CN113833480B

CN113833480B - Construction method for initial tunneling and arrival of shield

Info

Publication number: CN113833480B
Application number: CN202111148081.6A
Authority: CN
Inventors: 钱峰; 李健; 罗苗
Original assignee: Chengdu Construction Ninth Construction Engineering Co ltd
Current assignee: Chengdu Construction Ninth Construction Engineering Co ltd
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2024-05-24
Anticipated expiration: 2041-09-29
Also published as: CN113833480A

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; originating door opening configuration and negative ring assembly; the shield split starts and sinking steps; shield tunneling control and correction and auxiliary supporting dismantling; normal tunneling and synchronous grouting are carried out, and a complete tunneling cycle is realized until tunneling to an inspection well is carried out; the shield tunneling machine passes through the inspection well and performs secondary initial tunneling, and the initial tunneling and normal tunneling processes are repeated until the inspection well is reached; receiving a shield machine; and finally, performing secondary lining construction of the shield tunnel. The construction method is designed aiming at special geological conditions mainly comprising argillaceous siltstone and strong weathered gravel stratum, and the shield construction of the gravity type water inlet pipe is effectively improved through the targeted design and control of each link and condition, and the stable and reliable engineering quality is ensured on the basis of ensuring the engineering progress.

Description

Construction method for initial tunneling and arrival of shield

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 automatically flows by gravity according to the inclined gradient of the water outlet pipe under the condition of no pressure, which 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 deeper, generally has the depth of 14-20 m, and can be excavated and constructed by adopting a conventional construction method, but when the line area is arranged with more mature building distribution (such as park green belts, roads, bridges, various pipe network facilities, building (construction) and the like), the gravity type water inlet pipe building construction environment is complicated, and the conventional construction method is easy to influence related buildings. And when the geological conditions of the construction local soil layer belong to geological construction environments mainly comprising argillaceous siltstone and strong weathered gravel stratum, 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 above purpose, the technical scheme adopted by the invention is as follows:

the shield tunneling and arrival construction method is mainly used for gravity type water inlet pipe construction and comprises the following steps:

S100, preparation of construction: based on the configured shield shaft foundation pit and shield starting well, preparing corresponding construction materials and construction mechanical equipment, and arranging construction monitoring points in a shield construction whole interval;

s110, end reinforcing: reinforcing the shield end in a range of 10 meters in the tunneling direction of the shield tunnel and in a range of 3.2 meters on both sides of the center line of the shield tunnel by adopting a sleeve valve pipe sectional grouting mode;

S120, installing a shield starting matching device: installing an originating bracket in a shield originating well according to the size and position requirements of shield originating, and paving a temporary track for a trolley;

S130, installing and debugging shield equipment: installing and debugging related matched systems including a muck pool, a duct piece and other transportation systems, a mixing station grouting system, an electric vehicle charging system, a tunnel ventilation system and a communication system on the ground part, installing a shield machine set in a segmented manner, and carrying out no-load debugging and load debugging;

S140, originating door opening configuration: a pipe shed support is arranged at the upper part of the door opening in a backward type sectional grouting mode, the condition of the end reinforcement, stratum and water leakage is detected through a door opening advanced horizontal exploring hole, and a sealing water stop device is arranged at the door opening by adopting a curtain cloth rubber plate and a circular ring plate;

S150, assembling a negative ring: pre-jacking the shield machine to a position of 1 meter in a tunnel portal by adopting an auxiliary jack after the shield machine set goes down the well, installing a counter-force frame according to the positions of the shield machine and a base, smearing grease on a tail brush of the shield, and assembling a negative ring;

S200, shield split starting: the cutter head, the front shield, the middle shield, the screw machine and the tail shield are sequentially arranged and pushed in a trial manner, and a split starting matched pipeline comprising a hydraulic pipe, a water pipe, a foam pipe, a grouting pipe, a bentonite pipe and a cable is prolonged;

s210, sinking: taking the first 100 meters of shield tunneling as a test tunneling section, collecting tunneling parameters of each stratum in the process of finishing test tunneling, and matching and adjusting subsequent tunneling parameters;

S220, shield tunneling control: the method comprises the steps of adopting a mode of enabling a shield cutter to positively and negatively rotate, switching the rotating direction of the cutter when the rolling deviation exceeds 3 degrees, correcting the rolling deviation, correcting the deviation in the vertical direction by controlling the thrust of an upper jack and a lower jack, and correcting the deviation in the horizontal direction by controlling the thrust of a left jack and a right jack;

s230, auxiliary matched dismantling: sinking stopping the shield machine after finishing entering, and taking the rest of the shield machine into a well, and removing the negative ring and the reaction frame;

S300, normal tunneling: checking an equipment system during excavation and tunneling, setting a laser guiding system and related data, conveying and positioning segments, preparing grouting materials, positioning the segments in a well, tunneling by a shield machine, discharging soil, monitoring soil pressure of a soil cabin and a screw machine, and performing synchronous grouting to realize a complete tunneling cycle until tunneling to an inspection well;

S400, stopping the shield tunneling machine after passing through the inspection wells, performing secondary initial tunneling, and repeating the initial tunneling and normal tunneling processes until reaching the receiving well when a plurality of inspection wells are arranged in the whole shield construction section;

S500, receiving a shield machine: when the shield machine approaches to the receiving tunnel portal, the tunneling speed is slowed down, the receiving tunnel portal is reinforced, and after the shield machine penetrates through the tunnel to reach the receiving well, the large part and the main part of the shield machine are detached and lifted out of the well in a specified time;

s600, construction of a second lining of the shield tunnel: and pouring a lining cement mortar layer with the thickness of 25 cm in the shield tunnel by adopting the full-circle needle beam trolley.

Specifically, the shield shaft foundation pit and the shield originating well are constructed by adopting a guard pile and internal support open cut method, a guard pile structure adopts a spacing filling pile with the diameter of 1000mm, the end shield originating adopts a glass fiber reinforced pile 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 the retaining wall is adopted for supporting above the crown beam.

Specifically, the arrangement of the construction monitoring points in the whole section of the shield construction comprises arrangement of ground subsidence monitoring points in the uplink line axis of the section tunnel, arrangement of section monitoring points in the uplink line of the section tunnel, arrangement of building detection points around the section tunnel, arrangement of subsidence monitoring points in the section tunnel and arrangement of convergence monitoring points in the section tunnel.

Specifically, the process of performing end reinforcement by adopting the sleeve valve pipe sectional grouting mode is as follows:

s110a, field leveling: after pipeline investigation, removing obstacles which are within 2 meters below the ground of the construction site, performing protection measures which cannot be removed, leveling and tamping, and reasonably arranging the positions of the power lines of the construction machinery and the conveying pipeline to ensure the three-way and one-level construction site;

S110b, hole site lofting: measuring grouting hole sites of construction by using a total station, and making obvious marks by using reinforcing steel bars to ensure that the center displacement deviation of the pile holes is less than 5cm;

s110c, pore forming: drilling holes by a drilling machine, wherein the diameter of the final holes is not less than 90mm, the drilling depth reaches the height of a grouting reinforcement section, the hole site spacing is 2000mm, and the holes are arranged in an isosceles triangle;

S110d, preparing and filling a shell material: preparing a shell material while drilling, wherein the shell material adopts low-strength cement clay slurry, and after the drilling depth reaches the design requirement, filling the shell material into a drill rod of a drilling machine, pulling out the drill rod after filling, and timely supplementing slurry after pulling out;

S110e, manufacturing and inserting a sleeve valve tube: the outer diameter of the sleeve valve pipe is 76mm, the maximum pressure which can be borne is greater than 3MPa, 6 slurry overflow holes are formed in each section of the sleeve valve pipe at intervals of 800mm, the bottom end head of the sleeve valve pipe is tightly wrapped and tied by geotextile, the shell material is prevented from entering the sleeve valve pipe, the sleeve pipe is inserted into the sleeve valve pipe to the designed depth after the sleeve pipe is pulled out, and the orifice pipe is firmly buried;

s110f, grouting core pipe: 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 the 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 paste, the water-cement ratio of the slurry is 0.8-1.0, and the grouting liquid is pumped and injected after being uniformly stirred and sieved and is connected with Xu Jiaoban 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 length, grouting is started after the lower sleeve valve pipe is used for grouting the shell material and curing for 2-3 days, grouting pressure is controlled to be 0.2-0.4MPa, and grouting is ended when the designed grouting pressure or grouting amount reaches more than 80% of the designed grouting amount;

s110i, lifting a core tube: in the grouting process, the length of a grouting core pipe with one step distance is moved upwards after each section of grouting step distance is finished, the grouting core pipe is symmetrically clamped by lifting equipment or pipe tongs by manual work, the grouting core pipe is lifted upwards by two sides simultaneously and evenly with force, and one section of grouting core pipe is removed after 3-4m grouting is finished;

S110j, single hole completion: hole replacement and displacement are carried out after grouting is finished every time, a grouting machine, a stirrer and various pipelines are cleaned in time, follow-up grouting is guaranteed to be carried out normally, and then each hole is finished one by one to realize end reinforcing.

Specifically, the pipe shed support set in the step S140 is formed by adopting seamless steel pipes with the diameter of 108mm and the wall thickness of 6mm, arranging the seamless steel pipes at positions 200mm outside the excavation outline of the shield arch part, circumferentially spacing the seamless steel pipes by 400mm, externally inserting angles by 1-2 degrees, setting the length of the pipe shed support to be 10m, splicing and lengthening the pipe shed support by sections, connecting the two sections by threads, staggering joints of two adjacent seamless steel pipes to be not less than 1m, and arranging grouting holes on the joints;

the door opening advanced horizontal exploratory holes are provided with 9 evenly distributed on the door opening, the drilling diameter is 50mm, and the drilling depth is 1.4m;

The sealing water stop device is installed on a ring plate embedded in the hole, the ring plate is made of Q235A steel plates, fixed screw holes are reserved in the ring plate, and the curtain cloth rubber plate is fixed on the hole steel ring by the ring plate.

Specifically, in the test tunneling, 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 inner wall of the shield and the outer side of the duct piece; synchronous grouting: b. synchronous grouting: grouting pressure, quantity and consistency, grouting material proportion and grouting test block strength; c. measurement: shield inclination, tunnel ovality, total distance of propulsion, and exact position of the axle center of each ring of lining ring of the tunnel.

Specifically, the shield tunneling control further comprises the steps of controlling the stroke of a pushing oil cylinder of the shield and limiting the pushing quantity of each ring of the shield when the shield is pushed forward in an idle mode; the gesture is controlled through the stroke of a pushing cylinder of the shield tunneling machine; under the condition of ensuring normal pushing of the shield, reducing the total thrust and the cutter torque; after the shield tail completely enters the hole body, adjusting the hole seal, grouting the hole, and controlling the grouting pressure within 1.5 Bar; and the dismantling time of the reaction frame and the negative ring pipe piece is determined according to the mortar performance parameter of backing grouting and the initial tunneling thrust of the shield, the tunneling is performed for more than 100m, the front 50 rings complete tunneling for more than 7 days, and the dismantling of the reaction frame and the negative ring pipe piece is started.

Specifically, the receiving process of the shield machine comprises reinforcement of a hole-out soil body, installation of a receiving frame, hole-gate rechecking measurement, shield machine position and posture rechecking measurement, hole-gate chiseling, hole-opening waterproof device installation, shield hole-out, cutterhead cleaning, forward-moving of a shield body in place, cutterhead connection and lifting of a cutterhead, disconnection of a trolley and a host pipeline, backward-moving of the trolley, disassembly of a screw machine, backward-moving of the trolley, disassembly of a screw pipeline, driving, rear sleeve and auger rod and moving to a tunnel, front shield body connection and front shield lifting, hinge connection and hinged shield body disassembly, shield tail lifting, jack lifting, screw machine component lifting, support disassembly, trolley laying, trolley connection disconnection, trolley lifting in sequence, and underground related auxiliary support lifting.

Specifically, the matched arrival construction in the receiving process of the shield tunneling machine comprises the following steps:

s410a, tunneling is carried out according to the through gesture of the shield tunneling machine and a tunneling deviation correcting plan, and deviation correction is gradually completed by small deviation correcting amount of each ring;

S410b, when the shield tunneling machine is 50m away from the end wall, selecting reasonable tunneling parameters, gradually slowing down tunneling speed, controlling tunneling speed below 20mm/min, gradually reducing thrust, slowly and uniformly cutting soil body so as to ensure stability reaching the end wall and prevent stratum collapse;

s410c, after the shield enters the receiving section, monitoring and measuring through the earth surface, and feeding back measurement information in time to control the tunneling of the shield machine;

S410d, when the distance of the cutter head of the shield tunneling machine is less than 10m, actually adjusting tunneling parameters by observing the change condition of the hole outlet in the tunneling process;

S410e, changing slurry into quick hardening slurry after the spliced duct piece enters a reinforcing range, and plugging muddy water outside a reinforcing area in the reinforcing range in advance;

S410f, injecting double slurry to seal through the secondary grouting holes of the duct piece after the last annular duct piece of the duct piece is assembled;

S410g, when the shield precursor shield shell is pushed out of the tunnel portal, the folding plate is adjusted through the steel wire rope on the clamp ring of the pressing plate to enable the folding plate to be pressed against the curtain cloth rubber plate as much as possible, so that mud water and slurry of the tunnel portal are prevented from flowing out, and when the segment is separated from the tail of the shield, the steel wire rope is tensioned again, so that the pressing plate can be pressed against the rubber curtain cloth.

Specifically, the process of the shield tunnel secondary lining construction comprises the following steps:

S610a, firstly, automatically walking to a first warehouse section position by a trolley, accurately measuring to enable a second lining trolley to be positioned, ensuring that the center line of the trolley is consistent with the center line of a tunnel, then cleaning substrate sundries, accumulated water and scum, installing a blocking head template, and installing a water stop belt according to design requirements;

S610b, before concrete pouring, dedusting and sprinkling water on the surface of the waterproof layer from a trolley pouring window to ensure compactness in the concrete pouring process, prevent shrinkage and cracking of concrete, and pour the concrete from bottom to top, firstly, placing ash from one side of the waist, and pouring the bottom;

S610c, starting to discharge ash from an ash discharge hole at the top after reaching the waist beam position, beating the template by using a wood hammer during ash discharge, finding out an undensified part, and matching with a vibrating rod for assisting in vibrating 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 site 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 pouring concrete close to the bottom, slowing down the speed, and preventing honeycomb and pitting defects; the speed is increased when the top concrete is poured, so that the top arch concrete is prevented from being emptied;

s610f, uniformly lifting concrete pouring, controlling the height difference of concrete at two sides to be 30-50 cm, and controlling the local maximum height difference to be not more than 60cm.

Compared with the prior art, the invention has the following beneficial effects:

The invention designs the construction method aiming at special geological conditions (such as geology mainly comprising argillaceous siltstone and strong weathered gravel stratum), and effectively improves the shield construction of the gravity type water inlet pipe through the targeted design and control of each link and condition, and ensures the stable and reliable engineering quality on the basis of ensuring the engineering progress. The invention has ingenious design and convenient implementation, and is suitable for being applied to 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 invention will now be further described with reference to the accompanying drawings and examples, embodiments of which include, but are not limited to, the following examples.

Examples

As shown in FIG. 1, the shield tunneling and arrival construction method is mainly used for gravity type water inlet pipe construction and comprises the following steps:

Specifically, the embodiment specifically describes the construction of a gravity type water inlet pipe in the capital area, the gravity type water inlet pipe is about 1.6 km, a certain sewage treatment plant divides 30 ten thousand tons/day flow through a water diversion well, the gravity type water inlet pipe flows into a sewage water diversion pump station along the gravity type water inlet pipe, the gravity type water inlet pipe is routed to areas such as artificial lakes, highways, green belts, barrages and the like, park green belts of the areas are basically formed, roads, bridges, various pipe network facilities, buildings and the like are distributed, and the construction environment of the gravity type water inlet pipe is complex. 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 2.7m. The segment adopts C50P12 strength grade concrete, 25cm thick lining cement mortar is integrally poured in the segment at the later stage, and the inner diameter of a gravity water inlet pipeline after molding is 2.2m. The length of the shield segment is about 1.68km, the curvature radius of the line at the position of the common plane curve 5 is 200m and 500m, the whole line gradient of the line is 1 per mill, the shallowest buried depth of the tunnel is 18m, and the deepest buried depth is 20m. The lining ring is divided into 6 blocks, 1 block of capping block, 2 blocks of adjacent blocks and 3 blocks of standard blocks. Diameter allowed deviation after lining looping: 12mm; adjacent annulus gap: not more than 2mm; gaps between adjacent blocks of the longitudinal joint: not more than 2mm; corresponding circumferential bolt non-axiality: less than 1mm; allowable height difference (step allowable value) of adjacent ring segments: 4mm; adjacent pipe sheet rib surface unevenness deviation: 3mm; and (3) shield axis control: the elevation and plane control are all 50mm; the segment has no penetrating crack and no crack and concrete peeling phenomenon with the width of more than 0.2 mm. Allowing the plane position of the shield starting axis to deviate by +/-50 mm, checking by using a theodolite, and forming a 1-point/1-ring; the allowable deviation of the elevation is +/-50 mm, and the elevation is checked by a level gauge, and a1 point/1 ring is adopted; lining ring diameter ovality: 0.5% d (tunnel outside diameter), radial staggering of adjacent segments: 5mm, adjacent annular ring surface stagger: 6mm. And (3) carrying out daily production on 15 rings of shield segments, extracting 1 ring for inspection, and allowing deviation of width, arc, chord length and thickness to be +/-1 mm. And carrying out sequential horizontal assembly inspection on 200 rings of each production shield segment, wherein the allowable deviation of the annular gap, the longitudinal gap, the inner diameter after looping and the outer diameter after looping is +/-2 mm.

And configuring a shield shaft foundation pit at a sewage treatment plant in advance, wherein the shield shaft foundation pit and a shield originating well are constructed by adopting a guard pile and internal support open excavation method, and a shunt well is constructed by adopting an anchor net to spray and hang a well wall upside down. The foundation pit has a length of 15.6 m, a width of 11.6 m and a depth of 19.63 m. The fender pile structure adopts a spacing cast-in-place pile with the diameter of 1000mm@1600-1800, the end shield is started by adopting a glass fiber reinforced pile with the diameter of 1000mm@1700, three supports are vertically arranged in the starting well and the water diversion well, the first support and the second support adopt reinforced concrete ring frame beams and reinforced concrete supports, the third support adopts 609 steel pipes for supporting, the wall thickness is 16mm, and the horizontal distance between the steel supports is about 3m; the foundation pit above the crown beam is supported by a 300mm retaining wall.

Shield starting and tunneling, and production preparation in the early stage of approach:

Before construction, the production is ready for the preparation of the required personnel, materials and mechanical equipment, and the preparation is carried out for the subsequent construction: the mechanical equipment is provided in a selected mode, is formulated according to a construction total progress plan and a peak intensity, and meanwhile, emergency equipment and standby equipment under special conditions are considered to ensure the construction period and the engineering quality and meet the requirements of engineering construction; the performance of mechanical equipment on the ground is good, the quantity of the equipment is sufficient, the construction of engineering is guaranteed, and the requirements of owners are met; according to the daily tunneling condition, corresponding construction materials are reserved in advance, so that the construction is ensured to be carried out smoothly; construction teams and management configurations.

