.6A priority Critical patent/CN113833480A/en
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
    • E21D11/102Removable shuttering; Bearing or supporting devices therefor
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
    • E21D11/105Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/001Improving soil or rock, e.g. by freezing; Injections
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/093Control of the driving shield, e.g. of the hydraulic advancing cylinders

Abstract

The invention discloses a shield initial tunneling and arrival construction method, which comprises construction preparation and monitoring point arrangement; reinforcing the end head; installing a shield starting matching device; installing and debugging shield equipment; starting door opening configuration and negative ring assembly; starting and trial digging the shield in a split manner; controlling and correcting the shield tunneling, and assisting in supporting and dismantling; normally tunneling, synchronously grouting, and realizing a complete tunneling cycle until the tunneling is carried out to the inspection well; the shield machine passes through the inspection well and then carries out secondary initial tunneling, and the initial tunneling and normal tunneling processes are repeated until reaching a receiving well; receiving by the shield machine; and finally, performing secondary lining construction of the shield tunnel. The construction method is designed aiming at special geological conditions mainly comprising the argillaceous siltstone and the strongly weathered gravel stratum, effectively improves the shield construction of the gravity type water inlet pipe through the targeted design and control of all links and conditions, and ensures the stable and reliable engineering quality on the basis of ensuring the engineering progress.

Description

Shield initial tunneling and arrival construction method
Technical Field
The invention relates to the technical field of pipeline shield construction methods, in particular to a shield initial tunneling and arrival construction method for gravity type water inlet pipe construction.
Background
The gravity type water inlet pipe is under the condition of no pressure, depends on the gravity of the inclined gradient of the drain pipe to flow automatically, is the most common means in sewage discharge, and has the advantages of no power cost after being put into use, small maintenance and overhaul amount and the like. The gravity type water inlet pipe is deep in setting depth, generally 14-20 m in depth, and although the construction can be carried out by excavating construction with a conventional construction method, when mature building distribution (such as green belts in parks, roads, bridges, various pipe network facilities, buildings and the like) exists on a distribution line area, the construction environment of the gravity type water inlet pipe is complex, and the conventional construction method easily affects related buildings. And when the geological conditions of the local soil layer in construction belong to geological construction environments mainly comprising argillaceous siltstone and strongly weathered conglomerate, the stability of the construction process is more difficult to ensure by the conventional construction method. Thus, improvements are needed.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a shield initial tunneling and arrival construction method for gravity type water inlet pipe construction.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a shield initial tunneling and arrival construction method is mainly used for gravity type water inlet pipe construction and comprises the following steps:
s100, construction preparation: preparing corresponding construction materials and construction mechanical equipment based on the configured shield vertical shaft foundation pit and the shield starting well, and distributing a construction worker monitoring point in the whole shield construction region;
s110, end reinforcement: reinforcing the shield end in a range of 10 meters in the driving direction of the shield tunnel and in ranges of 3.2 meters on two sides of the center line of the shield tunnel by adopting a sleeve valve pipe sectional grouting mode;
s120, mounting a shield launching matching device: installing an originating bracket in the shield originating well according to the size and position requirements of shield originating and laying a temporary track for a trolley;
s130, mounting and debugging shield equipment: installing and debugging related matched systems including a slag-soil pond, a duct piece and other transportation systems, a mixing station grouting system, a storage battery car charging system, a tunnel ventilation system and a communication system on the ground part, and installing a shield unit in a segmented underground mode and carrying out no-load debugging and load debugging;
s140, initial door opening configuration: a pipe shed support is arranged on the upper part of the door opening in a retreating type sectional grouting mode, the end reinforcement, the stratum condition and the water leakage condition are detected through a door opening advanced horizontal exploring hole, and a sealing water stopping device is arranged at the door opening by adopting a cord fabric rubber plate and a ring plate;
s150, assembling a negative ring: pre-jacking the shield tunneling machine to a position 1m inside a tunnel portal by adopting an auxiliary jack after the shield tunneling machine goes into the well, installing a reaction frame according to the shield tunneling machine and the position of a base, smearing grease on a tail brush of the shield tunneling machine by hands, and assembling a negative ring;
s200, shield split starting: installing and trial pushing a cutter head, a front shield, a middle shield, a screw machine and a tail shield in sequence, and extending split starting matched pipelines including a hydraulic pipe, a water pipe, a foam pipe, a grouting pipe, a bentonite pipe and a cable;
s210, trial excavation: taking the first 100 meters of shield tunneling as a trial tunneling section, collecting and tidying tunneling parameters of each stratum in the trial tunneling process, and matching and adjusting subsequent tunneling parameters;
s220, shield tunneling control: switching the rotation direction of the cutter head when the rolling deviation exceeds 3 degrees by adopting a mode of rotating the shield cutter head forward and backward, correcting the rolling deviation, correcting the deviation in the vertical direction by controlling the thrust of the upper side jack and the lower side jack, and correcting the deviation in the horizontal direction by controlling the thrust of the left side jack and the right side jack;
s230, auxiliary matched dismantling: stopping the shield tunneling machine after the pilot tunneling is finished, putting the rest of the shield tunneling machine into the well in a matched mode, and removing the negative ring and the reaction frame;
s300, normal tunneling: the method comprises the steps of equipment system inspection during excavation and tunneling, setting of a laser guide system and related data, pipe piece conveying and positioning, grouting material preparation and well descending and positioning, tunneling and unearthing of a shield machine, monitoring of soil pressure of a soil cabin and a screw machine, synchronous grouting and realization of a complete tunneling cycle until the tunneling is carried out to an inspection well;
s400, stopping the shield tunneling machine after the shield tunneling machine passes through the inspection well for maintenance, performing secondary initial tunneling, and repeating the initial tunneling and normal tunneling processes until a receiving well when a plurality of inspection wells are configured in the whole shield construction interval;
s500, receiving by the shield machine: when the shield machine is close to a receiving tunnel portal, the tunneling speed is slowed down, the receiving tunnel portal is reinforced, and after the shield machine penetrates through the tunnel and reaches a receiving well, the disassembly and hoisting of large parts and main parts of the shield machine out of the well are completed within a set time;
s600, secondary lining construction of the shield tunnel: and a lining cement mortar layer with the thickness of 25cm is poured in the shield tunnel by adopting a full-circle needle beam trolley.
Specifically, the shield vertical shaft foundation pit and the shield starting well are constructed by adopting a fender pile and inner support open cut method, the fender pile structure adopts interval cast-in-place piles with the diameter of 1000mm, the end shield starting adopts glass fiber reinforced piles with the diameter of 1000mm, three supports are vertically arranged, the first support and the second support adopt reinforced concrete ring frame beams and reinforced concrete supports, the third support adopts 609 steel pipe supports, and retaining walls are adopted above crown beams for supporting.
Specifically, the arrangement of the monitoring points of the facility workers in the whole area of the shield construction comprises the steps of arranging ground settlement monitoring points on an ascending line of an interval tunnel, arranging section monitoring points on the ascending line of the interval tunnel, arranging building detection points around the interval tunnel, arranging settlement monitoring points in the interval tunnel and arranging convergence monitoring points in the interval tunnel.
Specifically, the process of performing end reinforcement by adopting a sleeve valve pipe sectional grouting mode is as follows:
s110a, leveling the field: after pipeline investigation is carried out, obstacles within 2 meters below the ground of a construction site are cleared, protective measures cannot be taken, then leveling and tamping are carried out, meanwhile, the positions of power lines of construction machinery and a conveying pipeline are reasonably arranged, and the tee joint of the construction site is guaranteed to be flat;
s110b, hole position lofting: measuring the construction grouting hole position by using a total station, and making an obvious mark by using a reinforcing steel bar to ensure that the displacement deviation of the center of the pile hole is less than 5 cm;
s110c, forming holes: drilling with a drilling machine to form holes, wherein the diameter of a final hole is not less than 90mm, the drilling depth reaches the height of a grouting reinforcement section, the hole site spacing is 2000mm, and isosceles triangles are arranged;
s110d, preparing and pouring a shell sealing material: preparing a shell sealing material while drilling, wherein the shell sealing material is low-strength cement clay slurry, when the drilling depth reaches the design requirement, pouring the shell sealing material into a drill rod of a drilling machine, pulling out the drill rod after the shell sealing material is filled, and timely replenishing the slurry after the shell sealing material is pulled out;
s110e, manufacturing and inserting a sleeve valve tube: the sleeve valve pipe has the outer diameter of 76mm, the maximum pressure capable of being borne by the sleeve valve pipe is greater than 3MPa, 6 grout overflow holes are formed in each section of the sleeve valve pipe at intervals of 800mm, the bottom end of the sleeve valve pipe is tightly wrapped by geotextile, sealing materials are prevented from entering the sleeve valve pipe, the sleeve valve pipe is inserted to the designed depth after the sleeve pipe is pulled out, and the orifice pipe is embedded firmly;
s110f, lower grouting core tube: the grouting core pipe is processed by adopting a 25mm welded steel pipe, the length of the grouting core pipe is 0.5-0.6m, 3-4 grouting-stopping rubber packing cups are respectively added at two ends of the grouting core pipe to form a grouting-blocking plug, and then the grouting core pipe is lowered to the bottom of the hole;
s110g, preparing grouting liquid: the grouting liquid adopts pure cement slurry, the water-cement ratio of the grouting liquid is 0.8-1.0, the grouting liquid is pumped for pressure injection after being uniformly stirred and sieved, and the grouting liquid is continuously stirred in the grouting process;
s110h, grouting: sectional grouting is adopted, the length of each section of grouting is the grouting step distance, the length of a grouting core pipe is the grouting step distance, grouting is started after curing for 2-3 days after the lower sleeve valve pipe is grouted with the sealing shell material, the grouting pressure is controlled to be 0.2-0.4MPa, and grouting is finished when the designed grouting pressure or grouting amount reaches more than 80% of the designed grouting amount;
s110i, lifting the core pipe: in the grouting process, after each section of grouting step is finished, the section of grouting core pipe is moved upwards by the length of one step, the grouting core pipe is symmetrically clamped by adopting lifting equipment or manually adopting a pipe wrench, the two sides of the grouting core pipe are lifted up by uniform force, and after 3-4m grouting is finished, one section of grouting core pipe is removed;
s110j, completing a single hole: and after grouting is finished each time, hole replacement and displacement are carried out, a grouting machine, a stirrer and various pipelines are cleaned in time, the normal operation of subsequent grouting is ensured, and then end reinforcement is realized by completing each hole one by one.
Specifically, the pipe shed support arranged in the step S140 is made of seamless steel pipes with the diameter of 108mm and the wall thickness of 6mm, the seamless steel pipes are arranged along the position 200mm outside the excavation contour line of the arch part of the shield, the circumferential center distance of the seamless steel pipes is 400mm, the outer inserting angle is 1-2 degrees, the length of the pipe shed support is 10m, the pipe shed support is spliced and lengthened by sections, the two sections are connected by screw threads, the joints of the two adjacent seamless steel pipes are staggered by not less than 1m, and grouting holes are arranged on the joints;
the door opening advanced horizontal probing holes are distributed on the door opening in an average manner, the diameter of each drilling hole is 50mm, and the depth of each drilling hole is 1.4 m;
the sealing and water stopping device is installed on a ring plate pre-embedded at the opening, the ring plate is made of a Q235A steel plate, fixing screw holes are reserved in the ring plate, and the curtain cloth rubber plate is fixed on a steel ring at the opening of the tunnel by the ring plate.
Specifically, in the trial excavation, the recording content includes: a. tunneling: construction progress, oil cylinder stroke, tunneling speed, shield thrust, soil pressure, cutter head and screw machine rotating speed, and annular gap between the shield inner wall and the segment outer side; synchronous grouting: b. synchronous grouting: grouting pressure, quantity, consistency, grouting material proportion and grouting test block strength; c. measurement: shield gradient, tunnel ovality, total propulsion distance and exact position of the axis of each lining ring of the tunnel.
Specifically, the shield tunneling control further comprises controlling the stroke of a propulsion oil cylinder of the shield and limiting the propulsion amount of each ring of the shield when the shield advances forwards in a no-load state; controlling the posture through the stroke of an oil pushing cylinder of the shield tunneling machine; under the condition of ensuring the normal propulsion of the shield, the total thrust and the cutter torque are reduced; after the shield tail completely enters the hole body, adjusting the hole opening for sealing, and grouting the hole opening, wherein the grouting pressure is controlled within 1.5 Bar; the dismantling time of the reaction frame and the negative ring pipe piece is determined according to the mortar performance parameters of the back lining grouting and the starting tunneling thrust of the shield, the tunneling is carried out for more than 100m, the tunneling of the front 50 rings is completed for more than 7 days, and the dismantling of the reaction frame and the negative ring pipe piece is started.
Specifically, the shield machine receiving process comprises the steps of reinforcing a hole outlet soil body, installing a receiving frame, performing tunnel portal rechecking measurement, performing tunnel portal chiseling, installing a tunnel portal waterproof device, performing tunnel portal discharging, cleaning a cutter head, moving a shield body forwards in place, removing a cutter head connection and lifting the cutter head, disconnecting a trolley and a host pipeline backward moving trolley, removing a screw machine backward moving trolley, removing a screw pipeline, a driving device, a rear sleeve and a screw rod and moving the screw rod to a tunnel, removing the front shield body connection and lifting the front shield, removing a hinge connection, transferring out a hinged shield body, ejecting a shield tail, removing a jack, lifting the shield tail and the jack, lifting screw machine components, removing a receiving support and laying trolley tracks, disconnecting the trolley connection, sequentially lifting the trolley, and removing and lifting out related underground auxiliary supports.
Specifically, the matched arrival construction in the receiving process of the shield tunneling machine comprises the following steps:
s410a, performing tunneling according to the penetration posture of the shield tunneling machine and the tunneling deviation rectifying plan, and gradually completing deviation rectifying according to the small deviation rectifying amount of each ring;
s410b, selecting reasonable tunneling parameters when the shield tunneling machine is 50m away from the end wall, gradually slowing down the tunneling speed, controlling the tunneling speed to be below 20mm/min, gradually reducing the thrust, and slowly and uniformly cutting the soil body to ensure the stability of the end wall and prevent the stratum from collapsing;
s410c, after the shield enters the receiving section, monitoring and measuring through the ground surface, and feeding back the measurement information in time to control the shield machine to tunnel;
s410d, when the distance between the cutter head and the shield tunneling machine is less than 10m, actually adjusting tunneling parameters by observing the change condition of the hole opening in the tunneling process;
s410e, after the assembled duct piece enters the reinforcing range, the slurry is changed into quick-hardening slurry, and muddy water is blocked outside the reinforcing area in the reinforcing range in advance;
s410f, when the last ring pipe piece of the pipe piece is assembled, injecting double-liquid slurry through the secondary grouting holes of the pipe piece for plugging;
s410g, when the shield shell of the shield front body is pushed out of the tunnel portal, the folding pressing plate is adjusted through the steel wire rope on the pressing plate clamping ring to press the cord fabric rubber plate as much as possible so as to prevent muddy water and serous fluid of the tunnel portal from flowing out, and the steel wire rope is tensioned again when the duct piece is pulled out of the shield tail, so that the pressing plate can press the rubber cord fabric.
Specifically, the process of the shield tunnel second lining construction comprises the following steps:
s610a, the trolley automatically walks to the position of the first bin section, the accurate measurement is carried out to position the two-lining trolley, the central line of the trolley is ensured to be consistent with the central line of the tunnel, then sundries, accumulated water and floating slag on the base are cleaned, a stop head template is arranged, and a water stop belt is arranged according to the design requirement;
s610b, before concrete pouring, removing dust on the surface of the waterproof layer from the trolley pouring window and spraying water to wet the waterproof layer, ensuring that the concrete is compact in the pouring process and preventing the concrete from shrinkage cracking, wherein the concrete is poured from bottom to top during pouring, firstly, ash is put from one side of the waist, and the bottom is poured;
s610c, starting to discharge ash from an ash discharge hole at the top after reaching the position of the waist beam, knocking the template by a wooden hammer during ash discharge, finding out an uncompacted part, and assisting vibration by a vibrating rod to ensure that concrete in the template is compact;
s610d, intensively mixing the self-compacting concrete by a mixing station, transporting the self-compacting concrete to a pouring place by a concrete mixing transport vehicle, lowering the self-compacting concrete to a concrete transport vehicle in a hole by a crane or a guide pipe, and pumping the self-compacting concrete into a template trolley by the concrete transport vehicle;
s610e, controlling the warehousing speed when concrete close to the bottom is poured, and slowing down the warehousing speed to prevent honeycomb and pitted surface defects; the speed is accelerated when the top concrete is poured, and the top arch concrete is prevented from being hollow;
s610f, uniformly pouring concrete, and controlling the height difference of the concrete on two sides to be 30-50 cm, wherein the local maximum height difference is not more than 60 cm.
Compared with the prior art, the invention has the following beneficial effects:
the construction method is designed aiming at special geological conditions (such as geology mainly comprising argillaceous siltstone and strongly weathered gravel stratum), shield construction of the gravity type water inlet pipe is effectively improved through targeted design and control of all links and conditions, and stable and reliable engineering quality is ensured on the basis of ensuring engineering progress. The invention has the advantages of ingenious design and convenient implementation, and is suitable for being applied to the shield construction of the gravity type water inlet pipe.
Drawings
FIG. 1 is a schematic overall flow chart of an embodiment of the present invention.
Detailed Description
The present invention is further illustrated by the following figures and examples, which include, but are not limited to, the following examples.
Examples
As shown in fig. 1, the shield initial tunneling and arrival construction method is mainly used for gravity type water inlet pipe construction, and comprises the following steps:
s100, construction preparation: preparing corresponding construction materials and construction mechanical equipment based on the configured shield vertical shaft foundation pit and the shield starting well, and distributing a construction worker monitoring point in the whole shield construction region;
s110, end reinforcement: reinforcing the shield end in a range of 10 meters in the driving direction of the shield tunnel and in ranges of 3.2 meters on two sides of the center line of the shield tunnel by adopting a sleeve valve pipe sectional grouting mode;
s120, mounting a shield launching matching device: installing an originating bracket in the shield originating well according to the size and position requirements of shield originating and laying a temporary track for a trolley;
s130, mounting and debugging shield equipment: installing and debugging related matched systems including a slag-soil pond, a duct piece and other transportation systems, a mixing station grouting system, a storage battery car charging system, a tunnel ventilation system and a communication system on the ground part, and installing a shield unit in a segmented underground mode and carrying out no-load debugging and load debugging;
s140, initial door opening configuration: a pipe shed support is arranged on the upper part of the door opening in a retreating type sectional grouting mode, the end reinforcement, the stratum condition and the water leakage condition are detected through a door opening advanced horizontal exploring hole, and a sealing water stopping device is arranged at the door opening by adopting a cord fabric rubber plate and a ring plate;
s150, assembling a negative ring: pre-jacking the shield tunneling machine to a position 1m inside a tunnel portal by adopting an auxiliary jack after the shield tunneling machine goes into the well, installing a reaction frame according to the shield tunneling machine and the position of a base, smearing grease on a tail brush of the shield tunneling machine by hands, and assembling a negative ring;
s200, shield split starting: installing and trial pushing a cutter head, a front shield, a middle shield, a screw machine and a tail shield in sequence, and extending split starting matched pipelines including a hydraulic pipe, a water pipe, a foam pipe, a grouting pipe, a bentonite pipe and a cable;
s210, trial excavation: taking the first 100 meters of shield tunneling as a trial tunneling section, collecting and tidying tunneling parameters of each stratum in the trial tunneling process, and matching and adjusting subsequent tunneling parameters;
s220, shield tunneling control: switching the rotation direction of the cutter head when the rolling deviation exceeds 3 degrees by adopting a mode of rotating the shield cutter head forward and backward, correcting the rolling deviation, correcting the deviation in the vertical direction by controlling the thrust of the upper side jack and the lower side jack, and correcting the deviation in the horizontal direction by controlling the thrust of the left side jack and the right side jack;
s230, auxiliary matched dismantling: stopping the shield tunneling machine after the pilot tunneling is finished, putting the rest of the shield tunneling machine into the well in a matched mode, and removing the negative ring and the reaction frame;
s300, normal tunneling: the method comprises the steps of equipment system inspection during excavation and tunneling, setting of a laser guide system and related data, pipe piece conveying and positioning, grouting material preparation and well descending and positioning, tunneling and unearthing of a shield machine, monitoring of soil pressure of a soil cabin and a screw machine, synchronous grouting and realization of a complete tunneling cycle until the tunneling is carried out to an inspection well;
s400, stopping the shield tunneling machine after the shield tunneling machine passes through the inspection well for maintenance, performing secondary initial tunneling, and repeating the initial tunneling and normal tunneling processes until a receiving well when a plurality of inspection wells are configured in the whole shield construction interval;
s500, receiving by the shield machine: when the shield machine is close to a receiving tunnel portal, the tunneling speed is slowed down, the receiving tunnel portal is reinforced, and after the shield machine penetrates through the tunnel and reaches a receiving well, the disassembly and hoisting of large parts and main parts of the shield machine out of the well are completed within a set time;
s600, secondary lining construction of the shield tunnel: and a lining cement mortar layer with the thickness of 25cm is poured in the shield tunnel by adopting a full-circle needle beam trolley.
Specifically, in this embodiment, the construction of a gravity type water inlet pipe in a metropolitan area is taken as an example for specific explanation, a gravity type water inlet pipe is about 1.6 kilometers, 30 ten thousand tons/day of flow is separated from a certain sewage treatment plant through a diversion well, and flows into a sewage water transfer pump station along the gravity type water inlet pipe, the gravity type water inlet pipe passes through areas such as artificial lakes, expressways, green belts, barrages and the like, the park green belts in the areas are basically formed, roads, bridges, various kinds of pipe network facilities, buildings and the like are distributed, and the construction environment of the gravity type water inlet pipe is complicated. The specific technical parameters after investigation and design are as follows:
the outer diameter of the pipe piece is 3.2m, the thickness of the pipe piece is 25cm, and the inner diameter of the tunnel is 2.7 m. The duct piece is made of concrete with the strength grade of C50P12, lining cement mortar with the thickness of 25cm is integrally poured in the duct piece in the later period, and the inner diameter of the formed gravity water inlet pipeline is 2.2 m. The length of the shield segment is about 1.68km, the line is arranged at a common plane curve 5, the curvature radius is 200m and 500m, the gradient of the whole line of the line is 1 per thousand, the shallowest buried depth of the tunnel is 18m, and the deepest buried depth is 20 m. The lining ring is divided into 6 blocks, 1 block of capping block, 2 adjacent blocks and 3 standard blocks. Allowable deviation of diameter after lining and looping: 12 mm; adjacent ring surface clearance: not greater than 2 mm; gap between adjacent blocks in longitudinal seam: not greater than 2 mm; the corresponding circumferential bolts have different axiality: less than 1 mm; allowable height difference (allowable step value) of adjacent ring segments: 4 mm; uneven degree deviation of rib surfaces of adjacent pipe pieces: 3 mm; controlling the shield axis: elevation and plane control are both 50 mm; the duct piece has no through crack, no crack with the width larger than 0.2mm and no concrete peeling phenomenon. The allowable deviation of the plane position of the shield starting axis is +/-50 mm, and the theodolite is adopted for inspection, wherein 1 point/1 ring is adopted; the allowable deviation of elevation is +/-50 mm, and a leveling instrument is adopted for inspection, wherein 1 point/1 ring is adopted; ovality of diameter of lining ring: ± 0.5% D (tunnel outer diameter), radial staggering of adjacent segments: 5mm, staggering the ring surfaces of adjacent ring sheets: 6 mm. And (4) producing 15 rings of shield segments every day, extracting 1 ring for inspection, and allowing the deviation of the width, the arc, the chord length and the thickness to be +/-1 mm. And (4) sequentially and horizontally assembling and checking 200 rings of the shield segment in each production, wherein the allowable deviation of the circumferential seam clearance, the longitudinal seam clearance, the inner diameter after ring formation and the outer diameter after ring formation is +/-2 mm.
And a shield shaft foundation pit is arranged at a sewage treatment plant in advance, the shield shaft foundation pit and a shield starting well are constructed by adopting a fender post and inner support open cut method, and a diversion well is constructed by adopting an anchor net jet inverted hanging well wall. The length of the foundation pit is 15.6 meters, the width of the foundation pit is 11.6 meters, and the depth of the foundation pit is 19.63 meters. The fender pile structure adopts interval cast-in-place piles with the diameter of 1000mm @ 1600-; and the foundation pit above the crown beam is supported by a 300mm retaining wall.
Shield initiation and tunneling, production preparation in the early stage of entry:
before construction, people, materials and mechanical equipment which are required to be prepared are produced, and preparation is made for subsequent construction: the model selection allocation of the mechanical equipment is made according to a total construction progress plan and the monthly peak intensity, and meanwhile, emergency equipment and standby equipment under special conditions are considered, so that the construction period and the engineering quality are ensured, and the requirement of engineering construction is met; the method has the advantages that the intact performance of the mechanical equipment on the scene and the sufficient quantity of the equipment are ensured, the construction of the project is ensured, and the requirements of owners are met; according to the daily tunneling condition, corresponding construction materials are reserved in advance, and smooth construction is guaranteed; construction teams and groups and management configuration.
And (3) laying construction monitoring points: the construction monitoring point range is the whole shield construction area, and mainly monitors deformation of ground surface buildings (particularly buildings, bridges, elevated frames and the like) and ground settlement along the line so as to timely adopt corresponding construction methods and technical measures for control and ensure the safety of various risk buildings and underground pipelines. 1) And (3) laying of the ascending line ground settlement monitoring points of the interval tunnel: are respectively arranged along the ascending line axis, and are arranged at intervals of 30 m. Deep soil monitoring points are adopted at ground settlement points within 30m from the hole opening, middle section monitoring points are buried underground according to geological conditions of a tunnel propulsion area, and leveling nail setting points are preferably adopted in a soil layer surface area. 2) And (3) laying monitoring points of the section of the upper line axis of the interval tunnel: the distances among all the points of the section are respectively 5m, 10m and 15m, and the total of 3 points (except the axis point) of each row of the section are obtained. The burying method of the surface deep layer settlement monitoring points comprises the following steps: firstly, a concrete core drill is used for directly drilling holes on the ground surface, wherein the hole depth is about 40cm, and the hole diameter is 10 cm. After drilling, a base with screw threads is embedded at the lower part of the hole, the length of the base is about 10cm, and the base is fixed by cement mortar. After the base is fixed, the reinforcing steel bar measuring point with the length of 30cm and the diameter of 18mm is firmly connected with the base. The screw thread that reinforcing bar measurement station lower part was equipped with matches with the base, and screw thread connection is firm through screwing up. And sleeving a PVC pipe with the diameter of about 20mm on the outer side of the measuring point, isolating the measuring point of the steel bar from peripheral cement mortar, filling cement mortar between the PVC pipe and the hole wall, and pre-burying a measuring point protective cover above. And after the engineering is finished, the reinforcing steel bar measuring point can be taken out by unscrewing the screw thread. 3) And (3) arranging detection points of buildings around the interval tunnel: in the range of 30m above the tunnel axis, points are directly distributed and nailed into the room corners by shooting nails, or original points are utilized. 4) And (3) laying settlement points in the interval tunnel: and (3) arranging one monitoring point at each 10m (10 rings) of the settlement monitoring point in the tunnel. The embedding method comprises the following steps: with the aid of the bolts at the bottom of the tunnel segment, the surfaces of the bolts are arc-shaped, and it must be ensured that the bolts are not allowed to loosen. 5) And (3) arrangement of convergence points in the interval tunnel: 1 convergence monitoring section is respectively arranged in the range of 50m (50 rings) of the upper line, and each monitoring section is divided into a longitudinal direction and a transverse direction. The embedding method comprises the following steps: and marking laser range finders at the bottom and the side wall of the tunnel at monitoring points. For the arrangement of surface subsidence points, determining the axis position of a tunnel on site by using a total station according to the design mileage and coordinates before arranging measuring points; the settlement monitoring points parallel to the tunnel axis and the settlement monitoring points vertical to the tunnel axis are arranged on the ground, and the settlement monitoring points parallel to the tunnel axis are set as follows: arranging an axis settlement monitoring point every 5m in 100m of the originating and receiving section, and arranging a monitoring section every 10m, wherein each section is 10-15 points; an axis settlement monitoring point is arranged every 10m in the standard interval, a monitoring section is arranged every 20m, at least 10-15 measuring points are arranged on each section, and the distance between each section measuring point and the tunnel axis is 23m, 18m, 13m, 8m, 3m, 0m (axis point), 3-5 m, 8m, 3-5 m, 0m (axis point), 3.0m, 8m, 13m, 18m and 23m respectively. For the segment lining clearance convergence, a monitoring point is buried on a structural section, the same segment lining vault is settled and has the same section, a main measuring section is arranged every 50m for each interval tunnel of shield construction, and sections are arranged at the shield starting position and the interface position; selecting the deformed steel bar with the diameter of 22mm, burying the deformed steel bar at two sides of the structural section, wherein the exposed length is 5cm, welding an oval steel ring at the exposed deformed steel bar head, marking the deformed steel bar with red paint by using a unified number, and arranging a protection device.
And (3) delivery inspection of the duct piece: when the duct piece leaves a factory, the strength of the duct piece should reach 100% of the design strength. The shipper should check the qualified seal and the inspector code seal of the duct piece before the duct piece leaves the factory and then allow the loading to leave the factory. The segment is transported to a construction site, and after the segment is qualified by inspection and acceptance of a construction unit, the segment is qualified by inspection and acceptance after the approval of the approval process. Before the duct piece is shipped, a shipper should register the data of the duct piece, such as the segment number, the production serial number, the production date, and the like. Meanwhile, informatization management is adopted, and the quality of the duct piece is monitored by using the two-dimensional code. Before the duct piece is shipped, the raw materials and test condition reports of the duct pieces in the batch are checked again, and the duct piece can be shipped after being qualified.
And (3) transporting and carrying the duct pieces: the total height is limited to within 3.6m when shipping the duct pieces. The duct pieces on the car must be supported by a base and tied firmly by ropes so as not to be damaged due to dislocation in the transportation process. The transportation road must be flat and firm, have sufficient road surface width and turning radius, and the driving speed should be grasped according to the road surface condition. And reasonable transport vehicles and loading and unloading machines are selected for loading and unloading according to the weight, the size and the specific situation of the construction site. The segment is set according to the designed position no matter when being loaded or unloaded, so that the stress condition of the segment is met. When stacking, the filler strips between the pipe pieces are on the same vertical line, and the thickness of the filler strips is equal. It is strictly forbidden for people to stay and walk under the crane arm and the hung heavy object. When more than two rope buckles are used for hanging the duct piece, if the included angle between the rope buckles is larger than 100 degrees, a clamping ring is additionally arranged to prevent the rope buckles from sliding. When the duct piece is hung, the lifting hook and the sling hook are guaranteed to be hooked stably and hung just before hoisting, and the sent signal is clear and definite. The pipe piece should be lightly lifted and lightly placed, and the lifting process should be kept stable.
End reinforcement: this engineering shield end is consolidated and is adopted
Figure BDA0003286195400000071
The reinforcing range of the sleeve valve pipe grouting mode is 10m in the tunneling direction, and the reinforcing range is 3.2m on each of two sides of the center line of the shield tunnel. The sleeve valve tube spacing is 2000 multiplied by 2000 and arranged in an isosceles triangle. The depth of the formed hole is from the earth's surface to the position 1.6m below the outer diameter of the shield segment, and the range of the grouting reinforced soil body is the range of 3.2m in total of 1.6m above and below the outer diameter of the shield tunnel. The sleeve valve type grouting pipe is inserted into the stratum through a drill hole, and the segmented grouting process is adopted, so that the grout can uniformly enter the stratum under the pressure condition, and the aims of segmented controllable and uniform diffusion of the grout in the stratum are fulfilled. The concrete process of end reinforcement is as follows:
a. leveling the field: after pipeline investigation is carried out, obstacles within 2 meters below the ground of a construction site are cleared, protective measures cannot be taken, then leveling and tamping are carried out, meanwhile, the positions of power lines of construction machinery and conveying pipelines are reasonably arranged, and the tee joint of the construction site is guaranteed to be one;
b. hole site lofting: measuring the construction grouting hole position by using a total station, and making an obvious mark by using a reinforcing steel bar to ensure that the displacement deviation of the center of the pile hole is less than 5 cm;
c. forming holes: drilling by adopting a drilling machine to form holes, wherein the diameter of a final hole is not less than 90mm, the drilling depth reaches the height of a grouting reinforcement section, a record is made in the drilling process for the reference of grouting operation, the hole site spacing is 2000mm, and isosceles triangles are arranged; when water burst occurs or rock stratum is broken to cause drill jamming in the drilling process, stopping drilling, and performing grouting hole sweeping or drilling after a sleeve is additionally arranged;
d. preparing and pouring a shell sealing material: and (3) preparing a shell sealing material while drilling, wherein the shell sealing material is low-strength cement clay slurry, and in order to ensure that the thickness of the shell sealing material is uniform, the sleeve valve pipe is positioned in the center of the drilling hole. When the drilling depth reaches the design requirement, pouring a shell sealing material into a drill rod of the drilling machine, pulling out the drill rod after the shell sealing material is filled, and timely replenishing slurry after the shell sealing material is pulled out;
e. manufacturing and inserting a sleeve valve tube: the sleeve valve pipe is 76mm in outer diameter and can bear the maximum pressure of more than 3MPa, 6 grout overflow holes are formed in each section of the sleeve valve pipe at intervals of 800mm, and the diameter of each grout overflow hole is 8-10 mm. The rubber sleeve is tightly hooped outside the pipe at the position of the opening to cover the grouting hole. The bottom end of the sleeve valve pipe is tightly wrapped and tied by geotextile, so that sealing materials are prevented from entering the sleeve valve pipe, the sleeve valve pipe is inserted to the designed depth after the sleeve pipe is pulled out, and the orifice pipe is firmly embedded;
f. and (3) lower grouting core pipes: the grouting core pipe is processed by adopting a 25mm welded steel pipe, the length of the grouting core pipe is 0.5-0.6m, 3-4 grouting-stopping rubber leather cups are respectively added at two ends of the grouting core pipe to form a grouting-stopping plug, and the condition of a grouting head, such as whether the state of a one-way valve is good or not, is checked; checking that the pipelines cannot be blocked, and ensuring the connection quality of each pipeline; if the sleeve valve pipe is blocked, washing the pipe, and then lowering the grouting core pipe to the bottom of the hole;
g. preparing grouting liquid: the grouting liquid adopts pure cement slurry, the water-cement ratio of the grouting liquid is 0.8-1.0, the cement used for grouting is P.O42.5 ordinary portland cement, the grouting liquid is pumped for pressure injection after being uniformly stirred and sieved, and is continuously stirred in the grouting process, and the stirring time is more than 3 min; in order to increase the groutability, a compound water-reducing early strength agent with the cement dosage of 0.3 to 0.5 percent can be added into the slurry;
h. grouting: sectional grouting is adopted, the length of each section of grouting is the grouting step distance, the length of a grouting core pipe is the grouting step distance, grouting is started after curing for 2-3 days after the lower sleeve valve pipe is grouted with the sealing shell material, the grouting pressure is controlled to be 0.2-0.4MPa, and grouting is finished when the designed grouting pressure or grouting amount reaches more than 80% of the designed grouting amount; along with the gradual rise of grouting pressure, grouting should be stopped when the ground or surrounding buildings change such as rise;
i. lifting the core tube: in the grouting process, after each section of grouting step is finished, the section of grouting core pipe is moved upwards by the length of one step, the grouting core pipe is symmetrically clamped by adopting lifting equipment or manually adopting a pipe wrench, the two sides of the grouting core pipe are lifted up by uniform force, and after 3-4m grouting is finished, one section of grouting core pipe is removed;
j. single hole completion: and after grouting is finished each time, hole replacement and displacement are carried out, a grouting machine, a stirrer and various pipelines are cleaned in time, the normal operation of subsequent grouting is ensured, and then end reinforcement is realized by completing each hole one by one.
k. And (3) grouting effect inspection: after grouting of the sleeve valve pipe is completed, waiting for 28 days, then performing core drilling sampling on the reinforced soil body according to design requirements, performing a physical experiment, and performing next procedure after the design requirements are met, or performing supplementary grouting until the reinforced soil body is qualified.
Grouting construction attention items of sleeve valve pipes: 1) and the drilling depth and the grouting step pitch are designed, the grouting hole position lofting is accurately carried out on a construction site according to a drilling layout, and the ground elevation of each hole position is measured simultaneously. Then accurately calculating the drilling depth of each grouting hole position according to the shield elevation and the grouting range requirement; the grouting reinforcement range is from the bottom of a foundation pit to the top surface of a medium-weathered rock stratum, the net distance between the bottom of the sleeve raft tube and the top of the tunnel is at least 1m, and the diffusion radius of a grouting hole is 0.4-0.8 m. 2) The drilling and grouting are performed sequentially from the periphery to the interior, the enclosing, blocking and cutting are performed from the periphery, the filling and pressing are performed from the interior, and the construction is performed at intervals in the same row. The grouting form adopts backward grouting, and forward grouting is adopted when the rock stratum is broken and easily causes hole collapse. 3) Before reinforcement construction, pipeline investigation and relocation are required to be completed, and if reinforcement measures conflict with underground pipelines, a construction unit should immediately notify a manager, an owner and related designers so as to take corresponding measures. 4) And (3) enhancing monitoring work, if the conditions of ground cracking, settlement acceleration and the like are found, immediately stopping construction, taking effective measures, and continuing construction after the conditions are confirmed by site construction supervision and reported to owners and designers. 5) If the construction reinforcing effect does not meet the expected requirement, the construction unit should immediately stop the construction and notify the supervision, owner and related designers to take corresponding measures.
And (3) installing and debugging a ground related matching system: the ground system mainly comprises a slag soil, a duct piece and other transportation systems, a mixing station grouting system, a battery car charging system, a tunnel ventilation system, a communication system and the like.
Installation of the origination bracket: the shield starting bracket is manufactured and installed according to drawings, and manufacturing and installation errors meet requirements, namely the upper, lower, left and right of an axis are respectively 50 mm. Before the assembly of the starting bracket of the shield machine, the spatial position of the starting bracket in the shield well is determined according to the height, width and length requirements of the starting bracket and the requirements of the outer diameter size of the shield and the height of the center of the starting tunnel opening and the tunnel bottom. However, in the initial tunneling process of the shield, because the gravity center of the shield tunneling machine is close to the front, a downward 'head collision' phenomenon is easily generated during initial tunneling, the elevation of the bracket needs to be 20-30 mm higher than the designed elevation, the bracket of the shield tunneling machine needs to be arranged according to the planned posture of the shield tunneling machine when being installed and is arranged in the direction perpendicular to the tunnel portal, and the bracket is formed by processing section steel and is assembled on site.
And (3) reaction frame installation: huge thrust is transmitted to the working well structure through the reaction frame when the shield machine starts, and the reaction frame needs to be installed in order to ensure that the shield machine starts smoothly. And after the reaction frame is manufactured on the ground, the reaction frame is hoisted and lowered into the well in a split mode, and the mounting position, the longitudinal verticality and the transverse verticality of the reaction frame are well adjusted according to the actually measured positions of the shield tunneling machine and the base. The reaction frame needs to be subjected to stress analysis work, and the maximum bearing capacity of the reaction frame is 1.5 times larger than the total thrust required by soil cutting.
Track laying: before the shield machine trolley enters the tunnel at the starting stage, a temporary track is laid for the power supply bottle trolley and the trolley.
Installing and debugging the shield tunneling machine in the well: the debugging of the shield machine comprises no-load debugging and load debugging. No-load debugging: after the assembling and the connecting of the shield machine are finished, no-load debugging can be carried out, and the no-load debugging mainly comprises the step of checking whether equipment runs normally or not. The main debugging contents are as follows: hydraulic system, lubricating system, cooling system, power distribution system, speed change system, segment erector and various instruments. Load debugging: the trial tunneling time is usually the debugging of the equipment load, and strict technology and management measures are adopted during the debugging of the load to ensure the engineering safety, the engineering quality and the linear precision.
A tunnel portal pipe shed: in order to further ensure the starting safety, besides the sleeve valve pipe grouting reinforcement, the upper part of the tunnel door is additionally provided with a sleeve valve pipe
Figure BDA0003286195400000081
And supporting the pipe shed by one step. The construction process comprises the steps of guide wall construction → drill machine in place → drilling and pipe shed installation → grouting. Pipe shed adopts
Figure BDA0003286195400000082
A seamless steel tube with a wall thickness of 6mm,the shield arch excavation profile line is arranged along the position 200mm outside the shield arch excavation profile line, the circumferential center distance of the steel pipe is 400mm, and the external insertion angle is about 1-2 degrees. The pipe shed length is 10m, adopts the segmentation to assemble the extension, connects with the screw thread between two sections, and screw thread section length is greater than 150mm, and two adjacent pipe shed joints will stagger, and the length of staggering is not less than 1 m. The pipe shed steel pipes are arranged according to a quincunx shape of @200 multiplied by 200
Figure BDA0003286195400000091
The grouting hole of (2) is used as a grout stopping section without drilling a flower hole at the tail part 2m of the steel pipe. The pipe shed grouting adopts cement mortar, the water cement ratio of the cement mortar is 0.8-1.0, and the grouting pressure is 0.2-0.4 Mpa. The grouting sequence is that the bottom is first and the top is last, and the backward sectional grouting is adopted.
Horizontal hole probing: the shield initial door opening advanced horizontal probing hole aims at probing the end reinforcement, the stratum condition and the water leakage condition, the number of the horizontal probing holes is 9, the diameter of a drilling hole is 50mm, the depth of the drilling hole is 1.4m, the 9 holes are evenly distributed on a door during construction, and one hole in the middle needs to be laterally shifted by 20cm so as to avoid knocking off the shield central point released by a measurement group. The drilling technical requirements are as follows: 1) scaffold steel pipes are erected on the scaffold platform and are phi 48 steel pipes without rust and cracks, the platform erection must be firm, and the scaffold is reliably connected to a cutter head of the shield tunneling machine in order to prevent overturning; 2) and paving wood boards or pedestrian pedals on the scaffold steel pipes of each vertical layer, and fixing the wood boards or the pedestrian pedals on the scaffold by using iron wires to serve as a horizontal hole-exploring construction platform. 3) The horizontal probe hole for positioning probe holes is provided with 4 50mm holes (90 degrees) on a circle with the distance R being 1100mm, and 4 50 holes (90 degrees) on a circle with the distance R being 1800 mm. The other one is arranged on the center of the tunnel portal and is deviated from the center by 200mm to the right side. During lofting, the hole sites are marked by red paint, and when the support of the steel ring of the tunnel door has influence, the hole site with the length of 100mm can be adjusted. 4) And drilling in place, fixing the drilling machine on the underground diaphragm wall of the tunnel door according to hole positions, and drilling by using the drill rod vertically to drill the underground diaphragm wall. The depth of the horizontal probing hole is 1.4m, and if the horizontal probing hole meets the bulge of the diaphragm wall, the hole depth is properly deepened; 5) and after the hole depth reaches the design requirement, checking and confirming are timely carried out on the spot on-duty engineer. Processing the emergency encountered in the drilling hole: in the drilling process, when water gushes or sand gushes in the hole, a grouting ball valve and double-liquid slurry are immediately installed and injected under pressure, and meanwhile, relevant constructors at the hole opening are evacuated from the site.
The hole door sealing device comprises: the hole sealing is used for preventing the back lining grouting mortar from leaking when the shield is started. In the process of the shield tunneling out of the tunnel, the steel ring at the tunnel opening and the shield shell can form an annular building gap. In order to prevent a large amount of muddy water from flowing into the well through the building gap from the outside of the tunnel portal when the shield is out of the tunnel, and influencing the establishment of the soil pressure of the excavation surface, the stability of the soil of the excavation surface and the construction in the working well and the shield, a sealing water stop device with good performance is required to be arranged, so that the correct establishment of the initial soil pressure balance and the construction safety are ensured. The sealing water-stopping device is arranged on a circular ring plate pre-embedded at the hole outlet, and the circular ring plate is made of a Q235A steel plate. The circular ring plate is provided with a fixing screw hole, and the cord fabric rubber plate used as the sealing water-stopping device is fixed on the steel ring of the opening by the circular ring plate.
Coating shield tail sealing grease: in the shield tunneling process, the pipe piece is static, and the shield body continuously moves, so that relative sliding exists between the shield tail and the installed pipe piece. In order to prevent external sewage, silt and the like from entering the shield, sealing treatment must be carried out between the shield tail and the pipe piece. The shield tail is sealed by three steel wire brushes arranged on the inner wall of the shield tail on one hand, and the pressure is established by grease filled in the whole grease cavity on the other hand for sealing; meanwhile, the grease injected into the grease cavity can also play a role in lubricating and protecting the steel wire brush and prolonging the service life of the steel wire brush. The shield tail grease is a paste prepared by taking grease as a main agent and adding additives such as fibers, a modifier, a filler and the like, and mainly plays roles in sealing, water proofing, lubricating and corrosion resistance. The shield tail grease is divided into hand-smearing grease and machine-pumped grease, wherein the hand-smearing grease is used during starting, and the machine-pumped grease is used during propelling. Function of shield tail grease: lubrication, friction between the shield tail and the outer wall of the segment, which can affect the propulsion of the shield and damage the shield tail device, effectively protects the shield tail; the sealing function-the seepage of mud in the soil layer can influence the normal work of the shield and increase the construction difficulty-the mud is isolated, the seepage of mud and mud is prevented, and the smooth propulsion of the shield is ensured; in addition, the shield tail sealing grease has the effects of rust prevention, corrosion prevention and abrasion reduction on the steel wire brush and the steel structure. Before the shield starts to assemble the negative ring, the shield tail brush is required to be smeared with grease by hands, and after the shield starts to assemble the negative ring, the grease can not enter the shield tail brush under the ordinary condition of mechanical grease smearing, so that smearing must be carried out according to requirements, and negligence cannot be caused.
Assembling a negative ring: because later stage initiating end portal ring roof beam design size is 700mm, section of jurisdiction width 1.0m, so first ring section of jurisdiction (zero ring) exposes wall of a well position L1 for 0.3m, directly pulls out first ring section of jurisdiction during later stage construction ring roof beam. In consideration of saving cost and reducing construction period, the negative ring pipe piece is as short as possible under the condition that the shield launching can be met, and in consideration of small size of a launching well, the strength of the reaction frame is improved to the maximum extent, and the reaction frame can directly lean against a launching well wall. The length of the shield machine is about 9.30 m. After the shield machine is put into the well, an auxiliary jack can be adopted to pre-jack the shield machine to about 1m in the tunnel portal, and then a reaction frame is started to be installed for bearing the propelling reaction force of the shield machine. And starting normal starting tunneling by adopting the shield with a jack.