Laying construction monitoring points: the construction monitoring point range is a shield construction whole area, and mainly is used for monitoring the deformation (especially the building, bridge, overhead and the like) of the surface building along the line and the ground subsidence, so that corresponding construction methods and technical measures can be adopted in time for control, and the safety of each risk building and underground pipelines can be ensured. 1) Layout of section tunnel uplink axis ground subsidence monitoring points: respectively along the uplink axis, and one every 30 m. The ground subsidence points within the range of 30m from the tunnel portal adopt deep soil monitoring points, and the middle section monitoring points are buried according to the geological conditions of the tunnel propulsion area, and the soil surface area is preferably provided with leveling nails. 2) Laying spool line profile monitoring points on the section tunnel: the intervals of the points of the section are 5m, 10m and 15m respectively, and the total number of the points (except the axial points) of each row of section is 3. The burying method of the deep subsidence monitoring point of the earth surface comprises the following steps: firstly, a concrete core drill is used for directly drilling holes on the ground surface, the depth of the holes is about 40cm, and the aperture is 10cm. After the drilling is completed, a base with screw threads is pre-buried at the lower part of the hole, the length is about 10cm, and the base is fixed by cement mortar. After the base is fixed, the reinforcement measuring point with the length of 30cm and the diameter of 18mm is firmly connected with the base. The screw thread arranged at the lower part of the steel bar measuring point is matched with the base, and is firmly connected by screwing the screw thread. And (3) sleeving a PVC pipe with the diameter of about 20mm on the outer side of the measuring point, isolating the steel bar measuring point from the peripheral cement mortar, and finally filling cement mortar between the PVC pipe and the hole wall, and covering a cover of the upper Fang Yumai measuring point. After the engineering is finished, the steel bar measuring point can be taken out by unscrewing the screw thread. 3) Building detection points around the section tunnel are arranged: in the range of 30m on two sides above the tunnel axis, the room angle is knocked in by using a nail for direct method point distribution, or the original point is utilized. 4) Setting the settlement points in the interval tunnel: the settlement monitoring points in the tunnel, namely, one monitoring point is arranged at each 10m (10 rings) of the uplink. The burying method comprises the following steps: by means of the bolts at the bottom of the tunnel segment, the surfaces of the bolts are arc-shaped, and the bolts must be ensured not to be loosened. 5) Layout of convergence points in the interval tunnel: and 1 convergent monitoring section is distributed in the upper line 50m (50 rings) range, and each monitoring section is in a longitudinal direction and a transverse direction. The burying method comprises the following steps: and designing the placement position of the laser range finder at the bottom and the side wall of the tunnel at the monitoring point. For the ground surface subsidence point layout, determining the tunnel axis position by using a total station on site according to design mileage and coordinates before the layout of the measuring points; arranging a settlement monitoring point parallel to the tunnel axis and a settlement monitoring point perpendicular to the tunnel axis on the ground, wherein the settlement monitoring point parallel to the tunnel axis is set as follows: each 5m of the originating and receiving sections are provided with an axis sedimentation monitoring point, each 10m of the originating and receiving sections are provided with a monitoring section, and each section is provided with 10-15 points; an axis sedimentation monitoring point is arranged every 10m in a standard interval section, a monitoring section is arranged every 20, at least 10-15 measuring points are arranged on each section, and the distance between the section measuring points 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 convergence of the clearance of the segment lining, the monitoring points are buried on the structural section and the same section as the subsidence of the vault of the segment lining, a main measuring section is arranged every 50m for each section tunnel of shield construction, and sections are arranged at the beginning and the joint part of the shield; screw steel with the diameter of 22mm is selected and buried at two sides of the section of the structure, the exposed length is 5cm, an oval steel ring is welded at the exposed screw steel head, the number is uniformly marked by red paint, and a protection device is arranged.

And (3) leaving the factory for inspecting the duct piece: when the pipe piece leaves the factory, the strength of the pipe piece reaches 100% of the design strength. Before the pipe piece leaves the factory, a shipper should check the qualification chapter of the pipe piece and the code chapter of the inspector to allow loading and leaving the factory. After the pipe piece is transported to a construction site and subjected to the check-in and check-out procedures of a construction unit, the pipe piece production process can be considered to be finished and checked to be qualified. Before the pipe pieces are shipped, a shipper should register the data such as the blocking number, the production serial number, the production date and the like of the pipe pieces. And meanwhile, informatization management is adopted, and the quality of the segments is monitored by using two-dimension codes. Before the duct pieces are shipped, the raw materials of the batch of duct pieces and the test condition report thereof should be checked again, so that the qualified duct pieces can be delivered from the factory.

Transportation and carrying of duct pieces: when the duct piece is shipped, the total height is limited to 3.6 m. The segments on the vehicle must be supported by the base and secured with ropes to avoid damage from dislocation during transport. The transportation road must be smooth and firm, have sufficient road surface width and turning radius, and must master the driving speed according to the road surface condition. And selecting reasonable transportation vehicles and loading and unloading machinery for loading and unloading according to the weight, the size and the specific condition of the construction site of the pipe piece. The pipe pieces are set according to the designed positions no matter the pipe pieces are loaded or unloaded for stacking, so that the stress condition of the pipe pieces is met. When the duct pieces are stacked, the filler strips between the duct pieces are on the same vertical line, and the thickness of the filler strips is equal. The forbidden person stays and walks under the lifting arm and the suspended weight. When more than two rope buckles are used for hanging the pipe 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 hanging the segment, the lifting hook, the sling must be ensured to be stable in hooking and just hung for lifting, and the sent signal is clear and definite. The pipe piece should be hung and placed lightly, and the lifting process should be kept stable.

And (3) end reinforcement: the shield end of the engineering is reinforcedThe reinforcing range is a range of 3.2m on both sides of the central line of the shield tunnel, and the reinforcing range is 10m in the tunneling direction of the tunnel. The sleeve valve pipe spacing is 2000 x 2000 and is distributed in isosceles triangle. The depth of the hole is 1.6m from the earth surface to the position below the outer diameter of the shield segment, and the range of grouting reinforcement soil is 3.2m total for each 1.6m above and below the outer diameter of the shield tunnel. The sleeve valve pipe grouting is to insert the sleeve valve type grouting pipe into the stratum through a drilling hole, and the sectional grouting process is adopted to enable the grout to enter the stratum more uniformly under the pressure condition, so that the purpose of sectional controllable and uniform diffusion of the grout in the stratum is achieved. The specific process of the end reinforcement is as follows:

a. Field leveling: after pipeline investigation, removing obstacles within 2 meters below the ground of a construction site, performing protection measures which cannot be removed, leveling and tamping, and reasonably arranging the positions of power lines of construction machinery and conveying pipelines to ensure 'three-way and one-level' of the construction site;

b. hole site lofting: measuring grouting hole sites of construction by using a total station, and making obvious marks by using reinforcing steel bars to ensure that the center displacement deviation of the pile holes is less than 5cm;

c. pore-forming: drilling holes by a drilling machine, wherein the diameter of the final hole is not less than 90mm, the drilling depth reaches the height of a grouting reinforcement section, records are made in the drilling process for reference of grouting operation, the hole site spacing is 2000mm, and the isosceles triangle is arranged; when water burst occurs or drilling is blocked due to stratum crushing in the drilling process, the drilling is stopped, grouting is performed to sweep holes or drilling is performed after a sleeve is added;

d. Preparing and filling a shell material: the shell material is prepared while drilling, and the shell material adopts low-strength cement clay slurry, so that the sleeve valve pipe is positioned in the center of the drilling in order to ensure that the thickness of the shell material is uniform. When the drilling depth reaches the design requirement, filling a sealing shell material into a drill rod of a drilling machine, pulling out the drill rod after filling, and timely supplementing slurry after pulling out;

e. Manufacturing and inserting a sleeve valve tube: the outer diameter of the sleeve valve pipe is 76mm, the maximum pressure which can be borne is more than 3MPa, 6 pulp overflow holes are formed in each section of the sleeve valve pipe at intervals of 800mm, and the diameter of each pulp overflow hole is 8-10 mm. And a rubber sleeve is tightly hooped outside the pipe at the opening to cover the grouting hole. The bottom end of the sleeve valve pipe is tightly packed and tied by geotextile to prevent the envelope material from entering the sleeve valve pipe, the sleeve valve pipe is inserted into the sleeve valve pipe to the designed depth after the sleeve pipe is pulled out, and the orifice pipe is firmly buried;

f. And (3) grouting a core pipe: 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 cups are respectively added at the two ends of the grouting core pipe to form a grouting blocking plug, and the condition of a grouting head, such as whether the condition of a one-way valve is good or not, is checked; checking that the pipeline cannot be blocked, and ensuring the connection quality of each section of pipeline; if the sleeve valve pipe is blocked, firstly 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 slurry is 0.8-1.0, the cement used for grouting is P.O42.5 ordinary Portland cement, the grouting liquid is pumped and pressed for grouting after being uniformly stirred and sieved, and stirring is carried out continuously in the grouting process for more than 3min; in order to increase the pourability, a composite water-reducing early strength agent with the cement dosage of 0.3-0.5% 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 length, grouting is started after the lower sleeve valve pipe is used for grouting the shell material and curing for 2-3 days, grouting pressure is controlled to be 0.2-0.4MPa, and grouting is ended when the designed grouting pressure or grouting amount reaches more than 80% of the designed grouting amount; along with the gradual lifting of grouting pressure, grouting should be stopped when the ground or surrounding buildings are raised and the like;

i. lifting the core tube: in the grouting process, the length of a grouting core pipe with one step distance is moved upwards after each section of grouting step distance is finished, the grouting core pipe is symmetrically clamped by lifting equipment or pipe tongs by manual work, the grouting core pipe is lifted upwards by two sides simultaneously and evenly with force, and one section of grouting core pipe is removed after 3-4m grouting is finished;

j. Single hole completion: hole replacement and displacement are carried out after grouting is finished every time, a grouting machine, a stirrer and various pipelines are cleaned in time, follow-up grouting is guaranteed to be carried out normally, and then each hole is finished one by one to realize end reinforcing.

K. And (3) grouting effect inspection: after sleeve valve pipe grouting is completed, waiting for 28 days, then drilling core for the reinforced soil body according to the design requirement, sampling, and performing physical experiment, and performing the next procedure after the design requirement is met, otherwise, performing supplementary grouting until the reinforced soil body is qualified.

Sleeve valve pipe grouting construction notice: 1) And (3) designing the drilling depth and the grouting step distance, accurately setting out the positions of grouting holes according to a drilling layout at a construction site, and simultaneously measuring the ground elevation of each hole site. Then accurately calculating the drilling depth of each grouting hole site according to the requirements of the shield elevation and the grouting range; grouting reinforcement range is from the bottom of the foundation pit to the top surface of the medium-pressure rock stratum, the net distance between the bottom of the sleeve raft pipe and the top of the tunnel is at least 1m, and the diffusion radius of the grouting holes is 0.4-0.8 m. 2) The drilling and grouting sequence is firstly carried out on the periphery, then the periphery is carried out on the inside, the periphery is surrounded, blocked and cut, the inside is filled and pressed, and the same row of interval construction is carried out. The grouting mode adopts backward grouting, and when the rock stratum is broken and the collapse hole is easy to cause, forward grouting is adopted. 3) And before reinforcement construction, the pipeline is required to be checked and changed, and if the conflict between the reinforcement measures and the underground pipeline is found, a construction unit immediately informs the supervision, the owners and related designers to take corresponding measures. 4) And (3) strengthening monitoring work, if conditions such as ground cracking, settlement acceleration and the like are found, stopping construction immediately, taking effective measures, and continuing construction after safety confirmation through on-site construction supervision and confirmation by a reporting industry owner and a designer. 5) If the reinforcement effect of the construction does not meet the expected requirement, the construction unit should stop the construction immediately, and inform the manager, the owner and the related designers to take corresponding measures.

Installing and debugging a ground related matched system: the ground system mainly comprises a conveying system such as dregs, segments and the like, a mixing station grouting system, an electric vehicle charging system, a tunnel ventilation system, a communication system and the like.

Mounting of the originating bracket: the shield originating bracket is manufactured and installed according to the drawing, and manufacturing and installation errors meet the requirements, namely 50mm above, below, left and right of the axis. Before the shield tunneling machine starting bracket is assembled, the spatial position of the starting bracket in a shield tunneling well is determined according to the height, width and length requirements of the starting bracket and combining the outer diameter size of the shield tunneling machine and the tunnel bottom elevation requirements of the starting tunnel portal. However, in the process of initial tunneling, the shield is considered to be positioned in the direction perpendicular to the tunnel portal because the gravity center of the shield machine is near the front, the downward phenomenon of 'knocking head' is easy to generate during initial tunneling, the elevation of the bracket is required to be 20-30 mm higher than the design elevation, the bracket of the shield machine is required to be arranged according to the planned posture of the shield machine during installation, and the bracket is formed by processing profile steel and assembled on site.

And (3) installing a reaction frame: when the shield machine starts, huge thrust is transmitted to the working well structure through the reaction frame, and the reaction frame is required to be installed in order to ensure that the shield machine starts smoothly. And the counterforce frame is lifted and lowered in a split mode after the ground is manufactured, and the mounting position and the longitudinal and transverse verticality of the counterforce frame are adjusted according to the actual measurement positions of the shield machine and the base. The reaction frame needs to be subjected to stress analysis, and the maximum bearing capacity of the reaction frame is 1.5 times of the total thrust required by cutting the soil body.

And (3) track laying: before the shield tunneling machine trolley does not enter the tunnel in the initial stage, a temporary track is paved, and the power supply bottle trolley and the trolley are used.

Installing and debugging a shield tunneling machine in a well: the shield machine debugging is divided into no-load debugging and load debugging. No-load debugging: after the shield machine is assembled and connected, no-load debugging can be performed, and the no-load debugging is mainly used for checking whether the equipment runs normally. The main debugging content is: hydraulic system, lubricating system, cooling system, distribution system, speed change system, section of jurisdiction kludge and various instruments. Load debugging: usually sinking time is to debug the load of the equipment, and strict technology and management measures are adopted to ensure engineering safety, engineering quality and linear precision during load debugging.

Portal pipe shed: in order to further ensure the safety of the starting, the upper part of the tunnel portal is additionally provided with a sleeve valve pipe for grouting reinforcementThe pipe shed supports one step. The construction process comprises the steps of guide wall construction, drilling machine positioning, drilling and pipe shed installation and grouting. Tube shed adopts/>The seamless steel pipe with the wall thickness of 6mm is distributed along the position 200mm outside the excavation contour line of the shield arch, the circumferential center distance of the steel pipe is 400mm, and the external insertion angle is about 1-2 degrees. The length of the pipe shed is 10m, the pipe shed is assembled and lengthened by sections, two sections are connected by threads, the length of the threaded section of each thread is larger than 150mm, two adjacent pipe shed joints are staggered, and the staggered length is not smaller than 1m. The steel pipes of the pipe shed are distributed according to @200 multiplied by 200 plum blossom shapes/>The grouting holes of the steel pipe tail 2m are not drilled with holes as grouting sections. The grouting of the pipe shed adopts cement mortar, the cement mortar water cement ratio is 0.8-1.0, and the grouting pressure is 0.2-0.4 Mpa. The grouting sequence is that the grouting is performed firstly downwards and then upwards, and the backward type sectional grouting is adopted.

Horizontal exploratory hole: the shield initial door opening advanced horizontal exploratory holes are used for exploring the conditions of end reinforcement, stratum and water leakage, the total number of the horizontal exploratory holes is 9, the drilling diameter is 50mm, the drilling depth is 1.4m, 9 holes are evenly distributed on the door during construction, and the middle hole needs to be shifted aside by 20cm so as to avoid the central point of the shield which is released by a measuring set. Drilling technical requirements are as follows: 1) The scaffold steel pipe is erected on the scaffold platform by adopting phi 48 steel pipes without rust or cracks, the platform erection is required to be firm, and the scaffold is reliably connected to a cutter head of the shield machine in order to prevent overturning; 2) And (3) fully paving wood boards or pedestrian pedals on the vertical scaffold steel pipes, and fixing the wood boards or the pedestrian pedals on the scaffolds by using iron wires, thereby being used as a horizontal exploratory hole construction platform. 3) The horizontal probe holes are arranged on a circle with R=1100 mm and 4 holes with 50mm (90 degrees between each other), and the horizontal probe holes are arranged on a circle with R=1800 mm and 4 holes with 50 degrees between each other. The other is arranged on the center of the tunnel portal and is offset from the center by 200mm to the right. When lofting, marking out the hole site with red paint, when the portal steel ring supports has an influence, can make 100 mm's hole site adjustment. 4) And (3) drilling holes in place, fixing the drilling machine on the underground continuous wall of the tunnel portal according to the hole positions, and drilling the drill rod vertically continuous wall. The depth of the horizontal exploratory hole is 1.4m, if the horizontal exploratory hole meets the bulge of the diaphragm wall, the depth of the horizontal exploratory hole is properly increased; 5) And after the hole depth reaches the design requirement, timely reporting and confirming to an on-site on-duty engineer. Processing emergency in drilling: in the drilling process, when water or sand gushes in the hole, the grouting ball valve and the pressure grouting double-liquid slurry are immediately installed, and meanwhile, relevant constructors at the hole opening are evacuated from the site.

Door sealing device: the hole sealing is used for preventing the back lining grouting mortar from leaking out when the shield starts. In the process of the shield tunneling, the tunnel portal steel ring and the shield shell can form an annular building gap. In order to prevent a large amount of muddy water from entering the well from outside the tunnel portal through the building gap during the shield tunneling, and influence the establishment of the soil pressure of the excavation surface, the stabilization 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 must be arranged to ensure the correct establishment and construction safety of the initial soil pressure balance. The sealing water stop device is arranged on a circular plate pre-buried at the exit hole opening, and the circular plate is made of a Q235A steel plate. The ring plate is reserved with a fixed screw hole, and the curtain rubber plate used as a sealing water stop device is fixed on the opening steel ring by the ring plate.

Brushing shield tail sealing grease: in the shield tunneling process, the pipe piece is stationary, and the shield body continuously moves, so that relative sliding exists between the shield tail and the pipe piece. In order to prevent external sewage, muddy sand and the like from entering the shield, sealing treatment is required between the shield tail and the duct piece. On one hand, the shield tail seal is sealed by three steel wire brushes arranged on the inner wall of the shield tail, and on the other hand, the seal is performed by establishing pressure by grease filled in the whole grease cavity; meanwhile, the grease injected into the grease cavity can also lubricate and protect the steel wire brush and prolong the service life of the steel wire brush. The shield tail grease is a paste which is prepared by taking grease as a main agent and adding additives such as fiber, modifier, filler and the like, and mainly has the effects of sealing, waterproofing, lubricating and corrosion preventing. The tail oil is divided into hand oil and machine oil, wherein the hand oil is used in the starting process, and the machine oil is used in the propelling process. Effect of shield tail grease: lubrication, friction between the shield tail and the outer wall of the duct piece, can influence the pushing of the shield and damage the shield tail device, and can effectively protect the shield tail; sealing effect-mud infiltration in soil layer can influence normal work of shield and increase construction difficulty-isolating mud, preventing infiltration of mud water and mud, ensuring smooth pushing of shield; 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 needs to be smeared with hand grease, and after the shield starts, the grease cannot enter the shield tail brush under the general condition, so the smearing must be carried out according to the requirement, and negligence is avoided.

Assembling a negative ring: because the design size of the hole gate ring beam of the later-stage originating end is 700mm and the width of the pipe piece is 1.0m, the position of the first ring pipe piece (zero ring) exposed out of the well wall is L1=0.3m, and the first ring pipe piece is directly pulled out during the later-stage construction of the ring beam. From the viewpoints of saving cost and reducing construction period, the negative ring segment is as short as possible under the condition of meeting the requirement of shield starting, and the size of the starting well is small, so that the strength of the reaction frame is improved to the greatest extent, and the reaction frame can directly lean against the starting well wall. The shield machine length is about l=9.30m. After the shield machine is in the well, an auxiliary jack can be adopted to pre-jack the shield machine to the position about 1m in the tunnel portal, and a reaction frame is installed for bearing the propulsion reaction force of the shield machine. At the moment, the shield is adopted to start normal initial tunneling by the jack.

Installing a portal originating device: after the enclosure structure is broken, a certain gap is necessarily generated between the end part of the shield starting platform and the surrounding rock of the hole, and in order to ensure that the shield is not in a shield 'head-knocking' phenomenon caused by suspension of the cutterhead during starting, a hole starting guide rail needs to be arranged in the starting hole. When the starting guide rail is arranged, enough space is reserved at the tail end of the guide rail so as to ensure that the cutter head rotation is not influenced by the arrangement of the starting guide rail when the shield starts. The shield starting guide rail is made of 30kg steel rails, and the length of the guide rail is 6m.

And (3) chiseling a tunnel portal: and (3) erecting a steel pipe scaffold in the hole ring in advance according to the work requirement of the chiseling-out hole door. After the positioning and the installation and the debugging of the shield (including all relevant equipment for the hole-outlet construction) are completed, the tunnel portal is started to be chiseled under the condition of ensuring that the shield has good running condition. The air pick is adopted in the project to carry out crushing chiseling treatment on the tunnel portal. Before chiseling concrete, drawing outline of the tunnel portal on the vertical wall according to design size. The chiseling is performed in two layers. Firstly, the reinforced concrete of a layer of the guard piles with the thickness of half of that of the hole ring, namely 500mm is chiseled, in order to ensure the safe chiseling operation, accidents occur so as to be plugged in time, the layer with the thickness of 500mm is left to be chiseled in a blocking mode from bottom to top, and nine blocks are divided until the outermost glass fiber main reinforcement is chiseled. The portal chisel is used for continuous operation, so that the working time is shortened, and the loss of soil on the front side is reduced. In the whole operation process, full-time safety personnel conduct overall process supervision, safety accidents are prevented, personal safety is guaranteed, and measures are taken to protect a sealing water stopping device of an opening.

Shield split starting: because the whole length of the shield tunneling machine is about 75m, and the clearance length of the shield initiation well is about 12 m, the whole initiation condition is not satisfied, and a split initiation mode is needed. The shield machine is debugged, and after the shield machine is connected, no-load debugging can be performed, wherein the main debugging content is as follows: 1) And (3) testing a cutter disc driving system: normal rotation, reverse rotation function, maximum speed, speed regulation, pressure, etc. 2) And (3) testing a hydraulic pump station: checking a hydraulic oil filtering and circulating system. 3) Segment installation system test: and detecting the functions of each degree of freedom and the function of grabbing the duct piece. 4) Grouting pump system test: whether each function meets the performance requirement, and whether reversing and speed regulation are normal. 5) Other auxiliary hydraulic system tests. 6) And (5) testing the function of the segment crane. 7) Gear oil circulation system test: whether normal, liquid level alarm function, etc. 8) And (3) 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) Main bearing system test: and (5) judging whether the working pressure is normal, and filling grease in the front of the cutterhead. 10 Whether the grease sealing system is normal and the main bearing is filled with grease until the grease overflows, whether the measured pressure reaches the requirement, whether the control part functions normally and the liquid level interlocking function of the small grease barrel is normal. 11 Testing whether the control portion of the air pressurization system is normal or not, and whether the pressure is normal or not. 12 Whether the water circulation system can work, whether the flow speed of the main driving part reaches the standard, and whether the pressure is normal. 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 Display test of shield machine fault. 15 Guiding system debugging. 16 No-load debugging proves that the shield machine can carry out load debugging after having working capacity. The main purpose of load commissioning is to check the load capacity of various pipelines and seals; so that each working system and auxiliary system of the shield machine reach the working state meeting the normal production requirement. Typically sinking times are the device load debugging times.

Split initiation order: after the front shield is lifted and lowered into the well and the cutterhead is lifted and lowered into the well, the cutterhead and the front shield are installed; then the middle shield is hoisted and lowered into the well, and the middle shield is installed; then lifting and descending the screw machine into the well, and installing the screw machine; then hoisting the tail shield and descending the well, and installing the tail shield; and then connecting the pipelines, debugging and trial pushing are carried out, and further construction is promoted. Meanwhile, the split starting needs to lengthen the matched pipeline, so that the tunneling requirement is met, and the split starting mainly comprises a hydraulic pipe, a water pipe, a foam pipe, a grouting pipe, a bentonite pipe, a cable and the like. The trolley is then lowered into the well.

Tunneling the shield: the method comprises the steps of a complete tunneling cycle, including equipment system inspection, setting of a laser guiding system and related data, duct piece conveying and positioning, grouting material preparation and well descending and positioning, shield tunneling and soil discharging, 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 argillaceous siltstone and strong weathered gravel stratum. The machine type of the shield machine is based on the study of geological conditions. In the present engineering, construction is performed by using an Earth Pressure Balance (EPB) shield machine. The shield cutterhead is specially designed for the geological conditions of the engineering, and has the following characteristics: 1) The soil cabin can safely work under the soil pressure, so that the soil pressure is balanced. The cutter head opening ratio (30-35%) can enable dregs to smoothly flow from the cutting surface to the soil cabin, is particularly important for the complexity, the variability and the viscosity of the geological condition of the tunnel route, can directly transmit soil pressure to the soil pressure sensor, is easy to enter the cutting surface to remove obstacles, and is easy to drill for soil treatment. The cutterhead is bi-directionally rotatable for preventing rotation of the machine itself. 2) The shield cutterhead cuts the soil body of the excavated surface, then stirs in the soil cabin, maintains certain soil pressure, and arranges a soil pressure sensor in the sealed soil cabin wall. The rotation speed of the screw conveyor (namely, the soil discharge amount is changed) is controlled by the soil pressure, so that the constant soil pressure value in the soil cabin is maintained, the excavation surface is supported, and the ground subsidence is controlled. Soil is conveyed to a belt conveyor by a screw conveyor and then conveyed into a soil bucket to be pulled out by a battery truck. 3) The shield thrust is provided by the jack, the oil cylinder acts on the convex surface of the pipe piece to overcome the resistance and push forward, and the pipe piece is assembled after the shield thrust is pushed to a ring lining distance.

The key points of shield starting construction are as follows: 1) When the shield is propelled forward in no-load, the stroke of a propulsion oil cylinder of the shield is mainly controlled, and the propulsion quantity of each ring of the shield is limited. The shield is required to be pushed forward, and meanwhile, whether the shield interferes with an originating station and an originating hole or whether other abnormal conditions or accidents occur or not is checked, so that the safe forward pushing of the shield is ensured. 2) The gesture is controlled mainly through the stroke of the pushing cylinder of the shield machine. 3) Under the condition of ensuring the normal pushing of the shield, the total pushing force and the cutter torque are slightly reduced. 4) And after the shield tail completely enters the hole body, adjusting the sealing of the hole, and grouting the hole. The slurry is required to be injected smoothly and to have early strength. The grouting pressure is controlled within +1.5Bar (higher than the section water and soil pressure). 5) And the dismantling time of the reaction frame and the negative ring segment is determined according to the mortar performance parameter of backing grouting and the initial tunneling thrust of the shield. In general, tunneling is performed for more than 100m (meanwhile, tunneling is completed for more than 7 days in the front 50 rings), and the counter-force frame and the negative ring pipe piece can be detached according to the working procedure conditions and the whole work arrangement.

Test tunneling: the first 100m of shield tunneling is used as a test tunneling section, and the following aims are to be achieved through the test tunneling section: 1) The new shield machine is debugged and familiar with mechanical properties in the shortest time, and the imperfect part of the shield machine is improved. 2) Knowing and knowing the geological conditions of the project and mastering the operation method of the composite shield under each geological condition. 3) The tunneling parameters of each stratum are collected, arranged, analyzed and summarized, and the operation rules of normally tunneling each stratum are formulated, so that a foundation is laid for realizing quick, continuous and efficient normal tunneling. 4) The operation procedures of duct piece assembly are familiar, the assembly quality is improved, and the construction progress is quickened. 5) By the construction of the section, the monitoring analysis of the ground deformation condition is enhanced, the influence of the shield machine on the surrounding environment during hole entering and pushing is reflected, and the shield pushing parameters and the synchronous grouting amount are mastered. 6) And (3) constructing through the shield sinking, and finding out tunneling attitude control measures and methods of the shield in the corresponding stratum.

The sinking of the test section is used for recording the footage conditions of different tunneling parameters adopted by different time periods and different strata in detail in construction; the same tunneling parameters are used for different stratum footage and abrasion conditions of cutterheads; and adopting different tunneling parameters for the same stratum, and recording the footage and cutter head abrasion conditions. Meanwhile, the relation between the grouting pressure and the stratum is recorded in detail. The specific record content comprises: 1) Tunneling: construction progress, oil cylinder stroke, tunneling speed, shield thrust, soil pressure, cutter head and screw machine rotating speed, and annular gaps (up, down, left and right) between the inner wall of the shield and the outer side of the duct piece; 2) Synchronous grouting: grouting pressure, quantity and consistency, grouting material proportion and grouting test block strength (daily sampling test); 3) Measurement: the shield gradient, the ovality of the tunnel, the total pushing distance and the exact position (X, Y, Z) of the axis of each ring of lining ring of the tunnel. After data collection, analysis and arrangement are carried out in time, and tunneling parameters which are needed to be adopted by different stratum in the tunneling process of the engineering are summarized, so that technical basis is provided for smooth engineering.

Device profile:

The shield machine of the composite earth pressure balance shield machine mainly comprises the following main structures: cutterhead, cutterhead drive, shell, propulsion system, man brake, screw conveyor and segment mounting machine. The shield host machine, the standard excavation diameter of the cutter head of the engineering is 3410mm, and 1) the cutter head has good excavation capability for different geology of the engineering. 2) The rotating speed of the cutterhead can be adjusted at any time according to the change of stratum conditions. 3) The cutter head can be convenient for checking the cutter head and the cutter, and the cutter can be ensured to be safely and quickly replaced. The front face of the cutterhead is provided with an injection port for foam, water and the like, thereby meeting the requirements of slag soil improvement. 4) The cutterhead can meet the requirement that personnel enter the tunnel face to remove obstacles in front of the cutterhead. 5) The cutterhead adopts a 12-inch disc hob, and the configured cutter has enough rock breaking capacity and wear resistance. 6) The requirement of enlarging the excavation diameter in the process of cutter replacement and construction can be met by configuring the super-cutter. 7) The shield machine has enough thrust, torque and power reserve, and can avoid the shield machine from being blocked or damaged under the condition of poor geology. 8) The working time of the main bearing and the driving assembly can meet 10000h running (or tunneling for 12 km), and the main bearing sealing system is reliable. 9) The shield machine can meet the minimum 50m turning radius of the active hinging system. The hinge seal is reliable. 10 Three rows of shield tail brushes are arranged at the tail part of the shield machine, so that the tunneling requirement under the condition of 40-50m of buried depth can be met. 11 The shield machine has good directional 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 azimuth and the attitude of the shield machine in time. 13 The electric equipment configured in the shield machine has good waterproof performance so as to meet the requirement that the shield machine can be smoothly constructed in a water-rich area. 14 The shield machine is internally provided with a good hydraulic and lubricating system. 15 The shield tunneling management system is a PLC automatic control function and can display various tunneling parameters in real time. 16 The shield machine is provided with data acquisition and processing and fault automatic display functions.

And (3) a rear matching auxiliary system: comprises a slag discharging system, a slag-soil modifying system, a pipe piece 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) Emergency lighting, ventilation capacity, drainage capacity can meet the needs of the project. 2) The automatic extension mechanism has good ventilation and tunnel main air pipe. 3) Slag is discharged by adopting a screw conveyor, a belt conveyor and a horizontal conveying system, and the inside of a tunnel is clean and tidy. 4) The material supply system and the lifting equipment are perfect, and the material storage space is enough. 5) The shield tunneling machine operation room is comfortable and humanized. 6) The electrical equipment has good waterproof performance, and the moving part is provided with a reliable safety protection device. 7) The system has the advantages of gas monitoring, fire protection, communication and closed-circuit television monitoring systems.

Initial tunneling engineering adjustment measures: after sinking times of the shield tunneling machine are completed, the tunneling parameters are adjusted in a necessary mode, and conditions are provided for subsequent normal tunneling. The main content comprises: 1) And further optimizing tunneling parameters according to geological conditions and monitoring results in the sinking advancing process. 2) The normal propulsion stage adopts the best construction parameters mastered in the 100m test tunneling stage. By enhancing the construction monitoring, the construction process is continuously perfected, and the ground subsidence 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. And controlling the mileage deviation to be as follows: moderating curve, circular curve segment: x (tunnel design longitudinal axis direction, namely along mileage direction), Y (perpendicular tunnel along design axis direction) < 50mm. 4) The shield is pushed according to the parameters set by the shift instruction, and the soil pushing and the lining back grouting are synchronously carried out. The construction process is continuously perfected, and the maximum deformation of the earth surface after construction is controlled within +10-30 mm. 5) In the shield tunneling process, the gradient cannot be suddenly changed, and the tunnel axis and the angle of refraction cannot be changed by more than 0.3%. 6) The whole process of the shield tunneling construction needs to be strictly controlled, and engineering technicians correctly give tunneling instructions per shift according to various exploration and measurement data information such as geological change, tunnel burial depth, ground load, earth surface subsidence, shield machine posture, cutter head torque, jack thrust and the like, and track and adjust in real time. 7) The shield machine operator needs to strictly execute instructions and carefully operate, small deviation which occurs initially should be corrected in time, the shield machine is prevented from walking in a snake shape as much as possible, and the primary deviation correction amount of the shield machine is not excessively large so as to reduce disturbance to stratum. 8) Making construction records, wherein the records comprise the following contents: the construction progress of tunneling, the stroke of a thrust cylinder, the stroke of a hinged cylinder, the tunneling speed, the shield thrust, the soil pressure, the rotating speed of a cutterhead, the torque, the rotating speed of a screw machine, the torque and the gap between the shield tails (up, down, left and right); synchronous grouting: grouting pressure, grouting amount and grouting material proportion. 9) And establishing a working daily report system, and carrying out omnibearing monitoring on a construction unit, a supervision unit and a construction unit through Internet informatization management.

The control key points of stabilizing the excavation surface during the initial tunneling are as follows: the stability of the excavation face is the precondition of normal tunneling and is ensured at any time. The stability of the excavation surface is mainly controlled through the following points in the tunneling process: 1) And (5) improving the shutdown pressure maintaining value. 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, and the earth pressure is properly increased by 0.1-0.15bar when the machine is stopped and the pressure is maintained, so that the stability of the earth cabin pressure and the excavation surface is ensured, and the earth surface subsidence is controlled. 2) And (5) keeping earth pressure tunneling. The speed is kept basically unchanged, and the rotating speed of the screw machine or the opening of a slag outlet door is regulated to achieve the aims of controlling the soil outlet amount and keeping the pressure of the soil cabin; under the condition of keeping the rotating speed of the screw machine and the opening of the slag hole unchanged, the propelling speed is adjusted to achieve the aim of adjusting the pressure of the soil cabin. 3) And (3) formulating a special tunneling scheme according to risk sources in different intervals. Reasonable propulsion parameters are set, the filling effect of synchronous grouting is guaranteed, and the phenomena of overexcavation and undercontrol in the tunneling process are prevented. 4) And (5) improving the dregs. High-quality foam is used, and meanwhile, high-molecular polymer or high-quality bentonite slurry is injected into a face, a soil cabin or a screw machine according to the slag discharge condition at a foam injection port of a cutter head, so that the water stopping effect is improved, the plastic flowability of slag soil is improved, and the dangers such as gushing and the like are controlled. 5) And (5) strengthening grouting to control sedimentation. And controlling synchronous grouting amount according to experimental data and theoretical calculation data, controlling pressure and flow in a dual mode, controlling pressure in a main mode, controlling flow in an auxiliary mode, and ensuring sufficient mortar injection. According to the geological condition, the mixing proportion of the mortar is adjusted, the initial setting time of the mortar is shortened, and the purpose of controlling the surface subsidence is achieved. According to the monitoring data of the earth surface subsidence, performing secondary grouting in time; the shield posture is controlled, the deviation correction amount is reduced, deviation correction is avoided as much as possible, and less correction work and correction are performed when deviation correction is needed. 6) And the soil output control is enhanced. The method for measuring the volume of the slag soil is adopted for control, and the soil outlet amount of each ring is determined according to the loosening coefficient of the slag soil obtained through experiments and the slag soil densities of different sections. 7) And the coordination is enhanced. The shield operator executes the operation instruction issued by the technical responsible person strictly, and when the instruction can not be implemented due to the change of geological conditions, the shield operator communicates with the technical department in time to negotiate and search for solutions and treatment measures. And each constructor needs to keep close connection and coordination in the tunneling process. If the equipment is required to be stopped due to equipment failure in tunneling, the soil pressure is reasonably set, and countermeasures and emergency plans are made according to actual conditions.

Control and adjustment of the initial tunneling direction of the shield: 1) And (3) rolling control: the rolling deviation is corrected by adopting a method of enabling the shield cutter head to rotate positively and negatively. And the allowable rolling deviation is less than or equal to 3 degrees, and when the allowable rolling deviation exceeds 3 degrees, the shield machine alarms to prompt an operator to switch the rotating direction of the cutterhead and carry out reversal deviation correction. 2) Vertical direction control: the main factor for controlling the direction of the shield machine is the single-side thrust of the jack, the relation between the single-side thrust and the attitude variation of the shield machine is very discrete, and the main factor is mastered by human experience. When the shield machine is downward, the pushing force of the lower jack can be properly increased, and when the shield machine is upward, the pushing force of the upper jack is increased to correct the deviation. 3) Horizontal direction control: and the pushing pressure of the left jack is increased when the left jack is deviated, and the pushing pressure of the right jack is increased when the right jack is deviated, as in the vertical deviation correcting principle.

Notes in initiating tunneling: 1) In the construction process, the deformation conditions of the reaction frame and the starting bracket need to be closely concerned, such as the phenomena of unwelding, curling of the steel plate, overlarge displacement and the like are found, and the tunneling needs to be stopped immediately, so that personnel can be arranged for processing. 2) The shield body rotation angle should be greater than 1 degree. 3) In the process of removing the shield tail from the negative ring canal slice, special persons are required to install the wooden wedge in time, so that the falling of the segment is avoided. 4) And after the shield completely enters the soil body, the hole ring seam gap is sealed by secondary injection of double slurry through the pipe piece lifting hole or the hole reserved in the tunnel portal immediately. 5) The chiseled concrete fragments must be cleared beyond the originating rack bottom edge and the originating rack area must not be piled up to provide a quick rescue channel. 6) The shield tunneling machine cutterhead can rotate behind the water stop curtain cloth. 7) And the cutter head of the shield tunneling machine needs to measure the tunneling posture of the shield in real time after entering the hole ring. Emergency preparation: a. before starting, carefully probing each probing hole of the tunnel portal and the water leakage condition of the tunnel portal, if the tunnel portal is turbid with sediment, starting an emergency plan and making treatment measures. b. The concrete blocks after the tunnel portal is chiseled are cleared, and sundries are not stacked in front of the shield. c. The security part checks whether the emergency material is ready in place. Emergency measures: a. after each preparation work of the shield is finished, the shield starts to advance and quickly passes through the tunnel portal sealing device to be propped against the face, the cutter head is not rotated first, the tunnel portal sealing device is checked, if the shield is damaged in passing, the advance is stopped, and the tunnel portal sealing device can be advanced again after being repaired. After the shield breaks the tunnel portal, the phenomenon of front soil collapse may exist, the soil cabin pressure should be quickly built, the ground settlement is prevented, if continuous collapse is serious, the tunnel portal should be reinforced again, and bentonite slurry can be injected into the gap by using the reserved holes of the tunnel portal. b. The water should be continuously dropped during the initial period and the special person should be assigned to pump water.

Initial tunneling operation requirements: (1) The installation and positioning precision of the starting platform, the counter-force frame and the negative ring are strictly controlled, and the basic coincidence of the starting posture of the shield and the design line is ensured. (2) When the first ring negative ring pipe piece is positioned, the rear end face of the pipe piece is vertical to the line center line. The axis of the negative ring pipe piece is overlapped with the axis of the line, and the negative ring pipe piece adopts a through seam assembling mode. (3) The axis of the shield machine is basically parallel to the design axis of the tunnel, and the shield central line can be properly raised by 2-3cm compared with the design axis. (4) When the shield advances on the starting platform, the groups of pushing cylinders should be kept synchronous. (5) When initial tunneling is started, the shield tunneling machine is positioned on an originating station. Therefore, opposite anti-torsion supports are required to be welded on the starting platform and the shield tunneling machine, and reactive torque is provided for the initial tunneling of the shield tunneling machine. (6) an initial stage, wherein the device is in a break-in period. The control of thrust and torque is noted, and the effective use of grease at each part is also noted. The total thrust force of the tunneling should be controlled below the bearing capacity of the reaction frame, while ensuring that the torque generated by the cutter cutting into the stratum under the thrust force is smaller than the reaction torque provided by the initiating platform. (7) The welding edges and corners on the shield shell are flattened before the shield enters the tunnel portal, so that the waterproof curtain cloth of the tunnel portal is prevented from being damaged.