Installation of a portal launching device: after the enclosure structure is broken, a certain gap is inevitably generated between the end part of the shield starting station and surrounding rocks at the opening of the tunnel, and in order to ensure that the phenomenon of 'knocking' of the shield caused by hanging of a cutter head is avoided when the shield is started, an opening starting guide rail needs to be installed in the starting tunnel. Enough space is reserved at the tail end of the guide rail when the starting guide rail is arranged, so that the rotation of the cutter head cannot be influenced by the arrangement of the starting guide rail when the shield is started. The shield starting guide rail is made of a 30kg steel rail, and the length of the guide rail is 6 m.
Chiseling a hole door: according to the need of chiseling the hole door, a steel pipe scaffold is set up in the hole ring in advance. After positioning, installation and debugging of the shield (including all relevant equipment for tunnel exit construction) are completed, a tunnel portal is chiseled under the condition that the shield is ensured to be in good operation condition. The engineering adopts an air pick to chiseling and removing the tunnel portal in a smashing way. Before chiseling concrete, the contour line of the tunnel door is drawn on the vertical wall according to the design size. The chipping is performed in two layers. Firstly chiseling a layer of reinforced concrete with the thickness of 500mm which is half of the thickness of the surrounding fender pile in the hole ring, in order to ensure that chiseling operation is safely carried out, accidents occur so as to be convenient for timely plugging, the remaining layer with the thickness of 500mm is chiseled in a sequence of blocking and from bottom to top, and nine blocks are formed in total until the outermost row of glass fiber main ribs are chiseled. The tunnel portal chiseling is used for continuous operation, so that the working time is shortened, and the loss of the front soil body is reduced. In the whole operation process, a full-time security worker supervises the whole process, so that safety accidents are avoided, personal safety is ensured, and measures are taken to protect a sealing water stopping device of the opening.
Starting the shield in a split manner: the whole length of the shield machine is about 75m, the clearance length of the shield starting well is about 12m, the whole starting condition is not met, and a split starting mode needs to be adopted. The debugging of shield structure machine, shield structure machine connect the back, can carry out no-load debugging, main debugging content is: 1) testing a cutter head driving system: normal or abnormal forward or reverse rotation, maximum speed, speed regulation, pressure, etc. 2) Testing a hydraulic pump station: and checking a hydraulic oil filtering and circulating system. 3) Testing a segment mounting system: and detecting functions of various degrees of freedom and grabbing the duct piece. 4) Testing of a grouting pump system: whether each function meets the performance requirement and whether the reversing and the speed regulation are normal or not. 5) Other auxiliary hydraulic system tests. 6) And (5) testing the function of the segment crane. 7) Testing a gear oil circulation system: normal or not, liquid level alarm function and the like. 8) Testing a shield tail grease injection system: whether the working pressure is normal or not and whether the automatic working condition is reasonable or not. 9) And (3) testing a main bearing system: and if the working pressure is normal, filling the grease at the front part of the cutter head. 10) Whether the grease sealing system is normal or not and the main bearing is filled with grease until the grease overflows, whether the measured pressure meets the requirement or not, whether the functions of the control part are normal or not and whether the liquid level linkage function of the small grease barrel is normal or not. 11) The control part of the air pressurization system is tested whether normal or not, and the pressure is tested whether normal or not. 12) Whether the water circulation system can work, whether the flow rate of the main driving part reaches the standard or not and whether the pressure is normal or not. 13) Whether the linkage control of the whole machine is normal or not and whether the control condition of each link in a control room is normal or not. 14) And (5) displaying and testing the fault of the shield machine. 15) And (5) debugging the guide system. 16) And no-load debugging proves that the shield machine can carry out load debugging after having working capacity. The main purpose of load debugging is to check the load capacity of various pipelines and seals; all working systems and auxiliary systems of the shield machine can reach the working state meeting the normal production requirement. The trial tunneling time is generally the time for debugging the equipment load.
Splitting starting sequence: after the front shield is hoisted and lowered into the well and the cutterhead is hoisted and lowered into the well, the cutterhead and the front shield are installed; then hoisting the middle shield and descending the well, and installing the middle shield; then hoisting and lowering the screw machine into the well, and installing the screw machine; then hoisting and descending the tail shield, and installing the tail shield; then the pipeline is connected, and debugging and trial pushing are carried out, so that the construction is further promoted. Meanwhile, the matched pipeline is required to be extended for split starting, the tunneling requirement is met, and the pipeline mainly comprises a hydraulic pipe, a water pipe, a foam pipe, a grouting pipe, a bentonite pipe, a cable and the like. And then the trolley is put into the well.
Shield initial tunneling: and a complete tunneling cycle comprises equipment system inspection, setting of a laser guide system and related data, pipe piece conveying and positioning, grouting material preparation and well descending and positioning, tunneling and unearthing of a shield tunneling machine, monitoring of soil pressure of a soil cabin and a screw machine, and synchronous grouting. The tunneling construction of the engineering section tunnel is mainly carried out in the argillaceous siltstone and the strongly weathered conglomerate. The selected machine type of the shield machine is based on the research on geological conditions. For this construction, an Earth Pressure Balanced (EPB) shield machine is used for construction. The shield cutter head is specially designed aiming at the geological conditions of the project, and has the following characteristics: 1) the soil cabin can work safely under soil pressure, and soil pressure balance is facilitated. The opening rate of the cutter head (30-35%) can make the dregs smoothly flow from the cutting face to the soil cabin, and is particularly important for the complexity, variability and viscosity of the geological condition of the tunnel route, so that the soil pressure can be directly transmitted to the soil pressure sensor, the soil pressure sensor can easily enter the cutting face to remove obstacles, and the soil treatment by drilling is easy. The cutterhead is reversible for preventing the machine from rotating itself. 2) The shield cutter head cuts soil on the excavated surface, then the soil is stirred in the soil cabin, certain soil pressure is kept, and a soil pressure sensor is arranged in the sealed soil cabin wall. The rotation speed of the screw conveyer is controlled by the soil pressure through an electronic signal (namely, the soil discharge amount is changed), and the constant soil pressure value in the soil cabin is maintained, so that the aims of supporting an excavation surface and controlling ground settlement are fulfilled. The soil body is conveyed to the belt conveyor through the spiral conveyor and then conveyed into the soil hopper to be transported out by the traction of the battery car. 3) The shield thrust is provided by the jack, and the hydro-cylinder is used in the convex surface of section of jurisdiction, overcomes the resistance and impels forward, after pushing away to a ring lining distance, assembles the section of jurisdiction.
The shield launching construction key points are as follows: 1) when the shield advances forward in no-load, the stroke of a thrust oil cylinder of the shield is mainly controlled and the thrust amount of each ring of the shield is limited. The shield is required to be pushed forwards, and meanwhile, whether the shield interferes with an originating station and an originating hole or whether other abnormal conditions or accidents occur is checked, so that the shield is ensured to be pushed forwards safely. 2) The attitude is mainly controlled by the stroke of an oil pushing cylinder of the shield tunneling machine. 3) And under the condition of ensuring the normal propulsion of the shield, the total thrust and the cutter torque are slightly reduced. 4) And after the shield tail completely enters the hole body, adjusting the hole opening for sealing, and grouting the hole opening. The slurry is required to have not only a smooth injection but also early strength. The grouting pressure is controlled within +1.5Bar (higher than the water-soil pressure of the section). 5) The dismantling time of the reaction frame and the negative ring pipe piece is determined according to the mortar performance parameters of the back lining grouting and the starting tunneling thrust of the shield. In general, tunneling is carried out for more than 100m (tunneling is completed for more than 7 days by the first 50 rings at the same time), and the reaction frame and the negative ring pipe piece can be dismantled according to the process condition and the whole work arrangement.
Trial tunneling: the first 100m of shield tunneling is taken as a trial tunneling section, and the following aims are achieved through the trial tunneling section: 1) the novel shield machine is debugged in the shortest time, the mechanical performance is familiar, and the imperfect part of the shield machine is improved. 2) Understanding and knowing the geological conditions of the project, and mastering the operation method of the composite shield under each geological condition. 3) Collecting, sorting, analyzing and summarizing the tunneling parameters of each stratum, and making an operation rule for normally tunneling each stratum, so as to lay a foundation for realizing quick, continuous and efficient normal tunneling. 4) Familiarizes with the operation process that the section of jurisdiction was assembled, improves and assembles the quality for the construction progress. 5) Through the construction of the section, the monitoring and analysis of the ground deformation condition are enhanced, the influence on the surrounding environment when the shield machine enters the hole and advances is reflected, and the shield advancing parameters and the synchronous grouting amount are mastered. 6) And (4) searching out a control measure and a control method for the tunneling attitude of the shield in the corresponding stratum through shield trial tunneling construction.
Recording the footage conditions of different tunneling parameters adopted in different time periods and different stratums in detail in the trial excavation construction of the test section; the same tunneling parameters are used for different strata, and the footage and the cutter head abrasion conditions are adopted; and adopting different tunneling parameters for the same stratum, and recording the conditions of the footage and the cutter head abrasion. Meanwhile, the relationship between the grouting pressure and the stratum is recorded in detail. The specific recording contents are as follows: 1) tunneling: construction progress, oil cylinder stroke, tunneling speed, shield thrust, soil pressure, cutter head and screw rotation speed, annular gaps (upper, lower, left and right) between the shield inner wall and the outer side of the duct piece; 2) synchronous grouting: grouting pressure, quantity, consistency, grouting material proportion and grouting test block strength (sampling test every day); 3) measurement: shield inclination, tunnel ovality, total distance of propulsion, exact position of the axis of the lining ring of each ring of the tunnel (X, Y, Z). And after data are collected, analyzing and sorting in time, summarizing tunneling parameters which should be adopted by different stratums in the tunneling process of the engineering, and providing technical basis for smooth engineering.
Device overview:
the combined type earth pressure balance equipment comprehensive performance, the shield machine main structure of the earth pressure balance shield machine: the device comprises a cutter head, a cutter head drive, a shell, a propulsion system, a man brake, a spiral conveyor and a segment mounting machine. The shield constructs the host computer, and this engineering blade disc standard excavation diameter is 3410mm, 1) blade disc has good excavation ability to the geology of this engineering difference. 2) The rotating speed of the cutter head can be adjusted at any time according to the change of the stratum conditions. 3) The cutter head can be convenient for checking the cutter head and the cutter, and the safe and quick replacement of the cutter can be ensured. The front of the cutter head is provided with injecting ports for foam, water and the like, so that the requirement of improving the muck is met. 4) The cutter head can satisfy personnel and get into the face and get rid of the barrier in cutter head the place ahead. 5) A12-inch disk-shaped hob is adopted in the cutter head, and the configured cutter has enough rock breaking capacity and abrasion resistance. 6) The super digging cutter can meet the requirement that the digging diameter needs to be enlarged in the cutter replacing and construction processes. 7) The shield machine has enough thrust, torque and power reserve, and can avoid the shield machine from being clamped or damaged under unfavorable geological conditions. 8) The working time of the main bearing and the driving component can both meet 10000h of operation (or tunneling 12 kilometers), and a reliable main bearing sealing system is provided. 9) The shield machine can meet the active articulated system with the minimum turning radius of 50 m. The hinge joint is reliable in sealing. 10) The tail part of the shield machine is provided with three rows of shield tail brushes, which can meet the tunneling requirement under the buried depth condition of 40-50 m. 11) The shield machine has good direction control capability and can meet the horizontal and vertical construction errors of the tunneling direction. 12) The shield machine is provided with an automatic measurement guiding system, has enough precision and can display the position and the posture of the shield machine in time. 13) The electrical equipment arranged in the shield tunneling machine has good waterproof performance so as to meet the requirement that the shield tunneling machine can be smoothly constructed in a water-rich area. 14) The shield machine is provided with a good hydraulic and lubricating system. 15) The shield machine excavation management system has a PLC automatic control function and can display various excavation parameters in real time. 16) The shield machine is provided with data acquisition processing and automatic fault display functions.
A rear matching auxiliary system: the system comprises a muck discharging system, a muck improving system, a segment conveying system, a synchronous grouting system, a hydraulic pump station, a grease injecting system, a control system, a power supply system, a compressed air system, a water system and a ventilation system. 1) The requirements of the project can be met by emergency lighting, ventilation capability and drainage capability. 2) The automatic extending mechanism has good ventilation and tunnel main air pipes. 3) The spiral conveyor, the belt conveyor and the horizontal conveying system are adopted for slag discharging, and the inside of the tunnel is clean and tidy. 4) Has perfect material supply system and hoisting equipment and enough material storage space. 5) Has a comfortable and humanized shield machine operation room. 6) The electrical equipment has good waterproof performance, and the moving part is provided with a reliable safety protection device. 7) It has gas monitoring, fire-fighting, communication and closed-circuit TV monitoring system.
Initial excavation engineering adjustment measures: after the shield machine finishes the trial excavation of 100m, necessary adjustment is carried out on excavation parameters, and conditions are provided for subsequent normal excavation. The main contents comprise: 1) and further optimizing the tunneling parameters according to the geological conditions and the monitoring results in the trial excavation process. 2) And in the normal propelling stage, the optimal construction parameters grasped by a 100m trial excavation stage are adopted. By enhancing construction monitoring, the construction process is continuously perfected, and ground settlement is controlled. 3) In the propelling process, the propelling mileage is strictly controlled, the construction measurement result is continuously checked with the calculated three-dimensional coordinates, and the construction measurement result is timely adjusted. The mileage deviation is controlled as follows: easement curve, circular curve segment: x (the longitudinal axis direction of the tunnel design, namely the direction along the mileage direction) and Y (the direction perpendicular to the tunnel along the design axis) are less than 50 mm. 4) The shield is propelled according to the parameters set by the current shift instruction, and the propelling out of the earth and the grouting at the back of the lining are synchronously carried out. And (4) continuously improving the construction process, and controlling the maximum deformation of the ground surface within + 10-30 mm after construction. 5) In the shield tunneling process, the gradient cannot change suddenly, and the change of the axis and the break angle of the tunnel cannot exceed 0.3 percent. 6) The whole process of shield tunneling construction needs to be strictly controlled, and engineering technicians correctly issue tunneling instructions for each shift and immediately track and adjust the tunneling instructions according to geological change, tunnel burial depth, ground load, ground surface settlement, shield machine posture, cutter head torque, jack thrust and other various exploration and measurement data information. 7) The shield machine operator must strictly execute the instruction and operate carefully, the small deviation appearing initially should be corrected in time, the shield machine should be avoided as far as possible from going "snake", the one-time deviation correcting amount of the shield machine should not be too large, in order to reduce the disturbance to the stratum. 8) And (3) making a construction record, wherein the record content comprises: construction progress of tunnel excavation, stroke of a propulsion oil cylinder, stroke of a hinged oil cylinder, excavation speed, shield thrust, soil pressure, rotation speed of a cutter head, torque, rotation speed of a screw machine, torque and shield tail clearance (upper, lower, left and right); synchronous grouting: grouting pressure, grouting amount and grouting material proportion. 9) And a working daily report system is established, and the construction unit, the supervision unit and the construction unit are monitored in an all-round way through Internet information management.
The control key points of the stable excavation surface during starting excavation are as follows: the stability of the excavation face is the premise of normal excavation and should be guaranteed at any time. The stability of the excavation face is mainly controlled by the following points in the tunneling process: 1) and the shutdown pressure maintaining value is improved. When the earth pressure balance mode is adopted for tunneling, the earth pressure passing through a tunneling section is calculated to be the tunneling earth pressure, the pressure is properly increased by 0.1-0.15bar when the machine is stopped for maintaining the pressure, the stability of the earth cabin pressure and the excavation surface is ensured, and the earth surface settlement is controlled. 2) And keeping the soil pressure tunneling. Keeping the speed basically unchanged, and adjusting the rotating speed of the screw machine or the opening degree of a slag outlet door to achieve the aims of controlling the soil output and keeping the pressure of the soil cabin; and under the condition of keeping the rotating speed of the screw conveyor and the opening degree of the slag hole unchanged, the propelling speed is adjusted to achieve the aim of adjusting the pressure of the soil cabin. 3) And (4) formulating a special tunneling scheme according to risk sources in different intervals. Reasonable propelling parameters are set, the filling effect of synchronous grouting is guaranteed, and the phenomena of over-excavation and under-control in the tunneling process are prevented. 4) And improving the residue soil. High-quality foam is used, and high-molecular polymer or high-quality bentonite slurry is injected into a tunnel face, an earth cabin or a screw machine at a foam injection port of the cutter head according to the condition of slag discharge, so that the water stopping effect is improved, the plastic fluidity of slag soil is improved, and the occurrence of dangers such as gushing is controlled. 5) And (5) reinforcing grouting to control sedimentation. And controlling the synchronous grouting amount according to experimental data and theoretical calculation data, and ensuring sufficient injection of mortar by mainly controlling pressure and flow and secondarily controlling pressure and flow. The mixing proportion of the mortar is adjusted according to the geological condition, the initial setting time of the mortar is shortened, and the purpose of controlling the surface settlement is achieved. According to the monitoring data of the surface settlement, secondary grouting is carried out in time; the shield posture is controlled, the deviation correction amount is reduced, the deviation correction is avoided as much as possible, and fewer correction tasks are required when the deviation correction is needed. 6) And enhancing the soil yield control. And (3) controlling by adopting a method for measuring the volume of the muck, and determining the soil output of each ring according to the loosening coefficient of the muck obtained by experiments and the density of the muck in different sections. 7) Strengthening the coordination. The shield operator executes the operation according to the operation instruction issued by the technical responsible person strictly, and when the instruction cannot be implemented due to the change of the geological condition, the shield operator communicates with the technical department in time to negotiate, communicate and explore a solution and a treatment measure. In the tunneling process, each constructor needs to keep close connection and cooperation. If the machine needs to be stopped due to equipment failure in the tunneling process, the soil pressure needs to be reasonably set, and corresponding measures and emergency plans are made according to actual conditions.
Controlling and adjusting the initial tunneling direction of the shield: 1) and (3) rolling control: and correcting the rolling deviation by adopting a method of rotating the shield cutter head forward and backward. The allowable rolling deviation is less than or equal to 3 degrees, and when the allowable rolling deviation exceeds 3 degrees, the shield machine gives an alarm to prompt an operator to switch the rotation direction of the cutter head to carry out reverse deviation correction. 2) Controlling the vertical direction: the main factor for controlling the direction of the shield tunneling machine is the unilateral thrust of the jack, and the relationship between the unilateral thrust of the jack and the attitude variation of the shield tunneling machine is very discrete and is mainly mastered by the experience of people. When the shield machine is bent downwards, the thrust of the lower side jack can be properly increased, and when the shield machine is bent upwards, the thrust of the upper side jack needs to be increased to correct the deviation. 3) Controlling the horizontal direction: the principle of correcting the deviation in the vertical direction is the same, the pushing pressure of the left jack is increased when the deviation is left, and the pushing pressure of the right jack is increased when the deviation is right.
The attention points when starting tunneling are as follows: 1) in the construction process, the deformation conditions of the reaction frame and the starting bracket need to be closely concerned, and if the phenomena of desoldering, steel plate curling, overlarge displacement and the like are found, the tunneling needs to be immediately stopped, and personnel are arranged to carry out treatment. 2) The rotating angle of the shield body is more than 1 degree. 3) In the process that the negative ring duct piece is separated from the shield tail, a specially-assigned person needs to be arranged to install the wooden wedge in time, and the duct piece is guaranteed not to fall down. 4) After the shield completely enters the soil body, secondary grouting and sealing are immediately carried out on the hole ring gap through the segment hoisting hole or the hole reserved in the hole door. 5) The concrete fragments after chiseling must be cleaned to the bottom side line of the starting frame, and the area of the starting frame cannot be piled up, so that a rapid rescue channel is provided. 6) The cutter head of the shield machine can rotate behind the water stop curtain cloth. 7) And after the cutter head of the shield tunneling machine enters the tunnel ring, the shield tunneling attitude needs to be measured in real time. Emergency preparation: a. before starting, carefully exploring each exploratory hole of the portal and the water leakage condition of the portal, if the flowing water is turbid and accompanied by silt, starting an emergency plan and making treatment measures. b. The concrete blocks after the tunnel door is chiseled are cleaned, and sundries are not piled in front of the shield. c. The safety department checks whether emergency material is ready in place. Emergency measures: a. after various preparation works of the shield are completed, the shield starts to advance and quickly supports to a tunnel face through the tunnel portal sealing device, a cutter head is not rotated at first, the tunnel portal sealing device is checked, if the shield is damaged in the process of passing through, the shield stops advancing, and the tunnel portal sealing device can be advanced again after being repaired. After the shield breaks the tunnel portal, the phenomenon of collapse of the front soil body may exist, the pressure of the soil cabin is required to be quickly established, the ground settlement is prevented, if the continuous collapse is serious, the tunnel portal is required to be reinforced again, and bentonite slurry can be injected into a reserved hole of the tunnel portal to fill the gap. b. During the starting period, the water should be continuously reduced and a specially assigned person should be responsible for pumping water.
The starting tunneling operation requirement is as follows: (1) the installation and positioning accuracy of an originating station, a reaction frame and a negative ring is strictly controlled, and the originating attitude of the shield is ensured to be basically coincident with a designed line. (2) When the first ring negative ring pipe piece is positioned, the rear end face of the pipe piece is perpendicular to the central line of the circuit. The axis of the negative ring pipe piece is coincided with the axis of the line, and the negative ring pipe piece is assembled in a through seam mode. (3) The axis of the shield machine is basically parallel to the design axis of the tunnel, and the center line of the shield machine can be properly raised by 2-3cm compared with the design axis. (4) When the shield advances on the starting platform, all groups of the advancing oil cylinders should keep synchronous. (5) When the initial tunneling is started, the shield machine is positioned on a starting platform. Therefore, opposite anti-torsion supports are required to be welded on the starting station and the shield tunneling machine so as to provide reaction torque for the initial tunneling of the shield tunneling machine. (6) The originating phase, the equipment is in the break-in period. Attention is paid to control of thrust and torque, and effective use of grease at various portions. The total tunneling thrust should be controlled below the reaction frame bearing capacity while ensuring that the torque generated by the cutter cutting into the formation at this thrust is less than the reaction torque provided by the origin. (7) The welding edges and corners on the shield shell are leveled before the shield enters the tunnel portal, so that the waterproof curtain cloth of the tunnel portal is prevented from being cut.
Normal tunneling construction of the shield:
the shield tunneling construction process comprises the following steps: firstly, controlling excavation and tunneling and synchronous grouting through equipment management, then judging whether the excavation cycle standard is met or not, if so, circularly tunneling the process, otherwise, controlling the marshalling train to go out of the tunnel, the marshalling train to discharge slag and charge, the marshalling train to enter the tunnel, segment lining ring assembly and track extension, and entering the next ring to start tunneling.
Shield tunneling slag tapping scheme: 1) calculating the excavation quantity and the diameter of the cutterhead
Figure BDA0003286195400000141
The length L of the pipe piece is 1000mm, the loose coefficient of the muck is 1.3, so the soil output of each ring is as follows: vT=π/4×3.412×1.3=11.8m3. The fluctuation range of the actual slag output quantity is strictly controlled not to exceed 10 percent of the theoretical square quantity in the tunneling process. 2) In the transportation in the hole, as the shield machine adopts the vacuum mud discharging system to discharge the slag, the storage battery car does not need to be provided with a slag car, and the slag mud is directly discharged to the side through a pipelineAnd (4) storing the soil in a soil yard at regular time, and loading the loader into a dump truck at night and transporting the dump truck to a specified spoil place. The battery car is 8t variable frequency type, and the marshalling mode is two sections of segment cars and one section of mortar car. A16 t/5t gantry crane is matched with a wellhead to hoist the pipe piece and relevant auxiliary materials. 3) Material transportation: the width of each pipe piece is 1.0m, each ring of pipe pieces is transported by two flat cars, the length of each car is 2.5m, and the width of each car is 1.0 m. Other small machines and materials are transported by a segment car. The slurry is manufactured and transported, the mortar is manufactured on site through a dry-mixed mortar mixing station, and the main equipment comprises: the automatic proportioning slurry mixing station, the bentonite stirring box, the storage tank, the mortar stirring box, the material pool, the delivery pump, the slurry conveying pipe and the like. After the mortar is manufactured, the mortar is conveyed into a mortar vehicle at the wellhead by a conveying pump and then conveyed to a grouting position by the mortar vehicle. The horizontal mortar conveying equipment comprises: mortar cars, battery cars, mortar transfer pumps and the like. The grouting amount of each ring is calculated according to the overbreak amount, the maximum grouting amount is 130-250% of the gap, and is about 1.7m3Left and right. And the slurry of the grouting after the wall is transported by a cement slurry stirring transport vehicle. The transport train can be provided with 2 groups, one group is provided with two segment transport vehicles, and one mortar stirring transport vehicle.
Improving the muck in shield tunneling: the tunneling construction of the engineering section tunnel is mainly carried out in the stroke basement rock. The upper part is a compact pebble layer with the characteristics of softness at the upper part and hardness at the lower part. The improvement of the residue soil mainly comprises: (1) the foam additive is used for improving the soil body, and is used during tunneling to improve the soil body and inhibit the disturbance of the shield machine to the surrounding soil layer, so that the aim of preventing the ground surface from sinking is fulfilled. The foaming agent can generate stable foam, is suitable for being used in viscous, sandy and silty soil, can reduce the viscosity of a soil body when being mixed with cohesive soil, improves the performance of the soil body on the section of the shield, reduces the adhesion effect of the soil body on the shield, and is beneficial to the propulsion of the shield. In addition, the foaming agent can reduce the internal friction force and reduce the abrasion of the soil on a cutter head, a spiral conveyor and a belt conveyor. (2) The bentonite additive is used for improving the soil body, and when the tunnel passes through a silt layer and a silt aquifer, instability of an excavation surface and ground settlement caused by water burst can occur in construction, and the phenomenon of surging can occur. In order to ensure the smooth construction, the soil body is improved by injecting bentonite slurry soil in the process of propelling the silt layer and the silt aquifer. The soil body improvement is to reduce the water permeability of the soil body, strengthen the leakproofness of working face, can effectually resist the artesian head. The stability of the supporting working face is uniform and controllable, the cutter head is protected, and normal unearthing of the shield spiral unearthing machine is guaranteed. And bentonite is injected in front of the shield and in the screw machine at intervals in the propelling process. The bentonite is injected to improve the soil body, so that the clay content in the process of unearthing reaches 20 percent. According to the calculation, each time one ring is pushed, bentonite slurry with certain concentration is added. The bentonite slurry can be injected into the front face of the cutter head and is stirred by the rear wing of the cutter head. And discharging from the screw machine. And (3) observing the dumping state of the screw machine and the settlement condition of the soil body below the screw machine while injecting bentonite slurry under pressure, and ensuring the stability of the soil body below the screw machine. The permeability coefficient of sandy soil is large, namely pore water pressure is increased quickly, and dissipation is also quick, and the time difference between the pore water pressure and the dissipation is the time effect of drying. Therefore, the speed control of the jack is matched with the shield tunneling machine, so that the shield tunneling machine achieves a better state of advancing speed.
Installing lining segments during tunneling: this section of jurisdiction external diameter 3200mm in engineering section tunnel, internal diameter 2700mm, wall thickness 250mm, for prefabricated reinforced concrete section of jurisdiction, the ring width 1000mm, the lining cutting ring comprises 1 capping piece, 2 piece adjacent blocks, 3 standard blocks. In order to meet the requirements of curve templates and construction deviation correction, a right-turning wedge-shaped ring is specially designed to fit curves with different radiuses or correct the deviation through various combinations of the right-turning wedge-shaped ring and a standard ring, wherein the wedge-shaped ring is a double-faced wedge, and the wedge amount is 20 mm. The prefabricated lining reinforced concrete is C50 in the specification, the impermeability grade is P12, and longitudinal and circumferential lining connecting bolts are all bolts. The bolt hole is waterproof by adopting a sealing ring, and the lining circular seam and the longitudinal seam are waterproof by adopting a water-swelling elastic sealing gasket. The process is carried out as follows: after leaving the factory from the segment factory, segment appearance inspection, segment faying face clearance are carried out, the sealing water stop is installed, segment hoisting, transportation and taking place are carried out afterwards, the corresponding jack is retracted simultaneously, then the segment is assembled, the corresponding jack is extended, segment position inspection is carried out, then grouting is backfilled behind the segment, caulking waterproof treatment is carried out, and finally the connecting bolt is tightened to carry out tunneling construction. Specifically, the pipe pieces are conveyed and assembled, and the pipe pieces are hoisted to a pipe piece conveying flat car in the pit by a gantry crane at a starting wellhead and conveyed to the foremost end of the track. The segment is lifted from the transportation flat car by the segment lifting machine, the segment is conveyed to the stacking platform by 90 degrees, the segment is lifted by the lifting machine and moved to the shield tail to be placed on the segment feeding machine when the segment is used, the segment feeding machine conveys the segment to the lower part of the assembling machine, and the segment is sequentially installed from bottom to top by the segment assembling machine during assembling. After the bottom segment is in place, the standard segments and the adjacent segments on the two sides are sequentially assembled, finally, the capping segment is installed, the capping block is overlapped with 1/3 of the length of the capping block, the capping block is pushed up in the radial direction, and then the capping block is longitudinally inserted into a ring. The mounting machine is mounted in the middle as much as possible to reduce the possibility of wrong platforms at the joint and ensure the assembling quality.
Segment assembling quality control: 1) for shield propulsion, the splicing quality of the first ring has a reference surface effect on the splicing of the whole tunnel, so that the splicing quality of the first ring pipe piece is strictly controlled to meet the specified requirement. First ring section of jurisdiction is assembled after the burden ring in the work well, assembles the work and goes on the shield structure base in the well, and section of jurisdiction elevation, direction, the slope of piecing together are all controlled easily, the quality standard that first ring section of jurisdiction was assembled: the diameter deviation is less than 10mm, and the ring surface unevenness is less than 1 mm. 2) The quality of the duct piece and the buffer material is ensured to meet the requirement of assembly. The strength, the geometric dimension, the positions and the diameters of the longitudinal and transverse screw holes of the duct piece are ensured to meet the quality standard. The quality of the buffer material meets the requirements of the assembly process, and the requirements of the strength, the compression performance, the resilience performance, the material uniformity and the thickness error of the material of the buffer material are met. 3) The quality of the assembly of the duct pieces is ensured. The assembling quality of the duct piece meets the requirement of quality standard, ensures that the construction meets the design regulation and meets the use requirement, and is the most basic requirement for smoothly, safely and excellently completing the shield propulsion task. 4) The reinforcing bolt is tightened once and tightened again for many times. The whole tunnel is formed by combining thousands of segments and is connected by longitudinal bolts and circumferential bolts, and the quality of the bolt connection is the key of the integrity of the tunnel lining. The bolts are not screwed tightly enough, the segment is easy to be dislocated under the action of the jack after the ring is formed, and the flatness of the ring surface is reduced, so that the next ring assembly is directly influenced. The quality of the ring can be improved by screwing and re-screwing, and the roundness of the ring can be improved by re-screwing for multiple times. 5) And after the assembly of each ring is finished, the longitudinal and circumferential bolts are screwed down in time, and when the next ring is pushed, the longitudinal bolts are retightened under the action of the jacking force of the jacks. After the ring-shaped duct piece is pushed out of the frame, the longitudinal and circumferential bolts are tightened again. And (4) after the tunnel is communicated, tightening the longitudinal and circumferential bolts for the fourth time. 6) The quality of the through joint assembly is generally bad, and the quality of the longitudinal joint is not in accordance with the requirements: front and rear horns, inner and outer opening angles and the like, unfilled corners, edge falling, breakage and the like of the duct pieces are prevented and actively corrected in construction according to operation requirements and by combining with the prior construction experience, and staggered joint assembly is adopted according to design requirements. 7) And the control of the shield posture is enhanced. The control of the shield attitude and the control of the segment assembling quality are complementary, the accurate shield attitude control can provide conditions for the accurate assembling of the segments, is the basis for improving the assembling quality, and also creates favorable conditions for the propelling of the shield. 8) The phenomena of cracks, damages, corner falling and the like cannot occur on the surface of the duct piece. And repairing the damage in the assembling process, and reporting a repairing scheme and executing the repairing scheme after approval of a supervision engineer.
And (3) synchronous grouting behind the segment wall: (1) the grouting is carried out, the periphery of the tunnel lining is synchronously grouted in a proper amount, and an annular building gap behind the stratum and the lining can be timely filled, so that a tunnel segment and a surrounding soil layer form an integral structure, and the ground surface settlement caused by stratum soil loss and disturbance caused by shield tunneling is reduced as much as possible. According to the related construction technology and experience, the grouting can effectively control the settlement of the earth surface, underground pipelines and ground building structures within the specification. (2) And in the grouting mode, synchronous grouting is carried out when the shield is propelled, the grouting system is connected with the tunneling system in a network, and slurry is immediately injected when a gap appears at the tail of the shield during tunneling. The grouting pipes on the shield machine are uniformly distributed in the shield tail steel plate in an up-down and left-right mode respectively, so that grout is injected into gaps at the shield tail, and the grouting is carried out symmetrically according to the sequence of first-down grouting and last-up grouting. (3) And grouting construction parameters, wherein shield grouting adopts newly developed rigid grout for synchronous grouting. Along with the advancing of the shield, a building gap is formed between the segment which is separated from the shield tail and the soil body, namely, the slurry is filled through a grouting pipe arranged at the shield tail. The excavation diameter of the cutter head is 3.41m, the outer diameter of the pipe piece is 3.2m, and the building clearance between the pipe piece and the excavation surface is (3.14 multiplied by 3.412/4-3.14 multiplied by 3.22/4) × 1.0 is 1.09m3. Due to pressing into the back of the liningThe grout can shrink, tunnel driving snaking in local sections, deviation correction and the like, so that the actual grouting amount is 1.3 to 2.5 times more than the theoretical building void volume. Excessive pressure injection can also cause localized swelling and grout leakage from the surface. Therefore, besides controlling the grouting quantity, the grouting pressure also needs to be controlled. And controlling the grouting quantity and grouting pressure according to the construction condition and the geological condition. Generally, the amount of each ring pressed is controlled to be 130-250% of the building gap, namely the grouting amount of a 1.0m ring width pipe piece is 1.42m3Ring 2.72m3A/ring. The grouting pressure is 0.1-0.2 MPa higher than the water-soil pressure of the tunneling surface during normal tunneling. Grouting and tunneling are kept synchronous, namely grouting is carried out while shield tunneling is carried out, and grouting is correspondingly stopped after tunneling is stopped. (4) And (3) grouting process flow, wherein the grouting operation process is dynamically monitored through the surrounding environment and the building grouting, the annular grouting effect check is carried out after the grouting operation is finished, the grouting effect check is started if the annular grouting effect check is not met, the full-tunnel grouting effect check is started if the annular grouting effect check is met, the grouting is finished if the annular grouting effect check is met, and the grouting is finished if the annular grouting effect check is not met, and the grouting is not met. (5) Grouting operation procedures: 1) grouting operators are specially trained and familiar with relevant operational precautions; 2) grouting operation and shield propulsion are carried out synchronously, the grouting amount is adapted to the tunneling speed, and each section of tunnel is clearly specified and strictly executed before being propelled; 3) the operator observes the grouting condition at any time. Controlling grouting pressure and volume, and keeping contact with a shield operator; 4) once a fault occurs, immediately informing the shift manager on duty, requiring to suspend shield propulsion, and reworking after the fault is eliminated; 5) the grouting amount is determined according to the gap of the shield shell and the ground condition, so that the environmental protection requirement is ensured, and the ground settlement is controlled; 6) the slurry is not separated and precipitated in the pressure feeding process, and the setting time, the hardening strength and the like of the slurry meet the technical requirements in specific engineering; 7) before the first grouting, lubricating all pipelines by grease; 8) after each work, the grouting pipeline is washed and emptied by a water circulating pump, and then lubricating slurry is injected to fill the grouting pipeline so as to facilitate the next grouting; the ground slurry stirring machine, the underground slurry transporting vehicle, the high-level tank slurry storage cylinder and other equipment are used for removing slurry, washing and emptying so as to prevent blockage and hardening; 9) and filling the quality control grouting record table in the shield construction process faithfully, and performing handover work of each shift.
Secondary grouting: the secondary reinforcing grouting is generally implemented under the condition that the filling compactness of a gap between a duct piece and a rock wall is poor, so that the ground surface settlement cannot be effectively controlled or the duct piece lining has serious leakage. And during construction, according to the ground surface settlement monitoring feedback information, a method for detecting whether a cavity is formed at the back of the segment lining by adopting ultrasonic waves or other means in the cavity is combined, and whether secondary grouting is needed or not is comprehensively judged. (1) The grouting material, the slurry proportion and the performance index, and the secondary grouting adopts double-slurry as the grouting material, so that the synchronous grouting can be further supplemented and enhanced. And simultaneously, the filling and reinforcing effects are also realized on the stratum around the pipe sheet. When groundwater is particularly abundant, groundwater needs to be blocked. Meanwhile, in order to establish high viscosity of the slurry as soon as possible so as to drain the underground water (press the underground water into the deep stratum) while filling the slurry into the gap and obtain the optimal filling effect, the gelling time of the slurry needs to be adjusted to 1-4 min, and cement-water glass double-liquid slurry can be adopted for secondary grouting if necessary. The cement is P.O.42.5 ordinary portland cement. (2) The grouting equipment adopts a self-contained double-liquid grouting pump for reinforcing and grouting. The secondary reinforcement slip casting pipe and the orifice pipe are self-made, the processing of the secondary reinforcement slip casting pipe and the orifice pipe has the matching capacity with a segment hoisting hole, the functions of quick connection and disconnection and sealing without slurry leakage can be realized, and a slurry discharge valve is arranged. In order to quickly perform secondary grout filling, the synchronous grouting pipe of the shield machine can be used for secondary grout filling, and the sedimentation control effect is good. (3) Quality inspection standards, quality assurance measures and quality control requirements, synchronous grouting materials are inspected according to requirements, and qualified materials can enter a field only after being checked, signed and approved. And (3) preparing an experimental block for the grouting slurry prepared by the mixing station, and performing a pressure intensity experiment on the experimental block, wherein the experimental block can be put into use after the experimental report is qualified. And (4) quality inspection standard, wherein the grouting quality can be checked by adopting a geological radar and an ultrasonic detection method, and the parts which do not meet the requirements are subjected to supplementary grouting. The circumferential measuring line is positioned in the middle of the ring pipe piece, and the ring pipe pieces are arranged at an interval of 10; for underground pipelines, box culverts or other important facility sections, an annular measuring line is arranged at a position with 3 annular pipe pieces at intervals.
Installing and disassembling a track: the rail is the basis of horizontal transportation, and the smooth transportation and the construction period of tunneling can be guaranteed only with safety and reliability. When the steel rail is disassembled, the steel rail is sequentially disassembled from the receiving well end of the tunnel to the other end, fasteners such as a steel rail pressing block, a fishplate fastening screw and the like are firstly disassembled, and then the steel rail is lifted to the conveying trolley and is sequentially conveyed to a well mouth to be lifted out. The installation use criteria are as follows: 1) the track fastener must be complete, closely paste, firm and conform to the rail type, and the track joint must use qualified way splint or fishplate to fixed with 4 bolts, lays the track in the pit and if needs change the track model, different model track joints must use suitable dysmorphism way splint. The road splint cannot be broken or have few eyes and the like; 2) when the joint is in suspension connection, the distance between the 22kg/m type track sleeper and the joint is 240mm, and the deviation is not more than 30 mm; when the joints are connected, the joints are 3 sleepers, one in the middle is arranged at the joint of the two rails, and the other two joints are 240mm away from the middle sleeper; the straight line segments are butted, and the relative offset is not more than 50 mm; the curve sections are connected in a staggered mode, and the relative staggered distance is not smaller than 2 m; 3) the central line of the single rail of the main transportation line track meets the design requirement, and the deviation is not more than +/-50 mm of the design value; the distance between the center lines of the double rails is not less than the design value and not more than 20mm of the design value, and the deviation between the center position of the double rails and the design position is not more than 50 mm; 4) the deviation between the actual elevation and the designed elevation of the rail surface of the main transportation line rail is +/-50 mm; the error in the slope 50m is not more than 2/1000, and the height difference is not more than 70 mm; 5) the allowable deviation of the straight line section of the transport line track is plus 15mm and minus 5 mm; after the curve section is widened, the allowable deviation is plus 15mm and minus 5mm, and a track gauge pull rod is arranged in the curve section. 6) The same type of steel rail must be used for the same line, and the same line has no mixed road (the two types of tracks within 50m are mixed roads) and no sandwiched road. 7) The quality of the rail and the sleeper is qualified, the laying meets the design requirement, the sleeper at the joint does not fail, more than two sleepers do not fail continuously (the non-functional one such as decay, damage, fracture, suspension and the like is failed), and the sleeper is vertical to the rail. 8) The rail spike specification should be supporting with the rail type, and is complete in quantity, and rail sleeper bolt, clamp plate fastening are complete, and the lift-off is not more than 3 mm. 9) The rail is not strictly cut by gas cutting, if a rail cutting machine is required to be used for cutting, the plane of a rail cutting head is vertical to the rail surface, and the cutting surface cannot be inclined. When the track cutting head reprocesses the way splint bolt hole, must process with the drilling machine, forbid strictly using the gas cutting to cut the hole. 10) The track has to be maintained by special persons and repaired regularly during the use. And dripping oil and fastening bolts at each part of the track and the sleeper once every half month. The ballast bed and the turnout are cleaned frequently to ensure no sundries, no muck, no water accumulation and the like.
Arranging pipelines in the tunnel: the high-pressure air and water pipes of the tunnel are erected according to standards, high-pressure air and water pipelines constructed in the tunnel are arranged along the wall of the tunnel in an overhead mode, supporting points are arranged at intervals of 3-5 m, and a signboard is arranged at intervals of 30 m. And the temporarily laid pipelines are fixed along the wall of the hole and are removed in time after the construction is finished. The high-pressure wind and water pipelines are arranged in a flat, smooth and straight way, the joints are tight, stable and firm, the turning is reduced as much as possible, and the bent angle forms an obtuse angle. Protection of high pressure wind and water pipelines. After high-pressure air and water pipelines are arranged, paint protection is carried out, wherein the high-pressure air is red, and the water pipelines are blue. The workers in high pressure wind and water pipelines patrol the pipelines every day, find the phenomena of running, overflowing, dripping, leaking and the like, and need to maintain and process in time. The ventilator is erected at a position where air is not polluted, a field is smooth, ventilation is good, and a space is wide, the height of the ventilator from the ground is preferably 3.0-4.0 m, the ventilator cannot be bent and fluctuated greatly on the same straight line as far as possible, and the support is firm and stable. And the positions 50-100 m close to the ventilator must be connected by air pipes with steel wires or air pipes of the same type made of white iron sheets, so that people are prevented from being injured by pipe explosion. The construction in the tunnel uses the standard of electric layout, the general erection principle is that high pressure is above, the low pressure is below, the power line is on the opposite side of wind, water pipe, lay according to high pressure, power, lighting line sequence up-middle-down; the excavation sections are distributed according to a movable line, temporary drill holes are arranged on the primary support structure according to a fixed line method, and the temporary drill holes are immediately removed after construction is finished; the distribution box is provided with a door and a lock, a 'one machine one brake one leakage one box' system is implemented, and a 'power on and danger' warning board is hung; the construction lighting electric line adopts three-phase five-wire system or cable according to the related standard requirements, the lighting must be provided with special lighting line, the height of the lighting electric line from the ground is not less than 2.5m, the distance between the lines is 10cm, the tunnel lighting ensures the sufficient and uniform light, and the light is not dazzled. One 60-watt energy-saving lamp is arranged every 5m in the non-tunnel section of the transportation road and every 8m in the tunnel section; the water leakage section uses a waterproof lamp holder and a lampshade; the special person overhauls the power consumption circuit, prevents the electric leakage. The rated voltage of the power equipment in the hole is 380V, the lighting voltage adopts 36V voltage in the operation section, and the voltage of 220V is adopted in the non-operation section.
Attitude control in the tunneling process: in the shield tunneling process, the cutter head can increase the disturbance to the soil body, so that the shield can pass through at a constant speed and in a straight line as far as possible under the condition of ensuring good control of the front settlement of the shield, and the correction amount and the correction times of the shield are reduced. The amount of wedge per ring is pre-calculated and pre-controlled as the shield advances. When the tunnel shield is pushed, the gap between the duct piece and the shield shell is observed with more attention, and the tunnel shield is pushed by adopting a slope stabilizing method and a gentle slope method so as to reduce the influence of shield construction on the tunnel and the ground. The middle shield and the tail shield are hinged, so that the length-diameter ratio of the shield is effectively reduced, the shield can flexibly adjust the posture during tunneling, and smoothly turns through a small radius; (2) the thrust difference of the left and right side oil cylinders is mastered, the integral thrust is reduced as much as possible, and slow and fast rotation is realized; (3) a shield machine driver enables the shield machine to enter a corresponding prepared attitude in advance according to geological conditions and line trend trends, and deviation rectification caused by poor attitudes is reduced; (4) the encrypted attendance-added laser system station-shifting measurement avoids the axis error generated by the encryption. Because we regard the short-distance curve as a straight line segment to guide the shield tunneling machine to tunnel, if the short-distance station shifting measurement is not carried out, the long-distance arc line is regarded as a straight line, and the axis deviation is naturally very different; (5) and (4) segment selection is made, and the position of the K block is determined according to real-time measurement of the shield tail gap. And a duct piece with a proper ring width is selected, so that the shield posture is effectively ensured to be matched with the designed axis as much as possible.
Measures for preventing the duct piece from floating up, sinking and laterally moving are as follows: when the tunnel segment enters the transition curve segment, the posture of the shield tunneling machine deviates 15-20 cm towards the inner side (side close to the circle center) of the curve to form reverse pre-deviation, so that the deviation of the duct piece towards the outer side (back circle center side) of the curve can be offset. The thrust of the oil cylinder is reduced, the disturbance to the soil body can obviously reduce the strength and the self-stability capability of the peripheral soil body in the process of tunneling small-radius circular curves in strong and medium-stroke stratum, and the soil body has the creep characteristic and appears in the horizontal directionThe pressure is uneven, and the pipe piece can move outwards integrally under the conditions that the pipe piece bears the horizontal component force of the jack for a long time and the like. The small radius curve tunneling segment displacement delta can be expressed by a formula:
Figure BDA0003286195400000181
wherein T is the reaction force of the thrust of the shield tunneling machine, R is the turning radius, P is the additional stress of the soil body to the side surface of the duct piece, and xi is the deformation coefficient. From the above equation: the larger the thrust of the shield tunneling machine is, the larger the lateral displacement of the duct piece is, and the smaller the turning radius of tunneling, the larger the lateral displacement of the duct piece is. Meanwhile, the thrust can be controlled between 900 t and 1150t according to construction experience during propulsion; and the thrust is timely adjusted according to the actual situation when in a special stratum. Additionally grouting is carried out in the direction of the deviation of the duct piece, and certain pressure is achieved to resist the deviation of the duct piece. After the slurry is solidified, the position of the pipe piece is basically determined. The position of grouting is preferably selected from 1-point and 4-point hand holes (right turning), so that not only can the horizontal deviation of the duct piece be resisted, but also the upward floating of the duct piece can be resisted.