Normal tunneling construction of the shield:

The shield tunneling construction process comprises the following steps: firstly, excavating tunneling and synchronous grouting are controlled through equipment management, then whether tunneling circulation standard is met is judged, if yes, tunneling is circulated, otherwise, the tunneling process of a grouping train is controlled, the hole outlet of the grouping train, the slag discharging and charging of the grouping train, the hole inlet of the grouping train are controlled, the pipe lining ring is assembled, the track is extended, and then the next ring tunneling is started.

The slag discharging scheme of shield tunneling: 1) Calculating the excavation quantity and excavating diameter of cutterheadThe length l=1000 mm of the segment, the coefficient of loosening the ballast soil is 1.3, so the soil output per ring is as follows: v _T＝π/4×3.41²×1.3＝11.8m³. The fluctuation range of the actual slag quantity is strictly controlled to be not more than 10% of the theoretical square quantity in the tunneling process. 2) In-tunnel transportation, because the shield machine adopts a vacuum sludge discharge system to carry out slag discharge, the storage battery truck does not need to be provided with a slag truck, and directly discharges the slag sludge to a temporary soil storage field through a pipeline, and a night loader is loaded into a dump truck to be transported to a designated waste soil site. The storage battery car is 8t variable frequency type, and the marshalling mode is two segment cars and one mortar car. The wellhead is provided with a 16t/5t gantry crane hoisting segment and related auxiliary materials. 3) And (3) material transportation: the pipe sheet is 1.0m wide, each ring of pipe sheet is transported by two flat cars, the car length is 2.5m, and the width is 1.0m. Other small-sized machines and materials are transported by a segment car. Slurry is manufactured and transported, the slurry is manufactured on site through a dry-mixed slurry stirring station, and main equipment comprises: automatic proportioning slurry mixing station, bentonite stirring tank, storage tank, mortar stirring tank, material pool, conveying pump, slurry conveying pipe, etc. After the mortar is manufactured, the mortar is conveyed into a mortar truck at a wellhead by a conveying pump and then conveyed to a grouting position by the mortar truck. The mortar horizontal transport apparatus includes: mortar vehicles, battery cars, mortar transfer pumps, and the like. The grouting amount of each ring is based on the overexcavation amount, and the maximum grouting amount is 130-250% of the gap, about 1.7m ³. The grouting slurry behind the wall is transported by a cement slurry stirring transport vehicle. The transport train can be provided with 2 groups of two or one mortar stirring transport vehicle for one group of segment transport vehicles.

Slag soil improvement in shield tunneling: the tunneling construction of the engineering section tunnel is mainly performed in the medium-wind bedrock. The upper part is a dense pebble layer and has the characteristics of upper softness and lower hardness. The improvement of the dregs mainly comprises: (1) The foam additive is used for improving soil, and the foam additive is used for improving the soil during tunneling, so that disturbance of the shield machine to surrounding soil layers is restrained, and the purpose of preventing the ground surface from sinking is achieved. The foaming agent can generate stable foam, is suitable for being used in viscous, sandiness and powdery soil, can reduce the viscosity of soil body when being mixed with the viscous soil, improves the performance of shield section soil body, reduces the adhesion of the soil body to the shield, and is beneficial to shield propulsion. In addition, the foaming agent can reduce the internal friction force and reduce the abrasion of soil on a cutter head, a screw conveyor and a belt conveyor. (2) When bentonite additives are used for improving soil, when a tunnel passes through a silt layer and a silt aquifer, instability of an excavation surface and subsidence of the ground caused by water burst occur in construction, and a sudden burst phenomenon occurs. In order to ensure smooth construction, the soil body is improved by injecting swelling slurry soil in the advancing process of the silt soil layer and the silt sand water-bearing layer. The soil body improvement is to reduce the water permeability of the soil body, strengthen the sealing performance of the working face and effectively resist the pressure-bearing water head. So as to provide the stability of a uniform and controllable supporting working surface, protect the cutter head and ensure the normal soil discharge of the shield spiral soil discharge machine. And (3) pressing bentonite in front of the shield and in the screw machine at certain intervals in the pushing process. The bentonite is injected under pressure to improve soil body, so that the clay content in the soil discharging process reaches 20%. According to the calculation, a certain concentration of bentonite slurry is needed to be added for each advancing ring. The bentonite slurry can be injected into the front surface of the cutterhead and stirred by the rear wing of the cutterhead. Discharged from the screw. And (5) observing the soil discharging state of the screw machine and the sedimentation condition of the soil below while injecting bentonite slurry under pressure, so as to ensure the stability of the soil below. The permeability coefficient of sandy soil is larger, namely the pore water pressure is increased faster, meanwhile, the dispersion is also faster, and the time difference between the two is the ageing of the drainage. Therefore, the speed control of the jack is matched with the speed control of the jack, so that the shield pushing speed reaches a better state.

Lining segment installation during tunneling: the outside diameter of the segment of the engineering segment tunnel is 3200mm, the inside diameter is 2700mm, the wall thickness is 250mm, the segment is a prefabricated reinforced concrete segment, the ring width is 1000mm, and the lining ring consists of 1 sealing block, 2 adjacent blocks and 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 deviation through various combinations with a standard ring, wherein the wedge-shaped ring is double-sided wedge-shaped, and the wedge-shaped quantity is 20mm. Prefabricated lining reinforced concrete is marked with a C50, impervious grade P12, and lining longitudinal and circumferential connecting bolts are bolts. The bolt hole is waterproof with a sealing ring, the lining circular seam and the longitudinal seam are waterproof with a water swelling elastic sealing gasket. The process is carried out as follows: after leaving factory from a segment factory, carrying out segment appearance inspection, segment joint surface cleaning, installing a sealing water stop, then carrying out segment lifting, transportation and positioning, simultaneously retracting a corresponding jack, then splicing, extending the corresponding jack, carrying out segment position inspection, then backfilling grouting behind the segment, carrying out caulking waterproof treatment, and finally re-tightening a connecting bolt, thereby carrying out tunneling construction. Specifically, the pipe pieces are conveyed and assembled, and are hoisted to a down-hole pipe piece transport flat car by a gantry crane of an originating wellhead and transported to the forefront end of a track. The pipe piece is lifted from the transportation flat car by the pipe piece crane, the pipe piece is transferred to the stacking platform by 90 degrees, the pipe piece is lifted by the crane and is moved to the shield tail to be placed on the pipe piece feeding machine when the pipe piece is used, the pipe piece feeding machine is used for conveying the pipe piece to the lower part of the splicing machine, and the pipe piece mounting machine is used for sequentially mounting the pipe pieces from bottom to top when the pipe piece is spliced. And after the bottom duct piece is in place, assembling the standard duct piece and the adjacent duct piece on two sides in sequence, finally installing a capping duct piece, overlapping 1/3 of the length of the capping piece, radially pushing up the capping piece, and longitudinally inserting the capping piece into a ring. The mounting machine is arranged in the middle as much as possible, so that the occurrence of dislocation of joints is reduced, and the assembly quality is ensured.

And (3) segment assembly quality control: 1) For shield pushing, the splicing quality of the first ring has the function of a datum plane for the splicing of the whole tunnel, so that the splicing quality of the first ring segment is strictly controlled to meet the specified requirement. The first ring pipe piece is assembled after the negative ring in the working well, the assembling work is carried out on the shield base in the well, the height, the direction and the gradient of the assembled pipe piece are easy to control, and the quality standard of the first ring pipe piece assembly is as follows: the diameter deviation is less than 10mm, and the ring surface unevenness is less than 1mm. 2) The quality of the duct piece and the buffer material is ensured to meet the assembling requirement. The strength, geometric dimension, longitudinal and transverse screw holes are guaranteed to meet the quality standard. The quality of the buffer material meets the requirements of an assembling process, and the strength, the compression performance, the rebound performance, the material uniformity and the thickness error of the buffer material are all ensured to meet the requirements. 3) Guaranteeing the quality of segment assembly. The assembly quality of the segments meets the requirements of quality standards, ensures that the construction meets the design rules and meets the use requirements, and is the most basic requirement for smoothly, safely and excellently completing the shield propulsion task. 4) And (5) one-time screwing and multiple re-screwing of the reinforcing bolt. The whole tunnel is formed by combining thousands of segments, and is connected by longitudinal and circumferential bolts, and the quality of the bolt connection is critical to the integrity of the tunnel lining. The bolts are not tightly screwed, so that dislocation is easily caused under the action of the jack after the pipe piece is looped, the flatness of the ring surface is reduced, and the next ring assembly is directly influenced. The tightening and re-tightening can improve the quality of the formed ring, and especially the multi-tightening is more beneficial to improving the roundness of the formed ring. 5) And after each ring is assembled, the longitudinal bolts are timely screwed, and when the next ring is pushed, the longitudinal bolts are re-screwed under the action of the jack. After the looped tube piece is pushed out of the frame, the longitudinal bolts and the circumferential bolts are re-tightened again. And after the tunnel is penetrated, the longitudinal bolts and the circumferential bolts are re-tightened for the fourth time. 6) The quality of the joint assembly is common, and the longitudinal joint quality does not meet the requirements: front and rear horns, inner and outer opening angles and the like, unfilled corners, edge drop, breakage and the like of the duct pieces are prevented in construction according to operation requirements and by combining with the prior construction experience, are positively corrected, and are assembled by staggered joint according to design requirements. 7) And the control of the shield posture is enhanced. The control of the shield posture and the control of the segment splicing quality complement each other, and the accurate shield posture control can provide conditions for the accurate splicing of the segments, is a foundation for improving the splicing quality and also creates favorable conditions for the pushing of the shield. 8) The phenomena of cracks, breakage, corner drop and the like on the surface of the duct piece are avoided. Repairing the damage in the assembly process, and executing after approval of a repairing scheme supervision engineer.

Synchronous grouting after segment wall: (1) The grouting purpose is that the periphery of the tunnel lining is synchronously and properly grouting, so that the annular building gap behind stratum and lining can be filled in time, the tunnel segment and surrounding soil layer form an integral structure, and the earth surface subsidence caused by stratum soil loss and disturbance due to shield tunneling is reduced as much as possible. Grouting can effectively control settlement of the earth surface, underground pipelines and ground building structures within the specification according to related construction technology and experience. (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, and the slurry is immediately injected when a gap appears at the tail of the shield during tunneling. Grouting pipes on the shield machine are uniformly distributed in the shield tail steel plate according to the upper, lower, left and right directions, so that slurry is injected into gaps at the shield tail, and grouting is symmetrically performed according to the sequence of the upper part and the lower part. (3) Grouting construction parameters, and synchronously grouting by using newly developed hard slurry for shield grouting. With the advance of the shield, a building gap appears 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 cutter head excavates the diameter 3.41m, and section of jurisdiction external diameter 3.2m, then the building space between section of jurisdiction and excavation face= (3.14x3.412/4-3.14x3.22/4) x1.0=1.09 m ³. Because the grout pressed into the back of the lining can shrink, local section tunnel tunneling is snaked, deviation is corrected and the like, the actual grouting amount is 1.3 to 2.5 times larger than the theoretical building void volume. Excessive injection may also cause local surface swelling and slurry run-out. Therefore, in addition to controlling the grouting amount, grouting pressure is also required to be controlled. And controlling the grouting quantity and grouting pressure according to the construction condition and the geological condition. In general, the pressing-in amount of each ring is controlled to be 130-250% of the building gap, namely, the grouting amount of 1.0m wide ring segment is 1.42m ³/ring-2.72 m ³/ring. The grouting pressure is 0.1-0.2 MPa higher than the water and soil pressure of the tunneling surface during normal tunneling. Grouting and tunneling are kept synchronous, namely grouting is carried out while shield tunneling, and grouting is correspondingly stopped after tunneling is stopped. (4) And in the grouting process flow, the grouting effect of the ring is checked after the grouting operation is completed through the dynamic monitoring of the surrounding environment and the grouting of the building, if the ring is not matched with the grouting effect, the grouting effect of the whole tunnel is checked, if the ring is matched with the grouting effect, the grouting is ended, and if the ring is not matched with the grouting effect, the grouting is supplemented. (5) grouting operation procedure: 1) Grouting operators are specially trained and familiar with related operation notes; 2) Grouting operation and shield propulsion are synchronously carried out, the grouting amount is adapted to the tunneling speed, and clear regulation is carried out before each section of tunnel propulsion and is strictly carried out; 3) And operators observe grouting working conditions at any time. The grouting pressure and the grouting quantity are well controlled, and the grouting pressure and the grouting quantity are kept in communication with a shield operator; 4) Once a fault occurs, immediately informing the shift on duty, requesting to pause the shield propulsion, and reworking after the fault is removed; 5) The grouting quantity is determined according to the shield shell gap and the ground condition, so that the environment protection requirement is ensured, and the ground subsidence is controlled; 6) The slurry is not isolated or precipitated in the process of pressure conveying, and the coagulation time, hardening strength and the like of the slurry meet the technical requirements in specific engineering; 7) Before the first grouting, lubricating all the pipelines by grease; 8) After each shift of work is finished, the grouting pipeline is firstly washed and emptied by a water circulating pump, and then the grouting pipeline is filled with lubricating slurry so as to facilitate grouting next time; the equipment such as a ground slurry stirring machine, an underground slurry conveying vehicle, a high-level tank slurry storage cylinder and the like are used for removing slurry, cleaning and emptying, so that blockage and hardening are prevented; 9) Filling a shield construction process quality control grouting record table, and making each shift of handover work.

And (3) secondary grouting: the secondary reinforcing grouting is generally implemented under the condition that the ground surface subsidence cannot be effectively controlled or the pipe lining is seriously leaked due to poor filling compactness of gaps between the pipe and the rock wall. And during construction, according to the ground subsidence monitoring feedback information, a method for detecting whether a cavity exists behind the segment lining by adopting ultrasonic waves or other means in the combined hole is adopted, and whether secondary grouting is needed or not is comprehensively judged. (1) The grouting material, the slurry proportion and the performance index, and the double-liquid slurry is adopted as the grouting material for secondary grouting, so that the synchronous grouting can be further supplemented and reinforced. And simultaneously, the filling and reinforcing functions are realized on the stratum around the pipe sheet. When groundwater is particularly abundant, it is necessary to plug the groundwater. Meanwhile, in order to establish high viscosity of the slurry as soon as possible, so as to drain the groundwater (to press the groundwater into the depth of the stratum) while filling the slurry into the gaps, the optimal filling effect is obtained, at this time, the gel time of the slurry needs to be adjusted to 1-4 min, and if necessary, cement-water glass dual-liquid slurry can be used for secondary grouting. The cement adopts P.O.42.5 ordinary Portland cement. (2) Grouting equipment, reinforcing grouting adopts a self-provided double-liquid grouting pump. The secondary reinforced grouting pipe and the orifice pipe are self-made, the processing of the secondary reinforced grouting pipe and the orifice pipe has the matching capability with the pipe piece lifting hole, the functions of quick connection and disconnection and sealing and no leakage can be realized, and a slurry leakage valve is arranged. In order to quickly carry out secondary slurry supplementing, the synchronous grouting pipe of the shield machine can be used for carrying out secondary slurry supplementing, and the sedimentation control effect is good. (3) The quality inspection standard and quality assurance measures, the quality control requirement, the synchronous grouting material is inspected according to the requirement, and the qualified material can enter the field only after inspection, inspection and signature approval. The mixing station is used for preparing the prepared grouting slurry, and the experimental block is subjected to a pressure experiment, so that the grouting slurry can be put into use after the experimental report is qualified. And (3) quality inspection standard, wherein grouting quality can be inspected by adopting geological radar and ultrasonic detection methods, and the parts which do not meet the requirements are subjected to supplementary grouting. The annular measuring line is positioned in the middle of the annular pipe sheet, and the interval is 10 annular pipe sheets; for underground pipelines, box culverts or other important facility areas, a circular measuring line is arranged at the interval of 3 circular pipe slices.

Track installation and disassembly: the track is a horizontal transportation foundation, and the smooth transportation and the tunneling period can be ensured only by safety and reliability. When the steel rail is detached, the fasteners such as the steel rail pressing blocks, the fishplate fastening screws and the like are detached from the tunnel receiving well end to the other end in sequence, and then the steel rail is lifted onto the conveying trolley and conveyed to the wellhead in sequence to be lifted out. The installation and use standards are as follows: 1) The rail fastener must be complete, closely adhered, firm and consistent with the rail, the rail joint must use qualified rail clamp plates or fishplates, and fixed by 4 bolts, the underground paved rail needs to be changed in the rail model, and the rail joint of different models must use proper special-shaped rail clamp plates. The road splint cannot be broken or has few eyes and other phenomena; 2) When the joint is in suspension connection, the distance between a 22kg/m type rail sleeper and the joint is 240mm, and the deviation is not more than 30mm; when the joint is used for bearing, the joint is provided with 3 sleepers, one middle sleeper is arranged at the joint of two tracks, and the other two sleepers are respectively 240mm away from the middle sleeper; the straight line segments should be butted, and the relative offset is not more than 50mm; the curve sections should be connected in a staggered way, and the relative offset is not less than 2m; 3) The single track center line 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 tracks is not smaller than the design value and not larger than 20mm of the design value, and the deviation between the center positions of the double tracks and the design position is not larger than 50mm; 4) The deviation between the actual elevation of the rail surface of the main transportation line and the designed elevation is +/-50 mm; the error in the gradient 50m is not more than 2/1000, and the height difference is not more than 70mm; 5) The allowable deviation of the straight line section of the transportation line rail is +15mm and-5 mm; the curve section is widened to allow the deviation to be +15mm and-5 mm, and a track gauge pull rod is arranged in the curve section. 6) The same line must use the same type of rail, the same line should have no mixed road (the two types of rail within 50m are mixed road), have no eye-clamping road. 7) The quality of the rail and the sleeper is qualified, the laying meets the design requirement, the sleeper at the joint has no failure, more than two sleepers continuously fail (decay, damage, fracture, suspension and other non-functional persons are failure), and the sleeper is vertical to the rail. 8) The rail spike specification should be matched with the rail, the number is complete, the rail sleeper bolts and the pressing plates are complete in fastening, and the floating distance is not more than 3mm. 9) If the rail is strictly forbidden to cut by gas cutting, a rail cutting machine is needed to be used for cutting, the plane of the rail cutting head is vertical to the rail surface, and the sawing surface is not inclined. When the track cutting head is used for reprocessing the bolt holes of the clamping plates, the track cutting head is required to be processed by a drilling machine, and gas cutting holes are strictly forbidden. 10 Special maintenance and periodic maintenance are necessary during the use of the rail. And the bolts at each part of the rail and the sleeper are dripped and fastened once every half month. The ballast bed and the turnout should be cleaned frequently to ensure no sundries, no dregs, no ponding and the like.

Pipeline arrangement in tunnel: the high-pressure air and water pipes of the tunnel are erected in standard, the high-pressure air and water pipes constructed in the tunnel are arranged in an overhead mode along the wall of the tunnel, a supporting point is arranged at each interval of 3-5 m, and a sign board is arranged at each interval of 30 m. The temporarily laid pipeline is fixed along the wall of the hole, and is removed in time after construction is finished. The high-pressure air and water pipelines are arranged, and are required to be flat, smooth, straight, tight in joint, stable and firm, turning is reduced as much as possible, and the bent angle is an obtuse angle. High pressure wind, protection of water lines. Paint protection is needed after the high-pressure air and water pipelines are arranged, the high-pressure air is red, and the water pipe is blue. The high-pressure air and water pipe workers can patrol the pipeline every day to find the phenomena of running, overflowing, dripping, leaking and the like, and the pipeline should be maintained and treated in time. The ventilator is erected at a position which is free from pollution, flat in field, good in ventilation and wide in space, the height of the ventilator from the ground is 3.0-4.0 m, the ventilator cannot be bent and fluctuated greatly on a straight line as much as possible, and the bracket is firm and stable. The positions close to 50-100 m of the ventilator are connected by using the same type of air pipes made of air pipes with steel wires or iron scales, so that the people are prevented from being injured by the burst pipes. The construction electricity layout standard in the tunnel is generally that the erection principle is that high pressure is up, low pressure is down, the power line is arranged on the opposite side of the wind pipe and the water pipe, and the high pressure, the power and the illumination lines are laid up and down in sequence; the excavated section is laid according to the movable line, temporary drilling holes are arranged on the primary support structure according to the method of the fixed line, and the temporary drilling holes are removed immediately after construction is finished; the distribution box is provided with a door and a lock, and a system of 'one machine one gate one box one leakage' is implemented, and a warning board of 'electricity and danger' is hung; the construction lighting electric line is required according to related specifications, a three-phase five-wire system or a cable is adopted, a lighting special line is required to be arranged for lighting, the height of the lighting electric line from the ground is not less than 2.5m, the distance between the lines is 10cm, and the tunnel lighting ensures sufficient and uniform light and cannot dazzle. The non-caving section of the transportation road is provided with one 60-watt energy-saving lamp every 5m and every 8 m; waterproof lamp caps and lamp covers are used for water leakage areas; the special man overhauls the electric wire and prevents electric leakage. The rated voltage of the power equipment in the hole is 380V, the illumination voltage is 36V in the working area, and 220V in the non-working area.

Attitude control in the tunneling process: in the shield tunneling process, the cutter head can increase disturbance to soil, so that under the condition of ensuring that the front subsidence control of the shield is good, the shield can pass through at a uniform speed and in a straight line as much as possible, and the correction quantity and correction times of the shield are reduced. The wedge amount of each ring is calculated in advance, and is controlled in advance when the shield advances. The method is characterized in that the method is not used for carrying out urgent correction and not used for carrying out violent correction during the propelling, the gap between the segment and the shield shell is observed, and a slope stabilizing method and a gentle slope method are adopted for the propelling so as to reduce the influence of shield construction on the tunnel and the ground. The middle shield and the tail shield are connected in a hinged manner, so that the length-diameter ratio of the shield is effectively reduced, the attitude of the shield can be flexibly adjusted during tunneling, and the shield can smoothly turn through a small radius; (2) The thrust difference of the oil cylinders at the left side and the right side is mastered, the overall thrust is reduced as much as possible, and slow and sharp rotation is realized; (3) Enabling a shield machine driver to enter a corresponding preparation gesture in advance according to geological conditions and line trend trends, and reducing deviation correction caused by bad gestures; (4) And the station-moving measurement of the encryption duty-adding laser system is avoided, and the axial error caused by the measurement is avoided. Because we regard the curve of short distance as the straight line segment to guide the tunneling of the shield machine, if the station-moving measurement of short distance is not carried out, the curve of long distance is regarded as the straight line, so the axis deviation will naturally be quite different; (5) And (3) segment selection is performed, and the position of the K block is determined according to real-time measurement of the shield tail gap. And the segment with proper ring width is selected, so that the fit between the shield posture and the design axis is effectively ensured.

Measures for preventing the pipe piece from floating, sinking and laterally moving: when the shield tunneling machine enters the gentle curve segment, the posture of the shield tunneling machine is shifted 15-20 cm towards the inner side (towards the center of a circle) of the curve to form reverse pre-shift, so that the shift of the segment towards the outer side (towards the center of a circle) of the curve afterwards can be counteracted. The thrust of the oil cylinder is reduced, the strength and self-stabilization capacity of peripheral soil bodies can be obviously reduced due to the disturbance of the soil bodies in the process of tunneling small-radius circular curves in strong and medium-stroke stratum, the creep characteristics of the soil bodies and uneven soil body pressure in the horizontal direction appear, and the pipe piece can integrally move outwards under the condition that the pipe piece bears the horizontal component force of a jack for a long time and the like. The displacement delta of the small-radius curve tunneling segment can be expressed by the following formula:

wherein T is the reaction force of the thrust of the shield machine, R is the turning radius, P is the additional stress of the soil body to the side face of the duct piece, and ζ is the deformation coefficient. From the above, it is known that: the larger the thrust of the shield machine is, the larger the lateral displacement of the duct piece is, and the smaller the turning radius of tunneling is, the larger the lateral displacement of the duct piece is. Meanwhile, the thrust can be controlled between 900 and 1150t according to construction experience during the propelling; the thrust is adjusted in time according to the actual situation when the stratum is special. Grouting is additionally carried out in the direction of the deflection of the pipe piece, and a certain pressure is reached to resist the deflection of the pipe piece. After the slurry has solidified, the segment position is substantially determined. The grouting position is 1 point and 4 points hand holes (right turning), so that not only can the horizontal deflection of the duct piece be resisted, but also the floating of the duct piece can be resisted.

And (3) shield receiving:

The shield receives the working content of the shield, which comprises the following steps: the shield machine is used for positioning and receiving the re-checking measurement of the position of the tunnel portal, reinforcing stratum, processing the tunnel portal, installing the sealing equipment of the tunnel portal ring, installing the receiving base and the like. The process flow is as follows: reinforcing a hole-out soil body, installing a receiving frame, carrying out re-checking measurement on the position and the posture of a shield tunneling machine, chiseling the hole, installing a hole opening waterproof device on the hole, carrying out shield tunneling, cleaning a cutter disc, moving the shield body forward in place, dismantling the cutter disc to connect, lifting the cutter disc, disconnecting the trolley from a host pipeline, moving the trolley backwards, and dismantling the screw machine, and moving the trolley backwards. Removing a propeller pipeline, driving, rear sleeve pipes, auger rods, moving to a tunnel, removing a front shield body, connecting and hanging out the front shield, removing a hinge connection, adjusting out the hinge shield body, ejecting a shield tail, removing a jack, hanging out the shield tail, removing the jack, hanging out a screw machine part, removing a receiving bracket, paving a trolley track, disconnecting the trolley connection, sequentially hanging out the trolley, and removing and hanging out a related auxiliary bracket in the pit.

And (3) arrival construction of the shield machine: 1) Tunneling is carried out according to the through gesture of the shield tunneling machine and the tunneling deviation correcting plan, deviation correction is gradually completed, and the deviation correcting quantity of each ring cannot be excessively large. 2) When the shield tunneling 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 below 20mm/min, the thrust is gradually reduced, and the soil body is slowly and uniformly cut, so that the stability of reaching the end wall is ensured, and the stratum collapse is prevented. 3) After the shield enters the receiving section, the monitoring and measurement of the earth surface is enhanced, and information is fed back in time to guide the tunneling of the shield machine. 4) When the distance of the cutter head of the shield machine is less than 10m, a special person is responsible for observing the change condition of the hole opening in the tunneling process, and is always in communication with a driver of the shield machine, and tunneling parameters are adjusted in time. 5) After the spliced duct piece enters the reinforcing range, the slurry is changed into quick hardening slurry, and mud water is blocked outside the reinforcing area in the reinforcing range in advance. 6) After the last ring pipe piece of the pipe piece is assembled, the double-liquid slurry is injected into the secondary grouting holes of the pipe piece to plug. The grouting process is closely focused on the condition of a tunnel portal, and the grouting is stopped immediately once the phenomenon of slurry leakage is found. 7) When the shield shell of the shield precursor is pushed out of the tunnel portal, the folding plate is adjusted through the steel wire rope on the clamp plate clamping ring to press the curtain rubber plate as much as possible, so that the mud water and the slurry of the tunnel portal are prevented from flowing out. When the segment is separated from the shield tail, the steel wire rope is tensioned again, so that the pressing plate can press the rubber curtain cloth, and the curtain cloth always plays a role. 8) Because the thrust is smaller when the shield arrives at a station, the connection between the segment rings near the tunnel portal is not tight enough, so that the bolt fastening and re-fastening work of 20-ring segments after the shield arrives at the station is needed. And the channel steel is used for longitudinally tensioning the rear 20-ring duct piece along the tunnel, so that the rear 20-ring duct piece is integrated, and the influence of the loosening of the duct piece on the sealing waterproof effect is prevented.

Disassembling and hanging out of the shield machine: and (3) according to the construction progress requirement, after the section tunnel is penetrated, the shield machine disassembling work is started, and the shield machine large part and main parts disassembling work is completed within 15 days. The on-site shield machine is completely arranged under the disassembly well, and the disassembly of the shield machine can be started after the pipeline is marked. Disassembly after arrival of the shield machine: before reaching the dismantling well, the shield machine needs to perform state detection and machine condition assessment so as to thoroughly recover the machine performance before the transition of the shield machine.

Shield construction abnormal condition treatment plan: the abnormal conditions of the shield tunneling machine in the tunneling process can be as follows: the spiral machine gushes out, the cutter disc forms mud cakes, shield tail leaks thick liquid and the like, and the concrete explanation is as follows: 1. the treatment measures of blocking and deflection in the active articulated tunneling comprise 1) the treatment measure of blocking of a shield machine, and 1) the adoption of an external antifriction measure of a shield shell, such as: bentonite or other lubricating liquid is injected into the shield shell through the radial holes of the middle shield so as to increase lubrication between the shield body and the peripheral soil body. 2) And the thrust of the shield machine is increased. The shield thrust is increased mainly through adjustment of a shield machine propulsion system or through a measure of adding an external oil cylinder, so that the shield machine is forced to be driven. 3) And replacing a hob at the peripheral edge of the cutterhead or starting an overexcavation cutter to increase the overexcavation amount. 4) If the shield machine is not trapped by the measures, adopting a blasting treatment scheme for treatment. 2. And due to the deviation treatment measures in tunneling, tunneling cannot be carried out completely according to the designed tunnel axis due to the influences of factors such as uneven stratum hardness, tunnel curve and gradient change, operation and the like, and certain deviation can be generated. When the deviation exceeds a certain limit, the tunnel lining is limited, the shield tail clearance is reduced, the local stress of the segment is deteriorated, the stratum loss is increased, and the ground surface subsidence is increased, so that effective technical measures must be adopted to control the tunneling direction in the shield construction, and the tunneling deviation is effectively corrected. (1) And controlling the shield direction, and carrying out shield attitude monitoring by adopting a laser automatic guiding 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 trend of the current position of the shield machine and the tunnel design axis in the main control room of the shield machine in all weather. The tunneling direction of the shield tunneling machine is adjusted and controlled according to the method, so that the tunneling direction of the shield tunneling machine is always kept within an allowable deviation range. As the shield thrust guiding system is advanced as desired for the reference point, accurate positioning must be performed by manual measurement. To ensure accurate and reliable propulsion direction, manual measurements are made twice a week to check automatic guidance. (2) And (3) tunneling control flow, measuring data of the system and rechecking the position and the posture of the shield tunneling machine, so that the accuracy of the tunneling direction of the shield is ensured. And fitting the shield attitude information reflected by the control plan and the guide system according to the sectional axis made by the line condition, and controlling the tunneling direction by operating the pushing oil cylinder of the shield machine in a partitioning way in combination with the tunnel stratum condition. When the shield tunneling machine is used for tunneling in an uphill section, the thrust of an oil cylinder at the lower part of the shield tunneling machine is properly increased; the thrust of the upper oil cylinder is properly increased when the downhill section is driven; when tunneling is performed on the left turning curve section, the thrust of the right cylinder is properly increased; when tunneling is performed on a right turning curve, the thrust of the left 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, adopting a method for reversing a shield cutter head to correct rolling deviation. And the allowable rolling deviation is less than or equal to 3, and when the allowable rolling deviation exceeds 3, the shield machine alarms to prompt an operator to switch the rotating direction of the cutterhead and carry out reversal deviation correction. 2) The main factor of the vertical direction control for controlling the direction of the shield machine is the single-side thrust of the jack, and the relation between the single-side thrust and the attitude variable quantity of the shield machine is very discrete and is mastered mainly by human experience. When the shield machine is downward, the thrust of the lower jack is increased, and when the shield machine is upward, the thrust of the upper jack is increased to correct the deviation. 3) And the horizontal direction control is the same as the correction principle in the vertical direction, and the pushing pressure of the left jack is increased when the left jack is deviated, and the pushing pressure of the right jack is increased when the right jack is deviated. 4) The shield adjusts notes, when switching the cutter head rotation direction, the proper time interval is reserved, and the switching speed is not too high. The propulsion parameters are timely adjusted according to the stratum condition of the face to adjust the propulsion direction, so that larger deviation is avoided. 3. Emergency measures for gushing of the screw conveyor are adopted, if accidents occur in the shield tunneling process, the following measures are adopted for processing after gushing occurs: (1) Immediately closing a rear door of the screw conveyor, and tunneling forward properly to establish balance in the soil cabin; (2) Stirring soil in the soil cabin uniformly by rotating the cutter disc; (3) Then the back door of the screw conveyor is slowly opened, the door opening degree is about 30%, the soil is excavated while tunneling, and the pressure in the soil cabin is always kept stable. (4) In the tunneling process, foaming agent, bentonite and the like are injected into the soil cabin to improve the fluidity and water stopping performance of the ballast soil. And simultaneously, the outlet of the screw conveyor is connected with a pressure maintaining and ballasting device in a fastening way to establish a soil pressure balance state. 4. And (2) treating slurry leakage of the shield tail, (1) treating small leakage of the shield tail, wherein 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 to treat the slurry, the grease injection amount is increased at the position and the adjacent position, and if the leakage is larger, the grease injection amount is increased until the slurry is completely sealed. After leakage is stopped, continuing to push and arranging a special person at the tail of the shield for observing, and enabling a main driver to pay attention to the change of grease injection pressure at the leakage at any time, so that the front and rear persons can be kept in contact at any time; if the blocking cannot be performed for a long time or the leakage amount is increased, a shield driver and an on-duty engineer inform a master worker to determine a next treatment scheme. (2) And 1) carrying out large-scale leakage treatment on the shield tail, namely manually injecting grease, immediately stopping tunneling, increasing the grease injection quantity aiming at the leakage position and the adjacent position, and if the leakage is large, regulating the grease injection quantity until the grease injection quantity is completely sealed. 2) Draining water in the tunnel, and pumping water into the mud pipe by a mud pump arranged at the bottommost part of the tunnel, so as to strive for time for emergency. 3) And if the problem of shield tail leakage cannot be solved by manually injecting grease, the tunneling speed is accelerated, the ring tunneling is completed rapidly, and the segment is spliced. 4) And plugging the wall of the duct piece, storing two cotton yarns on a duct piece mounting machine, and plugging the cotton yarns into the joint of the duct piece and the shield tail brush at the leakage position by using steel drills after the leakage of the shield tail occurs. 5) And (3) secondary grouting, namely preparing a hand-operated pressure pump grouting device on the shield tunneling machine, opening a penultimate secondary grouting hole nearby, installing a grouting joint and a ball valve, and injecting acrylic acid salt plugging material by using the hand grouting device to form a seal after the wall of the duct piece. 6) If slurry, mortar or clear water leaks at the joint of the inner pipe slice of the shield tail, the tunneling is stopped immediately, the manual grease injection is adopted for blocking, the grease injection quantity is increased at the position and the adjacent position, and if the leakage is large, the grease injection quantity is increased until the sealing is completed. If the leakage can not be blocked, the tunnel leakage blocking team is informed of timely blocking the pipe piece leakage part by injecting polyurethane, and after the treatment is finished, whether the tunneling is restored or not is determined by a general worker according to the blocking condition.

Problems and emergency treatment measures possibly encountered in shield arrival: (1) According to the hydrologic and geological conditions of the receiving end of the tunnel section, the ground water of the planned construction site is mainly bedrock fracture water. The bedrock fracture water is mainly reserved in the weathering and structural fracture of metamorphic rock and is used for receiving atmospheric precipitation and infiltration and replenishment of upper pore water. The local joint cracks of the bedrock under the field are relatively developed, but are mostly filled by secondary minerals, so that the connectivity is poor; the water quantity is very small, the water permeability of the upper earth layer is weak, the water storage space is limited, and the water is not seen in the investigation period. Therefore, during the process of breaking the end-of-arrival tunnel portal, the reinforcement is unstable, the tunnel portal gushes out sand and water, and the risk can cause secondary risks such as ground collapse, building and pipeline damage. (2) The method comprises the steps of 1) strictly controlling the construction quality of grouting reinforcement of a tunnel portal soil body, detecting the reinforcement strength and uniformity of the soil body in a horizontal and vertical core drilling sampling mode, and remedying by adopting a supplementary grouting method if the reinforcement strength and uniformity of the soil body are not up to the standard. 2) Drilling a horizontal observation hole in the range of a tunnel ring before chiseling the concrete of the tunnel portal, and observing whether water leakage occurs; if the situation occurs, adopting corresponding treatment measures such as horizontal grouting or precipitation according to the specific situation of the water leakage; 3) The temporary water stop device of the tunnel portal is firmly installed, and after the second time of tunnel portal concrete is quickly chiseled, the shield machine is quickly pushed into the tunnel ring to be close to the soil body, so that the condition of water leakage caused by overlong exposure of the tunnel portal soil body reinforcement time is prevented; 4) An effective monitoring mechanism is established, feedback is timely carried out, and an emergency plan is started immediately when the early warning is exceeded; 5) Carefully performing shield debugging before shield starting; and (5) grouting, injecting tail grease and the like are performed when the shield machine enters and exits the tunnel. 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 any personnel and objects are forbidden to block the channel during construction. 7) And (5) breaking the control of the opportunity of the tunnel portal. The tunnel portal breaking work before the shield is started is required to be performed after all the shield machine and the shield construction members are ready, and all the equipment and personnel are in the combat state. (3) The treatment measures are that if water and sand gushing occurs, the treatment is carried out according to the following steps: 1) Firstly, checking the leakage volume of a tunnel portal, blocking at the position of a horizontal exploratory hole by utilizing on-site self-resources of a project part, and checking the blocking effect; 2) If the plugging effect is not ideal and can not be effectively controlled, reporting to a unit, and requesting the support of an emergency team; 3) After the preliminary plugging of the tunnel portal water leakage is finished, holes are led at 1m positions on the north and south sides of the shield tunneling machine according to the interval of 2 m; 4) After the hole is introduced, grouting a flowtube for grouting cement mortar, and effectively backfilling and plugging the leakage hole; 5) Immediately stirring cement mortar at a ground mortar stirring station when dangerous situations occur, and preparing for continuous synchronous grouting filling in a subsequent hole; 6) When the ground grouting is carried out, the grouting mortar is continuously pressed at the shield tail, and the hollow area of the shield tail is filled and blocked; 7) Opening the existing grouting holes in the shield machine, and pressing cement slurry at the middle body part of the shield machine, so as to fill and seal the hole areas between the tail gates; 8) Determining whether an advanced grouting hole is required to be drilled at the lower part of the shield according to the site situation, and if so, timely arranging a shield machine maintenance personnel to enter the lower grouting hole to start to be drilled and installed; 9) Hoisting Kong Zaochuan the third and fourth ring segments behind the shield tail by adopting drilling equipment in a tunneling working process, and installing a grouting ball valve; 10 Conveying grouting equipment and water glass to the position of the shield tail from outside the tunnel by the tunneling working, and starting to press water injection glass outwards at the grouting hole of the shield tail pipe piece to form quick hardening slurry with cement slurry pressed before, so that leakage is effectively controlled finally; 11 If the measures still cannot prevent a large amount of water and sand from gushing, the tunnel portal is sealed by immediately casting concrete through a template, so that the situation is prevented from being further enlarged.