Shield receiving:
the shield receiving the working content comprises the following steps: the method comprises the steps of positioning and receiving a tunnel portal position by a shield machine, rechecking and measuring, stratum reinforcing, tunnel portal processing, mounting tunnel portal ring sealing equipment, mounting a receiving base and the like. The process flow is as follows: reinforcing a soil body going out of a hole, installing a receiving frame, performing tunnel portal rechecking measurement, performing shield tunneling machine position and posture rechecking measurement, chiseling the tunnel portal, installing a tunnel portal waterproof device, enabling the shield to go out of the hole, cleaning a cutter head, moving a shield body forwards in place, removing the cutter head to connect and lift the cutter head, disconnecting a trolley and a host pipeline backward-moving trolley, and removing a screw machine backward-moving trolley. Removing the propeller pipeline, driving, rear casing pipes and auger rods, moving the propeller pipeline, the driving, rear casing pipes and the auger rods to a tunnel, removing the connection of the front shield body, lifting the front shield out, removing the hinged connection, calling out the hinged shield body, ejecting the shield tail, removing the jack, lifting out the screw machine parts, removing the receiving support, laying the trolley track, disconnecting the trolley connection, sequentially lifting out the trolley, and removing and lifting out the underground related auxiliary support.
Arrival construction of the shield machine: 1) and (4) tunneling according to the penetration attitude of the shield tunneling machine and a tunneling deviation rectifying plan, wherein the deviation rectifying is completed step by step, and the deviation rectifying amount of each ring cannot be overlarge. 2) When the shield machine is 50m away from the end wall, reasonable tunneling parameters are selected, the tunneling speed is gradually slowed down, the tunneling speed is preferably controlled to be below 20mm/min, the thrust is gradually reduced, and the soil body is slowly and uniformly cut so as to ensure the stability of the end wall and prevent the stratum from collapsing. 3) After the shield enters the receiving section, the earth surface monitoring measurement is enhanced, and information is fed back in time to guide the shield tunneling machine to tunnel. 4) When the distance of the cutter head of the shield tunneling machine is less than 10m, a specially-assigned person is responsible for observing the change condition of the hole outlet in the tunneling process, always keeps contact with a driver of the shield tunneling machine, and timely adjusts tunneling parameters. 5) After the assembled duct piece enters the reinforcing range, the slurry is changed into quick-hardening slurry, and muddy water is blocked outside the reinforcing area in the reinforcing range in advance. 6) And after the last ring pipe piece of the pipe piece is assembled, injecting double-liquid slurry to block through the secondary grouting hole of the pipe piece. The grouting process needs to pay close attention to the situation of the portal, and the grouting is stopped immediately once the phenomenon of slurry leakage is found. 7) When the shield shell of the shield front body is pushed out of the tunnel portal, the folding pressing plate is adjusted through the steel wire rope on the pressing plate clamping ring to press the curtain cloth rubber plate as much as possible, so that muddy water and slurry of the tunnel portal are prevented from flowing out. When the duct piece is separated from the shield tail, the steel wire rope is tensioned again, so that the pressing plate can compress the rubber cord fabric, and the cord fabric can play a role all the time. 8) Because the thrust is small when the shield arrives at the station, the connection between the segment ring and the ring near the tunnel portal is not tight enough, and therefore the bolt fastening and the re-fastening work of the 20-ring segment are required. And the channel steel is used for longitudinally tensioning the rear 20 ring pipe pieces along the tunnel, so that the rear 20 ring pipe pieces are integrated, and the sealing and waterproof effects are prevented from being influenced by the loose pipe pieces.
Dismantling and hoisting the shield tunneling machine: according to the construction progress requirement, the shield machine disassembly work is started after the interval tunnel is communicated, and the disassembly work of the large parts and the main parts of the shield machine is completed within 15 days. The on-site shield machine is completely positioned at the underground part of the disassembly well, and the disassembly of the shield machine can be started after the pipeline is marked. Disassembling after the shield machine arrives: before the shield machine reaches the disassembly well, state detection is required, and machine condition evaluation is carried out, so that the performance of the shield machine can be completely recovered before transition.
Shield construction abnormal situation treatment plan: abnormal conditions of the shield tunneling machine in the tunneling process may be as follows: the concrete description of the surging of the screw machine, the mud cake of the cutter head, the slurry leakage of the shield tail and the like is as follows: 1. measures for treating jamming and deviation in active articulated excavation and measures for treating jamming of a shield machine, 1) measures for reducing abrasion outside a shield shell are adopted, such as: and bentonite or other lubricating liquid is injected outside the shield shell through the radial hole of the middle shield so as to increase the lubrication between the shield body and the peripheral soil body. 2) And the thrust of the shield tunneling machine is increased. The shield machine is forcibly pushed mainly by adjusting a shield machine pushing system or increasing shield pushing force by adding an external oil cylinder. 3) And the hob on the peripheral edge of the cutterhead is replaced or the super digging cutter is opened, so that the super digging amount is increased. 4) If the shield tunneling machine cannot be overcome by the measures, the shield tunneling machine is treated by adopting an explosion treatment scheme. 2. The deviation treatment measures in the tunneling process are influenced by factors such as uneven ground hardness, tunnel curve and gradient change, operation and the like, the tunneling cannot completely advance according to the designed tunnel axis, and certain deviation is generated. When the deviation exceeds a certain limit, the tunnel lining is cut into limits, the shield tail clearance is reduced, the local stress of the duct piece is deteriorated, the stratum loss is increased, the ground surface settlement is increased, and therefore effective technical measures are required to be adopted in the shield construction to control the tunneling direction and effectively correct the tunneling deviation in time. (1) And controlling the shield direction, and monitoring the shield attitude by adopting a laser automatic guide system and manual measurement assistance. The system is provided with guiding, automatic positioning, tunneling program software, a display and the like, and can dynamically display the deviation and the trend of the current position of the shield machine and the design axis of the tunnel in a main control room of the shield machine all day long. And adjusting and controlling the tunneling direction of the shield tunneling machine according to the deviation, so that the tunneling direction is always kept within an allowable deviation range. As the back vision datum point of the shield propulsion guide system needs to be moved forward, accurate positioning must be carried out through manual measurement. In order to ensure the accuracy and reliability of the propelling direction, two times of manual measurement are planned to be carried out every week so as to check the automatic guiding. (2) And (4) a tunneling control flow, measuring data of a system and rechecking the position and the posture of the shield tunneling machine to ensure the correctness of the tunneling direction of the shield tunneling machine. And according to the segmented axis fitting control plan made under the line condition and shield attitude information reflected by a guiding system, controlling the tunneling direction by operating a thrust cylinder of the shield tunneling machine in a partitioning manner by combining the tunnel stratum condition. When the shield machine is driven on an uphill section, the thrust of an oil cylinder at the lower part of the shield machine is properly increased; when the excavation is carried out on a downhill section, the thrust of the upper oil cylinder is properly increased; when the left-turning curve section is tunneled, the thrust of the right-side oil cylinder is properly increased; when the right turning curve is tunneled, the thrust of the left oil cylinder is properly increased; when the straight-line flat slope section is tunneled, the thrust of all the oil cylinders should be kept consistent as much as possible. (3) Direction control and adjustment, 1) rolling control, and correcting rolling deviation by adopting a method of reversing a shield cutter head. And the allowable rolling deviation is less than or equal to 3, and when the allowable rolling deviation exceeds 3, the shield tunneling machine gives an alarm to prompt an operator to switch the rotation direction of the cutter head to perform reverse deviation correction. 2) The control in the vertical direction is realized, the main factor for controlling the direction of the shield tunneling machine is the unilateral thrust of a jack, and the relation between the unilateral thrust and the attitude variation of the shield tunneling machine is very discrete and is mainly mastered by the experience of people. When the shield machine is bent downwards, the thrust of the lower side jack is increased, and when the shield machine is bent upwards, the thrust of the upper side jack can be increased to correct the deviation. 3) And (4) controlling in the horizontal direction, wherein the principle of deviation correction in the vertical direction is the same, the pushing pressure of the left jack is increased when the left jack deviates, and the pushing pressure of the right jack is increased when the right jack deviates. 4) The shield is adjusted to pay attention to, when the direction of rotation of the cutter head is switched, a proper time interval is reserved, and the switching speed is not suitable to be too fast. And adjusting the propulsion direction by adjusting the propulsion parameters in time according to the stratum condition of the face to avoid causing larger deviation. 3. The emergency measure of the spiral conveyer for gushing is that if the shield tunneling process is unexpected, the following measures are taken to process after the gushing occurs: (1) immediately closing a rear door of the screw conveyor, and properly tunneling forwards to establish balance in the soil cabin; (2) the soil body in the soil cabin is uniformly stirred by the rotation of the cutter head; (3) and then slowly opening the rear door of the screw conveyor, wherein the opening degree is about 30%, excavating while digging, and keeping the pressure in the soil cabin stable all the time. (4) During the tunneling process, a foaming agent, bentonite and the like are injected into the soil cabin to improve the flowability and water stopping property of the slag soil. Meanwhile, a pressure maintaining pump slag device is fastened at the outlet of the screw conveyor to establish a soil pressure balance state. 4. And (2) shield tail slurry leakage treatment measures are taken, (1) shield tail small-amount slurry leakage treatment is carried out, if slurry, mortar or clear water leaks from the shield tail in the tunneling process, a main driver immediately stops tunneling and adopts a manual grease injection method for treatment, grease injection amount is increased at the position and the adjacent position, and if the leakage is large, the grease injection amount is increased until the shield tail is completely sealed. After the leakage stops, the vehicle continues to be propelled and a special person is arranged to observe at the shield tail by a driving class, a main driver constantly pays close attention to the change of grease injection pressure at the leakage position, and the front person and the rear person keep contact at any time; if the plugging cannot be carried out for a long time or the leakage amount is increased, a shield driver and an on-duty engineer inform a general worker to determine a next processing scheme. (2) And (2) performing large-amount leakage treatment on the shield tail, 1) manually injecting grease, immediately stopping tunneling, increasing the grease injection amount aiming at a leakage position and an adjacent position, and if the leakage is large, increasing the grease injection amount until the shield tail is completely sealed. 2) And (4) draining water in the hole, and pumping water into the slurry pipe by using a slurry pump arranged at the bottommost part of the tunnel so as to strive for time for emergency rescue. 3) And (3) rapidly tunneling and assembling the duct piece, if the problem that the shield tail leakage cannot be solved by manually injecting grease, accelerating the tunneling speed, rapidly completing the circular tunneling and assembling the duct piece. 4) Plugging behind the segment wall, storing two cotton yarns on a segment mounting machine, and plugging the cotton yarns into the joint of the segment at the leakage position and a shield tail brush by using a steel chisel after shield tail leakage occurs. 5) And (3) secondary grouting, namely preparing hand-operated pressure pump grouting equipment on the shield machine, opening a penultimate secondary grouting hole nearby, installing a grouting joint and a ball valve, and performing pressure injection on the acrylate plugging material by using the hand-operated grouting equipment to form sealing behind the segment wall. 6) And if slurry, mortar or clear water leaks from the joint of the inner pipe sheet of the shield tail, stopping tunneling immediately, and plugging by manually injecting grease, wherein the grease injection amount is increased at the position and the adjacent position, and if the leakage is large, the grease injection amount is increased until the shield tail is completely sealed. If the leakage cannot be blocked, a tunnel leakage blocking team is informed to block the polyurethane injected at the leakage position of the pipe in time, and after the treatment is finished, a general worker decides whether to recover the tunneling according to the blocking condition.
Problems and emergency treatment measures which may be encountered when the shield arrives: (1) according to the hydrological and geological conditions of the receiving end of the tunnel interval, the underground water of the planned site is mainly bedrock fracture water. The bed rock fracture water is mainly generated in weathered and structural fractures of metamorphic rocks and is subjected to atmospheric precipitation and infiltration and replenishment of upper-layer pore water. The local joint cracks of the underlying bedrock in the field are relatively developed, but are mostly filled with secondary minerals, so that the connectivity is poor; the water quantity is very little, and the water-retaining agent is a crack water-containing layer with weak water-rich property, and the water permeability of an overlying soil layer is weak, so that the water-retaining space is limited, and the water-retaining space is not seen in the exploration period. Therefore, reinforcing body instability, portal sand gushing, water gushing accidents may occur during the process of reaching the end portal breakage, which may cause secondary risks of ground collapse, building and pipeline damage, etc. (2) And (2) preventive measures, namely 1) strictly controlling the construction quality of grouting reinforcement of the soil body of the portal, detecting the reinforcement strength and uniformity of the soil body in a horizontal and vertical core drilling sampling mode, and if the reinforcement strength and uniformity of the soil body do not reach the standard, adopting a supplementary grouting method for remediation. 2) Before chiseling out the concrete of the tunnel portal, drilling a horizontal observation hole in the range of a tunnel ring, and observing whether water leakage occurs or not; if the situation occurs, corresponding treatment measures such as horizontal grouting or precipitation are adopted according to the specific situation of water leakage; 3) the temporary water stopping device for the tunnel portal is firmly installed, after the second time of rapid chiseling of tunnel portal concrete, the shield machine is rapidly pushed into the tunnel ring to be close to the soil body, and the condition that the water leakage occurs due to overlong exposure of the reinforced soil body at the tunnel portal is prevented; 4) establishing an effective monitoring mechanism, feeding back in time, and starting an emergency plan immediately when early warning is exceeded; 5) the shield debugging work is carefully done before the shield is initiated; and (4) when the shield machine enters and exits the tunnel, performing grouting, injecting shield tail grease and the like. 6) An emergency safety channel is arranged by utilizing an open excavation station structure behind the shield well when a tunnel portal is broken, and during construction, any personnel and articles are strictly forbidden to block the channel. 7) And breaking the portal at a controlled time. The tunnel portal breaking work before the shield is started can be carried out only after the shield machine and shield construction members are all ready to work and equipment and personnel are all in a state of imminent war. (3) And (3) treating measures, if the phenomenon of water burst and sand gushing occurs, treating according to the following steps: 1) firstly checking the size of the leakage volume of a tunnel portal, plugging at the position of a horizontal exploratory hole by utilizing the on-site resources of a project part, and checking the plugging effect; 2) if the plugging effect is not ideal and the plugging effect cannot be effectively controlled, reporting to a unit to request the support of an emergency team; 3) after the initial plugging of the water leakage of the tunnel portal is finished, holes are led at 1m positions of the north and south sides of the shield tunneling machine according to the distance of 2 m; 4) after the hole guiding is finished, adopting a grouting pattern tube to squeeze cement mortar, and effectively backfilling and plugging the leakage cavity; 5) mixing cement mortar at a ground mixing station immediately when dangerous situations occur, and preparing for continuous synchronous grouting filling in subsequent holes; 6) when ground grouting is carried out, cement mortar is continuously injected at the shield tail, and a cavity area of the shield tail is filled and blocked; 7) opening the existing grouting hole in the shield tunneling machine, performing pressure injection on cement paste at the middle body part of the shield tunneling machine, and filling and plugging a hole area between shield tail holes; 8) determining whether an advanced grouting hole needs to be drilled at the lower part of the shield according to the field condition, and timely arranging maintenance personnel of the shield machine to start drilling and installing the lower grouting hole if necessary; 9) drilling hoisting holes of the third last and fourth ring segments behind the shield tail by drilling equipment in the driving class, and installing a grouting ball valve; 10) the tunneling team transports grouting equipment and water glass from the outside of the tunnel to the shield tail position, and water glass begins to be injected into a grouting hole of a shield tail segment in an outward pressure mode, so that quick-hardening slurry is formed between the grouting hole and the cement slurry injected in the past, and finally leakage is effectively controlled; 11) the phenomena of water burst and sand burst can not be prevented greatly by the measures, and the concrete is poured into the formwork immediately to close the tunnel portal so as to avoid further expansion of the situation.
And (3) auxiliary engineering construction:
constructing a hole gate ring: the hole sealing is used for preventing the back lining grouting mortar from leaking when the shield is started. In the process of the shield tunneling out of the tunnel, the steel ring at the tunnel opening and the shield shell can form an annular building gap. In order to prevent a large amount of muddy water from flowing into the well through the building gap from the outside of the tunnel portal when the shield is out of the tunnel, and influencing the establishment of the soil pressure of the excavation surface, the stability of the soil of the excavation surface and the construction in the working well and the shield, a sealing water stop device with good performance is required to be arranged, so that the correct establishment of the initial soil pressure balance and the construction safety are ensured. The engineering sealing water-stopping device is installed on a pre-buried circular plate of a hole outlet, and the circular plate is made of a Q235A steel plate. The circular ring plate is provided with a fixing screw hole, and the cord fabric rubber plate used as the sealing water-stopping device is fixed on the steel ring of the opening by the circular ring plate. 1) The construction process includes the steps of firstly removing tunnel portal ring duct pieces and a construction stage connection structure device before tunnel portal lining construction, laying a waterproof layer according to design, installing a water-swelling rubber waterstop and binding reinforcing steel bars to ensure that tunnel portal reinforcing steel bars are firmly connected with an end wall structure, and pouring concrete after formwork erection. And after the tunnel portal construction is finished, determining whether to supplement grouting to a tunnel portal segment backing according to the waterproof effect condition of the tunnel portal so as to improve the waterproof performance of the tunnel portal. 2) The construction process comprises the following steps: grouting near the opening, then removing the ring duct piece of the opening, installing a water stop, binding reinforcing steel bars, erecting a mold, pouring concrete, then removing the mold, maintaining, and finally checking the waterproof effect of the opening, if the waterproof effect meets the requirement, completing the construction process, otherwise grouting and pressure supplementing at the back lining of the ring duct piece of the opening. 3) The hole door ring dismantling process comprises the following steps: a. before the hole is sealed and removed, supplementary grouting is carried out from a grouting hole of the +1 ring duct piece, so that an effective water stopping effect is achieved behind the wall of the tunnel portal duct piece, and grouting slurry is cement and water glass double-liquid slurry; b. after grouting, drilling holes on the portal ring pipe sheet, detecting the water leakage condition of the portal, and if the water leakage phenomenon still exists, continuing grouting until no water seeps out after drilling; c. the temporary seal (a pressing plate, a rubber cord fabric and the like) of the hole is removed; d. removing the duct piece of the door ring of the tunnel, firstly building a scaffold operation platform, chiseling a sealing top block manually, and then sequentially removing the whole ring of duct pieces from top to bottom; e. chiseling off mortar behind the duct piece wall by using a manual hand-held pneumatic pick until the surface of an embedded annular steel plate in the portal ring is completely exposed, and cleaning; f. after mortar is chiseled off behind the duct piece wall, if the phenomena of water leakage and sand leakage exist, the pipe is firstly buried, quick-drying cement is used for temporary plugging, grouting plugging is then carried out until no water seeps out, and finally the buried pipe is dismantled.
Constructing a tunnel door ring beam: the tunnel portal lining construction method comprises the steps of firstly removing tunnel portal ring duct pieces before tunnel portal lining construction, laying a waterproof layer, installing a water-swelling rubber waterstop and binding reinforcing steel bars, ensuring that tunnel portal reinforcing steel bars are firmly connected with an end wall structure, and pouring concrete after erecting a mold. And after the tunnel portal construction is finished, determining whether to supplement grouting to a tunnel portal segment backing according to the waterproof effect condition of the tunnel portal so as to improve the waterproof performance of the tunnel portal.