And (3) auxiliary engineering construction:

And (3) constructing a hole door ring: the hole sealing is used for preventing the back lining grouting mortar from leaking out when the shield starts. In the process of the shield tunneling, the tunnel portal steel ring and the shield shell can form an annular building gap. In order to prevent a large amount of muddy water from entering the well from outside the tunnel portal through the building gap during the shield tunneling, and influence the establishment of the soil pressure of the excavation surface, the stabilization 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 must be arranged to ensure the correct establishment and construction safety of the initial soil pressure balance. The engineering sealing water stop device is installed on a circular plate pre-buried at a hole outlet opening, and the circular plate is made of a Q235A steel plate. The ring plate is reserved with a fixed screw hole, and the curtain rubber plate used as a sealing water stop device is fixed on the opening steel ring by the ring plate. 1) The construction process comprises the steps of dismantling the ring segments of the tunnel portal and the connection construction device at the construction stage before the tunnel portal lining construction, paving a waterproof layer according to the design, installing a water-swelling rubber water stop belt, binding reinforcing steel bars, ensuring firm connection between the reinforcing steel bars of the tunnel portal and the end wall structure, and pouring concrete after the formwork erection. After the construction of the tunnel portal is completed, whether to supplement grouting to the backing of the tunnel portal duct piece is determined according to the condition of the waterproof effect of the tunnel portal so as to improve the waterproof performance of the tunnel portal. 2) The construction process comprises the following steps: grouting at a near-opening, removing the ring segments of the opening, installing a water stop, binding reinforcing steel bars, standing a mould, pouring concrete, removing the mould, maintaining, finally checking the waterproof effect of the opening, if the waterproof effect meets the requirement, completing the construction process, otherwise, grouting and pressure supplementing on the ring segments of the opening. 3) The process of dismantling the portal ring: a. before the sealing and dismantling of the tunnel portal, carrying out supplementary grouting from the grouting holes of the +1 ring duct piece so as to achieve an effective water stopping effect after the duct piece wall of the tunnel portal, wherein the grouting slurry adopts cement and water glass dual-liquid slurry; b. drilling holes from the hole gate ring pipe piece after grouting is completed, detecting the leakage condition of the hole gate, and continuing grouting until no water seeps after drilling if the leakage phenomenon exists; c. removing the temporary seal (pressing plate, rubber curtain cloth, etc.) of the hole; d. removing the tunnel portal ring segment, firstly building a scaffold operation platform, manually chiseling a capping block, and then sequentially removing the whole ring segment from top to bottom; e. the mortar is chiseled by using a manual hand-held pneumatic pick after the duct piece wall is chiseled until the surface of the embedded annular steel plate in the portal ring is completely exposed, and the surface is cleaned; f. and after the mortar is chiseled off after the wall of the duct piece, if water and sand leak occur, burying the duct first, temporarily blocking with quick-drying cement, grouting and blocking until no water seeps out, and finally removing the buried duct.

And (3) constructing a portal ring beam: before the lining construction of the tunnel portal, the tunnel portal ring segments are removed, a waterproof layer is paved, a water-swelling rubber water stop belt is installed, steel bars are bound, firm connection between the tunnel portal steel bars and the end wall structure is ensured, and concrete is poured after the formwork is erected. After the construction of the tunnel portal is completed, whether to supplement grouting to the backing of the tunnel portal duct piece is determined according to the condition of the waterproof effect of the tunnel portal so as to improve the waterproof performance of the tunnel portal.

Shield waterproof: a segment 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 the principle of 'mainly preventing, combining hardness and softness, multiple fortification, local conditions and comprehensive treatment'. The self-waterproof performance of the reinforced concrete structure is ensured. Therefore, effective technical measures are adopted to ensure that the waterproof concrete achieves the compactness, impermeability, cracking resistance, corrosion resistance and durability specified in the specification. Reinforcing waterproof measures of deformation joints, construction joints, embedded parts, reserved holes, joints and cross section interfaces of various structures. The key of the self-waterproof pipe piece is concrete configuration and quality control. The concrete strength grade of the segment is C50, the impervious grade is P12, and the following measures are adopted: 1) And ordinary silicate cement with stable quality, low hydration heat and low alkali content is selected, and early strength cement and cement with higher C3A content cannot be used. 2) In order to improve the impermeability, high-quality fly ash is doped, the quality of the fly ash accords with the related regulations of the current national standard of fly ash for cement and concrete (GB 1596), the grade of the fly ash is not lower than grade II, the firing vector is not higher than 5%, and low-calcium ash with free calcium oxide not higher than 10% is selected; the dosage is preferably 20% -30% of the total amount of the cementing material, and when the water-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 mixing water consumption as much as possible, and adopting a high-efficiency water reducing agent; 4) The water, sand and stone of the waterproof concrete meet the relevant regulations of the 4.1.10 and 4.1.11 of the waterproof technical Specification of underground engineering, and clean aggregate with firm and durable structure, qualified grading and good grain shape is selected. 5) The engineering environment condition belongs to supermarket environment, and alkali active aggregate cannot be adopted. 6) The aggregate with low alkali content should be selected, and the maximum grain diameter of coarse aggregate is controlled to be not more than 25mm, and the consumption of 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/m ³. 8) The chloride ion content in the concrete is not more than 0.06% of the weight of the cementing material, and the alkali content is not more than 3kg/m ³. 9) And curing the concrete in time after final setting, wherein the curing period is not less than 14d, and the highest temperature of duct piece steam curing is not more than 60 ℃. The winter construction of the concrete meets the requirements of relevant specifications. 10 If segregation occurs after transportation, secondary stirring is needed, when the slump loss cannot meet the construction requirement, cement paste with the original water-cement ratio or a water reducer mixed with the same variety is added for stirring, and direct water addition is forbidden. 11 Leak detection test is carried out by spot check one piece for each production of 50 rings of duct pieces, and the test standard is as follows: the pressure of 0.2MPa is maintained for 3 hours, water leakage is avoided, and the water seepage depth is not more than 5cm. B. The pipe sheet joint is waterproof, and the joint is provided with a sealing gasket with a porous special section. The elastic gasket was spot checked at a rate of 0.2% and the test report was approved by a supervision engineer. In order to meet the waterproof requirement of the joint, two waterproof measures of a frame-shaped elastic sealing gasket and a caulking joint are arranged at the joint of the duct piece, and the elastic sealing gasket is used as a main waterproof measure. 1) The sealing gasket is waterproof, the sealing gasket adopts ethylene propylene diene monomer rubber, and the lower part is provided with a plurality of holes and grooves, so that the stress-strain characteristic can be improved, when a seam is opened in a certain range, the change of the compressive stress of the contact surface of the sealing gasket is smaller, and the splicing stress is reduced on the premise of meeting the watertight requirement. The deformation joint is additionally provided with water-swelling rubber outside the sealing gasket, so that the waterproof capacity of the deformation joint is further enhanced. 2) The caulking is waterproof, the caulking groove sealing material adopts a mode of filling the caulking by adding PE sponge strips and polyurethane sealant, and the inner side of the duct piece is integrally coated with an interface treating agent for treatment after the caulking is finished. Caulking range: the longitudinal seam of the whole tunnel whole ring is embedded and filled. For places with obvious water leakage points, quick hardening cement is used for sealing the buried pipe for water diversion (or grouting). Before caulking, dust and sundries in the joint should be cleaned, and the construction of caulking materials is carried out in a dry state. C. The connecting bolt holes and the grouting holes are waterproof, the connecting bolt holes are blocked by sealing rings made of water-swelling rubber materials, and the waterproof is enhanced by the dual functions of compaction and swelling; the grouting holes are waterproof, and the water facing surface of the grouting holes is pre-poured with the same-grade concrete with the thickness of 25mm during the production of the pipe piece, so that the grouting holes can play a good role in waterproof. After grouting is finished through the grouting holes, the movable end head part is removed, and the grouting pipe cover with the sealing gasket is screwed up for waterproofing. D. Grouting reinforcement waterproof, after shield pushing, grouting filling is timely carried out on a shield tail gap before surrounding rock slumps, so that not only ground subsidence can be prevented, but also the waterproof of tunnel lining is facilitated, proper slurry (the slurry has the characteristics of low initial viscosity, micro-expansion, high later strength and the like), grouting parameters and grouting technology are selected, a stable duct piece peripheral waterproof layer can be formed, the duct piece is surrounded, and a protection ring is formed. E. The tunnel portal is waterproof, 1) the waterproof design of the tunnel portal is that water expansion rubber water stop bars are arranged in rigid joints of the tunnel portal, the section tunnel duct pieces and the shaft structure except waterproof concrete. And a water stop strip or a water stop belt is arranged at the construction joint. According to the specific construction condition, pre-grouting in advance or post-grouting of pre-buried grouting pipes during construction can be performed as necessary. In the waterproofing treatment, the time can be divided into three stages: firstly, the shield machine is processed before entering the starting gate, secondly, the shield machine enters the starting gate, and the waterproof measure is performed during the starting period, and thirdly, the waterproof plugging measure is performed after the shield machine enters the starting gate. 2) Performing tunnel portal treatment before starting and reaching, performing end stratum reinforcement, performing inspection and test after the reinforcement is finished, checking the reinforcement effect, and performing grouting treatment if necessary; and determining a door sealing (mainly referred to as a reserved door after the vertical shaft structure is manufactured) treatment scheme of the door according to geological conditions and burial depth of the door. Conventionally, concrete sealing doors are mainly adopted, pre-buried steel rings are arranged at the positions of the holes, and necessary structural treatment is required between the holes and the end walls. And when the shield arrives, the concrete sealing door is removed. 3) When the tunnel portal is opened, the shield should be pushed against the excavation surface as soon as possible to seal the tunnel portal; when the receiving door arrives, the receiving door is pushed out as soon as possible and is closed; according to the design requirement, waterproof devices such as a curtain cloth rubber plate, a circular plate and the like are arranged on the tunnel portal, and when the shield is started, quick setting hydraulic double-liquid slurry is injected to seal the tunnel portal. 4) After the shield is started and reached, the shield is started and prepared, the cutter head enters the tunnel portal and immediately seals the tunnel portal ring, and after the shield tail completely enters the soil body of the face, the hydraulic double-liquid slurry is injected to seal the tunnel portal; when the shield arrives, after the shield machine is completely separated from the tunnel, the turning plate is immediately fixed to seal the tunnel portal ring, and the tunnel is timely grouting and filled so as to ensure the stability of the earth surface after the shield arrives at the station. The caulking work of the construction joint is actually finished, and as a second defense line, leakage caused by the fact that the sealing of the joint of the water stop strip is not tight or the corner is cracked or the joint of the elastic sealing gasket and the corner of the duct piece is damaged by construction can be made up, neoprene latex cement mortar is adopted as the caulking material, and the interface treatment agent YJ-302 and the PE film are adopted as the interface treatment.

The shield passes through the special section and adopts the construction measures:

A. Control and treatment measures for shield passing through a building: (1) The auxiliary measure before tunneling 1) protection monitoring is needed to be carried out on structures such as houses, bridges and the like in the range of direct penetration and influence of the shield, and deformation observation of the structures can be divided into settlement observation, inclinometry observation and crack observation. The settlement measuring points are arranged on a foundation or a wall body, and a plurality of measuring points are also arranged on the ground surface outside the structure and the bottom plate of the structure and measured by using a level gauge; the inclination monitoring of the structure can adopt a theodolite measuring method, and an inclinometer can also be 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 observer. 2) The real-time settlement monitoring is carried out on the crossing section, and the concrete scheme is that monitoring points are arranged at relevant positions of piers and buildings, emergency supplementary grouting is adopted when a monitoring value is close to an early warning value (15 mm), settlement is controlled in time, and the traffic safety of a roof tunnel is ensured. 3) Third party monitoring is introduced, and rechecking work is carried out on the first party monitoring data through the third party monitoring and monitoring management, so that the accuracy of the first party monitoring data is ensured. The deformation condition caused by shield construction is accurately reflected, and relevant early warning or alarm is sent to places with obvious deformation which is equal to or not smaller than a prediction standard, so that relevant technical departments can solve and process the deformation, the safety order is kept, and the stable expansion of shield construction is ensured. 4) Before crossing, the equipment can be maintained according to the outline (the tool changing can also be considered), so that the equipment can pass through the box culvert section smoothly during construction. The maintenance projects mainly comprise: the system comprises a main driving system, a cabin system, a propulsion and hinging system, a grease system, a foam system, a shield tail sealing condition, a splicing machine, 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 wiring terminals, and comprehensively cleaning and maintaining the belt conveyor; by checking and replacing the hidden trouble parts, the reliable operation of the equipment is ensured. In addition, the maintenance is carried out on the matched equipment such as the battery truck, the gantry crane, the mortar station and the like. (2) And (1) controlling the tunneling process, namely 1) improving the shutdown pressure maintaining value, and when tunneling in a soil pressure balance mode, because the section is mainly ⑥ 1 strong-wind conglomerate stratum, the top is ② pebble stratum, and the water permeability coefficient is large. The calculated soil pressure determined by the test section is the tunneling soil pressure, the pressure is properly increased by 0.1-0.15bar when the machine is stopped and the pressure is maintained, the stability of the soil cabin pressure and the excavation surface is ensured, and the earth surface subsidence is controlled. 2) The soil pressure tunneling is kept, the speed is kept unchanged basically, 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 machine or the opening of the slag discharging door. 3) And according to the quick passing principle, 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 an upper stratum caused by the disturbance of a cutter head. 4) And controlling possible gushing, using high-quality foam, simultaneously injecting high-molecular polymer or high-quality bentonite slurry into the tunnel face, the soil cabin or the screw machine according to the slag discharge condition at a foam injection port of the cutterhead, increasing the water stopping effect, improving the plastic flow property of the slag soil and controlling the gushing. 5) The grouting is enhanced to control sedimentation, synchronous grouting quantity is controlled according to experimental data and theoretical calculation data, pressure and flow are controlled in a dual mode, pressure control is mainly used, flow control is auxiliary, and sufficient mortar injection is guaranteed. According to the geological condition, the mixing proportion of the mortar is adjusted, the initial setting time of the mortar is shortened, and the purpose of controlling the surface subsidence is achieved. According to the monitoring data of the earth surface subsidence, performing secondary grouting in time; the shield posture is controlled, the deviation correction amount is reduced, deviation correction is avoided as much as possible, and less correction work and correction are performed when deviation correction is needed. 6) The soil output control is enhanced, the control is carried out by adopting a method for measuring the volume of the slag soil, and the soil output of each ring is determined according to the loosening coefficient of the slag soil obtained through experiments and the slag soil densities of different sections. 7) In the segment assembly and shield pushing process, segment assembly must be carried out, and the segment assembly should be completed rapidly and with high quality by experienced workers. The duct piece should be assembled in the middle as far as possible, so that the duct piece is prevented from being damaged due to uneven gaps between the shield tails to form a water seepage channel. 8) The coordination is enhanced, shield operators execute the operation instructions strictly according to the operation instructions issued by technical responsible persons, and when the operation instructions cannot be implemented due to the change of geological conditions, the shield operators communicate with technical departments in time to negotiate, and communicate with research solutions and treatment measures. And each constructor needs to keep close connection and coordination in the tunneling process. If the equipment is required to be stopped due to equipment failure in tunneling, the soil pressure is reasonably set, and countermeasures are taken according to actual conditions. (3) Grouting reinforcement is adopted, and sleeve valve pipe grouting reinforcement is adopted on the outer side of a structure before a shield passes through in order to ensure the safety of the structure when the shield passes through the building. 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 plum blossom shape; the distance between the grouting pipe at the inner ring and the outer wall is not less than 1m, houses right above the tunnel are arranged around, and houses at the tunnel-side can be arranged on one side of the tunnel in a u-shape according to three sides. The deep length of the grouting pipe is performed according to the following standard: shallow foundation: the vertical length of the foundation bottom is not less than 3m and passes through the sand layer and the silt layer. The silt layer is not less than 0.5m, and the exposed ground is not less than 0.2m; friction pile: the diameter of the pile below the pile bottom is one time and is not less than 0.5m; end bearing wall: the bottom of the shield construction influence range is not less than 1m, or the stratum entering the number <8> or more is not less than 0.5m. When the grouting pipe is used for construction, the building foundation is prevented from being damaged. If the outside of the wall is limited in field, the wall can enter the house for construction. Corresponding measures should be determined to be taken according to the monitoring result. When the settlement of building structures such as houses is large and approaches to an alarm value, tunneling is stopped, an oblique grouting pipe is arranged on the side of a foundation from the ground, and tracking grouting is performed according to monitoring feedback data. Grouting effective range: 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 sleeve valve pipe construction process is the same as the process adopted in the process of end reinforcement.

B. The control and treatment measures when the shield passes through the ditch are as follows: (1) The shield tail sealing design is adopted, and the shield machine adopts three shield tail steel wire sealing brushes, so that the shield tail can be effectively prevented from being permeated. The injection of shield tail sealing grease is enhanced in tunneling, and the pressure of the shield tail sealing grease is ensured to be not less than 5Bar; strengthen the sealed inspection of articulated department, guarantee its sealed effect, prevent groundwater from gushing in. The attitude of the duct piece is controlled, the duct piece and the duct tail are prevented from being not concentric, the gap between the duct tail and the duct piece is locally oversized, and the sealing function limit of the sealing device is exceeded; the extrusion degree of the duct piece to the shield tail sealing brush is reduced; injecting grease in time, and adopting high-quality shield tail grease, wherein 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 completed; the shield is prevented from backing, so that the brushing direction is opposite to that of the shield tail brush and the duct piece, the brushing is reversely rolled, and the shield tail brush is deformed to reduce the sealing performance; if leakage occurs, a sponge is stuck to the outer side of the duct piece, and polyurethane is pressed into the shield tail through a grouting pipe orifice to seal the water passage. (2) The bentonite pressure maintaining system is used for injecting bentonite into the top of the soil cabin to form a mud film on the top of the soil cabin when the water-rich stratum is tunneled, so that underground water can infiltrate into the soil cabin to dilute ballasted soil, and the underground water can be effectively prevented from infiltrating into the soil cabin from the top. And because the system controls the injection pressure through compressed air, the soil cabin pressure 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 compensate for the out-of-cabin seepage and decompression of the soil cabin. (3) The design of the slag discharging gate of the screw conveyor controls the opening size of the gate through the oil cylinder, thereby ensuring the pressure of the cylinder body and the pressure of the excavation cabin, the design of the slag discharging gate adopts a double-gate design, a pressure maintaining pump interface is reserved between two gates, the gate is rapidly closed when the gushing occurs, the flange of the interface is opened to connect with the pressure maintaining pump for slag discharging, the screw conveyor is used for controlling the double gates when the section with larger water quantity is driven, and mud or high-efficiency polymer is filled, so that the gushing and water gushing are prevented. (4) The construction process is controlled, 1) the improvement work of the soil body with the cutting surface is finished, the shield penetrating through the ditch section is mainly positioned in the medium-vibration rock stratum, the soil layer strength is high, the soil body can be improved by adding bentonite or foaming agent to the front Fang Tuti of the mud adding hole, and the flow plasticity of the soil body is increased. The method comprises the following steps: the soil pressure value reflected by the soil pressure meter in front of the shield machine is more accurate; and two,: ensuring smooth soil discharge of the screw conveyor and reducing extrusion of the shield to the soil in front; and thirdly,: and timely filling gaps formed after the cutter head rotates. 2) And (3) reasonably controlling the soil pressure and the soil discharge, starting from the shield, strictly controlling the soil pressure value, and adjusting the soil pressure value by combining with the ground surface monitoring data to perform informatization construction. The part passing through the ditch should be in principle extracted according to the theoretical amount of the extracted soil, and the soil body can be properly underexcavated to ensure the compaction of the soil body so as to prevent river water from penetrating into the soil body and entering the shield. 3) The propelling speed is strictly controlled, the stability of the propelling speed is ensured, the lower speed is adopted for propelling when the water channel is traversed, the speed is generally controlled to be lower than 30mm/min, the total thrust of the jack is strictly controlled, and the disturbance of soil around the shield is reduced so as to avoid bursting the soil at the river bottom. 4) The shield posture is well controlled, abrupt deviation correction is avoided, tunnel axis measurement is enhanced in a crossing ditch area, accurate and detailed measurement data are guaranteed, and meanwhile, a shield main driver should strictly control the shield posture deviation to guarantee accurate shield axis position; when the attitude deviation occurs, correction processing is timely carried out according to the measured data, so that correction is reduced as much as possible, and particularly, correction with a large amount is stopped, disturbance of soil is reduced, and the shield tunneling machine is ensured to stably pass through from the lower part of the ditch. 5) The grouting quality is strictly controlled, the intensity, specific gravity, setting time, water seepage, consistency and the like of the slurry are detected before the grouting quality is ensured, the slurry with high early strength is selected as much as possible on the premise of ensuring the grouting quality, the grouting pressure is reduced, the water channel formed by the penetration of the grouting pressure and soil at the top of a tunnel due to the over-high pressure breakdown and soil covering is prevented, the grouting quantity is properly increased, the grouting quantity is adjusted in real time according to ground surface monitoring data, and the stability of soil around a ditch is ensured; and (3) performing secondary grouting treatment by adopting high-strength slurry according to monitoring data in time after the pushing is finished, filling gaps between the shield body and the duct piece which are not filled due to the reduction of synchronous grouting pressure, and preventing later leakage. 6) The waterproof quality of the duct piece is enhanced, a sealing water stop adhesive tape meeting the requirements is selected, the adhesion condition of the sealing adhesive tape and the breakage condition of the duct piece are checked and accepted before the duct piece goes down in the well, and the sealing effect is ensured by timely replacement which does not meet the requirements; the segment splicing quality control is enhanced, proper segment types are selected according to the shield posture conditions, the waterproof glue strips are prevented from being clamped with mud and slag, meanwhile, the segment cannot be damaged by collision or the waterproof glue strips cannot fall off when the segment is spliced, the sealing effect is guaranteed by connecting and re-tightening the segment with bolts immediately after the segment is spliced, and the overall waterproof performance of a tunnel is improved. (5) Grouting reinforcement is carried out in the tunnel, and when the shield passes through the ditch, a steel flowtube is arranged in the tunnel through a hand hole for grouting reinforcement after the shield passes through in order to ensure the safety of the ditch foundation. The reinforcing range is a range of 1.6m outside the duct piece, cement slurry is adopted for grouting, the grouting pressure is not too high, and the ground surface is prevented from being raised to damage the ditch foundation.

C. And (3) small radius curve construction: the shield engineering small radius curve has 5 positions and the radius is 200m and 500m. To ensure the construction of small radius curve segments, the I'm section will take the following measures: the technical support of 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 gesture control of curve tunneling is assisted. The active hinging is the function of bending the segmented machine body of the shield machine by the internal control of the shield machine without the help of soil layer pressure. The setting of the active hinge can be connected with a guide system of the shield machine, the attitude of the shield body is calculated by calculating the travel difference between the active cylinders, and the tunneling attitude of the shield machine is reflected in real time through the control interface. (2) The spherical hinge mechanism is characterized in that the front shield, the middle shield and the tail shield are connected by adopting an active hinge oil cylinder type, the bending part is sealed by adopting a spherical hinge ring type matched with a lip type, the gap formed by bending the shield body is effectively sealed, and a larger bending angle is realized. The front hinge of the hinge mechanism provided by the engineering can 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 of 10 times of the diameter of the shield body. (3) And in the profiling cutter structure, when tunneling with a small curve radius, the turning side is required to be overexcavated. However, the excessive clearance of 360 degrees of super-digging by the super-digging cutter can cause the risk of ground subsidence or shrinkage cavity. The shield tunneling machine cutterhead adopted in the engineering is provided with a profiling cutter structure. The profiling cutter can accurately cut the necessary construction gap for turning the shield body, so that the risks of ground subsidence, shrinkage cavity and the like are reduced. When the shield tunneling machine is tunneling or correcting, the profiling cutter can be reasonably used according to specific conditions. (4) In the construction of the acute curve section, the measurement guide system needs to be frequently moved in order to ensure the visual effect, and extremely high requirements are put on accurate measurement. The guiding measurement system adopted in the engineering is suitable for the internal use of a small shield tunneling machine and is developed and developed by a company of China and a system manufacturer, and can realize accurate measurement feedback under the condition of frequent station shifting to guide the tunneling construction of the shield tunneling machine. (5) A small radius construction auxiliary construction method, a.a front shield auxiliary grouting technology, in small curve radius tunneling, soft soil layers or occasions where counterforces cannot be expected when tunneling are encountered, tunneling after shield body bending cannot reach a set target, at the moment, the bearing capacity of surrounding soil bodies needs to be increased, and enough steering counterforces are established. The engineering shield machine utilizes the slurry mixing and pumping device of the shield machine to perform slurry injection to one side of the shield machine to form gel solid, and establishes steering counterforce. b. In the miniature fixed bag technology, when the shield body establishes counterforce, enough steering counterforce is also required to be established for the formed tunnel, and the posture of the supporting equipment is adjusted, so that the miniature fixed pile technology is designed and adopted. The folded nylon yarn bag was housed in a cylinder having a length of about 9.5cm and a diameter of about 5.5 cm. After the cylinder is screwed into the grouting hole of the pipe piece and the strong grouting material is injected, 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 bags are arranged in grouting holes of pipe ring pieces at the outer side of the sharp bending section, and each ring of pipe pieces (the pipeline is 50cm or 80 cm) is provided with 3-4 miniature fixing bags. And when the segment 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 segment is filled. The adopted shield small radius curve construction process (1) comprises the following process flows: and (3) pre-setting shield parameters after construction preparation, combining with shield machine type selection and segment selection meeting the small-radius curve tunneling requirement, and auxiliary measures such as axis pre-deflection setting, segment grouting reinforcement, longitudinal reinforcing rib adding, reinforcing bolt tightening and the like, tunneling, judging whether the tunnel is smaller than a standard, and combining with monitoring of settlement, displacement and convergence of a tunnel, if so, completing small-radius curve construction, otherwise, continuing optimizing shield construction parameters, and tunneling again. (2) Corresponding equipment construction technology is configured, and the hinged shield is adopted for construction. As the hinging part is added to the shield, the shield cuts to the supporting ring and the supporting ring to the shield tail form living bodies, the sensitivity of the shield is increased, the axial 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. The cutter head of the shield is provided with a profiling cutter with a certain overexcavation range. When the curve is constructed, partial overbreak can be carried out according to the condition of the pushing axis, and the greater the overbreak amount is, the easier the curve is constructed. On the other hand, the over-excavation causes the synchronous grouting slurry to wind into the excavation surface due to loosening of soil body, and causes a problem of increasing tunnel deformation due to factors of a reaction force drop during curve pushing. Therefore, the overexcavation amount is preferably controlled within the minimum limit of the overexcavation range. b. The hinging angle meets the requirement, the hinging part is added to the shield machine, so that the shield incision is formed to the support ring, and the support ring forms living bodies to the shield tail, thereby increasing the sensitivity of the shield, reducing the over-excavation amount during the propelling, generating the propelling component force and ensuring the control of the propelling axis of curve construction. The conditions of segment outer arc fragmentation, segment water seepage and the like are greatly improved. The hinging angle alpha= (L1+L2) multiplied by 180/pi multiplied by R, wherein L1 and L2 are respectively a front body and a rear body of the hinging shield, R is the radius of a curve, alpha is the hinging angle of the shield machine on a small radius curve, and the angle is smaller than the maximum hinging angle of the shield machine. The hinging angle of the shield machine is fixed through fixing the stroke difference of the hinging jack, so that the shield machine is adapted to the corresponding curve radius. Articulated jack travel difference mm = jack maximum travel difference x (left-right articulation angle deg)/maximum left-right articulation angle deg. (3) And (c) carrying out grouting reinforcement after the wall of the tunnel duct piece, namely carrying out secondary grouting reinforcement on the soil body through the assembly holes of the duct piece on the duct piece outside the 10 rings of the shield tail after completing 2 rings of tunneling of the tunnel. b. A longitudinal reinforcing rib is arranged in the tunnel, and is arranged in a range of 50-60 m after the tunnel is close to the excavation surface so as to enhance the longitudinal rigidity of the tunnel and control the longitudinal displacement of the tunnel aiming at the large longitudinal displacement of the tunnel on a small radius curve. The reinforcing rib is formed by welding double-spliced [22a channel steel with a steel plate, and is connected with the reserved grouting holes of the duct piece by bolts, so that the tunnel is longitudinally connected to strengthen the longitudinal rigidity of the tunnel. c. After each ring is pushed, the connecting bolts of the front ring segment are required to be screwed, and the connecting bolts are required to be screwed when the lower ring is pushed, so that the vertical component force generated by pushing force acting on the segment is overcome, and the floating of the ring-formed tunnel is reduced. And 3 rings are completed in every tunneling, and the segment connecting bolts within 10 rings are screwed again. d. The propulsion axis is pre-biased, and the control of the propulsion axis is enhanced in the shield tunneling process. The shield is actually positioned on a tangent line of the curve during curve pushing, so that the key of pushing is to ensure the control of the posture of the shield machine. Because the dual-slurry effect of synchronous grouting and tracking and filling in the shield tunneling process can not fundamentally ensure the bearing strength of the soil body behind the segment, the segment is deflected to the outer side of the arc 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 relevant construction practice experience, the stratum condition of a tunneling area is considered, and the pre-deflection is set to be 20-40 mm in the tunneling process of the small semi-curve tunnel. The pre-deflection is properly adjusted by monitoring the deflection of the small-radius tunnel during construction. (4) And (a) selecting construction parameters, namely strictly controlling the pushing speed of the shield, wherein the pushing speed is controlled to be 1-2 cm/min. The lateral pressure increase caused by overlarge thrust is avoided, and the disturbance to surrounding soil in the shield pushing process is reduced. b. The front balance pressure of the shield is strictly controlled, and the shield needs to strictly control the incision balance soil pressure in the crossing process, so that the stratum at the incision of the shield has tiny uplift (0.5-1 mm) to balance the stratum settlement after the shield is constructed. And meanwhile, construction parameters related to the balance pressure of the cut, such as the soil yield, the propelling speed, the total propelling force, the difference of actual soil pressure around the set soil pressure fluctuation and the like, must be strictly controlled. Excessive overexcavation and underexcavation are prevented, and fluctuation of balance pressure is reduced as much as possible. The fluctuation value is controlled within 0.02 MPa. c. The synchronous grouting amount and the slurry quality are strictly controlled, and the stratum loss caused by curve propulsion and the disturbance to soil mass are increased due to the increase of deviation correction times caused by the increase of curve propulsion, so that the synchronous grouting amount and the slurry quality are strictly controlled during the curve propulsion, the total grouting amount of each ring is ensured to be in place in the construction process by adopting a propulsion and grouting linkage mode, the slurry is uniformly and reasonably stressed and injected during the shield propulsion of each soil box, and the proportion of the slurry is ensured to meet the quality standard. And the construction gaps are filled in time through synchronous grouting, so that soil deformation in the construction process is reduced. When grouting does not meet the requirement, the shield pauses the pushing so as to prevent the soil from deforming. The grouting amount of each ring is generally 130-250% of the building gap, 2.25-3.75 m 3/ring, thick slurry is adopted, the thickness of the slurry is 12-14 cm, and the pressure at the pumping outlet is not more than about 0.5 MPa. The specific grouting amount and grouting point are selected according to the pressure value and formation deformation monitoring data during grouting. According to the deformation monitoring condition in construction, grouting parameters are adjusted at any time, so that the axis is effectively controlled. (5) The soil loss and secondary grouting are characterized in that the design axis is a small-radius smooth curve, and the shield is a straight line, so that the actual tunneling axis is necessarily a section of broken line in the actual pushing process, and the soil output outside the curve is large. This necessarily results in loss of soil outside the curve and the existence of construction voids. Therefore, in the process of advancing the curve segment, the grouting amount of the outer side of the curve segment needs to be enhanced in the engineering of synchronous grouting so as to fill the construction gap. And (3) carrying out secondary pressure injection on the composite pre-setting slurry on the two ring pipe slices at the back of each two rings to strengthen soil body at the outer side of the tunnel, thereby ensuring that the shield is smoothly propelled along the design axis. The proportion of the slurry adopts cement, water glass=30:1, and the water-cement ratio is 0.6. The secondary grouting pressure is controlled below 0.3 Mpa; the grouting flow is controlled to be 10-15L/min, and the grouting amount is about 0.5m ³/ring. (6) The method is characterized in that the deviation correction amount of shield construction is controlled, the curve pushing of the shield is actually positioned on a tangent line of the curve, the key of pushing is to ensure the control of the head of the shield, as the ring of the shield is corrected by curve pushing, the correction of the duty measurement is required, the deviation correction amount of each time is as small as possible, and the ring surface of the wedge block is always positioned in the radial vertical plane of the curvature radius. Besides the wedge-shaped duct piece, a wedge-shaped low-pressure cotton rubber plate is adopted at proper time for correcting the duct piece in order to control the displacement of the duct piece, so that the purpose of effectively controlling the axis and the stratum deformation is achieved. The deviation rectifying amount of the shield propulsion is controlled to be 2-3 mm/m. And aiming at the deviation correction quantity of each ring, calculating the travel difference of the left jack and the right jack of the shield machine, and analyzing the selection type of the pipe piece by utilizing the travel difference of the jacks of the shield machine. (7) The gap control between the shield tail and the pipe piece is critical to the pipe piece assembly in the section with small curvature radius, and one key problem affecting the pipe piece assembly quality is the gap between the pipe piece and the shield tail. Reasonable peripheral gaps can facilitate segment assembly and shield correction. a. The gap between the shield tail and the duct piece is paid attention to at any time in construction, and once the unilateral gap is smaller, the gap is timely adjusted through the pushing direction of the shield, so that the gaps around the gap are basically the same. b. When the duct piece is assembled, the gap between the duct piece and the duct piece is reasonably adjusted according to the gap between the duct piece tail and the duct piece, so that the duct piece is conveniently assembled, and the shield can have enough gap to rectify the deviation in the propelling process of the duct piece. c. And reasonably selecting the wedge-shaped duct piece according to the gap between the shield tail and the duct piece. When the radius of curvature is small, the change of the gap between the shield tail of the shield machine and the segments is mainly reflected on two sides of the horizontal axis, the segments turn to normally follow the shield machine, and when the shield machine turns too fast, the gap between the shield tail on the outer side of the tunnel is relatively small; when the segment is advanced to the turning of the shield machine due to the wedge amount and the like, the shield tail clearance at the inner side of the tunnel is relatively smaller. Therefore, when the shield tail clearance cannot be adjusted through shield pushing and segment assembly, the mode of exchanging wedge-type segments and linear segments can be considered to be adopted for adjusting the shield tail clearance. (8) And (3) correcting the shield and correcting the measured gesture, and correcting the shield and the duct piece, wherein in the process of shield tunneling, the deviation between the shield pushing track and the tunnel design central line is ensured to be within the design allowable range by the following method. The deflection correction can be realized by adjusting the stroke of the shield hinged jack, the shield hinged jack is distributed according to four sectors, namely an upper sector, a lower sector, a left sector and a right sector, and when the shield needs to be adjusted in direction, the bending angle of the shield body can be adjusted by adjusting the stroke of the oil cylinder in the corresponding area. If the shield deviates from the design axis and deviation is needed, the stroke of the hinged oil cylinder can be increased at one side of the deviation direction to obtain the stroke difference. The stroke difference is adjusted through the hinged oil cylinder, so that the condition that the acting force of the shield jack on the lining segment is consistent and the segment is prevented from being damaged is avoided. The tunnel duct piece correction can also be carried out by adopting a micro wedge-shaped material, and the straight line segment is fitted with the micro wedge-shaped axis and the design axis by adopting a method of sticking a wedge-shaped low-pressure asbestos rubber plate on the duct piece ring surface at the curve segment. The compression ratio of the asbestos rubber plate is 12%, and the asbestos rubber plate which is pasted in sections is compressed by the jack in the pushing process to form a flat wedge-shaped ring surface. In the manufacturing process of the duct piece, tiny errors (particularly errors of the ring width) exist, errors are generated in the assembling process of the duct piece, the accumulation and development of the errors can lead to the fact that although a shield is not deviated from a design axis, the duct piece at the tail of the shield becomes more and more difficult to assemble, the deviation of the duct piece is measured, the fact that the central line of the duct piece is deviated from the design axis is found, and the following preventive measures are adopted: a. when each circular pipe piece is assembled, the gaps between the upper circular pipe piece and each point on the upper, lower, left and right of the shield inner shell are measured, and if the gaps between each point are above 1cm, the fitting of the pipe piece axis and the shield axis can be considered. If the gap at a certain point is measured to be smaller than 1cm, the pipe piece can be regarded as being deviated from the axis of the shield, at the moment, a trace amount of asbestos rubber wedge materials can be used for correcting the deviation, and the maximum wedge amount is attached to the lining surface at the position with small gap. b. The maximum wedge-shaped amount at one time is not more than 6mm, and if the maximum wedge-shaped amount exceeds 6mm, the compression amount of the pipe piece rubber sealing strip is reduced, and the sealing effect can be lost. Therefore, when the correction strip still needs to be stuck after the wedge-shaped duct piece is installed during tunneling of the curve segment, the correction strip should be stuck in a fractional ring, and the correction strip should not be stuck in a ring too thick. c. If the maximum wedge is 6mm (5.28 mm after compression). And after the deviation slope of the segment and the shield is measured, the deviation correcting ring number can be calculated. The measurement of the shield machine is the root of ensuring the tunnel axis, and the measurement of the shield machine is extremely important in a small curve radius section. 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 propelling and deviation correcting of the shield machine can be fed back through the measurement data. During construction, tracking measurement can be implemented if necessary, so that the shield tunneling machine is caused to form a good posture. Since the tunnel turning radius of curvature is small, the viewing conditions inside the tunnel are relatively poor, and thus new measurement points and rear view points must be set multiple times. After setting new measuring points, repeated measurement should be strictly performed to ensure the accuracy of the measuring points and prevent false measurement. Meanwhile, because the lateral component force of the turning of the shield machine is large, the horizontal displacement of the ring-formed tunnel can be caused, the rear view point must be periodically retested, and the accuracy of the rear view point is ensured. Because of the sharp turn of the line, measuring baskets are arranged at intervals of 20-30 rings, and the wire points are retested once every 5 rings are pushed. The shield machine is propelled by an automatic measurement system, and the shield posture is automatically measured every 2-3min during the propulsion. After the shield machine is assembled, the measurement of the longitudinal axis and the radial axis of the shield is required, and the main measurement content comprises the measurement of the length between a cutter edge, a connecting center of a machine head and a machine tail and between the machine head and the shield tail; measuring the length of the shield shell; and measuring diameters of the shield knife edge, the shield tail and the supporting ring. Attitude measurement during shield tunneling shall include measurement of plane deviation, elevation deviation, longitudinal gradient, transverse rotation and incision mileage from the line center line.