Shield waterproof: the segment A concrete is self-waterproof, and the shield lining waterproof grade is designed according to the secondary waterproof standard of underground engineering. The shield lining waterproof design follows' taking defense as a main part, being rigid and flexible, multiple defences, being suitable according to local conditions and comprehensiveAnd (5) combining the treatment principle. The self-waterproofing of the structure is emphasized, and the waterproofing capacity of the concrete and reinforced concrete structures is ensured. Therefore, effective technical measures are adopted to ensure that the waterproof concrete reaches the compactness, impermeability, crack resistance, corrosion resistance and durability specified by the specification. And (3) waterproof measures for reinforcing deformation joints, construction joints, embedded parts, reserved holes, various joints and various structural section interfaces. The key of the self-waterproof pipe piece lies in concrete configuration and quality control. The concrete strength grade of the project segment is C50, the impermeability grade is P12, and the following measures are taken: 1) ordinary portland cement with stable quality, low hydration heat and low alkali content is selected, and early strength cement and cement with high C3A content are not used. 2) In order to improve the anti-permeability performance, high-quality fly ash is added, the quality of the fly ash meets the relevant regulations of the existing national standard fly ash for cement and concrete (GB1596), the grade of the fly ash is not lower than II grade, the burning vector is not more than 5 percent, and low-calcium ash with free calcium oxide not more than 10 percent is selected; the dosage is preferably 20 to 30 percent of the total amount of the cementing material, and when the water-to-gel ratio is less than 0.45, the dosage of the fly ash can be properly increased; the amount of the silicon powder is preferably 3 to 5 percent of the total amount of the cementing material. 3) Reducing the dosage of mixing water as much as possible, and adopting a high-efficiency water reducing agent; 4) the water, sand and stone of the waterproof concrete should meet the relevant regulations of item 4.1.10 and item 4.1.11 of the waterproof technical Specification of underground engineering, and clean aggregate which is firm, durable, qualified in grading and good in particle shape is selected. 5) The engineering environmental condition belongs to a supermarket environment, and alkali active aggregate cannot be adopted. 6) The aggregate with low alkali content is selected, and the maximum grain diameter of the coarse aggregate is controlled to be not more than 25mm, and the using amount of the fine aggregate is controlled to be not more than 45%. 7) The water-gel ratio is strictly controlled to be not more than 0.36, and the dosage of the cementing material is controlled to be 360-480 kg/m3. 8) The content of chloride ions in the concrete is not more than 0.06 percent of the weight of the cementing material, and the content of alkali is not more than 3kg/m3. 9) And (3) curing the concrete in time after final setting, wherein the curing period is not less than 14d, and the highest temperature of the steam curing of the pipe piece is not more than 60 ℃. The winter construction of concrete should meet the relevant standard requirements. 10) The waterproof concrete mixture must be stirred for the second time if segregation occurs after transportation, and when the slump loss cannot meet the construction requirementAdding cement slurry with the original water-to-gel ratio or adding the same type of water reducing agent for stirring, and strictly prohibiting direct water addition. 11) The method is characterized in that the leakage detection test should be performed on one segment in each 50-ring segment production, and the test standard is as follows: maintaining the pressure of 0.2MPa for 3h without water leakage, and the water penetration depth is not more than 5 cm. B. The seams of the pipe pieces are waterproof, and the sealing gaskets with porous special sections are arranged at the seams to be waterproof. The elastomeric gasket was spot checked at a rate of 0.2% and the test report was submitted to a supervision engineer for approval. In order to meet the waterproof requirement of the joint, two waterproof measures of a frame-shaped elastic sealing gasket and caulking are arranged at the joint of the duct piece, and the elastic sealing gasket is taken as the main waterproof measure. 1) The sealing gasket is waterproof, the sealing gasket is made of ethylene propylene diene monomer rubber, the lower part of the sealing gasket is provided with a plurality of holes, the stress-strain characteristic can be improved, when the joint is opened in a certain range, the pressure stress change of the contact surface of the sealing gasket is small, and the splicing stress is reduced on the premise of meeting the watertight requirement. The deformation joint is located and adds the water-swelling rubber outside sealed the pad, further strengthens deformation joint department waterproof ability. 2) The caulking groove sealing material adopts a mode of filling a PE sponge strip and polyurethane sealant for caulking, and the interface treating agent is integrally coated on the inner side of the pipe piece for treatment after caulking is finished. Caulking range: and (5) filling the whole tunnel whole-ring longitudinal seam whole-ring. And (3) sealing and burying the pipe with quick-hardening cement to introduce water (or grouting) for places with obvious water leakage points. Before caulking, dust and sundries in the caulking joint are cleaned, and the caulking material is constructed in a dry state. C. The connecting bolt holes and the grouting holes are waterproof, the connecting bolt holes are waterproof and are sealed by water-swelling rubber material sealing rings, and the waterproof performance is enhanced by using the dual functions of compaction and swelling; the grouting holes are waterproof, and plain concrete of the same grade with the thickness of 25mm is precast on the upstream faces of the grouting holes when the duct pieces are produced, so that a good waterproof effect can be achieved. And (4) removing the movable end part after grouting is finished through the grouting hole, and screwing the grouting pipe cover with the sealing gasket for waterproofing. D. The grouting is used for enhancing water resistance, after the shield is propelled, grouting filling is carried out on a shield tail gap before the collapse of surrounding rocks in time, not only can the ground be prevented from settling, but also the water resistance of tunnel lining is facilitated, and a stable segment peripheral waterproof layer can be formed by selecting proper slurry (the slurry has the characteristics of low initial viscosity, micro expansion, high later strength and the like), grouting parameters and grouting processes, so that the segment is surroundedTo form a guard ring. E. The tunnel portal is waterproof, 1) the waterproof design of the tunnel portal, except adopting waterproof concrete, set up the water swelling rubber sealing rod in the rigid joint of tunnel portal and interval tunnel segment and shaft structure. And a water stop strip or a water stop belt is arranged at the construction joint. According to the specific construction condition, pre-grouting can be carried out in advance when necessary or post-grouting can be carried out by pre-embedding a grouting pipe during construction. In the waterproof treatment, the waterproof treatment can be carried out in three stages according to time: the method comprises the steps of firstly, processing the shield machine before entering the initial door, secondly, taking a waterproof measure during the initial period when the shield machine enters the initial door, and thirdly, taking a waterproof and leak-stopping measure after the shield machine enters the initial door. 2) Performing portal treatment before starting and arriving, well reinforcing the stratum of the end, inspecting and testing after reinforcing, checking the reinforcing effect, and performing grouting treatment if necessary; and determining a processing scheme of sealing the tunnel door (mainly referring to the tunnel door reserved after the shaft structure is made) according to the geological condition and the burial depth of the tunnel door. In the conventional situation, concrete is mainly adopted for sealing the door, an embedded steel ring is arranged at the position of the portal, and necessary structural treatment needs to be carried out between the portal and the end wall. And when the shield arrives, the concrete seal door is removed. 3) Waterproof measures during starting and reaching periods, wherein when starting, after a tunnel portal is opened, the shield is pushed against an excavation surface as soon as possible to seal the tunnel portal; when the receiving door arrives, the receiving door is pushed out and closed as soon as possible; and arranging waterproof devices such as a cord fabric rubber plate, a circular plate and the like at the tunnel portal according to design requirements, and injecting quick-setting hydraulic double-liquid slurry to plug the tunnel portal when the shield is started. 4) Starting and stopping water and leakage after arrival, finishing the preparation of starting the shield, immediately plugging a tunnel portal ring after a cutter head enters a tunnel portal, and pressing and injecting quick-setting hydraulic double-liquid slurry to plug the tunnel portal after a shield tail completely enters a tunnel face soil body; when the shield arrives, after the shield machine is completely separated from the tunnel, the turning plate is immediately fixed to plug the gate ring, and the tunnel is timely filled by grouting to ensure the stability of the earth surface after the shield arrives at the station. The caulking work of the construction joint is practically well done and can make up leakage caused by poor sealing at the joint of the water stop strip or cracking at the corner or construction damage of the elastic sealing gasket and the corner part of the duct piece as a second defense line, wherein the caulking material is neoprene latex cement mortar, and the interface treating agent YJ-302 and a PE film are selected for interface treatment.
The shield passes through the construction measures of the special section:
A. the control and treatment measures when the shield passes through the building are as follows: (1) auxiliary measures before tunneling, 1) protection monitoring, wherein the buildings such as houses, bridges and the like in the range of direct penetration and influence of the shield are required to be protected and monitored, and deformation observation of the buildings can be divided into three contents of settlement observation, inclinometry observation and crack observation. Setting settlement measuring points on a foundation or a wall, and setting measuring points on the ground surface outside the structure and on a bottom plate of the structure, and measuring by using a level gauge; the structure inclination monitoring can adopt a theodolite measuring method, and can also adopt an inclinometer arranged on the wall body to continuously monitor the inclination of the wall body; the cracks of the structure can be measured by a crack viewer. 2) The settlement monitoring is carried out in real time, and the settlement monitoring is carried out in real time to the section of crossing, and the concrete scheme is that setting up the monitoring point at pier, building relevant position, adopting urgent supplementary slip casting when the monitoring value is close early warning value (15mm), in time controlling subsides, ensures the current safety of roof tunnel. 3) And introducing third-party monitoring, and performing rechecking work on the monitoring data of the first party through third-party monitoring and monitoring management to ensure the accuracy of the monitoring data of the first party. Accurately reflects the deformation condition caused by shield construction, and sends out related early warning or alarm to the place where the deformation is obvious and equal to or not less than the prediction standard, so that related technical departments can solve and process the deformation, the safety order is kept, and the stable development of the shield construction is ensured. 4) And (4) equipment maintenance, namely, before crossing, equipment can be maintained (tool changing can be considered) according to the general profile, so that the equipment can smoothly pass through the box culvert section during construction. The maintenance items mainly include: a main driving system, a man-cabin system, a propelling and hinging system, a grease system, a foam system, a shield tail sealing condition, an erector, a screw machine, an air system, a hydraulic system, a water system, a cleaning grouting and bentonite pipeline and the like; checking all control lines, fastening connecting terminals and cleaning the belt conveyor comprehensively; and the parts with hidden danger are checked and replaced, so that the reliable operation of the equipment is ensured. In addition, the maintenance of the battery car, the gantry crane, the mortar station and other matched equipment is required. (2) And (2) controlling the tunneling process, and 1) improving the shutdown pressure maintaining value, wherein when the earth pressure balance mode is adopted for tunneling, the section mainly comprises a strongly weathered conglomerate stratum and a top-8 pebble stratum, so that the water permeability coefficient is high. The soil pressure determined by calculation and through a test section is the soil pressure for tunneling, the soil pressure is properly increased by 0.1-0.15bar when the machine is stopped for pressure maintaining, the soil cabin pressure and the stability of an excavation surface are ensured, and the ground surface settlement is controlled. 2) The soil pressure tunneling is kept, the speed is kept basically unchanged, and the aims of controlling the soil output and keeping the pressure of the soil cabin are achieved by adjusting the rotating speed of the screw conveyor or the opening degree of a slag outlet door. 3) According to the principle of quick passing, the reasonable propelling speed ensures the filling effect of synchronous grouting, and meanwhile, the improvement of the propelling speed is beneficial to reducing the change of the upper stratum caused by the disturbance of the cutter head. 4) The method controls the possible gushing, uses high-quality foam, and injects high-molecular polymer or high-quality bentonite slurry into the palm surface, the soil cabin or the screw machine at the foam injection port of the cutter head according to the condition of slag discharge, thereby increasing the water stopping effect, improving the plastic fluidity of the slag soil and controlling the occurrence of the gushing. 5) And (3) grouting is strengthened to control sedimentation, synchronous grouting amount is controlled according to experimental data and theoretical calculation data, pressure and flow are controlled, pressure control is used as a main part, and flow control is used as an auxiliary part, so that sufficient injection of mortar is ensured. The mixing proportion of the mortar is adjusted according to the geological condition, the initial setting time of the mortar is shortened, and the purpose of controlling the surface settlement is achieved. According to the monitoring data of the surface settlement, secondary grouting is carried out in time; the shield posture is controlled, the deviation correction amount is reduced, the deviation correction is avoided as much as possible, and fewer correction tasks are required when the deviation correction is needed. 6) And enhancing the soil output control, adopting a method for measuring the volume of the muck to control, and determining the soil output of each ring according to the loosening coefficient of the muck obtained by experiments and the density of the muck in different sections. 7) And (3) assembling the duct pieces, wherein in the shield propelling process, the duct pieces must be assembled, and the assembling of the duct pieces can be rapidly completed with high quality by experienced workers. The segments should be assembled in the middle as much as possible, so that the segment is prevented from being damaged due to the uneven gap between the shield tails to form a water seepage channel. 8) The coordination is strengthened, shield operators execute the operation according to the operation instructions issued by technical responsible persons strictly, and when the instructions cannot be implemented due to the change of the geological conditions, the shield operators communicate with technical departments in time to negotiate, communicate and explore solution methods and treatment measures. In the tunneling process, each constructor needs to keep close connection and cooperation. If the machine needs to be stopped due to equipment failure in the tunneling process, the soil pressure needs to be reasonably set, and corresponding measures are taken according to actual conditions. (3) Grouting and reinforcing, namely grouting and reinforcing by adopting sleeve valve pipes outside the structure before the shield passes through the structure in order to ensure the safety of the structure when the shield passes through the structure. The distance between the inner layer and the outer layer of the grouting pipe is about 1m, and the grouting pipe is approximately arranged in a quincunx shape; the distance between the inner ring grouting pipe and the outer wall is not less than 1m, the houses right above the tunnel are arranged on the periphery, and the houses on the tunnel side can be arranged in a u shape on one side of the tunnel according to three sides. The depth length of the grouting pipe is performed according to the following standard: shallow foundation: the vertical length of the bottom of the foundation is not less than 3m, and the foundation penetrates through a sand layer and a sludge layer. The sludge layer is not less than 0.5m and the exposed ground is not less than 0.2 m; and (3) friction pile: the diameter of the pile is one time of the pile bottom and is not less than 0.5 m; end bearing wall: the bottom of the shield construction influence range is not less than 1m, or the depth of the stratum with the number <8> or above is not less than 0.5 m. When the grouting pipe is constructed, the foundation of the building is prevented from being damaged. If the site outside the wall is limited, the building can be constructed in the house. And determining to take corresponding measures according to the monitoring result. When the settlement of buildings such as houses and the like is large and approaches to an alarm value, the tunneling is stopped, an oblique grouting pipe is arranged on the side of the foundation from the ground, and tracking grouting is carried out according to monitoring feedback data. Effective range of grouting: shallow foundation: grouting the bottom of the pipe to the bottom surface of the foundation; pile foundation: grouting the bottom of the pipe to 3m below the ground; the construction process of the sleeve valve pipe is the same as the process adopted when the end head is reinforced.
B. The control and treatment measures when the shield passes through the ditch are as follows: (1) the shield tail is sealed and designed, and the shield machine adopts three shield tail steel wire sealing brushes, so that the shield tail can be effectively prevented from permeating water. The injection of shield tail sealing grease is enhanced during tunneling, and the pressure of the shield tail sealing grease is ensured to be not less than 5 Bar; strengthen the sealed inspection of articulated department, guarantee its sealed effect, prevent that groundwater from gushing into. The posture of the duct piece is controlled, the duct piece is prevented from being eccentric with the shield tail, and the gap between the shield tail and the duct piece is locally too large and exceeds the sealing function limit of the sealing device; the extrusion degree of the duct piece on the shield tail sealing brush is reduced; grease is injected in time, and high-quality shield tail grease is adopted, so that sufficient viscosity, fluidity, lubricity and sealing performance are required to ensure the sealing effect; timely replacing the shield tail sealing brush after the interval is finished; the shield is prevented from retreating, so that the movement of the brush hair in the opposite direction between the shield tail brush and the duct piece is caused, the brush hair is reversely coiled, and the shield tail brush is deformed to reduce the sealing performance; when the measures are implemented, if leakage happens, sponge is stuck on the outer side of the duct piece if necessary, and polyurethane is pressed into the tail of the shield through a grouting pipe opening to close the water passage. (2) The bentonite pressure maintaining system is characterized in that when a water-rich stratum is tunneled, an improvement blind area often exists at the top of the soil cabin, underground water can permeate into the soil cabin to dilute muck, and the bentonite additionally injected into the top of the soil cabin by the bentonite pressure maintaining system additionally forms a mud film at the top of the soil cabin, so that the underground water can be effectively prevented from permeating into the soil cabin from the top. And because the system controls the injection pressure through compressed air, the pressure of the soil cabin can be accurately obtained through the display of the air pressure, and the defect of distortion of the soil pressure sensor is overcome. Meanwhile, when the machine is stopped for a long time, the system can automatically inject bentonite to make up for the leakage and pressure loss outside the soil cabin. (3) The design of screw conveyer slag discharge door, screw conveyer slag discharge door passes through hydro-cylinder control gate opening size to guarantee in the barrel and excavate the cabin pressure, to rich water stratum, slag discharge door design adopts the double gate design, reserve the pressurize pump interface between twice gate, the gate is closed rapidly when taking place to gush, open interface flange and connect the pressurize pump and arrange the sediment, adopt screw conveyer double gate control when the great section of water yield is tunneled, filling mud or high-efficient polymer, prevent gushing. (4) And (2) controlling the construction process, namely 1) well improving the soil body of the cutting surface, wherein the shield tunneling ditch section is mainly positioned in the medium induced hydration rock stratum, the soil layer strength is higher, the soil body can be improved by adding bentonite or a foaming agent to the soil body in front of a mud adding hole, and the flow plasticity of the soil body is increased. One is as follows: the earth pressure value reflected by the earth pressure meter in front of the shield machine is more accurate; the second step is as follows: the screw conveyor can be guaranteed to be smoothly unearthed, and the extrusion of the shield to the front soil body is reduced; and thirdly: and the gap formed after the cutter head rotates is filled in time. 2) And reasonably controlling the soil pressure and the soil output, starting from the shield, strictly controlling the soil pressure value, adjusting the soil pressure value by combining the earth surface monitoring data, and performing information construction. The part penetrating through the ditch should be excavated according to the theoretical soil output in principle, and can be dug under the condition of proper depth, so as to ensure the soil body to be compact and prevent river water from permeating into the soil body and entering the shield. 3) The propelling speed is strictly controlled, the propelling speed is ensured to be stable, when the shield tunnel passes through a ditch, the shield tunnel is propelled at a lower speed, the speed is generally controlled to be lower than 30mm/min, the total propelling force of the jack is strictly controlled, and the disturbance of soil around the shield tunnel is reduced so as to avoid bursting the soil at the bottom of the river. 4) The shield attitude is controlled well, rapid deviation correction is avoided, the tunnel axis measurement is enhanced in the ditch crossing area, the measured data is accurate and detailed, and meanwhile, a shield main driver strictly controls the shield attitude deviation to ensure the shield axis position to be accurate; and when the attitude deviation occurs, deviation rectification is timely performed according to the measurement data, so that the deviation rectification is reduced as much as possible, especially, the deviation rectification of a large number of values is avoided, and the disturbance of the soil body is reduced, thereby ensuring that the shield tunneling machine stably passes through the lower part of the ditch. 5) The grouting quality is strictly controlled, the strength, specific gravity, setting time, water permeability, consistency and the like of the grout are detected before propulsion, the grout with high early strength is selected as far as possible on the premise of ensuring the grouting quality, the grouting pressure is reduced, the situation that the grout penetrates through the top soil of the tunnel to form a water channel due to over-high pressure to puncture the covering soil is avoided, meanwhile, the grouting amount is properly increased, and the grouting amount is adjusted in real time according to ground surface monitoring data, so that the soil around the ditch is ensured to be stable; after the propelling is completed, high-strength slurry is adopted in time according to monitoring data to perform secondary grouting treatment, and gaps between the shield body and the duct piece which are not filled due to the reduction of synchronous grouting pressure are filled, so that later-stage leakage is prevented. 6) The waterproof quality of the duct piece is enhanced, a sealing water-stopping adhesive tape meeting the requirement is selected, the condition of adhering the sealing adhesive tape and the condition of damaging the duct piece are checked and accepted before the duct piece is put into a well, and the sealing effect is ensured by timely replacing the sealing adhesive tape which does not meet the requirement; strengthen the section of jurisdiction and assemble quality control, combine the shield structure gesture condition to choose for use suitable section of jurisdiction type, prevent that waterproof adhesive tape presss from both sides mud and presss from both sides the sediment, must not collide damage the section of jurisdiction or make waterproof adhesive tape drop when paying attention to assembling simultaneously, connect with the bolt immediately after assembling the completion and retighten tight assurance seal effect, improve the whole waterproof performance in tunnel. (5) Grouting and reinforcing in the hole, and when the shield passes through the ditch, in order to ensure the safety of the ditch foundation, after the shield passes through, drilling a steel perforated pipe in the tunnel through a hand hole to perform grouting and reinforcing. The reinforcing range is the range of 1.6m outside the segment, and the slip casting adopts grout, and slip casting pressure should not be too big, prevents to cause the earth's surface uplift, destroys the ditch basis.
C. And (3) small radius curve construction: the small radius curve of the shield engineering is 5 in total, and the radius is 200m and 500 m. In order to ensure the construction of the small-radius curve segment, the following measures are taken: the technical support of the equipment is that (1) a double-active hinged oil cylinder mechanism is arranged on the earth pressure balance shield machine of the engineering, and the posture control of curve tunneling is assisted. The active hinging function is the function of bending the segmented body of the shield tunneling machine by itself without the help of soil layer pressure through the internal control of the shield tunneling machine. The setting of the active hinge can be connected with a guiding system of the shield machine, the posture of the shield body is calculated by calculating the stroke difference between the active oil cylinders, and the tunneling posture of the shield machine is reflected in real time through a control interface. (2) The spherical hinge mechanism, the front shield, the middle shield and the tail shield are connected in a driving hinge oil cylinder type, the bending part is sealed in a spherical hinge ring type matched lip type, the gap formed by bending the shield body is effectively sealed, and the larger bending angle is realized. The front of the hinge mechanism equipped in the project is hinged to realize 4-degree turning; the rear hinge joint can realize 6-degree turning and can realize small-radius curve construction with the minimum curve radius being 10 times of the diameter of the shield body. (3) The profiling cutter structure ensures that when the small curve radius is used for tunneling, the turning side needs to be over-dug. However, the overexcavation gap of 360 ° using the overexcavation cutter is too large, which may cause the risk of ground subsidence or shrinkage. The shield machine cutter head adopted in the project is provided with a profiling cutter structure. The profiling cutter can be used for accurately cutting the necessary construction clearance for turning the shield body, and the risks of ground settlement or shrinkage cavity and the like are reduced. When the shield machine is used for curve tunneling or deviation correction, the profiling cutter can be reasonably used according to specific conditions. (4) A measurement guide system is used for ensuring the visibility effect in the construction of a sharp curve section, and the measurement system needs to frequently move a station and provides high requirements for accurate measurement. The guiding measurement system adopted by the engineering is developed and researched by the department of China and a system manufacturer together, is suitable for being used inside a small shield machine, can realize accurate measurement feedback under the condition of frequently moving stations, and guides shield tunneling construction. (5) A small radius construction auxiliary construction method, a front shield auxiliary grouting technique, in small curve radius tunneling, when the tunneling encounters soft soil layer or the counterforce cannot be expected on the soil layer, the tunneling after the shield body is bent can not reach the set target, the methodThe bearing capacity of the surrounding soil body needs to be increased, and sufficient steering counterforce is established. The engineering shield machine can utilize a slurry distribution and pumping device equipped with the shield machine to perform slurry injection to one side of the shield machine to form gel-like solid, and establishes steering counter force. b. According to the micro fixing bag technology, when the shield body establishes the counter force, the formed tunnel also needs to establish enough steering counter force to support the posture adjustment of equipment, so that the micro fixing pile technology is adopted in design. The folded nylon yarn bags were stored in a cylinder having a length of about 9.5cm and a diameter of about 5.5 cm. The cylinder is screwed into the grouting hole of the pipe piece, and then strong grouting material is injected, so that a cushion-shaped hard block with the diameter of about 30-50 cm is formed on the periphery of the ring piece. The miniature fixing bag is arranged in a pipe ring piece grouting hole on the outer side of the sharp-turn bending section, and 3-4 miniature fixing bags are arranged on each ring of pipe piece (the pipeline is 50 or 80 cm). When the duct piece leaves the shield tail, the miniature fixing bag starts to be filled, the filling pressure is about 0.2MPa, and then the residual space on the outer wall of the duct piece is filled. The adopted shield small-radius curve construction process (1) comprises the following process flows: the method comprises the steps of initially setting shield parameters after construction preparation, matching with shield machine type selection and segment selection meeting the small-radius curve tunneling requirements, and auxiliary measures such as axis pre-deviation setting, segment grouting reinforcement, longitudinal reinforcing rib adding and reinforcing bolt tightening, then tunneling, judging whether the parameters are smaller than a reference, matching with monitoring of settlement, displacement and convergence of a tunnel, completing small-radius curve construction if the parameters are smaller than the reference, and continuing to optimize shield construction parameters and tunneling again if the parameters are not smaller than the reference. (2) And configuring corresponding equipment construction technology, and constructing by adopting an articulated shield. Because the shield is additionally provided with the hinged part, the shield cuts to the support ring, and the support ring to the shield tail form a living body, the sensitivity of the shield is increased, the axial line control of the tunnel is more convenient, and the conditions of segment outer arc fragmentation, segment water seepage and the like are greatly improved. a. And the proper over-digging amount is realized, and the profiling cutter is arranged on the cutter head of the shield, so that a certain over-digging range is realized. During curve construction, partial overbreak can be carried out according to the condition of the pushing axis, and the larger the overbreak amount is, the easier the curve construction is. On the other hand, the problem of tunnel deformation increase is caused by the fact that synchronous grouting slurry winds into an excavation surface due to soil loosening and the factor that reaction force is reduced during curve propulsion. Therefore, the overbreak is preferably controlled to be overbreakWithin the minimum limit of the digging range. b. The hinge angle meets the requirement, the hinge part is added to the shield machine, so that the shield notch is formed to the support ring, and the support ring is formed to the shield tail to form a living body, the sensitivity of the shield machine is increased, the over-excavation amount can be reduced during propulsion, the propulsion component force is generated, and the control of the propulsion axis of curve construction is ensured. The conditions of the fragmentation of the outer arc of the pipe piece, the water seepage of the pipe piece and the like are greatly improved. The hinge angle alpha is (L1+ L2) x 180/pi x R, wherein L1 and L2 are respectively the front body and the rear body of the hinged shield, R is the curve radius, and alpha is the hinge angle of the shield machine on the curve with small radius, and the angle is smaller than the maximum hinge angle of the shield machine. The hinging angle of the shield tunneling machine is fixed through the stroke difference of the fixed hinging jack, so that the shield tunneling machine is adaptive to the corresponding curve radius. The difference mm of the travel of the hinged jack is equal to the maximum difference x of the travel of the jack (left and right hinged angle deg)/the maximum left and right hinged angle deg. (3) And (2) performing secondary pressure injection reinforcement on the soil body of the segment which is separated from the ring of the shield tail 10 through an assembling hole of the segment after the segment is tunneled for 2 rings by matching with corresponding auxiliary construction measures and a. b. Longitudinal reinforcing ribs are arranged in the tunnel, the longitudinal displacement of the tunnel on a small-radius curve is large, and the reinforcing ribs are arranged on segments in the range of 50-60 m behind the tunnel close to an excavation face to enhance the longitudinal rigidity of the tunnel and control the longitudinal displacement of the tunnel. The reinforcing rib is formed by welding double-spliced (22 a channel steel plates) and is connected with the reserved grouting holes of the duct pieces by bolts, so that the tunnel is longitudinally connected to enhance the longitudinal rigidity of the tunnel. c. The reinforcing bolts are tightened again, after each ring is pushed, the connecting bolts of the segments of the current ring need to be screwed, and the lower ring is pushed to be tightened again, so that the vertical component force generated by the pushing force acting on the segments is overcome, and the floating of the ring-forming tunnel is reduced. And re-screwing the segment connecting bolt within 10 rings once every 3 rings of tunneling completion. d. The propulsion axis is pre-deviated, and the control on the propulsion axis is enhanced in the shield tunneling process. When the curve is advanced, the shield is actually positioned on the tangent line of the curve, so the key point of the advancement is to ensure the control of the attitude of the shield machine. Because the double-liquid-slurry effect of synchronous grouting and tracking and supplementary grouting in the shield tunneling process cannot fundamentally ensure the bearing strength of the soil body behind the segment, the segment can deviate to the outer side of the arc line after bearing lateral pressure.In order to ensure that the final deviation of the tunnel axis is controlled within the range allowed by the specification, a certain offset is reserved for the tunnel during shield tunneling. According to theoretical calculation and comprehensive analysis of related construction practical experience, the stratum condition of a tunneling area needs to be considered, and the pre-offset is set to be 20-40 mm in the tunneling process of the small-half curved tunnel. The pre-deviation amount is properly adjusted by monitoring the deviation of the small-radius section tunnel in the construction process. (4) Selecting construction parameters, and a, strictly controlling the propelling speed of the shield, wherein the propelling speed is controlled to be 1-2 cm/min. The lateral pressure increase caused by overlarge thrust is avoided, and the disturbance of the shield to the surrounding soil body in the propelling process is reduced. b. The front balance pressure of the shield is strictly controlled, the cut balance soil pressure needs to be strictly controlled in the crossing process of the shield, so that the stratum at the cut of the shield has a small uplift amount (0.5-1 mm) to balance the stratum settlement amount after the shield construction. Meanwhile, construction parameters related to the notch balance pressure, such as the soil output, the propelling speed, the total propelling force, the difference value of the actual soil pressure fluctuation around the set soil pressure, and the like, must be strictly controlled. Excessive overbreak and underbreak are prevented, and fluctuation of the balance pressure is reduced as much as possible. The fluctuation value is controlled within 0.02 MPa. c. The synchronous grouting amount and the grout quality are strictly controlled, because the curve section propulsion increases the stratum loss caused by curve propulsion and the increase of the deviation correction times leads to the increase of disturbance to the soil body, the synchronous grouting amount and the grout quality are strictly controlled when the curve section is propelled, a propulsion and grouting linkage mode is adopted in the construction process, the total grouting amount of each ring is ensured to be in place, the grout is uniformly and reasonably injected in the process of propelling each box of soil by a shield, and the proportioning of the grout is ensured to meet the quality standard. And the construction gap is filled in time through synchronous grouting, so that the soil deformation in the construction process is reduced. When the grouting does not meet the requirement, the shield stops propelling to prevent the deformation of the soil body. The grouting amount of each ring is generally 130-250% of the building gap and is 2.25-3.75 m 3/ring, thick slurry is adopted, the slurry consistency is 12-14 cm, and the pressure at a pumping outlet is not more than about 0.5 MPa. And selecting specific grouting amount, a pressure value of a grouting point during grouting and formation deformation monitoring data. According to the deformation monitoring condition in construction, the grouting parameters are adjusted at any time, so that the shaft is effectively controlledA wire. (5) In the process of actual propulsion, the actual driving axis is necessarily a section of broken line, and the soil outlet amount outside the curve is large. Therefore, the loss of soil outside the curve is inevitably caused, and a construction gap exists. Therefore, in the process of propelling the curve segment, the grouting amount of the outer side of the curve segment needs to be enhanced in the project of synchronous grouting so as to fill up the construction gap. And carrying out secondary pressure injection on the composite early-setting slurry on the two ring pipe sheets at the back when every two rings are assembled so as to reinforce the soil body outside the tunnel and ensure that the shield is smoothly propelled along the designed axis. The slurry adopts cement and water glass in a ratio of 30:1, and the water cement ratio is 0.6. Controlling the secondary grouting pressure below 0.3 Mpa; the grouting flow is controlled to be 10-15L/min and is about 0.5m3A/ring. (6) The deviation correction amount is controlled in the shield construction, the curve propulsion of the shield is actually on the tangent line of the curve, the key of the propulsion is to ensure the control of the head of the shield, the deviation correction of the ring of the curve propulsion shield is required to be carried out, the deviation correction amount at each time is required to be as small as possible, and the ring surface of the wedge block is ensured to be always in the radial vertical surface of the curvature radius. Except for the wedge-shaped duct piece, in order to control the displacement of the duct piece, the duct piece deviation rectification adopts a wedge-shaped low-pressure cotton rubber plate at proper time, thereby achieving the purpose of effectively controlling the deformation of the axis and the stratum. The deviation correcting amount of the shield propulsion is controlled to be 2-3 mm/m. And calculating the stroke difference of a left jack and a right jack of the shield tunneling machine according to the deviation correction amount of each ring, and analyzing the type selection of the segment by utilizing the stroke difference of the jacks of the shield tunneling machine. (7) The gap between the shield tail and the duct piece is controlled, duct pieces in the small-curvature radius section are assembled to be crucial, and the gap between the duct pieces and the shield tail is the key problem influencing the assembling quality of the duct pieces. The reasonable peripheral gap can facilitate the assembly of the duct pieces and the correction of the shield. a. The gap between the shield tail and the duct piece is concerned at any time in the construction, and once the unilateral gap is found to be small, the shield tail is timely adjusted through the shield advancing direction, so that the surrounding gaps are basically the same. b. When the duct pieces are assembled, the clearance between the shield tail and the duct pieces is reasonably adjusted to adjust the clearance between the duct pieces and the shield tail, so that the assembly of the lower-ring duct pieces is facilitated, and the propelling process of the lower-ring duct pieces is facilitatedThe middle shield can have enough clearance for deviation correction. c. And (4) reasonably selecting the wedge-shaped duct piece according to the gap between the shield tail and the duct piece. When the radius section of the curvature is small, the change of the clearance between the shield tail and the segment of the shield machine is mainly reflected on two sides of the horizontal axis, the segment turns normally to follow the shield machine, and when the shield machine turns too fast, the clearance between the shield tail and the segment outside the tunnel is relatively small; when the segment is ahead of the shield machine for turning due to wedge amount and other reasons, the gap between the shield tail and the inner side of the tunnel is relatively small. Therefore, when the shield tail clearance cannot be adjusted through shield propulsion and segment assembly, the mode of interchanging wedge-shaped segments and linear segments can be considered to be adopted to adjust the shield tail clearance. (8) The method comprises the steps of correcting the deviation of a shield and a measuring attitude, correcting the deviation of a shield and a duct piece, and ensuring that the deviation of a shield propelling track and a tunnel design central line is within a design allowable range in the shield tunneling process by the following method. The deflection correction can be realized by adjusting the stroke of the shield hinging jack, the shield hinging jack is distributed in four sectors of an upper sector, a lower sector, a left sector and a right sector, and when the direction of the shield needs to be adjusted, the bending angle of the shield body can be adjusted by adjusting the stroke of the corresponding area oil cylinder. If the shield deviates from the designed axis and needs to be corrected, the stroke of the hinged oil cylinder can be increased on one side of the deviation direction, and the stroke difference is obtained. The stroke difference is adjusted through the hinged oil cylinder, so that the situation that the acting force of the shield jack on the lining segment is consistent is avoided, and the segment is prevented from being damaged. The correction of the tunnel segment can also be carried out by adopting a trace wedge-shaped material, and the method of sticking a wedge-shaped low-pressure asbestos rubber plate on the ring surface of the segment in the curve section is adopted, so that the segment in the straight line section becomes a trace wedge-shaped axis to be fitted with the designed axis. The compression ratio of the asbestos rubber plate is 12%, and the asbestos rubber plate stuck in sections is compressed by a jack in the propelling process to form a flat wedge-shaped ring surface. The section of jurisdiction can have small error (especially the error of ring width) in making, and the section of jurisdiction also can produce the error in assembling the process, and the accumulation and the development of these errors can lead to the shield not to deviate from the design axis, but the section of jurisdiction of shield tail becomes more and more difficult to assemble, measures the deviation of section of jurisdiction, can discover that the section of jurisdiction central line has been the trend of deviating from the design axis, takes following precaution: a. when each ring segment is assembled, the gap between the upper ring segment and each point of the shield inner shell is measured,if the gaps of all points are more than 1cm, the fitting between the segment axis and the shield axis can be regarded as. If the measured gap at a certain point is less than 1cm, the segment can be regarded as deviating from the shield axis, and at the moment, a trace amount of asbestos rubber wedge-shaped material can be used for correcting the deviation, and the maximum wedge-shaped amount is attached to the lining surface at the small position of the gap. b. The maximum wedge-shaped amount at one time is not more than 6mm, if the maximum wedge-shaped amount exceeds 6mm, the compression amount of the segment rubber water stop strip is reduced, and the water stop effect is lost. Therefore, when the deviation correcting strips are required to be adhered after the wedge-shaped duct pieces are installed during the curve section tunneling, the deviation correcting strips are adhered in a fractional ring mode, and the deviation correcting strips are not adhered in a ring mode too thick. c. If the maximum wedge amount is 6mm (5.28 mm after compression). After the deviation slope of the pipe piece and the shield is measured, the number of the deviation-correcting rings can be calculated. The measurement of the shield machine is the root for ensuring the tunnel axis, and the measurement of the shield machine in a small curve radius section is extremely important. When the small curvature section advances, the frequency of tunnel measurement is properly increased, and the accuracy of shield measurement data is ensured through multiple measurements. Meanwhile, the propulsion and the deviation correction of the shield tunneling machine can be fed back through the measured data. During construction, tracking measurement can be carried out if necessary, so that the shield machine is promoted to form a good posture. Because the tunnel turning curvature radius is small, the visibility condition in the tunnel is relatively poor, and therefore new measuring points and rear view points must be set for many times. After setting a new measuring point, the method should strictly retest to ensure the accuracy of the measuring point and prevent error detection. Meanwhile, the shield tunneling machine has a large lateral component force when turning, which may cause horizontal displacement of the ring-forming tunnel, so that the rear viewpoint must be periodically retested to ensure the accuracy of the rear viewpoint. Due to sharp turning of the line, the measuring hanging baskets are arranged at intervals of 20-30 rings, and the wire points are retested once every 5 rings of pushing. The shield machine adopts an automatic measuring system to advance, and the shield attitude is automatically measured every 2-3min during advancing. After the shield machine is assembled, the longitudinal axis and the radial axis of the shield machine are measured, and the main measurement contents comprise the length measurement among a knife edge, a machine head and tail connecting center and a shield tail; measuring the length of the shield shell; and measuring the diameters of the shield knife edge, the shield tail and the supporting ring. The attitude measurement of the shield tunneling machine during tunneling comprises the measurement of plane deviation, elevation deviation, longitudinal gradient, transverse rotation and incision mileage of the shield tunneling machine and the centerline of a line.
And (3) secondary lining construction of the shield tunnel: the engineering shield tunnel is constructed by adopting a full-circle needle beam trolley, a trolley template consists of a bottom mould, a top mould and a left side mould and a right side mould, the bottom mould and the side moulds and the right side mould and the top mould are connected in a hinged mode, and the top mould and the left side mould are connected through bolts. The longitudinal total length of the trolley template is 12.2m, and the effective lining length is 12 m. 18 template work windows are reserved on the trolley, and 3 grouting ports are reserved on the trolley. Because the newly poured concrete is in a semi-liquid state, the full-circle trolley has larger upper buoyancy due to the buoyancy effect generated by the pressure difference of the liquid on the upper surface and the lower surface of an object soaked in the full-circle trolley in the concrete pouring process. In order to prevent the template from floating upwards, special anti-floating devices are arranged at the free section (unlined section), the position and the lined end of the template. The anti-floating device consists of an anti-floating jack and an installation frame body. One end of the anti-floating jack is provided with a screw nut pair, the height of the anti-floating jack is adjustable, the requirements of different mounting heights of over-digging or under-digging are met, and the template is effectively prevented from floating upwards. The anti-floating jacks are all arranged on the corresponding side surfaces of the trolley through supports and form a reliable positioning system which is omnibearing up and down, left and right together with the bottom lifting oil cylinder. The second lining construction process comprises the following steps: after construction preparation, base surface treatment is carried out, mortar transportation is carried out, then base acceptance and measurement paying-off are respectively carried out, waterproof board installation and acceptance are carried out after the base acceptance, embedded parts (grouting pipes) are installed after the measurement paying-off and waterproof board installation acceptance, then a steel mould trolley is in place, end enclosure formwork installation is carried out, mortar pouring is carried out, a sampling test is carried out after the mortar is solidified, the mould can be disassembled when the requirement is met, and finally maintenance and finishing are carried out. Specifically, the second lining construction is carried out, the trolley automatically walks to the position of a first cabin section, the second lining trolley is positioned by accurate measurement, the central line of the trolley is ensured to be consistent with the central line of the tunnel, a template is fixed after being formed, and the measurement is checked again; then cleaning up sundries, accumulated water and floating slag on the substrate, installing a stop template, installing a water stop according to design requirements, and self-checking the setting condition of a waterproof system. The self-compacting concrete was transported in holes using a small 3m3 tanker truck. 1) Before concrete pouring, the surface of the waterproof layer is dedusted and watered and wetted from a trolley pouring window, so that the compactness of the concrete in the pouring process is ensured, and the concrete is prevented from shrinkage cracking. The concrete is poured from bottom to top, firstly, ash is put from one side of the waist part, and the bottom part is poured. 2) The ash hole begins to put the ash from the top after reaching the waist rail position, arranges that the special person strikes the masterplate with the wooden hammer during putting the ash, finds out the uncompacted part, is equipped with the supplementary vibration of vibrating rod, guarantees that the concrete is closely knit in the masterplate. During the concrete pouring, survey personnel are arranged to stare and control in the whole process, and the trolley displacement condition is closely monitored. And if the floating rate is larger than the preset value, the pouring is suspended. 3) The self-compacting concrete is intensively mixed by a mixing plant, the concrete mixing transport vehicle is transported to a pouring place, the self-compacting concrete is transferred to a concrete transport vehicle in a hole by a crane or a conduit, and then the self-compacting concrete is pumped into the template trolley by the concrete transport vehicle. 4) When concrete close to the bottom is poured, the warehousing speed is strictly controlled and is slow, and defects such as honeycombs and pitted surfaces are prevented. The speed is fast when the top concrete is poured, and the top arch concrete is prevented from being hollow. 5) Concrete is poured and rises uniformly, the height difference of the concrete on two sides is controlled to be 30-50 cm, and the local maximum height difference cannot exceed 60 cm. 6) When the concrete is poured, the conditions of the template, the bracket, the reinforcing steel bar, the embedded part and the reserved hole are observed frequently, when deformation and displacement are found, pouring is stopped immediately, and the poured concrete is finished well before being solidified. 7) The free-fall height during concrete pouring should not exceed 5 m. 8) Because the second lining concrete adopts self-compacting concrete, a vibrating rod is not adopted for vibrating. When the mold is removed, the strength of the concrete reaches 100% of the designed strength, and when the humidity is not enough, the concrete is sprayed and maintained after the mold is removed. 9) In order to ensure that the second lining concrete and the waterproof board are closely attached to each other, a grouting pipe is pre-buried before the second lining concrete is poured, and backfill grouting is carried out after the concrete reaches the strength and the second backing is carried out.
Calculation and inspection of design and construction in the project:
and calculating a reaction frame, wherein the section of the welded box steel beam is formed by combining I63, an A3 steel plate with the thickness of 16mm is machined, welded and formed, and a shield propulsion load acts on the beam. Yield strength fy of 235N/mm2Yield shear force fv of 136N/mm2. The load factor is 1.2 for constant load and 1.4 for live load, and the design value fd of tensile strength, compression strength and bending strength of the steel is 215N/mm2Designed shear strength value fvd-125N/mm2. (1) Long beam meterThe beam section a is 16750 × 3+178 × 3 × 16 is 67338 (mm)2) For the modulus of the elastic section of the two main shafts, the distance between the X-axis and the edges of the upper flange and the lower flange: 332(mm) for y1, 267(mm) for y2, moment of inertia: iy 3 × 980840000+2 × 534 × 16 × 3232 4725293952 (mm)4)、Ix=3×18120000+2×16×5343/12+2×16750×1782=1115774000(mm4) Section modulus: Wx-Ix/y 2-1115774000/267-4178928.8 (mm)3)、Wy=Iy/x2=4725293952/332=14232813.11(mm3). (2) The total thrust of the shield starting is 1680T and is borne by four cross beams, so that the load borne by a single cross beam is uniformly distributed at 420T, and the design value F of the concentrated load is 4200 (KN). (3) And (4) load combination, namely determining the worst combination, performing mechanical modeling according to the supporting condition behind the reaction frame, and calculating according to the unequal-span continuous beam. (4) Concentrated load, wherein the uniformly distributed load accounts for 1.97 percent of the concentrated load according to the bending moment and the shearing force, and is ignored here; load combination: mmax 5285.78(KN/mm) and Vmax 3169.24 (KN). (4) Section strength checking, bending normal stress according to the edge strength criterion: Mx/Wnx 5285.78 × 103/14232813.11 0.4 (N/mm)2)<fd=215N/mm2And the requirements are met. (5) Shear stress: τ max (Q/a) 3169.24 × 103/663378 (N/mm) 4.82)<fvd=125N/mm2And the requirements are met. (6) And (3) calculating the stability of the web stiffening rib cells, arranging stiffening ribs on the box girder, separating the spacing of the stiffening ribs by 150mm, fixing the stiffening ribs on four sides, and carrying out non-checking calculation on the local stability of the stiffening rib cells. (7) The box girder integral stability is checked and calculated by l1/b 1-9000/630-14.28>Overall stability needs to be checked 13.β b is 0.73+0.18 ξ is 0.8, [ where ξ is (l1t1)/(b1h1) ═ 9000 × 15)/(543 × 630) ═ 0.39]I y ═ Iy/a ═ 4725293952/663378 ═ 7123, × y ═ l1/Iy ═ 9000/7123 ═ 1.26, and I1 ═ 16 × 5433/12 (mm)4)、I2=16×5433/12(mm4) Therefore, α b is 0.5 and yb is 0, I1/(I1+ I2), so the overall stability factor: ψ b ═ β b (4320/λ y2) (Ah/Wx) [ yb +1+ (λ yt/4.4h)2](235/fy)=0.794×(4320/1.262)×(663378×543/4178928.8)×[0+1+[(1.26×16)/(4.4×543)]2=1.3>0.6, looking up table to get ψ b' 0.83, Mcr ψ bMex 0.838 × 4178928.8 × 235 8229.56(KN/m) > Mmax 5285.78KN/m, the section is stable and full ofThe requirements are satisfied. (8) And in the calculation of the cross beam, the long beam and the short beam are supported at the back in the same size, and the size of the cross beam is far smaller than that of the long beam, so that the cross beam also meets the requirement. (9) The design of the back support of the reaction frame is that the design value of the axial force N is 3169.24KN, the support length is the most unfavorable, and the design is designed according to 3.73 meters. I32 two pieces are spliced into a lattice column, and the geometrical characteristic of the section is that A is 146.9cm 3; ix is 23242cm 4; iy 1004; Wy-Wx-646 cm 3; ix is 12.58 cm; iy 2.61 cm; design basis: specification for design of Steel Structure (GB 50017-2003). (10) And (3) calculating the intensity: fixing limbs at one end, freely calculating at one end, and checking the attached table of a building construction calculation manual to obtain: psi 0.994, sigma N/An 215N/mm2<f=235N/mm2. (11) Stability calculation, N/(ψ a) ═ 3169000/(0.994 × 14690) ═ 217N/mm2<And f is 235N/mm2, and the stability meets the requirement.
Calculating tunneling parameters, wherein (1) the slag output is pi/4 × D2 × L or 3.14/4 × 3.412 × 1 or 9.13m3 per ring of theoretical slag output (real square) of the shield tunnel; wherein D is the diameter of a cutter head of the shield tunneling machine, and L is the tunneling distance of each cycle; as the shield machine mainly tunnels in the pebble layer, the loosening coefficient is 1.3, the quantity of the pushed ballast of the shield machine is controlled between 98 percent and 102 percent, namely 11.5m312.1 m/ring3A/ring. When the slag output is less than 11.5m3When in use, the pressure set value of the soil bin is properly reduced in the next ring, the adjustment amount is generally about 0.2bar, and the condition of surface uplift is closely noticed; if the slag discharge is more than 12.1m3And immediately closing the screw conveyor, stopping mucking, paying attention to the ground surface sedimentation, and if the sedimentation is too large, continuously increasing the pressure of the soil bin until the ground surface sedimentation is controlled within an allowable range. (2) And (3) tunneling thrust, wherein the tunnel burial depths along the shield project are greatly different, the time of passing the shield from the tunnel is relatively short, according to a common algorithm, the external load of the shield is calculated according to the loose soil pressure at the maximum burial depth and the soil pressure generated by the total soil column height twice the diameter of the shield, and the maximum value is taken as the external load calculated by the shield. The maximum buried depth of the tunnel is 10 meters. Therefore, the shield is calculated to take the section burial depth as the maximum burial depth value. In the soft soil calculation, the geological parameters are selected as follows according to the stratum of the section: the rock-soil capacity gamma is 20.9KN/m3(ii) a The internal friction angle phi of the rock soil is 29.5 degrees; of soilAdhesion force c 39KN/m2(ii) a Thickness H of the cover layermax8 m; ground load P0=20KN/m2(ii) a The horizontal side pressure coefficient lambda is 0.5; the outer diameter D of the shield is 4.13 m; the length L of the shield host is 8.44 m; the weight W of the shield main machine is 120 t; empirical soil pressure coefficient K01 is ═ 1; loose soil pressure (taishaji formula) calculation:
Figure BDA0003286195400000291
Figure BDA0003286195400000292
B1=(D/2)×ctg[(45°+φ/2)/2]3.59 m; substituted into the above formula to obtain
Ps=63.69×0.717+20×0.283=51.33KN/m2
Calculating the soil pressure of the all-soil column with twice the diameter of the heading machine: pq=2×γ×D=172.63KN/m2(ii) a Because of Ps<PqAnd so Pq is taken as the calculated data. The earth pressure of the upper part of the shield, which is obtained by adding the ground load, is 172.63+ 20-192.63 KN/m2(ii) a The earth pressure at the bottom of the shield is Pn=Ps+W÷(D×L)=54.77KN/m2(ii) a The lateral pressures of the upper part and the lower part of the shield are respectively as follows: pλ=Ps×λ=25.67KN/m2、Pm=Pn×λ=27.39KN/m2
The thrust of the shield should include the following components in the soil pressure balance mode: sigma F is FM + FBAEPB + FS + FNL + FSP,
frictional force F of shield shell and soil layerM=0.25×[π×4.13×8.44×(192.63+54.77+25.67+27.39)/4]2055KN, wherein mu is the friction coefficient between the shield shell and the soil body, and 0.25 is taken according to an empirical value; the propulsion force of the cutter head FBA is increased, 68 cutters are arranged on the cutter head, the propulsion force of each cutter in soft soil is about 5.6KN according to empirical values,
Figure BDA0003286195400000301
friction force of shield tail seal, FS110KN/m (empirical value, friction per meter of seal in the circumferential direction), FS4 × pi × 10 ═ 125.6(KN) (segment outer diameter 4 m); force FNL (empirical value) matched after pulling
Figure BDA0003286195400000302
FNL750 KN; the front clapboard counter force caused by the soil pressure of the ballast bin (the soil bin pressure is calculated according to 1 bar), and the total thrust is calculated as follows:
Figure BDA0003286195400000303
F2055+380.8+125.6+750+1339 KN of 4650.4; when the shield climbs and turns, the thrust of the shield is considered to be 1.5 times of the straight horizontal section, and the actual thrust of the shield is as follows: sigmaF4742.4 × 1.5 ═ 6975.6 KN. (3) And calculating the torque, wherein the torque when the shield tunneling machine propels in the soft soil comprises cutting torque, rotation resistance torque of the cutter head, counter torque generated by thrust load borne by the cutter head, friction torque generated by the sealing device, friction torque of the front end surface of the cutter head, friction torque behind the cutter head, shearing torque of an opening of the cutter head and stirring torque in the soil pressure cavity. With the development of the soil bin and the improvement technology of the ballast on the tunnel face, the torque of the cutter head can be greatly reduced in soft soil excavation. The only thing calculated here is an approximate theoretical torque without modification, which in practice is generally less than the calculated value. Cutting torque of tool, cutting torque of tool Vmax4.8 m/h; the rotating speed n of the cutter head is 1.2rpm (empirical value is selected according to similar engineering); cutting depth h of cutter head per rotationmaxV/n 6.67 cm; compressive strength q of rock and soilu157KPa, the compressive strength of the powdery clay is selected as the calculation basis; the diameter Dd of the cutter head is 4.15 m; t is1=0.5×[qu×hmax×(Dd×0.5)2]=0.5×[157×0.0667×(4.15×0.5)2]22.54 KN/m; main bearing rotation counter moment T generated by self weight of cutter head2=G×R1×μgWherein the dead weight of the cutter head: g-72.52 KN, main bearing rolling radius: r11.1m, rolling friction coefficient: mu.sgWhen the value is equal to 0.004, T is2=72.52×1.1×0.004 ═ 0.32 kn.m; rotary resistance moment T generated by thrust load of cutter head3=Pt×R×μgWherein the thrust load Pt=α×π×R2×PdThe cutter head has no opening ratio: alpha is 37 percent to 0.37 and cutter radius R2=2.075m,Pd=(Ph+Ph1)/2=80.18KN/m,Pt0.37 × pi × 2.075 × 80.18 ═ 193.29KN, then T3193.29 × 1.3 × 0.004 ═ 1.01 kn.m; sealing device friction torque
Figure BDA0003286195400000304
Wherein the coefficient of friction between the seal and the steel: mu.smThrust of seal 0.2: fm1.5KPa, seal number: n-3, installation radius of seal: rm11.1m, then T4=2π×0.2×1.5×3×1.126.8 KN.m; frictional moment T of front surface of cutter head5=(α×π×μp×R2 3×Pd) X 2/3, wherein the coefficient of friction between the soil layer and the cutterhead: mu.spWhen the value is equal to 0.15, then T5=(0.37×π×0.15×2.0753X 80.18) x 2/3 ═ 83.22 kn.m; friction counter torque T of cutter head circumference6=2π×Dd×B×Pz×μpWherein the width of the edge of the cutter head is as follows: b is 0.3m, the cutter head circumference soil pressure Pz=(Ph1+Ph+Pv1+Pv) If/4 is 120.3KPa, then T62 pi × 4.15 × 0.3 × 120.3 × 0.15 equals 141.1 kn.m; the friction torque on the back of the cutter head is generated by the pressure in the soil chamber, assuming that the soil pressure in the soil chamber is Pd,
Figure BDA0003286195400000311
shear moment of cutter head open slot
Figure BDA0003286195400000312
Wherein the shear stress of the soil:
Figure BDA0003286195400000313
in the cutting cavity, because the slag contains water, C is 15KPa,internal angle of friction of
Figure BDA0003286195400000314
Then T8=2/3×π×22×2.0753X (1-0.37) ═ 271.56 kn.m; stirring moment in cutter head soil chamber
Figure BDA0003286195400000315
Wherein the diameter of the cutter head support column:
Figure BDA0003286195400000316
length L of supporting column of cutter headz0.8 m; number of support columns nb1, then T90.85 × 0.8 × 80.18 × 1 ═ 54.5 kn.m; total torque of cutter head
Figure BDA0003286195400000317
Calculating T ═ alpha x D according to the earth pressure balance shield torque estimation formula3Calculating the torque of the shield, wherein alpha is the earth pressure balance shield coefficient, the value is generally 14-23 according to the difference of the shield diameter, and the torque is calculated by taking alpha as 18.79 to obtain T as 18.79 multiplied by 4.1331323.66 KN.m; the torque value is the torque value for escaping the trouble of the shield machine.
The above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, but all changes that can be made by applying the principles of the present invention and performing non-inventive work on the basis of the principles shall fall within the scope of the present invention.

Claims (10)

1. A shield initial tunneling and arrival construction method is mainly used for gravity type water inlet pipe construction and is characterized by comprising the following steps:
s100, construction preparation: preparing corresponding construction materials and construction mechanical equipment based on the configured shield vertical shaft foundation pit and the shield starting well, and distributing a construction worker monitoring point in the whole shield construction region;
s110, end reinforcement: reinforcing the shield end in a range of 10 meters in the driving direction of the shield tunnel and in ranges of 3.2 meters on two sides of the center line of the shield tunnel by adopting a sleeve valve pipe sectional grouting mode;
s120, mounting a shield launching matching device: installing an originating bracket in the shield originating well according to the size and position requirements of shield originating and laying a temporary track for a trolley;
s130, mounting and debugging shield equipment: installing and debugging related matched systems including a slag-soil pond, a duct piece and other transportation systems, a mixing station grouting system, a storage battery car charging system, a tunnel ventilation system and a communication system on the ground part, and installing a shield unit in a segmented underground mode and carrying out no-load debugging and load debugging;
s140, initial door opening configuration: a pipe shed support is arranged on the upper part of the door opening in a retreating type sectional grouting mode, the end reinforcement, the stratum condition and the water leakage condition are detected through a door opening advanced horizontal exploring hole, and a sealing water stopping device is arranged at the door opening by adopting a cord fabric rubber plate and a ring plate;
s150, assembling a negative ring: pre-jacking the shield tunneling machine to a position 1m inside a tunnel portal by adopting an auxiliary jack after the shield tunneling machine goes into the well, installing a reaction frame according to the shield tunneling machine and the position of a base, smearing grease on a tail brush of the shield tunneling machine by hands, and assembling a negative ring;
s200, shield split starting: installing and trial pushing a cutter head, a front shield, a middle shield, a screw machine and a tail shield in sequence, and extending split starting matched pipelines including a hydraulic pipe, a water pipe, a foam pipe, a grouting pipe, a bentonite pipe and a cable;
s210, trial excavation: taking the first 100 meters of shield tunneling as a trial tunneling section, collecting and tidying tunneling parameters of each stratum in the trial tunneling process, and matching and adjusting subsequent tunneling parameters;
s220, shield tunneling control: switching the rotation direction of the cutter head when the rolling deviation exceeds 3 degrees by adopting a mode of rotating the shield cutter head forward and backward, correcting the rolling deviation, correcting the deviation in the vertical direction by controlling the thrust of the upper side jack and the lower side jack, and correcting the deviation in the horizontal direction by controlling the thrust of the left side jack and the right side jack;
s230, auxiliary matched dismantling: stopping the shield tunneling machine after the pilot tunneling is finished, putting the rest of the shield tunneling machine into the well in a matched mode, and removing the negative ring and the reaction frame;
s300, normal tunneling: the method comprises the steps of equipment system inspection during excavation and tunneling, setting of a laser guide system and related data, pipe piece conveying and positioning, grouting material preparation and well descending and positioning, tunneling and unearthing of a shield machine, monitoring of soil pressure of a soil cabin and a screw machine, synchronous grouting and realization of a complete tunneling cycle until the tunneling is carried out to an inspection well;
s400, stopping the shield tunneling machine after the shield tunneling machine passes through the inspection well for maintenance, performing secondary initial tunneling, and repeating the initial tunneling and normal tunneling processes until a receiving well when a plurality of inspection wells are configured in the whole shield construction interval;
s500, receiving by the shield machine: when the shield machine is close to a receiving tunnel portal, the tunneling speed is slowed down, the receiving tunnel portal is reinforced, and after the shield machine penetrates through the tunnel and reaches a receiving well, the disassembly and hoisting of large parts and main parts of the shield machine out of the well are completed within a set time;
s600, secondary lining construction of the shield tunnel: and a lining cement mortar layer with the thickness of 25cm is poured in the shield tunnel by adopting a full-circle needle beam trolley.
2. The shield initial tunneling and arrival construction method according to claim 1, wherein the shield vertical shaft foundation pit and the shield initial shaft are constructed by using a fender pile + internal support open cut method, a fender pile structure adopts interval cast-in piles with the diameter of 1000mm, an end shield initial is constructed by using glass fiber reinforced piles with the diameter of 1000mm, three supports are vertically arranged, the first support and the second support adopt reinforced concrete ring frame beams and reinforced concrete supports, the third support adopts 609 steel pipe supports, and retaining walls are adopted above crown beams for supporting.
3. The shield tunneling method according to claim 1, wherein the step of arranging the monitoring points for the facility in the whole shield construction area comprises the steps of arranging ground settlement monitoring points on the ascending line of the tunnel in the area, arranging profile monitoring points on the ascending line of the tunnel in the area, arranging building detection points around the tunnel in the area, arranging settlement monitoring points in the tunnel in the area and arranging convergence monitoring points in the tunnel in the area.
4. The shield tunneling and arrival construction method according to claim 1, wherein the end reinforcement by means of sleeve valve pipe sectional grouting is performed as follows:
s110a, leveling the field: after pipeline investigation is carried out, obstacles within 2 meters below the ground of a construction site are cleared, protective measures cannot be taken, then leveling and tamping are carried out, meanwhile, the positions of power lines of construction machinery and a conveying pipeline are reasonably arranged, and the tee joint of the construction site is guaranteed to be flat;
s110b, hole position lofting: measuring the construction grouting hole position by using a total station, and making an obvious mark by using a reinforcing steel bar to ensure that the displacement deviation of the center of the pile hole is less than 5 cm;
s110c, forming holes: drilling with a drilling machine to form holes, wherein the diameter of a final hole is not less than 90mm, the drilling depth reaches the height of a grouting reinforcement section, the hole site spacing is 2000mm, and isosceles triangles are arranged;
s110d, preparing and pouring a shell sealing material: preparing a shell sealing material while drilling, wherein the shell sealing material is low-strength cement clay slurry, when the drilling depth reaches the design requirement, pouring the shell sealing material into a drill rod of a drilling machine, pulling out the drill rod after the shell sealing material is filled, and timely replenishing the slurry after the shell sealing material is pulled out;
s110e, manufacturing and inserting a sleeve valve tube: the sleeve valve pipe has the outer diameter of 76mm, the maximum pressure capable of being borne by the sleeve valve pipe is greater than 3MPa, 6 grout overflow holes are formed in each section of the sleeve valve pipe at intervals of 800mm, the bottom end of the sleeve valve pipe is tightly wrapped by geotextile, sealing materials are prevented from entering the sleeve valve pipe, the sleeve valve pipe is inserted to the designed depth after the sleeve pipe is pulled out, and the orifice pipe is embedded firmly;
s110f, lower grouting core tube: the grouting core pipe is processed by adopting a 25mm welded steel pipe, the length of the grouting core pipe is 0.5-0.6m, 3-4 grouting-stopping rubber packing cups are respectively added at two ends of the grouting core pipe to form a grouting-blocking plug, and then the grouting core pipe is lowered to the bottom of the hole;
s110g, preparing grouting liquid: the grouting liquid adopts pure cement slurry, the water-cement ratio of the grouting liquid is 0.8-1.0, the grouting liquid is pumped for pressure injection after being uniformly stirred and sieved, and the grouting liquid is continuously stirred in the grouting process;
s110h, grouting: sectional grouting is adopted, the length of each section of grouting is the grouting step distance, the length of a grouting core pipe is the grouting step distance, grouting is started after curing for 2-3 days after the lower sleeve valve pipe is grouted with the sealing shell material, the grouting pressure is controlled to be 0.2-0.4MPa, and grouting is finished when the designed grouting pressure or grouting amount reaches more than 80% of the designed grouting amount;
s110i, lifting the core pipe: in the grouting process, after each section of grouting step is finished, the section of grouting core pipe is moved upwards by the length of one step, the grouting core pipe is symmetrically clamped by adopting lifting equipment or manually adopting a pipe wrench, the two sides of the grouting core pipe are lifted up by uniform force, and after 3-4m grouting is finished, one section of grouting core pipe is removed;
s110j, completing a single hole: and after grouting is finished each time, hole replacement and displacement are carried out, a grouting machine, a stirrer and various pipelines are cleaned in time, the normal operation of subsequent grouting is ensured, and then end reinforcement is realized by completing each hole one by one.
5. The shield initial tunneling and arrival construction method according to claim 1, wherein the pipe shed supports arranged in step S140 are seamless steel pipes with a diameter of 108mm and a wall thickness of 6mm, and are arranged along the position 200mm outside the excavation contour line of the arch part of the shield, the circumferential center distance of the seamless steel pipes is 400mm, the external insertion angle is 1-2 degrees, the length of the pipe shed supports is 10m, the pipe shed supports are lengthened by section assembly, two sections are connected by screw threads, the joints of two adjacent seamless steel pipes are staggered by not less than 1m, and grouting holes are arranged on the joints;
the door opening advanced horizontal probing holes are distributed on the door opening in an average manner, the diameter of each drilling hole is 50mm, and the depth of each drilling hole is 1.4 m;
the sealing and water stopping device is installed on a ring plate pre-embedded at the opening, the ring plate is made of a Q235A steel plate, fixing screw holes are reserved in the ring plate, and the curtain cloth rubber plate is fixed on a steel ring at the opening of the tunnel by the ring plate.
6. The shield initial tunneling and arrival construction method according to claim 1, wherein in the trial tunneling, recording contents include: a. tunneling: construction progress, oil cylinder stroke, tunneling speed, shield thrust, soil pressure, cutter head and screw machine rotating speed, and annular gap between the shield inner wall and the segment outer side; synchronous grouting: b. synchronous grouting: grouting pressure, quantity, consistency, grouting material proportion and grouting test block strength; c. measurement: shield gradient, tunnel ovality, total propulsion distance and exact position of the axis of each lining ring of the tunnel.
7. The shield initial tunneling and arrival construction method according to claim 1, wherein the shield tunneling control further comprises controlling the stroke of a thrust cylinder of the shield and limiting the thrust amount of each ring of the shield when the shield advances forward in the idle state; controlling the posture through the stroke of an oil pushing cylinder of the shield tunneling machine; under the condition of ensuring the normal propulsion of the shield, the total thrust and the cutter torque are reduced; after the shield tail completely enters the hole body, adjusting the hole opening for sealing, and grouting the hole opening, wherein the grouting pressure is controlled within 1.5 Bar; the dismantling time of the reaction frame and the negative ring pipe piece is determined according to the mortar performance parameters of the back lining grouting and the starting tunneling thrust of the shield, the tunneling is carried out for more than 100m, the tunneling of the front 50 rings is completed for more than 7 days, and the dismantling of the reaction frame and the negative ring pipe piece is started.
8. The shield tunneling and arrival construction method according to claim 1, the process of receiving by the shield machine comprises the steps of reinforcing a hole-exiting soil body, installing a receiving frame, performing tunnel portal rechecking measurement, performing position and posture rechecking measurement on the shield machine, chiseling a tunnel portal, installing a tunnel portal waterproof device, discharging the shield, cleaning a cutter head, moving a shield body forwards in place, removing the cutter head connection, lifting the cutter head, disconnecting the trolley and a host pipeline backwards-moving trolley, removing the screw machine backwards-moving trolley, removing a screw pipeline, a driving pipe, a rear sleeve pipe and a screw rod, moving the screw rod to a tunnel, removing the front shield body connection, lifting the front shield out, removing a hinge connection, calling out a hinged shield body, ejecting a shield tail, removing a jack, lifting the shield tail, removing the jack, lifting screw machine parts, removing a receiving support, laying trolley tracks, disconnecting the trolley connection, sequentially lifting the trolley out and removing and lifting out a related underground auxiliary support.
9. The shield tunneling and arrival construction method according to claim 8, wherein the arrival construction matched with the shield tunneling machine receiving process comprises the following steps:
s410a, performing tunneling according to the penetration posture of the shield tunneling machine and the tunneling deviation rectifying plan, and gradually completing deviation rectifying according to the small deviation rectifying amount of each ring;
s410b, selecting reasonable tunneling parameters when the shield tunneling machine is 50m away from the end wall, gradually slowing down the tunneling speed, controlling the tunneling speed to be below 20mm/min, gradually reducing the thrust, and slowly and uniformly cutting the soil body to ensure the stability of the end wall and prevent the stratum from collapsing;
s410c, after the shield enters the receiving section, monitoring and measuring through the ground surface, and feeding back the measurement information in time to control the shield machine to tunnel;
s410d, when the distance between the cutter head and the shield tunneling machine is less than 10m, actually adjusting tunneling parameters by observing the change condition of the hole opening in the tunneling process;
s410e, after the assembled duct piece enters the reinforcing range, the slurry is changed into quick-hardening slurry, and muddy water is blocked outside the reinforcing area in the reinforcing range in advance;
s410f, when the last ring pipe piece of the pipe piece is assembled, injecting double-liquid slurry through the secondary grouting holes of the pipe piece for plugging;
s410g, when the shield shell of the shield front body is pushed out of the tunnel portal, the folding pressing plate is adjusted through the steel wire rope on the pressing plate clamping ring to press the cord fabric rubber plate as much as possible so as to prevent muddy water and serous fluid of the tunnel portal from flowing out, and the steel wire rope is tensioned again when the duct piece is pulled out of the shield tail, so that the pressing plate can press the rubber cord fabric.
10. The shield initial tunneling and arrival construction method according to claim 1, wherein the shield tunnel second lining construction process comprises:
s610a, the trolley automatically walks to the position of the first bin section, the accurate measurement is carried out to position the two-lining trolley, the central line of the trolley is ensured to be consistent with the central line of the tunnel, then sundries, accumulated water and floating slag on the base are cleaned, a stop head template is arranged, and a water stop belt is arranged according to the design requirement;
s610b, before concrete pouring, removing dust on the surface of the waterproof layer from the trolley pouring window and spraying water to wet the waterproof layer, ensuring that the concrete is compact in the pouring process and preventing the concrete from shrinkage cracking, wherein the concrete is poured from bottom to top during pouring, firstly, ash is put from one side of the waist, and the bottom is poured;
s610c, starting to discharge ash from an ash discharge hole at the top after reaching the position of the waist beam, knocking the template by a wooden hammer during ash discharge, finding out an uncompacted part, and assisting vibration by a vibrating rod to ensure that concrete in the template is compact;
s610d, intensively mixing the self-compacting concrete by a mixing station, transporting the self-compacting concrete to a pouring place by a concrete mixing transport vehicle, lowering the self-compacting concrete to a concrete transport vehicle in a hole by a crane or a guide pipe, and pumping the self-compacting concrete into a template trolley by the concrete transport vehicle;
s610e, controlling the warehousing speed when concrete close to the bottom is poured, and slowing down the warehousing speed to prevent honeycomb and pitted surface defects; the speed is accelerated when the top concrete is poured, and the top arch concrete is prevented from being hollow;
s610f, uniformly pouring concrete, and controlling the height difference of the concrete on two sides to be 30-50 cm, wherein the local maximum height difference is not more than 60 cm.
CN202111148081.6A 2021-09-29 2021-09-29 Shield initial tunneling and arrival construction method Pending CN113833480A (en)

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CN114217088A (en) * 2021-12-25 2022-03-22 中铁工程装备集团有限公司 Automatic cooperative detection method for external grouting of shield machine pipe sheet
CN114278325A (en) * 2021-12-31 2022-04-05 中铁五局集团有限公司 Shield receiving method in subway construction
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CN115506417A (en) * 2022-10-12 2022-12-23 中交第二公路工程局有限公司 Construction method for quickly receiving shield under support of hanging wall
CN117266888A (en) * 2023-11-21 2023-12-22 中铁电气化局集团有限公司 Grouting device is reserved in upper and lower overlapping tunnel

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Publication number Priority date Publication date Assignee Title
CN114217088A (en) * 2021-12-25 2022-03-22 中铁工程装备集团有限公司 Automatic cooperative detection method for external grouting of shield machine pipe sheet
CN114217088B (en) * 2021-12-25 2024-03-26 中铁工程装备集团有限公司 Automatic cooperative detection method for grouting outside pipe sheet of shield tunneling machine
CN114278319A (en) * 2021-12-27 2022-04-05 中交第三航务工程局有限公司 Shield construction method for small clear distance tunnel
CN114278319B (en) * 2021-12-27 2023-09-26 中交第三航务工程局有限公司 Shield construction method for small-clear-distance tunnel
CN114278325A (en) * 2021-12-31 2022-04-05 中铁五局集团有限公司 Shield receiving method in subway construction
CN114544399A (en) * 2022-01-18 2022-05-27 上海应用技术大学 Model experiment device and method for deformation of subway shield interval tunnel and foundation
CN114607833A (en) * 2022-03-09 2022-06-10 苏州城市地下综合管廊开发有限公司 Vertical curve downward-penetrating construction method for rectangular jacking pipe meeting obstacle
CN114596013A (en) * 2022-05-10 2022-06-07 山东志诚地理信息技术有限公司 Geotechnical engineering investigation safety monitoring system based on cloud computing
CN114596013B (en) * 2022-05-10 2022-07-22 山东志诚地理信息技术有限公司 Geotechnical engineering investigation safety monitoring system based on cloud computing
CN115506417A (en) * 2022-10-12 2022-12-23 中交第二公路工程局有限公司 Construction method for quickly receiving shield under support of hanging wall
CN117266888A (en) * 2023-11-21 2023-12-22 中铁电气化局集团有限公司 Grouting device is reserved in upper and lower overlapping tunnel
CN117266888B (en) * 2023-11-21 2024-01-23 中铁电气化局集团有限公司 Grouting device is reserved in upper and lower overlapping tunnel

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