And (3) construction of a second lining 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 die, a top die and left and right side dies, the bottom die is connected with the side dies and the right side die is connected with the top die through hinges, and the top die is connected with the left side die through bolts. The longitudinal overall length of the trolley template is 12.2m, and the effective lining length is 12m. The trolley is reserved with 18 template working windows and 3 grouting openings. Because the newly poured concrete is semi-liquid, the full-circle trolley has larger upward buoyancy due to the buoyancy effect of the liquid on the pressure difference between the upper surface and the lower surface of the object immersed in the full-circle trolley in the concrete pouring process. In order to prevent the template from floating up, special anti-floating devices are arranged on 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 a mounting frame body. One end of the anti-floating jack is provided with a screw-nut pair, and the height of the anti-floating jack is adjustable so as to meet different installation height requirements of over-digging or under-digging and effectively prevent the template from floating upwards. The anti-floating jacks are arranged on the corresponding side surfaces of the trolley through brackets and form an all-around reliable positioning system together with the bottom lifting oil cylinder. The construction process of the second lining is as follows: after construction preparation, processing a foundation surface, carrying out mortar transportation, then respectively carrying out foundation acceptance and measurement paying off, carrying out waterproof board installation and acceptance after the foundation acceptance, carrying out embedded part (grouting pipe) installation after the measurement paying off and waterproof board installation acceptance, then carrying out steel mould trolley in place, carrying out seal head template installation, then carrying out mortar pouring, carrying out sampling test after mortar solidification, removing a mould according with requirements, and finally carrying out maintenance and trimming. Specifically, the secondary lining construction is carried out, the trolley automatically walks to the first bin section position, the accurate measurement is carried out to enable the secondary lining trolley to be positioned, the center line of the trolley is ensured to be consistent with the center line of the tunnel, the template is fixed after being molded, and the measurement rechecking is correct; then cleaning up sundries, accumulated water and scum on the substrate, installing a blocking head template, installing a water stop belt according to design requirements, and self-checking the setting condition of the waterproof system. Self-compacting concrete is transported in the hole by a 3m3 tank car. 1) Before concrete pouring, the surface of the waterproof layer is dedusted and sprayed with water from the trolley pouring window to be wetted, so that the compactness in the concrete pouring process is ensured, and the shrinkage and cracking of concrete are prevented. Concrete is poured from bottom to top, firstly, ash is discharged from one side of the waist, and the bottom is poured. 2) When the waist beam position is reached, the top is provided with an ash discharging hole for discharging ash, a special person is arranged to knock the template by a wood hammer during the ash discharging period, the non-compact part is found, and the vibrating rod is matched for assisting in vibrating, so that the compaction of concrete in the template is ensured. And during the concrete pouring period, measuring personnel are arranged to stare and control in the whole process, and the displacement condition of the trolley is closely monitored. If the floating rate is larger, pouring is suspended. 3) The self-compacting concrete is intensively mixed by a mixing station, the concrete mixing transport vehicle is transported to a pouring site, the self-compacting concrete is lowered to a concrete transport vehicle in a hole by a crane or a guide pipe, and then the self-compacting concrete is pumped into a template trolley by the concrete transport vehicle. 4) When concrete close to the bottom is poured, the warehouse-in speed is strictly controlled, the speed is slow, and the defects of honeycombs, pitting surfaces and the like are prevented. The speed is high when the top concrete is poured, and the top arch concrete is prevented from being emptied. 5) The concrete pouring is evenly lifted, the concrete height difference at two sides is controlled to be 30-50 cm, and the local maximum height difference is not more than 60cm. 6) When the concrete is poured, the conditions of the templates, the brackets, the reinforcing steel bars, the embedded parts and the reserved holes are observed frequently, and when deformation and displacement are found, the pouring is stopped immediately and the poured concrete is well dressed before being coagulated. 7) The free-falling height during concrete casting should not exceed 5m. 8) The self-compacting concrete is adopted as the secondary lining concrete, so that the vibrating rod is not adopted for vibrating. When the mould is removed, the strength of the concrete reaches 100% of the design strength, and when the humidity is insufficient, the concrete is sprayed and cured after demoulding. 9) In order to ensure that the secondary lining concrete and the waterproof board are closely adhered to each other, a grouting pipe is pre-buried before the secondary lining concrete is poured, and the secondary lining is back-filled and grouting is carried out after the concrete reaches the strength.

Calculation and inspection of design and construction in the project:

And calculating a reaction frame, wherein the section of the welded box-shaped steel beam is formed by combining I63, a 16mm thick A3 steel plate is processed, welded and formed, and shield pushing load acts on the beam. Steel yield strength fy=235N/mm ², yield shear fv=136N/mm ². The load coefficient is 1.2 for constant load and 1.4 for active load, the design value fd=215N/mm ² for tensile, compressive and bending strength of the steel is fvd =125N/mm ² for shear strength. (1) Long beam calculation, beam section a=16750×3+178×3×16= 67338 (mm ²), elastic section modulus for two principal axes, distance of X-axis from upper and lower flange edges: y1=332 (mm), y2=267 (mm), the moment of inertia ：Iy＝3×980840000+2×534×16×3232＝4725293952(mm⁴)、Ix＝3×18120000+2×16×5343/12+2×16750×1782＝1115774000(mm⁴), section modulus ：Wx＝Ix/y2＝1115774000/267＝4178928.8(mm³)、Wy＝Iy/x2＝4725293952/332＝14232813.11(mm³).(2) load and internal force, the shield starting total thrust is 1680T, and the total thrust is borne by four beams, so that the load born by a single beam is 420T uniformly distributed load, and the concentrated load design value F=4200 (KN). (3) And (3) load combination, determining the most unfavorable combination, carrying out mechanical modeling according to the back support condition of the reaction frame, and calculating according to the unequal-span continuous beam. (4) The concentrated load, wherein the uniformly distributed load accounts for 1.97% of the concentrated load according to the bending moment and the shearing force, and is ignored here; load combination: mmax= 5285.78 (KN/mm), vmax= 3169.24 (KN). (4) Checking section strength, wherein bending positive stress is calculated according to an edge strength criterion: mx/wnx= 5285.78 x103/14232813.11 =0.4 (N/mm ²)＜fd＝215N/mm², meeting the requirements. (5) Shear stress: τmax=q/a= 3169.24 ×103/663378=4.8 (N/mm ²)＜fvd＝125N/mm², meet the requirements) (6) stable calculation of web stiffener cell, box Liang She stiffener, separation stiffener spacing 150mm, four-sided fixed, stiffener separation can not check local stability..7) box girder overall stability check, known from l1/b1=9000/630=14.28 >13, required overall stability check. βb=0.73+0.18ζ=0.8, [ wherein ζ= (l1t1)/(b1h1) = (9000×15)/(543×630) =0.39 ], I y =iy/a= 4725293952/663378 =7123, λy=l1/iy=9000/7123=1.26, and i1=16×5433/12 (mm ⁴)、I2＝16×5433/12(mm⁴), so αb=i1/(i1+i2) =0.5, so yb=0, so the overall stability coefficient ：ψb＝βb(4320/λy2)(Ah/Wx)[yb+1+(λyt/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, looks up ψb' =0.83, mcr=ψ bMex =0.838× 4178928.8 ×235= 8229.56 (KN/m) > mmax= 5285.78KN/m, the overall stability of the cross section meeting the requirements. (8) And calculating the cross beam, wherein the long beam and the short beam have the same back support size, and the cross beam is far smaller than the long beam in size, so that the cross beam also meets the requirements. (9) The back support of the reaction frame is designed, the design value of the axial force is N= 3169.24KN, the support length is the most unfavorable, and the design is 3.73 meters. Two I32 columns are assembled into a lattice column, and the geometric characteristics of the section are that A=146.9cm3; ix= 23242cm4; iy=1004; wy=wx=646 cm3; ix=12.58 cm; iy=2.61 cm; the design basis is as follows: steel structural design Specification (GB 50017-2003). (10) Intensity calculation: according to the fixed limb at one end and free calculation at one end, checking the attached table of the building construction calculation manual to obtain: ψ=0.994, σ=n/an=215N/mm 2< f=235N/mm ². (11) Stability calculation, N/(ψa) = 3169000/(0.994×14690) =217N/mm 2< f=235N/mm 2, stably meets the requirement.

Tunneling parameter calculation, namely (1) slag discharge amount, wherein the theoretical slag discharge amount (real) of each ring of the shield tunnel is pi/4×d2×l=3.14/4×3.412×1=9.13 m3; wherein D is the diameter of a cutter head of the shield tunneling machine, and L is the tunneling distance per cycle; because the shield tunneling machine mainly tunnels in the pebble bed, the loosening coefficient is 1.3, and the pushing and ballasting quantity of the shield is controlled between 98% and 102%, namely 11.5m ³/ring-12.1 m ³/ring. When the ballasting amount is smaller than 11.5m ³, the pressure set value of the soil bin is properly reduced in the next ring, the general adjustment amount is about 0.2bar, and the earth surface bulge condition is closely noted; if the amount of the slag is larger than 12.1m ³, the screw conveyor is immediately shut down, the slag is stopped, the ground surface subsidence is concerned, and if the subsidence is overlarge, the soil bin pressure is continuously increased until the ground surface subsidence is controlled within an allowable range. (2) The tunneling thrust force is calculated according to the loose soil pressure at the maximum burial depth and the soil pressure generated by the total soil column height with double shield diameter according to a common algorithm, and the maximum value is taken as the calculated external load of the shield due to the fact that the tunnel burial depth along the shield engineering is large in difference, the time when the shield passes through the tunnel is relatively short. The maximum burial depth of the tunnel is 10 meters. So the section burial depth is calculated as the maximum burial depth value for the shield. Geological parameters in soft soil calculation are selected as follows according to stratum of the section: the rock-soil capacity gamma=20.9 KN/m ³; internal friction angle phi=29.5° of the rock-soil; the binding power of the soil c=39KN/m ²; cover layer thickness H _max = 8m; ground load P ₀＝20KN/m²; the horizontal side pressure coefficient λ=0.5; shield outer diameter d=4.13 m; shield host length l=8.44 m; shield main machine weight w=120t; an empirical soil pressure coefficient K ₀ =1; loose soil pressure (taisha formula) calculation:

B ₁ = (D/2) x ctg [ (45 ° + phi/2)/2 ] =3.59 m; substituting into the above to obtain

P_s＝63.69×0.717+20×0.283＝51.33KN/m²

Calculating the soil pressure of the full soil column with the diameter twice that of the heading machine: p _q＝2×γ×D＝172.63KN/m²; because of P _s＜P_q, pq is taken as the calculated data. The soil pressure of the upper part of the shield is 172.63+20= 192.63KN/m ² when the ground load is added; the soil pressure at the bottom of the shield is P _n＝P_s+W÷(D×L)＝54.77KN/m²; the lateral pressures of the upper and lower shield portions should be: p _λ＝P_s×λ＝25.67KN/m²、P_m＝P_n×λ＝27.39KN/m².

The thrust of the shield should contain the following parts, in earth pressure balance mode: Σf=fm+ FBAEPB +fs+fnl+fsp,

Friction force F _M =0.25× [ pi×4.13×8.44× (192.63+54.77+25.67+27.39)/4 ] =2055 KN between shield shell and soil, wherein μ is a friction coefficient between shield shell and soil, and 0.25 is taken according to an empirical value; cutter propulsion force FBA, 68 cutters are mounted on the cutter, the propulsion force of each cutter in soft soil is about 5.6KN according to an empirical value,Friction force of shield tail seal, F _S1 =10kn/m (empirical value, friction force of seal per meter in circumferential direction), F _S =4×pi×10=125.6 (KN) (segment outer diameter 4 m); force FNL (experience value) matched after draggingF _NL =750kn; front baffle counter force caused by ballast bin soil pressure (soil bin pressure is calculated according to 1 bar), total thrust is calculated: /(I)Σ _F =2055+380.8+125.6+750+1339= 4650.4KN; when the shield is in ascending and turning, the thrust of the shield is considered as 1.5 times of the straight horizontal section, and the actual thrust of the shield is as follows: Σ _F = 4742.4 ×1.5= 6975.6KN. (3) The torque calculation comprises cutting torque, rotation resistance torque of a cutter head, counter torque generated by thrust load borne by the cutter head, friction torque generated by a sealing device, friction torque of the front end face of the cutter head, friction torque of the rear face of the cutter head, shearing torque of an opening of the cutter head and stirring torque in a soil pressure cavity. With the development of the soil bin and the tunnel ballast soil improvement technology, the torque of the cutterhead in soft soil excavation can be greatly reduced. The calculated theoretical torque is only an approximation without improvement, and is generally smaller than the calculated value in practical cases. Cutter cutting torque, V _max = 4.8m/h; cutter rotational speed n=1.2 rpm (empirical values are chosen based on similar engineering); the cutting depth h _max = V/n = 6.67cm for each revolution of the cutter head; the compressive strength q _u = 157KPa of the rock and soil is calculated by selecting the compressive strength of the silty clay; cutter head diameter Dd＝4.15m;T₁＝0.5×[q_u×h_max×(D_d×0.5)²]＝0.5×[157×0.0667×(4.15×0.5)²]＝22.54KN/m; main bearing rotational counter moment T ₂＝G×R₁×μ_g generated by cutter head dead weight, wherein the cutter head dead weight: g= 72.52KN, main bearing rolling radius: r ₁ = 1.1m, rolling friction coefficient: μ _g =0.004, then T ₂ = 72.52 ×1.1×0.004=0.32kn.m; rotational resistance T ₃＝P_t×R×μ_g generated by thrust load of the cutterhead, wherein the thrust load P _t＝α×π×R₂×P_d is the non-opening ratio of the cutterhead: α=37% =0.37, and the radius R₂＝2.075m,P_d＝(P_h+P_h1)/2＝80.18KN/m,P_t＝0.37×π×2.075×80.18＝193.29KN, is T ₃ =193.29×1.3×0.004=1.01kn.m; sealing device friction moment/>Wherein the coefficient of friction between seal and steel: μ _m = 0.2, thrust of seal: f _m =1.5 KPa, sealing number: n=3, the installation radius of the seal: r _m1 =1.1m, then T ₄＝2π×0.2×1.5×3×1.1² =6.8kn.m; friction distance T ₅＝(α×π×μ_p×R₂ ³×P_d) x 2/3 of the front surface of the cutterhead, wherein the friction coefficient between the soil layer and the cutterhead is as follows: μ _p =0.15, then T ₅＝(0.37×π×0.15×2.075³ ×80.18) ×2/3=83.22kn.m; friction counter moment T ₆＝2π×D_d×B×P_z×μ_p for the circumference of the cutterhead, wherein the cutterhead edge width: b=0.3 m, cutter disc circumferential soil pressure P _z＝(P_h1+P_h+P_v1+P_v)/4=120.3 KPa, then T ₆ =2pi×4.15×0.3×120.3×0.15=141.1kn.m; friction torque on the back of the cutter head, which is generated by pressure in the soil chamber, is assumed to be Pd,/>Shearing moment of cutter head open slot/>Wherein the shear stress of the soil: in the cutting cavity, because the ballast soil contains water, C=15KPa is taken, and the internal friction angle is/> Then T ₈＝2/3×π×22×2.075³ × (1-0.37) =271.56kn.m; stirring moment in cutter soil cavityWherein the diameter of the cutter head support column is as follows: /(I)Cutter head support column length L _z = 0.8m; the number of support columns n _b =1, then T ₉ =0.85×0.8×80.18×1=54.5kn.m; total torque of cutterhead

Calculating T=alpha×D ³ according to a soil pressure balance shield torque estimation formula, and calculating the torque of the shield, wherein alpha is a soil pressure balance shield coefficient, and the values are generally 14-23 according to different sizes of the diameters of the shield, wherein alpha=18.79 is taken to calculate the torque to obtain T=18.79×4.13× 4.13 ³ =1323.66KN.m; the torque value is the escaping torque value of the shield tunneling machine.

The above embodiments are only preferred embodiments of the present invention, and not intended to limit the scope of the present invention, but all changes made by adopting the design principle of the present invention and performing non-creative work on the basis thereof shall fall within the scope of the present invention.

Claims

1. The method is mainly used for gravity type water inlet pipe construction, and is characterized in that the method is applied to the geological construction environment mainly comprising argillaceous siltstone and strong weathered gravel stratum in the geological condition of the construction local soil layer, the construction environment of the gravity type water inlet pipe is complex, roads, bridges, various pipe network facilities and buildings of the area are distributed, and the method comprises the following steps:

S100, preparation of construction: based on the configured shield shaft foundation pit and shield starting well, preparing corresponding construction materials and construction mechanical equipment, and arranging construction monitoring points in a shield construction whole interval; the method comprises the steps of arranging construction monitoring points in a whole shield construction section, wherein the arrangement of the construction monitoring points in the whole shield construction section comprises the arrangement of ground subsidence monitoring points in the uplink line axis of a section tunnel, the arrangement of section monitoring points in the uplink line of the section tunnel, the arrangement of building detection points around the section tunnel, the arrangement of subsidence monitoring points in the section tunnel and the arrangement of convergence monitoring points in the section tunnel;

S110, end reinforcing: reinforcing the shield end in a range of 10 meters in the tunneling direction of the shield tunnel and in a range of 3.2 meters on both sides of the center line of the shield tunnel by adopting a sleeve valve pipe sectional grouting mode; the process of reinforcing the end by adopting the sleeve valve pipe sectional grouting mode is as follows:

S110g, preparing grouting liquid: the grouting liquid adopts pure cement slurry, the water-cement ratio of the slurry is 0.8-1.0, and the grouting liquid is pumped, pressed and injected after being uniformly stirred and sieved and is continuously stirred in the grouting process;

s110j, single hole completion: hole replacement and displacement are carried out after grouting is finished each time, a grouting machine, a stirrer and various pipelines are cleaned in time, the normal operation of subsequent grouting is ensured, and then each hole is finished one by one to realize end reinforcing;

S600, construction of a second lining of the shield tunnel: pouring a lining cement mortar layer with the thickness of 25 cm in the shield tunnel by adopting a full-circle needle beam trolley; the construction process of the second lining of the shield tunnel comprises the following steps:

2. The method for constructing the shield tunneling and reaching of claim 1, wherein the shield shaft foundation pit and the shield initiation well are constructed by adopting a fender pile and internal support open excavation method, the fender pile structure adopts a spacing filling pile with the diameter of 1000mm, the end shield initiation adopts a glass fiber reinforced pile 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 pipes, and the retaining wall is adopted for supporting above the crown beam.

3. The method for constructing the initial tunneling and reaching of the shield according to claim 1, wherein the pipe shed support 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 distributed at positions 200mm outside the excavation outline 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 support is 10m, the pipe shed support is assembled and lengthened in sections, the two sections are connected by threads, the adjacent two seamless steel pipe joints are staggered by not less than 1m, and grouting holes are distributed on the adjacent two seamless steel pipe joints;

4. The shield tunneling and arrival construction method according to claim 1, wherein said sinking in-process recording contents comprises: 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 inner wall of the shield and the outer side of the duct piece; synchronous grouting: b. synchronous grouting: grouting pressure, quantity and consistency, grouting material proportion and grouting test block strength; c. measurement: shield inclination, tunnel ovality, total distance of propulsion, and exact position of the axle center of each ring of lining ring of the tunnel.

5. The method for constructing an initial tunneling and arrival of a shield according to claim 1, wherein the shield tunneling control further comprises controlling a stroke of a thrust cylinder of the shield and limiting a thrust amount of each ring of the shield when the shield is thrust forward in an idle state; the gesture is controlled through the stroke of a pushing cylinder of the shield tunneling machine; under the condition of ensuring normal pushing of the shield, reducing the total thrust and the cutter torque; after the shield tail completely enters the hole body, adjusting the hole seal, grouting the hole, and controlling the grouting pressure within 1.5 Bar; and the dismantling time of the reaction frame and the negative ring pipe piece is determined according to the mortar performance parameter of backing grouting and the initial tunneling thrust of the shield, the tunneling is performed for more than 100m, the front 50 rings complete tunneling for more than 7 days, and the dismantling of the reaction frame and the negative ring pipe piece is started.

6. The method of claim 1, wherein the process of shield tunneling and arrival construction comprises the steps of reinforcing a tunneling soil body, installing a receiving frame, measuring a tunnel door rechecking, measuring a shield machine position and posture rechecking, removing the tunnel door, installing a tunnel opening waterproof device, removing a cutter head, moving the shield body forward in place, removing the cutter head connection, lifting the cutter head, disconnecting the trolley from a host pipeline, moving the trolley backwards through a host pipeline, removing a screw machine, removing a screw pipeline, driving, a rear sleeve, a screw rod, moving to a tunnel, removing a front shield body connection and lifting a front shield, removing a hinged connection, lifting a hinged shield body, ejecting a shield tail, removing a jack, lifting a tail, lifting screw machine parts, removing a receiving bracket, laying a trolley track, disconnecting the trolley connection, sequentially lifting the trolley, and removing and lifting a related auxiliary bracket in the pit.

7. The shield tunneling and arrival construction method according to claim 6, characterized in that the arrival construction matched with the shield machine in the receiving process comprises the following steps: