CN112081595B

CN112081595B - Shield construction method, and waterproof and monitoring method for shield construction

Info

Publication number: CN112081595B
Application number: CN201910509202.1A
Authority: CN
Inventors: 傅珺; 邓文全; 许颖儿; 鲍廉梵; 赵余夫
Original assignee: Hongrun Construction Group Co Ltd
Current assignee: Hongrun Construction Group Co Ltd
Priority date: 2019-06-14
Filing date: 2019-06-14
Publication date: 2022-09-23
Anticipated expiration: 2039-06-14
Also published as: CN112081595A; CN115539095A; CN115539056A

Abstract

The invention discloses a shield construction method and a waterproof and monitoring method for shield construction, and relates to the field of engineering construction. The shield construction method comprises the following steps: the shield base is hoisted into the underground according to the baseline of measurement lofting, and the shield base is ensured to be consistent with the axis of the tunnel outlet section in the laying process; after the shield base is in place, a steel rear shield support is additionally arranged between the last ring negative ring and the well wall structure; after rechecking and measuring the position of the portal, chiseling out the portal concrete in a shape of Chinese character jing in blocks according to the analysis of ground monitoring information, and marking out the positions of the blocks; chiseling the concrete at the joint of the blocks before chiseling the door, and well preparing block hoisting points; and (5) after the whole shield machine enters the hole ring, carrying out synchronous grouting. The method ensures that the axis of the shield base is consistent with the axis of the tunnel outlet section in the process of placing the shield base, can ensure that the shield base can play a role in guiding the shield machine when the shield machine goes out of the tunnel, and further improves the tunneling precision of shield construction.

Description

Shield construction method and waterproof and monitoring method for shield construction

Technical Field

The invention relates to the technical field of engineering construction, in particular to a shield construction method and a waterproof and monitoring method for shield construction.

Background

The shield method is a construction method for performing operations such as tunnel excavation and lining by using a shield. A construction method for tunneling a tunnel in a soft foundation or a broken rock stratum by using a shield. The shield is a special device with a shield, and the shield is pushed forward by taking the lining blocks with installed tails as pivots, cuts the soil body by a cutter head, and simultaneously discharges the soil and assembles the following precast concrete lining blocks.

The shield is a construction machine and a powerful temporary supporting structure. The shield machine looks like a large steel pipe machine, slightly larger than the tunnel part, and is designed to withstand external water pressure and formation pressure. It comprises three parts: a front incision ring, a middle support ring and a rear shield tail. Most shields are circular in shape, and have other shapes such as oval, semicircular, horseshoe-shaped, box-shaped and the like. And the tunneling precision of the existing shield construction is consistent and can not meet the requirements.

Disclosure of Invention

In view of this, the embodiments of the present invention provide a shield construction method and a waterproof and monitoring method for shield construction, which can ensure that the axis of the shield base is consistent with the axis of the tunnel exit section during the placement process of the shield base, ensure that the shield base can play a role in guiding the shield machine when the shield machine exits the tunnel, and further improve the tunneling accuracy of the shield construction.

To achieve the above object, according to an aspect of an embodiment of the present invention, a method of shield construction is provided.

The shield construction method of the embodiment of the invention comprises the following steps: hoisting a shield base into the underground according to a baseline for measurement lofting, and ensuring that the shield base is consistent with the axis of the tunnel outlet section in the process of placing; after the shield base is in place, a steel rear shield support is additionally arranged between the last negative ring and the well wall structure; after rechecking and measuring the position of the portal, chiseling out the portal concrete in a shape of Chinese character jing in blocks according to the analysis of ground monitoring information, and marking out the positions of the blocks; chiseling the concrete at the joint of the blocks before chiseling the door, and well preparing block hoisting points; and (5) after the whole shield machine enters the hole ring, carrying out synchronous grouting.

Optionally, the method further comprises: erecting a scaffold in the hole ring area, and installing a water stopping device on the scaffold; and a circle of arc-shaped inserting plates serving as a water-stopping barrier are arranged on the hole ring.

Optionally, the method further comprises: two guide rails are arranged in the hole ring and at the position of a 70cm chiseled groove wall, extend to the shield base, and are connected with the two guide rails on the base into a whole, and the installation angle and the position of the guide rails are required to be along the track on the shield base.

Optionally, the method further comprises: arranging grouting ball valves around the hole ring; and connecting a 1.5-inch steel pipe with a preset length to the stratum outside the door at the rear end of the grouting ball valve.

Optionally, the step of additionally arranging a steel rear shield support between the last ring negative ring and the well wall structure comprises: pouring cement mortar into a gap between the steel rear shield support and the negative ring pipe sheet; and 2 double-frame 70# H steel is adopted for supporting the rear steel shield.

Optionally, after rechecking and measuring the position of the portal, chiseling away the portal concrete in a shape like a Chinese character jing in blocks according to analysis of ground monitoring information, and marking the positions of the blocks; chiseling the concrete at the joint of the blocks before chiseling the door with the holes, wherein the step of making the block hoisting points comprises the following steps: chiseling a hole in the center of the portal for observing the condition of an external soil body, then chiseling away portal concrete in a shape like a Chinese character jing in blocks, and marking the position of the block; exposing the inner and outer steel bars, cutting off the inner steel bars, and chiseling the remaining concrete on the soil facing surface and the outer steel bars; cleaning concrete fragments falling on the bottom of the tunnel ring; chiseling concrete at the joint of the blocks before chiseling the tunnel door, making block hoisting points, and hoisting the tunnel door concrete blocks sequentially from top to bottom.

Optionally, the steel template is customized according to the structure size, and the vertical mold adopts

Arch bones made of channel steel are used as template supports, the arch bone distance is 900-1200mm, the arch bones are vertically arranged on a poured bottom plate concrete surface, and a section steel cross brace is added at the arch bone foot; the arch foot bottom is padded with a 20mm thick wood plate to prevent the bone legs from sinking; the arch bone is arranged according to the middle waist line; in the process, a mold release agent is uniformly coated on the steel template, and the steel template is installed according to the structural characteristic sequence.

To achieve the above object, according to another aspect of an embodiment of the present invention, there is provided a method for shield construction waterproofing.

The method for shield construction waterproofing of the embodiment of the invention is used for the shield construction method of any one of the above mentioned items, and comprises the following steps: installing a sealing device around the hole ring, wherein the sealing device consists of a rubber curtain cloth belt, a ring plate and a turning plate; arranging waterproof and leaking stoppage grouting holes at the hole, and embedding grouting pipes around the hole ring; and sealing and waterproofing are carried out by pressing and injecting double-liquid slurry through the grouting pipe under the condition that water and soil leakage occurs in the shield tunneling construction.

Optionally, after the shield debugging is finished, uniformly and densely smearing shield tail grease between the shield tail steel brushes to fill the grease cavity of the shield tail brushes.

Optionally, an elastic sealing gasket is arranged along the periphery of the rib surface of the duct piece; wherein, the elastic sealing gasket is made of water-swelling rubber material.

In order to achieve the above object, according to still another aspect of the embodiments of the present invention, a method for monitoring shield construction is provided.

The monitoring method of shield construction of the embodiment of the invention is used for the method of shield construction as described in any one of the above, and comprises the following steps: setting a temporary point location at the bottom of the well, measuring the transverse diameter and the plane coordinate of the door ring according to the temporary point location station, calculating the plane center coordinate of the door ring, and calculating the plane deviation value of the door ring; measuring the bottom elevation and the top elevation of the portal ring by using a temporary level point transmitted to the bottom of the well by using the elevation, and solving the ring diameter and elevation deviation value; calculating the coordinates of the portal ring center, the shield base front center and the shield base rear center, actually measuring the value of the coordinates by using an instrument, and calculating the deviation of the value of the coordinates and a theoretical value; and adjusting the plane position of the base according to the deviation.

Optionally, the method further comprises: respectively sticking a metal stainless steel plate on two sides of the middle part of the monitored crack, drilling a round hole in the center of the steel plate, enabling the connecting line direction of the round hole to be vertical to the crack during burying, and respectively marking two ends of the crack so as to observe the development condition of the crack; and arranging gypsum sheets at two ends of the crack, wherein the gypsum sheets are firmly bonded with two sides of the crack.

Optionally, the method further comprises: and an abnormal gas monitor is arranged at the outlet of the shield spiral machine to monitor abnormal gas.

Optionally, the method further comprises: laying ground settlement measuring points along the axis of the tunnel, laying settlement tank observation sections at certain intervals, adding the settlement tank observation sections when passing through important buildings and pipeline groups, setting measurement marks on the hard ground by using shooting nails or spikes, and using reinforcing steel bars as the measurement marks on the soft ground; arranging a monitoring section every 20 meters within the range of 100m of the shield starting section; arranging a monitoring section every 30 meters in other sections; the interval of the measuring points on the monitoring section is 2-5m, and 7-11 measuring points are arranged in one monitoring section.

Optionally, the method further comprises: three steel wires are hung, and the steel wires and the above-well and underground observation platforms form two straight triangles on the plane; the ratio of the long sides and the short sides of the triangle is at least more than 2.5 times, and the angle in the triangle is less than 2 degrees; hanging a drop ball at the tail end of the steel wire, wherein the drop ball is immersed in an oil drum filled with oil and cannot be contacted with the oil drum; dividing the measurement data into two groups, wherein each group of data comprises an aboveground position, four connecting angles and five side lengths; when the triangle is calculated, the conditions of the triangle closure difference are utilized, and the simple adjustment difference is used for calculating to obtain the coordinates of the underground position and the underground control point; the other set of data is calculated as above and the orientation and coordinates obtained are checked against the first set to ensure that no errors occur.

One embodiment of the above invention has the following advantages or benefits: the accuracy of the exit position of the shield machine mainly depends on the placement position of the shield base, and the shield base is ensured to be consistent with the axis of the exit section in the placement process, so that the shield base can be ensured to play a role in guiding the exit of the shield machine. Because a certain gap exists between the diameter of the working well hole ring and the outer diameter of the shield, in order to prevent soil from losing from the gap when the shield goes out of the hole and during construction, a sealing device consisting of a rubber curtain cloth belt, a ring plate, a turning plate and the like is arranged around the hole ring, and a grouting hole is arranged to be used as a preventive measure for preventing water and leakage of a hole opening.

Further effects of the above-described non-conventional alternatives will be described below in connection with the embodiments.

Drawings

The drawings are included to provide a further understanding of the invention, and are not to be construed as unduly limiting the invention. Wherein:

fig. 1 is a schematic view of a main flow of a method of shield construction according to an embodiment of the present invention;

FIG. 2 is a schematic view of a shield foundation according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a zonal shield initiation reclining architecture, according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a shield tunneling construction process according to an embodiment of the present invention;

FIG. 5 is a schematic view showing the installation of a section steel prestressing bracket according to an embodiment of the present invention;

FIGS. 6 and 7 are schematic illustrations of a tube sheet being pulled apart according to an embodiment of the present invention;

FIG. 8 is a schematic illustration of a convergence gauge test using an SL-2 steel rule according to an embodiment of the invention;

FIG. 9 is a schematic diagram of a wire dot placement within a tunnel according to an embodiment of the invention; and

FIG. 10 is a schematic illustration of orientation measurement according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which various details of embodiments of the invention are included to assist understanding, and which are to be considered as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

Fig. 1 is a schematic diagram of a main flow of a shield construction method according to an embodiment of the present invention, and as shown in fig. 1, the method for determining shield construction according to the embodiment of the present invention mainly includes:

step S101: and hoisting the shield base into the underground according to the baseline of measurement lofting, and ensuring that the shield base is consistent with the axis of the tunnel outlet section in the laying process.

Step S102: after the shield base is in place, a steel rear shield support is additionally arranged between the last ring negative ring and the well wall structure.

Step S103: after rechecking and measuring the position of the portal, chiseling out the portal concrete in a shape of Chinese character jing in blocks according to the analysis of ground monitoring information, and marking out the positions of the blocks; and chiseling the concrete at the joint of the blocks before chiseling the door, and well preparing the block hoisting points. Specifically, a hole is chiseled in the center of a portal for observing the condition of an external soil body, then the portal concrete is chiseled in a shape like a Chinese character jing in blocks, and the position of the block is marked; exposing the inner and outer steel bars, cutting off the inner steel bars, and chiseling the remaining concrete on the soil facing surface and the outer steel bars; cleaning concrete fragments falling on the bottom of the tunnel ring; and chiseling concrete at the joint of the blocks before chiseling the tunnel door, making block hoisting points, and hoisting the tunnel door concrete blocks sequentially from top to bottom.

Step S104: and (5) after the whole shield machine enters the hole ring, carrying out synchronous grouting.

The embodiment of the invention also comprises the following steps: and erecting and installing a scaffold in the hole ring area, and installing a water stopping device on the scaffold. And a circle of arc-shaped inserting plate serving as a water-stopping barrier is arranged on the hole ring.

The embodiment of the invention also comprises the following steps: two guide rails are arranged in the hole ring and at the position of a 70cm chiseled groove wall, extend to the shield base and are connected with the two guide rails on the base into a whole, and the installation angle and the position of the guide rails are arranged along the track on the shield base.

The embodiment of the invention also comprises the following steps: arranging grouting ball valves around the hole ring; and the rear end of the grouting ball valve is connected with a 1.5-inch steel pipe with a preset length to penetrate into the stratum outside the door.

The last step that sets up steel rear shield support between ring burden ring and the wall of a well structure includes: cement mortar is poured into a gap between the steel rear shield support and the negative ring pipe sheet; and 2 double-component 70# H steel is adopted for supporting the rear steel shield.

Customizing a steel template according to the structure size, and adopting a vertical mold

For the construction scheme of hoisting and transporting the shield machine, the shield shaft loading mainly comprises hoisting of a front barrel, a cutter head and a middle barrel, and well heads of working wells are hoisted out, wherein the front barrel and the cutter head assembly are the heaviest and about 110 tons. The shield constructs to tear open and hangs and includes: (1) and (5) putting the shield into the hole. (2) Powering off the shield tunneling machine: all the shield equipment stops to the normal position and is fixed, and all the oil cylinders retract to the zero position; and the shield machine is disconnected from the brake and the power is cut off. (3) Dismantling a pipeline: dismantling pipelines among the bridge frame, the main frame and the frame; dismantling a pipeline in the shield host; and (5) dismantling the pipeline between the frames. (4) Dismantling the single beam and the belt machine head: dismantling a belt of the belt conveyor and pulling out the belt from the tunnel; laying a motor vehicle track to the bottom of the screw machine; removing the single beam by using a hoist, and pulling out the single beam from the tunnel; and (4) removing the belt head by using a hoist and pulling out the belt head from the tunnel. (5) Dismantling the double beams and the bridge frame: removing the double beams by using a hoist and pulling out the double beams from the tunnel; and (4) removing the pull rod and the bridge frame by using a hoist, and pulling out the pull rod and the bridge frame from the tunnel. (6) Welding the lifting lug: building a lifting lug welding platform; and welding a rear barrel, a cutter head, a front barrel and a middle barrel lifting lug. (7) Hanging and detaching the upper part of the rear cylinder: the inner parts of the upper part and the lower part of the rear cylinder are welded, supported and reinforced by steel pipes, so as to prevent deformation. Cutting the upper part of the rear cylinder and hanging out. (8) Hanging, disassembling and assembling the platform: and (4) removing the connecting bolts of the middle assembling platform and hoisting the middle assembling platform. And (5) removing the connecting pin and hoisting out the left splicing platform. And (4) removing the connecting pin and hoisting out the right splicing platform. (9) Hanging and dismantling the screw machine: and (5) removing the screw machine pull rod and the connecting bolt after the screw machine is lifted by a crane. And (5) hoisting out the screw machine, and adjusting the angle by using 25 t hoists. (10) Hoisting, disassembling and assembling machine: and (5) dismantling the blocking wheel of the assembling machine. And (5) hanging out the assembling machine and turning over. (11) Hanging and detaching the lower part of the rear cylinder: and cutting the lower part of the rear cylinder. And hanging out the lower part of the rear cylinder. (12) Hanging and dismantling the middle barrel: and cutting the welding seam between the middle barrel and the front barrel by using a carbon plane. And removing the connecting bolt between the middle barrel and the front barrel. And welding and fixing the front barrel on the base by using an iron plate. The middle cylinder is lifted out and turned over. The main crane uses a 350t crane, and the auxiliary crane uses a 130t crane; and (5) hoisting the middle cylinder to the well (firstly, translating the middle cylinder to a turning radius of 9m by using 35 t hoists on an underground jig frame and matching with 350t cranes, and then hoisting the middle cylinder out of the well). (13) Hoisting and dismounting the cutter head and the front barrel: and cutting the front barrel and the fixed iron plate of the base. The anti-roll support is cut off. The front barrel and the cutter head are lifted out and turned over. (14) Hoisting and detaching the pedestrian gate: and removing the connecting bolt of the pedestrian gate. And (5) hoisting the pedestrian gate. (15) Hanging and dismantling the frame: and laying a track to the bottom of the well. Pulling out and hanging out the frame. (16) Ending work: and removing the bottom hole sleeper. And (5) hoisting the shield base. And (4) cleaning the bottom of the well.

For the equipment hoisting method determination and hoisting method, the AC350 type 350T ton full hydraulic type truck crane can be determined to be selected as the main crane for mechanical construction according to the conditions of the engineering construction site, the weight of the equipment, the external dimension, the performance characteristics of a large crane and other actual conditions.

And considering the hoisting capacity and the overall dimension of the part, the shield host machine is decomposed into the following key parts: the assembly machine comprises a cutter head, a notch ring, a supporting ring, a shield tail ring (an upper half ring and a lower half ring), an assembly machine, a working platform and a subsequent frame. For the selection of the crane, the self weight of the maximum part of the shield machine is selected; the size of the working well and the position of the shield component need to be placed. According to the embodiment of the invention, a 350T crane can be selected for hoisting, and a 130T crane is used for assisting a large crane to turn over, stand or lay down the shield component on the ground.

In the shield hoisting process, the support ring, the notch ring, the cutter head, the assembling machine, the shield tail and the like are hoisted into the well in sequence according to the descending sequence of the components, and then are assembled. And the shield debugging construction period can be about 30 days, and all parts of the shield machine can be debugged after being installed underground. The specific debugging content is as follows:

no-load debugging: and checking whether the equipment can normally operate. The debugging content is as follows: the hydraulic system, the lubricating system, the cooling system, the power distribution system and the grouting system are calibrated by using the instrument.

Load debugging: and checking the load capacity of various pipelines and seals, and further perfecting the work which cannot be completed by idle load debugging so as to enable various systems and auxiliary systems of the shield machine to reach the working state meeting the normal production requirements. The trial tunneling time is the load debugging time of the equipment, and strict management measures are adopted during load debugging to ensure engineering safety, engineering quality and linear precision.

The shield base is prefabricated into steel structures into roof trusses, the shield base is accurately lofted according to a design axis, and the shield base is hung underground to be in place and welded according to a baseline for measuring lofting during installation. The central lines of the two tracks and the shield on the base are aligned to the center of the tunnel portal and basically consistent with the reverse extension line of the designed axis of the tunnel, and the base is additionally provided with a support reinforcement, and the shield base is shown in figure 2.

For the shield rear shield support manufacturing, a steel rear shield support is additionally arranged between the last ring of the negative ring and the well wall structure, 2 pieces of double-frame 70# H steel are adopted for the steel rear shield support, and cement mortar is poured into a gap between the steel rear shield support and the negative ring pipe piece. And a phi 609 surrounding purlin diagonal brace is arranged at the rear part of the 70# H steel. After the rear shield support is arranged, when the shield is pushed forward, the deformation of the rear shield support is observed, and the damage caused by overlarge displacement is prevented. And setting a deformation observation point on the rear shield support, measuring once when a box of soil is pushed at the beginning, measuring once every circle when the deformation of the rear shield support is stable, and stopping observation until the rear shield support is stable. If the deformation of the rear shield support is too large, a reinforcing measure is immediately taken, and a schematic diagram of a backward leaning system for starting the interval shield is shown as 3.

For the manufacture of the guide rail, the manufacture of the shield support in the tunnel ring needs to meet the requirement of supporting the weight of the body of the shield machine when the shield machine goes out of the tunnel, and plays a role in guiding. The support material adopts 43kg/m heavy rails, 2 heavy rails are arranged in total, and the accurate position is the extension of the 2 43kg/m heavy rails on the shield base in the tunnel circle.

Because a certain gap exists between the diameter of the working well hole ring and the outer diameter of the shield, in order to prevent soil from losing from the gap when the shield goes out of the hole and during construction, a sealing device consisting of a rubber curtain cloth belt, a ring plate, a turning plate and the like is arranged around the hole ring, and a grouting hole is arranged to be used as a preventive measure for preventing water and leakage of a hole opening. This waterproof device that goes out hole design is: a turning plate, a cord fabric rubber plate and the like. And when the station structure is constructed, grouting pipes are embedded around the tunnel ring, and when the shield is constructed out of the tunnel, if water and soil leakage occurs, double-liquid slurry can be injected through the grouting pipes for sealing and water proofing.

And in order to ensure the sealing and waterproof effect of the shield tail, after the shield debugging is finished, shield tail grease is smeared between the shield tail steel brushes, and the grease smearing needs to be uniform and compact, so that a grease cavity filled with the shield tail brushes is taken as the standard.

For negative ring assembly, a gap between the rear part of the first ring split ring and a section steel rear shield support (reaction frame) is filled with high-grade mortar, so that the concrete segment is uniformly stressed, and the ring surface is smooth. The 1 st ring negative ring pipe piece assembling is the first step of controlling the assembling quality of the pipe pieces, and the ring surface of the pipe pieces is corrected to the position vertical to the design axis according to the axis elevation and the plane lofting position. In order to ensure that the duct piece does not deform after being separated from the shield tail, a support is additionally arranged on the outer cambered surface of the duct piece for fixing.

And (4) the process of shield tunneling out of the hole and reaching construction, including shield tunneling out of the hole and foundation reinforcement construction. Specifically, in consideration of the soil property condition of the shield in-out hole, the foundation of the shield in-out hole must be reinforced in advance, and a ground rotary spraying or rotary spraying and mixing pile combined reinforcing method is adopted. Reinforcing length: the hole is 9m, and the hole is 12 m; and (3) reinforcing the upper and lower 3m of the tunnel by strong reinforcement, and reinforcing the upper 3m of the tunnel to the ground by weak reinforcement (the lower reinforcement in the shield range of the south end well of the iron-forging station to the right line of the tunnel is 3m of the upper tunnel to the bottom plate of the wind pavilion). The unconfined compressive strength of the reinforced soil body is not less than 1.0Mpa, the permeability coefficient is less than 10-8cm/s, and the reinforced soil body has good uniformity, self-standing property and sealing property so as to prevent the sand flowing phenomenon of the shield in and out of the hole. And before the shield goes out of the hole, multiple hole probing and punching are carried out on the reinforced area, and if necessary, grouting is adopted among structural joints for reinforcing, so that the safety of the shield going in and out of the hole is ensured.

And (4) checking and accepting the reinforcement of the foundation outside the well before the shield enters and exits the hole, and performing exit construction after the reinforced soil body index meets the requirement of a bidding drawing. And if the foundation reinforcement effect does not meet the preset requirement, adopting a supplementary reinforcement measure until the foundation reinforcement effect is qualified. And (4) finishing the reinforcement of the outlet foundation before the shield is hoisted and lowered into the well.

The accuracy of the tunnel outlet position of the shield tunneling machine mainly depends on the placing position of the shield base, so that the shield base is required to be consistent with the axis of the tunnel outlet section in the placing process. The shield base can play a role in guiding the shield tunneling machine when going out of the tunnel. In addition, the base track is extended between the base and the hole ring, and the lower part of the guide rail is reasonably supported, so that the stability of the guide rail when the shield tunneling machine passes through is ensured.

Fig. 4 is a schematic diagram of a shield tunneling construction process according to an embodiment of the present invention. As shown in fig. 4, the shield machine is debugged, and the tunnel portal is removed when the shield machine is in good operation. And erecting a steel scaffold in the hole ring. And drilling a hole in the center of the portal for observing the condition of the external soil body, then cutting off the portal concrete in a cross shape in blocks, and marking the positions of the blocks. Adopting air pick to break. Firstly, the inner and outer rows of reinforcing steel bars are exposed, the inner row of reinforcing steel bars are cut off, and the remaining concrete on the soil-facing surface and the outer row of reinforcing steel bars are chiseled off. And cleaning concrete fragments falling on the bottom of the hole ring. In order to ensure that soil bodies are separated once when the tunnel portal concrete blocks are hoisted, chiseling concrete at the joint of the blocks before chiseling the tunnel portal, and well preparing block hoisting points. Cutting and hoisting in sequence: the upper part is arranged first and the lower part is arranged later. The tunnel portal chiseling needs continuous construction, and the operation time is shortened as much as possible so as to reduce the loss of the soil body on the front side. The full-process supervision is carried out by a full-time security officer, potential safety hazards are avoided, the life safety is ensured, and meanwhile necessary protective measures are taken for the sealing device on the opening.

Because of the thickness of the working well structure and the thickness of the groove wall structure, a certain distance is reserved between the guide track on the shield base and the soil body, in order to ensure the shield to safely and correctly go out of the hole, two guide extension steel tracks are arranged in the hole ring and at the position of the chiseled 70cm groove wall, and the installation angle and the installation position are required to be along the track on the shield base.

And because a building gap exists between the opening and the shield (or the lining), muddy water is easy to lose, so that the ground surface subsides, and therefore, a hole-outlet sealing water-stopping device is required to be installed at the opening, and the hole-outlet device comprises a cord fabric rubber plate, a circular ring plate, a sector plate, a corresponding connecting bolt and a corresponding gasket. Before installation, the position and the size of a screw hole formed in the cord fabric rubber plate are rechecked to ensure that the position of the screw hole is consistent with the position of a reserved screw hole on the hole ring, and the screw tap is used for cleaning the internal thread of the screw hole. The mounting sequence is cord fabric rubber plate → circular plate → sector plate, from top to bottom. When the shield is installed, the pressing plate bolt of the circular plate is reliably screwed, so that the curtain cloth rubber plate is tightly attached to the tunnel door, and the leakage of synchronous grouting slurry after the shield is out of the tunnel is prevented.

And when the shield is installed and debugged and all the shield is normal, entering a hole-out state. Meanwhile, clay is filled in the soil bin in front of the shield in a mode of reversing by using a screw conveyor. In order to prevent the cutter head on the cutter head from damaging the hole sealing device, grease is coated on the cutter head and the sealing device to reduce friction. The shield tail steel brush must be filled with shield tail grease. The sealing effect of the water stopping device is enhanced and observed in the process of hole exit, so that the soil body is prevented from flowing away from the gap to cause the collapse of the ground. When the tunnel is initially excavated, the shield is positioned in a strengthening area, the soil on the front side is hard, and in order to control the propulsion axis and protect a cutter head, when the area is constructed, the set value of the equilibrium pressure is lower than a theoretical value, the propulsion speed is not too fast, and the gradient of the shield can be slightly larger than the designed gradient. And the following measures are taken:

(1) technical measure for shield to pass through reinforced area

Firstly, encrypting measuring points and enhancing monitoring frequency

② strictly controlling soil pressure

The soil pressure can be set to be lower due to the reinforced soil body just above the shield. Meanwhile, the settlement report and other construction parameters are combined for analysis and adjustment, and the settlement report is fed back to the propulsion team to ensure the safety of the hole-out construction.

Thirdly, strictly controlling the soil output

The soil output is reasonably controlled according to the building clearance between the shield and the duct piece and the characteristics of each soil layer, and is about 98-100% of the building clearance. And through analysis and adjustment, the most reasonable numerical value is searched.

Fourthly, controlling the propulsion speed

The shield advancing speed is controlled within 1-2cm/min, the shield jacking pressure and the cutter head torque are not too large to influence the performance of the shield machine, the shield tunneling safety is ensured, and foaming agent or mud is added to the front face of the shield according to needs to improve the front soil body.

Fifthly, synchronous grouting

The synchronous grouting amount, the slurry quality and the pressure are strictly controlled. After the whole shield machine enters the hole ring, synchronous grouting is carried out in time, the quality of slurry is guaranteed to reduce secondary settlement of the ground in the area, and grouting pressure is not too large, so that disturbance to the soil body is reduced, and ground deformation is avoided.

Sixth, dynamic information transfer

In the shield construction, according to the analysis of ground monitoring information, the correlation among thrust, propelling speed, soil output, grouping of jacks and the like is combined, the relatively stable propelling gradient is kept, the one-time deviation rectifying amount is controlled, and the disturbance to a soil body is reduced.

(2) And the attention points of crossing the reinforced area

Firstly, after the negative circular tube sheet is separated from the shield tail, the periphery of the negative circular tube sheet is free from constraint, and the negative circular tube sheet is easy to deform under the action of thrust, so that necessary reinforcement measures (such as transverse temporary support) need to be taken.

Secondly, the total thrust of the jack is controlled within a proper range (not exceeding the design load of steel reclining).

Thirdly, when the shield machine enters the tunnel ring, the close attention needs to be paid to whether the water stopping device of the tunnel ring is intact, and if necessary, reinforcing measures need to be taken to ensure the sealing effect.

And fourthly, when the negative ring duct piece is installed, a reasonable gap between the duct piece and the lower part of the shield tunneling machine needs to be ensured.

Fifthly, ensuring the pressing-in amount and uniformity of the shield tail grease and ensuring the sealing effect of the shield tail.

And sixthly, setting grouting pressure during initial grouting, wherein ground settlement monitoring data and the pressure bearing capacity of the tunnel door sealing device are comprehensively considered.

After the shield exits the strengthening area, in order to prevent the shield from suddenly breaking head caused by the change of the soil property of the front side, the balance pressure value is set to be slightly higher than a theoretical value. Meanwhile, construction parameters such as a balance pressure set value, a propelling speed and the like are adjusted in time according to information feedback such as stratum deformation and the like.

And after the first ring closed ring pipe piece is separated from the shield tail, immediately mounting a rear shield support, and transmitting axial force between the transverse support of the first ring rear seat closed ring pipe piece and the 2 double H-shaped steel backrests through four phi 609 steel pipes, wherein the force is transmitted to a station structure by the section steel. Therefore, the jack area and the oil pressure can have a larger selection range when the shield is driven out of the tunnel for propulsion, and the control of the axis is convenient when the shield is driven out of the tunnel for construction. After the rear shield support is arranged, when the shield is pushed forward, attention should be paid to observing the deformation of the rear seat, and damage caused by overlarge displacement is prevented. And setting a deformation observation point on the back rest, measuring once when a box of soil is pushed at the beginning, measuring once when the deformation of the back rest is stable, and stopping observation until the back rest is stable.

In order to prevent the shield tail from pulling the duct piece of the opening open to cause tunnel deformation and seam water leakage in the process of shield entry, channel steel is required to connect about 11 ring duct pieces of the opening into a whole before entry, and a longitudinal contact strip is usually arranged in the middle of 6 duct pieces of one ring.

And after the tail part is away from the hole ring by a certain distance, performing single-liquid slurry pressure-supplementing injection reinforcement on the hole ring.

And (4) the shield is pushed to a section 50m away from the receiving well wall to the receiving well, and the construction stage of the tunnel entering section is adopted. All the preparation work in the receiving well is ready before the shield is driven into the hole. And (4) rechecking and measuring the position of the tunnel portal, installing a shield receiving base and preparing for shield arrival construction.

And accurately lofting the placing position of the shield base according to the exact position of the tunnel portal. And when the base is installed, the base is hoisted to the underground in-place assembly and welding according to the baseline of measurement lofting. The base is placed according to the flat slope, and after the base is in place, the base is supported and reinforced to enhance the overall stability of the base.

A scaffold for installing a water stopping device is set up in a hole ring area in advance, the water stopping device is installed, and a circle of arc-shaped inserting plate is installed on the hole ring and serves as a water stopping barrier.

In order to ensure that the shield can achieve good guidance during construction, a guide rail is arranged on the hole ring. The guide rails are placed at the bottom of the hole ring for 2, extend to the shield base and are connected with the two guide rails on the base into a whole.

In order to prevent the shield from leaking slurry when reaching construction, double-liquid slurry is timely injected at a leakage point in a pressing mode, and 6 grouting ball valves are arranged around the hole ring. In order to ensure that the grouting effect is better, the rear end of the grouting ball valve is connected with a 1.5-inch steel pipe with a certain length to penetrate into the stratum outside the door.

Because the hole door water stopping device, the arc-shaped inserting plate for sealing the hole door and the like need to be welded on the inner side and the outer side of the hole ring, the hole ring is cleaned up, and the steel hole ring can be firmly welded with other iron devices.

The measurement before the shield penetration is an important basis for rechecking the direction of the shield, confirming the shield posture, evaluating the posture when the shield reaches the construction, drawing up the construction axis of the shield reaching section, the control value of the propulsion gradient, the construction scheme and the like, so that the shield is always implemented according to the preset scheme in the construction of the stage, the shield reaches the construction in a good posture, and is accurately positioned on the shield receiving base.

In the process of shield tunneling construction, segments are pushed and assembled as soon as possible in the process of shield tunneling construction, and the shield tunneling time is shortened. After the special ring of the tunnel ring is separated from the shield tail, the arc-shaped steel plate is immediately welded with the special ring of the tunnel ring to form a whole, and the gap between the duct piece and the tunnel ring is filled with slurry to reduce water and soil loss.

And (4) properly adjusting the posture of the shield in the construction stage according to the size of the well ring at the end of the station actually measured on site. When the shield passes through the reinforced area and the enclosure structure, the following matters are noted:

firstly, the propelling speed is controlled within 1cm/min, and the soil pressure on the front surface is gradually reduced;

secondly, parameters such as cutter head moment and the like need to be closely noticed during crossing;

arranging a specially-assigned person to closely observe the deformation of the tunnel portal and the water and soil conditions, accelerating the information feedback speed, stopping the propulsion immediately when abnormal conditions exist, and taking corresponding countermeasures.

Before the shield enters the hole, the main equipment of the shield machine is comprehensively checked once, the existing problems are solved in time, the equipment is kept in a good running state, the difficult problem of engineering caused by the equipment is avoided when the construction is achieved, and the construction time is shortened as much as possible.

In order to prevent tunnel deformation and seam water leakage caused by pulling open tunnel opening pipe pieces by a shield tail in the shield tunneling construction process, channel steel is required to connect about 11 ring pipe pieces at a tunnel opening into a whole before the shield tunneling, and a longitudinal connection strip is usually arranged between 6 pipe pieces in a ring.

After the shield is close to the underground continuous wall, the concrete plates of the underground continuous wall are chiseled out in blocks and lifted out, and in the whole operation process, a full-time supervision is carried out by a professional safety worker, so that potential safety hazards are avoided, and the personal safety is ensured.

The connecting piece of the annular duct piece is tightened again, so that the duct piece is ensured to be connected tightly, and the deformation of the tunnel in the process that the shield enters the receiving well is prevented. In the process of chiseling the tunnel portal, measures are needed to be taken to protect the tunnel portal water stopping device.

And carrying out secondary hole entering construction if necessary according to the hole entering construction condition of the project. The method comprises the steps that a door is sealed after a shield machine enters a tunnel ring for the first time, and then filling and grouting are carried out by utilizing grouting holes pre-buried in the tunnel ring; when grouting reaches a certain strength and the soil body is stable and has no leakage, the shield machine continues to advance, the last ring pipe piece is completely separated from the hole ring, the last ring pipe piece is lengthened on the basis of the original fan-shaped plate and is welded with the hole entering ring pipe piece into a whole, the gap between the pipe piece and the hole ring is filled with hydraulic slurry, grouting is continuously carried out on the hole ring to fill the gap of the soil body, and the stability of the soil body is maintained.

For normal shield propulsion construction, after 100m trial propulsion of the tunnel outlet section, personnel operation, equipment running-in and the like can be mastered, proper shield construction parameters and soil output are adjusted, and the shield normal section starts to enter the shield tunneling construction.

Wherein, the main construction parameter control includes:

(1) principle for setting equilibrium pressure value

Front equilibrium pressure: k is ₀ γh

P: equalizing pressure (including ground water)

γ: average soil body weight (KN/cm) ³ )

h: tunnel buried depth (m)

k ₀ : lateral static equilibrium pressure coefficient of soil

The shield obtains the set value of the balance pressure in the tunneling construction by referring to the method. The specific construction set value is dynamically adjusted according to the shield burial depth, the soil layer condition of the position and the monitoring data.

(2) Control of advancing and unearthing amount

Theoretical soil output of pi/4 × D ² ×L＝37.88m ³ A/ring.

The soil discharging amount of the shield propelling is controlled between 98 percent and 100 percent, namely 37.12m ³ Ring-37.88 m ³ A/ring.

(3) Speed of propulsion

The speed is controlled between 3 cm/min and 5cm/min during normal propelling. The advancing speed is controlled within 2cm/min when the underground pipeline with high sedimentation requirement passes through.

(4) Shield axis and ground deformation control

The deviation value from the designed axis is not more than +/-50 mm during shield tunneling; the ground settlement is controlled to (+10) - (-30 mm).

The synchronous grouting in the shield propulsion is a main means for filling a building gap between a soil body and a segment ring and reducing later deformation, and is also an important process in the shield propulsion construction. The grout is timely, uniform and sufficient in pressure injection, so that the building gap can be timely and sufficiently filled, the ground surface deformation and the duct piece deviation are controlled to be minimum, and water leakage of duct piece joints is prevented. The synchronous slurry can be quickly and uniformly filled in each part of the shield tail gap, so that the disturbance of the construction to the soil body is reduced to the minimum. The amount of grouting per ring is typically 200% to 250% of the building void (the actual amount of grouting is adjusted based on the monitored data). And according to the ground surface monitoring feedback data, effective measures are taken in time for control, and the slurry ratio is adjusted. The grouting belongs to an important process, a specially-assigned person is assigned to take charge of construction, the pressing-in position, the pressing-in amount and the pressure value are recorded in detail, and the construction quality of the grouting process is ensured by adjusting in time according to stratum deformation monitoring information. The transport vehicle in the tunnel and the slurry mixing system on the ground are cleaned regularly, and the cleaning time is basically controlled to be once per shift. Because the grouting pipeline of the shield working face is cleaned and other reasons, certain waste slurry is formed, the working environment is polluted, and the soil box is utilized to transport outside in time.

The embodiment of the invention can also carry out secondary grouting after the wall. The secondary grouting is carried out when the leakage is serious or the ground subsidence alarm is required or other requirements are met. The slurry for secondary grouting after the wall is selected from double-liquid slurry, and the proportion of the double-liquid slurry is as follows:

the slurry proportion is adjusted according to specific conditions in actual construction.

The shield tail sealing function during tunneling of the tunnel in the interval is particularly important due to the fact that a large number of pipelines are arranged on the ground. In order to safely and smoothly complete the tunneling task of the sectional tunnel, the pressure injection work of the shield tail grease must be done reliably. Under normal conditions, shield tail grease is automatically injected through a shield tail grease pump, and is timely supplemented according to grease pressure in the shield tunneling process.

And (4) checking and accepting the segments transported to the site, and sorting and stacking the segments after confirming that the problems of corner missing, edge falling, maintenance period and the like do not exist. And cleaning each waterproof processing surface of the pipe piece. The lining joint adopts an elastic rubber sealing gasket arranged in a sealing gasket groove for water prevention. The elastic sealing gasket is extruded and vulcanized by ethylene propylene diene monomer rubber, and water-swelling rubber is embedded into the top surface of the elastic sealing gasket for prefabrication and molding. The water-swelling rubber sealing ring is adopted to strengthen the screw hole for water proofing, and the elastic sealing gaskets on the two sides of the capping block are coated with surface lubricant before being assembled so as to reduce the frictional resistance between the elastic sealing gaskets when the capping block is inserted. The surface lubricant should be an aqueous paint having a viscosity of 300 cps. The rubber can expand when meeting water and moisture, so that a plastic film is covered on the rubber or an expansion-retarding agent is coated on the rubber in rainy days.

The tunnel lining is assembled by six prefabricated reinforced concrete segments in a staggered joint mode, the top sealing blocks are pushed up in the radial direction and then inserted in the longitudinal direction, and the flatness of the lining ring surface, the advance amount of the ring surface, the ellipticity and the like are controlled strictly in the segment assembling process. According to height and planar measurement report and section of jurisdiction clearance, the gesture that the section of jurisdiction was assembled is in time adjusted, and the control main points are assembled to the section of jurisdiction:

(1) strictly controlling the flatness of the ring surface: the self-supporting ring is used for checking, the step size of adjacent block segments is smaller than 4mm, and each segment cannot protrude out of the ring surface of the adjacent segment, so that the segment at the joint of the adjacent blocks is not cracked.

(2) And controlling the annular surface lead quantity: the perpendicularity between the ring surface of the pipe piece and the design axis of the tunnel is often detected in construction, and when the advance of the pipe piece exceeds the control quantity, the angle of the assembled pipe piece is adjusted to correct the advance, so that the perpendicularity between the ring surface of the pipe piece and the design axis of the tunnel is ensured.

(3) Adjacent ring height difference control: the magnitude of the adjacent ring height difference directly affects the quality of the built tunnel axis and the effective section of the tunnel, so that the ring height difference must be strictly controlled within the allowable range.

(4) And controlling the tunnel ellipticity: when each ring is assembled, the ovality of the tunnel is measured in time, the deviation of the horizontal and vertical diameters of the lining assembled ring is less than or equal to +/-3 mm, and unqualified lining assembled ring is corrected in time until the ovality meets the requirement and then the next ring is propelled.

(5) And before assembly, removing the garbage at the assembly part of the shield tail, checking the model and the appearance of the duct piece and the adhesion condition of the sealing material, and if the duct piece is damaged, the duct piece can be assembled only by repairing. The assembling quality of the first positioning segment directly influences the assembling quality of the whole ring segment and the relative position of the whole ring segment and the shield, and the perpendicularity of the whole ring segment and the axis of the tunnel is ensured besides general requirements of no step, centered assembling and the like of the whole ring segment and the front ring segment are ensured.

(6) The jacks correspondingly retract according to the sequence of the assembled duct pieces, and the jacks are closed in time after the assembly is completed, so that the shield is prevented from retreating. After assembling is finished, all jacks are extended out, required jacking force is controlled, and then assembling of the next segment is carried out, so that assembling of each ring is finished block by block, and sudden change of the shield posture is prevented.

(7) The longitudinal bolts and the circumferential bolts are connected into the ring-shaped pipe pieces and are connected by the longitudinal bolts and the circumferential bolts, and the tightness of the connection directly influences the overall performance and quality of the tunnel. Therefore, the longitudinal and circumferential bolts for connecting the linings are screwed in time after the assembly of each ring of linings is finished; when the next ring is pushed, the longitudinal bolt is tightened again under the action of the jacking force of the jack; after the ring-shaped duct piece is pushed out of the frame, the longitudinal and circumferential bolts are tightened again.

In the shield construction, according to different soil qualities and covering soil thicknesses, the analysis of ground monitoring information is matched, and the interrelation among thrust, propelling speed and soil output is combined, so that the propelling gradient is kept relatively stable, the one-time deviation rectifying amount is controlled, and the disturbance to the soil body is reduced. And simultaneously, adjusting the grouting amount in time according to the monitoring data of the propelling speed, the soil output and the formation deformation, so as to control the axis and the formation deformation within an allowable range.

(1) And reasonably controlling the oil pressure of the area

The axial control of the shield is an important link in the shield construction, and the shield is pushed forward by the thrust of a jack. In order to facilitate axis control, the jack is divided into different areas, and the shield is propelled along the designed axis direction by adjusting the oil pressure of the areas during propelling.

Under the prerequisite that incision equilibrium pressure correctly set for, each regional oil pressure of strict control, the stroke of simultaneous control jack is rationally rectified, accomplishes frequently to rectify, reduces the single volume of rectifying.

(2) Positive equilibrium pressure setting

Due to the restriction of different factors such as geological conditions, ground additional load and the like, the soil pressure in front of the cutter head is different and needs to be adjusted in time.

(3) Amount of soil discharged

During the propelling process, the deviation of the propelling axis and the ground settlement caused by over-excavation or under-excavation should be avoided as much as possible.

(4) And balanced construction

The shield propulsion should be as continuous as possible, reducing unnecessary pauses, to prevent shield sinking.

On the premise of ensuring safe construction, the tunnel section arrangement mainly considers reasonable utilization space, and is favorable for construction convenience in the shield propelling process.

(1) The frame sleeper: the sleeper is a floor sleeper made of 14# channel steel, each ring is arranged, and the wellhead slope-releasing sleeper is made of H20 steel.

(2) The electric locomotive track: and arranging a motor vehicle track (30kg/m) on the sleeper for transporting shield tunneling materials. A fork is arranged at the wellhead, so that the utilization rate of the electric locomotive is improved.

(3) And a pedestrian path: a pedestrian walkway frame is manufactured on the lower square pipe sheet on the side of the tunnel, and a walkway plate (0.5 multiplied by 2m) is placed on the pedestrian walkway frame and firmly fixed.

(4) And tunnel lighting: a lamp holder is arranged on the upper side of the tunnel side at an interval of 10m, the lighting cable and the lamp are fixed on the lamp holder, and the power cable is arranged below the lamp holder.

(5) And a pipeline: and water supply and drainage pipelines are arranged on one side of the tunnel and are fixed by hanging brackets every 10 m.

(6) And a ventilation pipe: ventilating pipes are arranged laterally above the ventilating pipes and fixed by hanging brackets every 10 m.

(7) Cables and communication lines: and cables and shield machine communication lines are arranged on the opposite sides of the lamp holders.

(8) And fire extinguishers are arranged in the tunnel every 100m, and an electronic box and a telephone are arranged in the tunnel every 200 m.

Further, portal well joint construction rules mainly include:

(1) and the progress of the main tunnel engineering cannot be delayed at any time during the construction of the portal well joint.

(2) And before the duct piece is removed or chiseled, the condition of a grouting layer outside the duct piece is detected and whether pre-grouting is needed or not is determined.

(3) The cast-in-place concrete is closely attached and stably connected with the tunnel and the station end wall.

(4) All measures should be taken to ensure the waterproof construction quality.

(5) The cast-in-place concrete pouring can be implemented after the approval of a supervision engineer.

(6) And effective measures are taken to ensure the safety of constructors and the safety of transport vehicles and personnel on the channel.

(7) And the repair plan is implemented after the report and supervision engineer reviews and approves.

The portal well joint construction method mainly comprises the following steps:

(1) removing zero-ring duct piece

The air pick is used for chiseling a wide gap between the bottom block and the standard block to loosen the standard block for convenient removal. Two phi 12 double-strand steel wire ropes are threaded into the outer longitudinal screw holes of the standard blocks at the hoisting points. In order to prevent the danger of the swinging of the segment after the lifting, the inner side longitudinal screw hole and the +1 ring outer side longitudinal screw hole are bound and pulled by a steel wire rope, and then the segment is stably moved to a vertical lifting position and lifted. According to the construction method, the adjacent block, the top sealing block, the adjacent block and the standard block are sequentially detached.

(2) Steel bar forming welding

The length of the steel bar is determined according to the actual size of the site, the single-component neoprene-phenolic adhesive is used for adhering and bending the positioning steel bar to cooperatively fix the water-swelling rubber water stop bar, and the expansion-retarding agent is coated outside the positioning steel bar. Evenly set up the loop type reinforcing bar, welded fastening steel skeleton to whether check its reinforcing bar and section of jurisdiction pre-buried steel sheet, station inside lining entrance to a cave pre-buried steel sheet switch on with the electric bridge, obstructed person's repair welding.

(3) And template production

And (3) adopting a wood pattern, lofting an inner arc according to the inner diameter size of the hole ring, and forming an inner ring by using 10 circular arc wood patterns after lofting. And (4) lofting the outer ring according to the outer diameter of the hole ring, and using 23 plywood with the thickness of 20mm as an end socket after lofting. The rail of the fixed template is welded on the steel hole ring by phi 12 round steel, is externally connected with a phi 12 pull rod screw and is fixed by a three-shaped clamp and a 1-inch semi-steel pipe.

(4) Concrete pouring and tamping

The method adopts the commercial concrete self-discharging and string barrel construction modes, the ground is connected with the string barrel by a chute about 1.5 meters, and the length of the string barrel can be adjusted according to the depth of the open caisson. The serial cylinders are directly communicated to the opening of the template and are compacted by using an inserted oscillator.

For the waterproof caulking construction of the tunnel, the waterproof grade of the interval tunnel is two levels, the top plate does not allow water seepage, the structure does not allow water seepage, and the surface of the structure can have a small amount of wet stains. The total wet area should not be larger than 6/1000 of waterproof area, and is arbitrarily 100m ² The water-proof area has no more than 4 wet spots, and the maximum area of single wet spot is not more than 0.2m ² . The strength of the concrete of the segment is C50, the impervious grade is not less than P10, the width of the crack is not more than 0.2mm, and the erosion resistance coefficient of the concrete is required to be more than 0.8 when underground water corrodes the concrete. The tunnel top does not allow dripping, and the side allows to have a small amount of wet performance, and the masonry joint does not allow hourglass silt particle and water clock, encircles the bottom block and after the caulking operation, does not allow to have the infiltration. The method for measuring the water leakage and the wet stain comprises the following steps: the water accumulation is measured day and night by a water storage earth dam for calculation, and the leakage and the wet area are calculated by a method for measuring the wet area by a scale (the leakage and the wet area are measured under the condition that a tunnel is not communicated yet).

The interval tunnel structure is waterproof, the concrete of the segment is self-waterproof, the seam of the segment is waterproof, and the interval tunnel is waterproof with the joint of the station or the working well and the joint of the communication channelAnd the integral waterproof performance of the interval tunnel is ensured. The main structure of the tunnel adopts waterproof concrete, the concrete adopts 'double-doping technology', 20 percent of high-quality fly ash and anti-cracking additive are added, and the permeability coefficient K of the duct piece is less than or equal to 5 multiplied by 10 ^-13 m/s, chloride ion diffusion coefficient less than or equal to 8 x 10 ^-9 cm ² And s. When the tunnel is in an aggressive medium, corresponding erosion-resistant concrete or erosion-resistant waterproof paint is coated on the outer surface of the lining structure, and the permeability coefficient K of the concrete is less than or equal to 5 multiplied by 10 ^- ¹⁴ m/s, ion diffusion coefficient less than or equal to 2 x 10 ^-9 cm ² /s。

The joint of the duct piece is provided with an elastic rubber sealing gasket (sealing gasket for short) as a main joint waterproof measure, caulking and wall back grouting are auxiliary measures, and a force transferring gasket is required to be arranged on the longitudinal joint of the duct piece so as to disperse concentrated stress.

(1) Elastic sealing gasket (shield segment water stop strip)

The method of arranging the elastic sealing gaskets around the rib surface of the duct piece is adopted to waterproof the duct piece joint, the adopted sealing gaskets still meet the waterproof requirement when construction errors occur, the approved adhesive is adopted to firmly bond the sealing gaskets on the duct piece according to an operation method, and when the water-swelling rubber waterproof material is adopted, damp-proof measures are required to be taken during transportation and storage, and special storehouses are arranged for storage.

The resilient gasket should meet the relevant specifications. The performance index test method should meet the relevant regulations of the national standard.

(2) Caulking

The caulking operation can be started after the shield is pushed to the end and the tunnel is thoroughly cleaned. The caulking operation is allowed to be performed on the micro-seepage and wet pipe sheet, and if water leaks, the caulking operation can be performed after the plugging is finished. If the segment caulking groove has large defects, the segment caulking groove is used after being repaired, the strength of the repair material is close to that of the original concrete, and the repair material can be used after being approved by a supervision engineer.

(3) Force transmission gasket

The nitrile-butadiene cork rubber force-transferring liner is processed according to a design drawing, is pasted on a construction site, floating ash and sludge are removed by a steel wire brush before pasting, and the condition that the liner does not shift or fall off after pasting and all the adhesives are the same as the sealing gasket is ensured.

For the flow of waterproof construction, mainly include:

1. longitudinal and circumferential seam caulking of duct piece

Removing silt and garbage in longitudinal and circular seams, brushing an interface agent, embedding a closed-cell foamed polyethylene strip, and manufacturing a polyurethane sealant protective layer.

2. Bolt corrosion prevention treatment

Checking and screwing the screw cap, removing the floating rust and mud dust of the metal piece, coating an antirust material, and sleeving a high-pressure polyethylene plastic cup filled with quick-setting micro-expansion cement.

3. Segment hand hole filling

Cleaning up garbage and sundries in the hand hole, cleaning floating dust and floating mud, coating an interface agent, and filling the hand hole with micro-expansion cement.

4. Water-proof mode

(1) Segment outer grouting waterproof

In the shield tunneling construction process, a gap between the shield and the duct piece is filled through synchronous grouting and secondary grouting after the wall, so that a peripheral waterproof layer is formed, and the waterproof of the interval tunnel is facilitated.

(2) Self-waterproof pipe piece

The high-performance self-waterproof concrete with good durability as the characteristic is adopted by the duct piece, the anti-permeability grade of the duct piece is ensured through measures such as reasonable mix proportion design, standard material selection and strict production control, and the anti-permeability grade of the concrete duct piece is not less than P10.

(3) Waterproof of segment joint

In order to meet the waterproof requirement of the joint, two waterproof measures of a frame-shaped elastic sealing gasket and caulking are arranged at the joint of the pipe sheet ring and the longitudinal joint, and the elastic sealing gasket is taken as the main waterproof measure.

(4) And the elastic sealing gasket is waterproof

1) The elastic sealing gasket is a main measure for preventing water of a lining joint, is formed by extruding and vulcanizing ethylene propylene diene monomer rubber, and is embedded with water-swelling rubber on the top surface.

2) And before the sealing gasket is adhered, the duct pieces transported to the field are checked and accepted, the problems of corner defect, edge falling, maintenance period and the like are confirmed, the duct pieces are stacked in a classified mode, floating ash and dirt in the grooves of the duct pieces are brushed by a steel wire brush, and the duct pieces are adhered by adopting a neoprene-phenolic adhesive.

The gasket must be firmly bonded in the groove without falling, peeling, or shifting.

If the lining stuck with the sealing gasket is not used temporarily or is in rainy days, the lining is tightly covered by a plastic film or oilcloth, and a swelling-relieving agent is coated at the same time, so that a movable rain shelter is prepared on site.

3) And in order to strengthen the waterproof property of the corner part of the elastic sealing gasket, a self-adhesive rubber sheet is coated on the outer corner part of the sealing gasket.

4) Before assembling, the waterproof sealing gaskets on the two sides of the top sealing block and the adjacent block are coated with a water-based surface lubricant (water-based coating agent with the viscosity of 300 CP) so as to reduce the friction resistance between the elastic sealing gaskets when the top sealing block is inserted to cause dislocation or pull damage.

5) When the shield curve is pushed forward or the posture needs to be adjusted due to other reasons, the adjustment amount of one time (pushing one ring) is not too large, so that the shield tail steel plate is prevented from pulling the duct piece, damaging the sealing gasket and influencing the water stopping effect.

(5) Water swelling rubber water bar

In order to ensure the waterproof effect of the tunnel, a water-swelling rubber water retaining strip with the thickness of 20 multiplied by 4mm is additionally attached to the outer side of the elastic sealing gasket of the segment, and a water-swelling rubber strip with the thickness of 3mm is additionally attached to the elastic sealing gasket at the deformation joint of the tunnel.

The lap joint part of the water bar should avoid the corner, and the lap joint is butted at an angle of 45 degrees and fixed by adhesive.

(6) Waterproof for caulking

Caulking waterproofing is the second line of defense that makes up the seam waterproofing. After the gasket life has expired, the caulk material, which is the lane line, is easily removed and re-caulked.

1) The caulking groove sealing material adopts polymer cement (such as neoprene latex cement mortar), and the joint surface of the material and the concrete is treated by using an interface treating agent.

2) And caulking range: and (3) performing full-ring embedding on lining ring segments with large deformation quantity at positions of 30m of the door section and 8-10m of each of two sides of the communication channel, wherein the rest segments are in a vault angle range of 45 degrees and a vault angle range of 90 degrees.

(7) Waterproofing of bolt holes and hoisting holes (grouting holes)

The bolt holes are waterproof: adopt and meet water inflation rubber seal circle as the bolt hole sealing washer, utilize the dual function of compaction and inflation to strengthen waterproof.

Waterproof of hoisting holes (grouting holes): when the hoisting hole and the grouting hole are used in a combined mode, in order to reduce the weak link of the grouting hole as water seepage of the tunnel, 50mm of plain concrete is reserved on the outer side of a segment of the hoisting hole, and when secondary grouting is needed on the back of the lining, the plain concrete of the hoisting hole is broken to be used as the grouting hole. The grouting hole is provided with a water expansion screw hole sealing ring to strengthen water resistance.

(8) Waterproof when shield constructs in and out of hole

The thrust is reduced when the shield enters and exits the hole, the elastic sealing gasket of the duct piece is difficult to compress, a duct piece tensioning measure is adopted in construction, and comprehensive water prevention is carried out by combining duct grouting and shield entering and exiting hole reinforcing soil layers.

(9) Corrosion prevention

Lining bolts, other metal connectors and exposed parts must be treated with hot dip zinc or zinc based chromate coatings.

(10) Water-proof of communication channel

The connection channel and the pump station adopt flexible waterproof layers (non-woven fabrics + EVA waterproof boards), and the interval tunnel and the connection channel joint adopt water-swelling rubber strips for water prevention.

The caulking waterproofing measure includes:

firstly, cleaning the seam, brushing off mud and sand sundries in the seam, and washing the seam with clean water.

② embedding closed-cell foam polyethylene strips. When the seam is stepped, the embedding depth of the sealant is at least 12mm, and the sealant can reach the preset depth after being embedded and is tightly attached.

And thirdly, after the closed-cell foamed polyethylene strip is embedded, the surface is smooth.

And fourthly, connecting the closed-cell foamed polyethylene strips at the joints.

Painting an interfacial agent YJ-302 (two components), and mixing the interfacial agent with the components of group A: group B: 1, cement: 3: 4, pouring the mixture into a container to be uniformly stirred, wherein the stirring amount in each time is used up within 2 hours.

Sixthly, the coating range of the interface agent is within 15mm of the inner wall of the slot, 15mm of each of two sides of the longitudinal seam and 16mm of each of two sides of the circular seam.

And seventhly, sealing a polyurethane sealant protective layer. And (4) sealing by using polyurethane sealant, wherein the sealing time is required to be before the interface agent is dried.

For the caulking range, the inlet and outlet holes 20 are annularly and longitudinally caulked. And (3) performing whole-ring caulking (including ring longitudinal seam) on each 5 rings in front and at the back of the central circular seam of the steel pipe sheet ring of the communication channel. And performing full-circle caulking on the deformation joint circular seam (only circular seam). The segment arch in other areas is embedded and filled in the range of 45 degrees and the range of 90 degrees.

The anticorrosive treatment of the exposed part of the assembling bolt comprises the following steps: the exposed bolt, nut and washer in the upper 180 deg range are treated to prevent corrosion. The construction requirements are as follows:

1) removing rust slag and rust;

2) coating water-based antirust paint;

3) tightly sealing the end by using quick setting cement and sleeving a plastic protective sleeve on the end;

4) the end enclosure and the plastic protective sleeve should be perpendicular to the wall surface of the orifice, and the screw cap and the gasket should not be exposed.

To interval tunnel and station end well, contact channel joint waterproof, mainly include:

(1) tunnel and end well

The tunnel is waterproof with the joint of shaft includes: and the temporary joint in the construction stage is waterproof with the completed permanent joint.

a. The temporary joint mainly comprises a cord fabric rubber ring and a fastening device thereof, and is assisted by a walling crib for grouting and water plugging.

b. The permanent joint is a reinforced concrete well ring, and a plurality of flexible waterproof materials such as a grouting pipe with full-section grout output, a single-component polyurethane sealant and the like are preset at the joint of the permanent joint, the well wall and the pipe piece.

(2) Tunnel and communication channel

The joint of the connection channel and the shield region is a waterproof weak link. The waterproof plate is subjected to closing-up treatment at the joint of the waterproof plate and the shield segment. And adopting a water-swelling rubber water stop strip and an externally-attached water stop belt, and grouting and stopping water on the peripheral stratum at the node through a grouting pipe.

For the connection channel and the pump house soil excavation and support, the soil excavation should have some conditions, for example:

1) inspection of temperature measurement hole

The development speed of the frozen soil can be calculated according to measured data of the temperature measuring holes, the circle crossing time is calculated, the development radius of the frozen soil in the freezing time is further calculated, the thickness of a frozen soil curtain is calculated, the average temperature of the frozen soil curtain is obtained by a formula method or a drawing method according to the thickness, and if the thickness and the average temperature of the frozen soil curtain of each layer and each part meet design requirements, excavation can be carried out.

2) Pressure relief hole inspection

In the positive freezing process, the pressure relief hole has two functions, namely the function of unloading the frost heaving pressure, and the displayed pressure can be used as an important basis for judging whether the frozen soil curtain is coiled or not to a certain extent. Generally speaking, in the initial freezing stage, the pressure of a pressure relief hole is the original formation pressure, water continuously migrates along with the gradual expansion of frozen soil, the frozen soil forms a closed soil body after circling, the frost heaving pressure cannot be released, but gradually increases, the appearance of the frost heaving pressure is the sharp increase of the pressure relief hole, the pressure relief valve is opened to relieve the pressure and then the pressure relief valve is closed to gradually return to the original value, and the difference between the front and the rear circling values of the pressure relief hole is 0.15-0.3 Mpa.

3) Temperature difference of brine to return circuit

Because the cooling loss after circle intersection is less than that before circle intersection, the temperature difference of the brine and the loop before circle intersection is larger than that after circle intersection, and if the temperature difference of the brine and the loop (other freezing parameters are unchanged) suddenly becomes smaller in a certain period, the circle intersection is likely to happen, but the phenomenon is only used as a reference for judging the circle intersection, and the comprehensive consideration in aspects of measuring temperature hole data, pressure relief hole pressure, hole probing condition and the like is needed to be combined for determining excavation.

Before connection passageway, pump house soil body excavation construction, include:

1) inspection of exploratory hole

And (3) detecting a probe hole before formal excavation, wherein the probe hole is drilled at the weak part of the frozen soil curtain, the sand gushing and water bursting phenomenon does not exist at the probe hole, the frozen soil curtain is normal in stratum stability, the temperature measurement effect is good, and the formal excavation can be realized.

2) And a working platform in the tunnel is set up

According to the size of the outlet of the connecting channel and the construction requirement, an intermediate working platform is erected at the opening of the connecting channel, the intermediate working platform is mainly used for reversing the channel material transportation trolley, and a material equipment platform is erected for temporarily stacking construction materials.

3) Emergency safety door installation

The emergency safety door is used for ensuring the safety of a tunnel under the conditions that a large amount of sand and water are gushed out or displacement deformation of a reinforced soil body is beyond a certain value and other measures are ineffective in rescue during excavation construction. The safety door is firm and reliable to install, the door leaf is convenient to open and close, the safety emergency door is installed before the connecting channel is actively frozen, and the air quantity is not less than 6m ³ And the air compressor is used for pressure test and air supply of the safety door, and the safety door can be detached after the communication channel is completed.

And, considering that the stress of the connecting channel opening lining ring is redistributed after the steel pipe sheet at the opening is pulled open, the safety of the main tunnel structure is influenced, and before the bell mouth of the excavation construction, the section steel prestressed tunnel support is arranged in the opening ring of the tunnel pipe sheet at the opening of the channel so as to reduce the adverse influence of the excavation construction of the connecting channel on the tunnel. The single steel bracket is composed of a middle rectangular closed steel bracket, 5 prestress jacks, 2 fixed supports, a support protection plate and the like, as shown in fig. 5. The installation method comprises the following steps: two steel supports are respectively arranged on two sides of the opening of the section tunnel connecting channel, the distance between the two steel supports is 2m, the two steel supports are symmetrically arranged at two ends of the connecting channel along the tunnel direction, and the two steel supports are combined by lap welding through 67mm equal-side angle steel. Each support has seven fulcrums, and 5 screw jacks of 50t provide prestress, each jack needs to slowly and stably pressurize at the same time when prestress is applied, and each jack is preferably used for compacting a supporting point. When the main frame is erected, a specially-assigned person is required to command, the bolts must be screwed down when the main frame is assembled, and the high-altitude jack should be fixed on the main frame to prevent the main frame from falling off. The pressure condition of the jack is checked regularly, and abnormal conditions such as looseness and the like are treated in time.

4) Installation of pneumatic installation

In order to ensure the safety of soil excavation construction, 20m is considered to be equipped ³ One air compressor machine and relevant pipeline are supporting, can be connected with emergency exit compressed air valve, in case take place seriously to leak in the contact passageway, must add atmospheric pressure in the contact passageway, balance outside water pressure, reduce the water yield and flow in, guarantee tunnel safety, under the emergency, can increase atmospheric pressure to 180 Kpa.

5) Reserve of emergency supplies

In order to deal with the possible emergency situations in the freezing hole construction and excavation construction process, besides the establishment of feasible emergency measures, a certain amount of emergency materials need to be stacked on the construction site: liquid nitrogen, an emergency sand bag, a clay bag, a wood wedge, cement, hemp, a wood back plate and the like, so as to ensure the safety of the construction of the connecting channel. The emergency rescue materials should be stacked orderly and set up with a striking signboard, the emergency materials should be specially used, and should not be used at any place, and special persons are provided to take care, keep and check regularly.

The strength of the reinforced soil body meets the design requirement, the soil body excavation work can formally start after the construction preparation work is ready, and before the duct piece is excavated, 2 jacks of 5t are firstly prepared, and one each of the chain block of 5t and the chain block of 2t is respectively prepared. The duct piece opening method comprises the following steps: two jacks are erected at two sides of the opened pipe sheet, a section steel beam is directly connected with the steel pipe sheet in the middle, and the steel pipe sheet is pushed outwards by pushing the beam through the jacks, as shown in fig. 6 and 7. During operation, the stress and displacement conditions of the duct piece are carefully observed, local blocking factors are eliminated, and the duct piece is prevented from deforming.

Wherein, the 5t calabash is used as supplementary drawing the section of jurisdiction, and the section of jurisdiction is expected to be torn open in the hanging of one end, and one end system is on opposite tunnel section of jurisdiction, and the section of jurisdiction is drawn to outside (in the tunnel) to the slight afterburning of horizontal direction, will cooperate the jack operation. The 2t calabash is suspended above the duct piece to be removed, and one end of the 2t calabash hooks the duct piece to be removed so as to prevent the duct piece from being suddenly smashed and falling on the working platform when being pulled out. During the drawing process with the jack and the 5t hoist, the outward movement of the pipe piece is observed, and the tensioning degree and direction of the 2t hoist are adjusted at any time. When the drawing is difficult, the cause of the blockage should be checked and disposed of. If the pipe piece is rusted, a sledge hammer is needed to vibrate the pipe piece so as to reduce the drawing resistance.

According to the characteristics of engineering structures, the circulating footage of connection channel excavation is controlled to be 0.5m or 0.6m, 2-level step excavation is adopted, the upper step excavation is carried out in advance, the excavation height is 1.6m, an arch steel arch is erected, then the lower step soil body is excavated, the height is 1.65m, side wall steel arch connecting legs and inverted arch steel arches are installed, the distance between excavation surfaces of the 2-level steps is kept to be about 2m, and the excavation step distance is controlled to be 0.5m in order to reduce the influence of excavation on tunnel deformation. After the connection channel is excavated and communicated, a water collecting well of a drainage pump room is excavated, the excavation of the drainage pump room is implemented in a step-down mode, and the excavation is carried out in layers, wherein each layer is 0.5 m.

In another aspect, the invention further provides a method for shield construction waterproofing.

And after the shield is debugged, uniformly and densely smearing shield tail grease between the shield tail steel brushes to fill a grease cavity of the shield tail brushes. And an elastic sealing gasket is arranged along the periphery of the rib surface of the duct piece. Wherein, the elastic sealing gasket is made of water expansion rubber material.

As another aspect, the present invention further provides a method for monitoring shield construction, where the method for monitoring shield construction according to the embodiment of the present invention is used for any one of the above methods for shield construction, and includes: setting a temporary point location at the bottom of the well, measuring the transverse diameter and the plane coordinate of the door ring according to the temporary point location station, calculating the plane center coordinate of the door ring, and calculating the plane deviation value of the door ring; measuring the bottom elevation and the top elevation of the portal ring by using a temporary level point transmitted to the bottom of the well by the elevation, and solving the ring diameter and elevation deviation value; calculating the coordinates of the portal ring center, the shield base front center and the shield base rear center, actually measuring the value of the coordinates by using an instrument, and calculating the deviation of the value of the coordinates and a theoretical value; and adjusting the plane position of the base according to the deviation.

The monitoring method for shield construction of the embodiment of the invention also comprises the following steps: sticking a metal stainless steel plate on each of two sides of the middle part of the monitored crack, drilling a round hole in the center of the steel plate, enabling the connecting line direction of the round holes to be vertical to the crack during embedding, and marking two ends of the crack respectively to observe the development condition of the crack; and gypsum sheets are arranged at two ends of the crack, and are firmly bonded with two sides of the crack.

The shield construction monitoring method of the embodiment of the invention further comprises the following steps: and an abnormal gas monitor is arranged at the outlet of the shield spiral machine to monitor abnormal gas.

The shield construction monitoring method of the embodiment of the invention further comprises the following steps: laying ground settlement measuring points along the axis of the tunnel, laying settlement tank observation sections at certain intervals, adding the settlement tank observation sections when passing through important buildings and pipeline groups, setting measurement marks on the hard ground by using shooting nails or spikes, and using reinforcing steel bars as the measurement marks on the soft ground; arranging a monitoring section every 20 meters within the range of 100m of the shield starting section; arranging a monitoring section every 30 meters in other sections; the interval of the measuring points on the monitoring section is 2-5m, and 7-11 measuring points are arranged in one monitoring section.

The shield construction monitoring method of the embodiment of the invention further comprises the following steps: hanging three steel wires, wherein the steel wires and the above-well and underground observation platforms form two straight triangles on the plane; the ratio of the long side and the short side of the triangle is at least more than 2.5 times, and the angle in the triangle is less than 2 degrees; the end of the steel wire is hung with a plumb bob which is immersed in the oil drum filled with oil and can not contact with the oil drum; dividing the measurement data into two groups, wherein each group of data comprises an aboveground position, four connecting angles and five side lengths; when the triangle is calculated, the condition of the triangle closure difference is utilized, and the simple adjustment difference is used for calculation to obtain the coordinates of the underground position and the underground control point; the other set of data is calculated as above and the orientation and coordinates obtained are checked against the first set to ensure that no errors occur.

The shield construction is a disturbance process to the soil body, and the soil body is extruded or the soil body is lost and the soil body is solidified to cause the ground to generate heaving and sinking changes, and the shield construction method is particularly related to the following factors: the shield sealing bin balances pressure; the unearthing speed; shield attitude; dragging action of the shield shell; the sealing degree of the segment lining joint; building gaps; deforming the tunnel lining; soil consolidation and secondary consolidation settlement; grouting filling materials are solidified, contracted and settled and the like. And monitoring and considering shield construction design and surrounding environment conditions, wherein the following factors are mainly considered:

(1) the shield construction depth and the penetration of the soil layer are calculated, and the possible range and degree of disturbance influence are estimated;

(2) the structural characteristics of the building (structure) penetrated by the shield, the adjacent building (structure), the drainage box culvert, the pile foundation and the like and the distance relation with the tunnel;

(3) the distribution condition and the respective characteristics of pipelines adjacent to shield construction;

(4) during tunnel construction, soil deformation and ground vertical displacement monitoring and deformation monitoring of ground buildings, structures and underground pipelines are carried out, and ground settlement is controlled within a specified range by proper measures, so that the safety of roads, pipelines and buildings is ensured.

The monitoring items are as follows: monitoring vertical and horizontal displacement of the underground comprehensive pipeline; monitoring vertical displacement inclination and cracks of surrounding buildings (structures); monitoring the shield tunnel settlement and the settlement section of the ground surface along the line; monitoring the convergence of the tunnel; and (5) moving the interior of the soil body.

The convergence deformation measurement is carried out by adopting a convergence meter (if the conditions are available, a TCRA1200 series total station instrument is selected), two convergence measurement hooks are respectively embedded at the two sides of the upper part and the lower part of the waist of the tunnel ring, when a measuring point is embedded, a hole slightly larger than the diameter of an expansion bolt is drilled at the measuring point by using impact, then the expansion bolt with a screw hole processed at the top end is screwed, and then one end of a hook made of stainless steel is screwed into the expansion bolt. Before testing, the ambient temperature is first read to perform temperature correction. The temperature correction formula is as follows:

△L _C ＝K×△T×L

wherein: delta Lc temperature correction value (mm)

Correction factor K (12X 10-6 mm/DEG C in this apparatus)

Delta T difference (. degree. C.) between this temperature and initial temperature

L reading distance (mm) between two measuring points

In high-temperature and severe winter, after entering the tunnel, the convergence meter is ensured to be stable for more than 15 minutes. When the distance between any two points is tested, the distance is continuously measured and read for more than 3 times, and the average value is taken as the reading. And the difference value between the current convergence value after the temperature correction is carried out on the current reading and the last convergence value is the current convergence variation. The sign "+" indicates elongation and the sign "-" indicates contraction. The cross-section of the convergence monitoring point is as follows, A, B, C, D is the monitoring point, and the convergence meter is used to measure the distance between the six edges AB, AC, BD, BC, BD and CD during the convergence test: FIG. 8 is a schematic diagram of a convergence gauge test using an SL-2 steel rule according to an embodiment of the invention.

Harmful gases such as methane and the like may exist in an engineering soil layer, in order to ensure the smooth operation of the engineering, superstrong monitoring of harmful gases in a soil body is required, an abnormal gas monitor is installed at the outlet of the shield screw machine, and once the abnormal gases are found, an alarm is immediately sounded. The monitoring items of the interval tunnel construction in the embodiment of the invention are summarized as follows:

in order to monitor the influence degree and range of the tunnel in the interval on the surrounding earth surface during propulsion, earth surface settlement profile monitoring points are required to be arranged for vertical displacement monitoring, and the monitoring points are specifically arranged as follows:

the ground settlement measuring points are generally distributed along the axis, the distance between the points is 4-5m, and the ground settlement measuring points are properly encrypted when entering or exiting a hole and meeting important buildings. And arranging the observation sections of the settling tanks at a certain distance (about 30m), arranging the observation sections of the settling tanks when the settlement tanks pass through important buildings and pipeline groups, arranging measurement marks on a hard ground by using shooting nails or spikes, and using reinforced piles as the measurement marks on a soft ground.

Arranging a monitoring section every 20 meters within the range of 100m of the shield starting section; and arranging a monitoring section every 30 meters in other sections. The interval of the measuring points on the cross section is generally 2-5m, and 7-11 measuring points are arranged in one monitoring section. And laying ground surface settlement monitoring points along the line according to the actual situation of the lines in the interval after entering the field.

And laying convergence monitoring sections in the tunnel, and setting the convergence sections on the tunnel structure of the left line and the right line at an interval of 10m, wherein the convergence sections and the settlement points have the same cross section.

In order to enable the shield propulsion parameter setting to be more scientific and accurate, a monitoring information communication network is established on site, and the purpose of controlling ground settlement is finally achieved.

Due to the restriction of different factors such as geological conditions, ground additional load and the like, the soil pressure in front of the cutterhead is different, and therefore adjustment needs to be carried out in time. And meanwhile, the settlement report is analyzed, adjusted in time and fed back to the team. If the ground subsides before the shield cuts, the set value of the balance pressure needs to be increased, otherwise, the set value is decreased. If the ground at the rear part of the shield tail is settled, the synchronous grouting amount needs to be increased, otherwise, the synchronous grouting amount is reduced.

The soil output is reasonably controlled according to the building clearance between the shield and the segment and the characteristics of each soil layer, the settlement monitoring data along the line is controlled, and the most reasonable numerical value is searched through analysis and adjustment.

The reasonable propelling speed is controlled, so that the shield can be constructed at a uniform speed in a balanced manner, and the disturbance of the shield to the soil body is reduced. The purpose of controlling the ground deformation is achieved.

And in the shield propelling process, other grouting pipelines are synchronously started according to the actual condition. The synchronous grouting amount and the slurry quality are strictly controlled, and the construction gap is timely filled through synchronous grouting, so that the soil deformation in the construction process is reduced. The synchronous grouting amount is generally 140-200% of the building gap. Because a certain gap may exist when the grout for synchronous grouting during shield propulsion fills a building gap, and the shrinkage deformation of the grout also has the hidden danger of ground settlement, secondary grouting is performed when necessary. The slurry is injected into the stratum through the grouting holes of the segments, and a propulsion and grouting linkage mode is adopted during construction, so that the grouting is not required, and the shield suspends propulsion to prevent the deformation of the soil body. According to the deformation monitoring condition in construction, the grouting amount and grouting parameters are adjusted at any time, and the secondary grouting behind the wall is adjusted at any time according to the ground monitoring condition, so that the stratum deformation is stable.

Each measurement result is collected to a construction technical department in time so that construction technicians can know the construction current situation and the deformation condition of pipelines in corresponding areas in time, determine new construction parameters, grouting amount and other information and instructions, transmit the information and the instructions to a shield propulsion surface to correspondingly adjust the propulsion construction surface in time, and finally determine the effect through monitoring, thereby repeatedly circulating, verifying and perfecting to ensure the tunnel construction quality

In order to ensure the safety of the tunnel structure and the surrounding environment, the structure monitoring and the environment monitoring are enhanced, the information management is realized, the monitored data can be fed back in time, and the construction is guided. Besides convergence deformation monitoring, the excavation of the soil body reinforced by the freezing method also needs to be monitored preventively for the temperature of the frozen soil so as to grasp the development state of the frozen soil body and provide construction safety early warning. The construction measurement and monitoring content comprises: 1. monitoring content of freezing pipe drilling construction: drilling hole length, freezing pipe laying length, freezing pipe deflection monitoring, freezing equipment sealing performance and liquid supply pipe laying length; 2. and freezing the monitoring content of the system: the temperature of the brine of a return circuit of the freezing equipment, the temperature of the inlet and outlet water of cooling circulating water, the working pressure of a brine pump, the suction and exhaust pressure of a refrigerator, the suction and exhaust pressure of the refrigerator, the condensation pressure of a refrigeration system and the vaporization pressure of the refrigeration system; 3. frozen wall monitoring content: measuring temperature of temperature measuring holes on the inner side and the outer side of the frozen wall, monitoring pressure releasing holes of the frozen wall, and monitoring temperature and frost heaving pressure of the well wall of the excavated frozen wall; 4. monitoring contents of the main tunnel and the contact channel structure: monitoring deformation of the supporting structure and the structure, and monitoring deformation of the tunnel (the radial deformation of the interval tunnel is less than 15mm, and the horizontal and vertical displacements are less than or equal to 10 mm).

For the contact channel of freezing method construction, different monitoring methods and means are adopted for different parts and different stages, and the method comprises the following steps:

1. the temperature of the de-loop saline water of the freezing system is managed by arranging a temperature sensor on a pipeline and completely incorporating a computer monitoring system.

2. For the freezing effect of the frozen soil curtain, a method of arranging a temperature sensor in a temperature measuring hole and arranging a pressure sensor in a pressure relief hole is adopted, and the method is also brought into a computer monitoring system for collection and management.

3. Monitoring the structural deformation of the tunnel by arranging monitoring points on duct pieces within 30 meters of a communication channel and measuring the deformation and settlement of a plane and an elevation by using a total station and a precision level gauge.

4. And other conventional monitoring projects need to acquire monitoring data in time according to the standard requirements and record and summarize the monitoring data.

An important work in construction is to control the plane by the method of connecting the geometric orientation of the triangle at the upper part and the lower part of the well, and correct the axis of the shield propulsion. During construction, each block is subjected to a plurality of directional measurements as the case may be, typically the first time at about 150-200 m of propulsion and the last time at about 100m of departure from the hole. The connection triangle orientation is that three steel wires are used for transmitting coordinates and directions, and in the specific implementation, the three steel wires are hung, and the steel wires on the plane and the observation platforms above and below the well form two straight-extending triangles. A schematic side view is shown in fig. 10.

When laying, the ratio of the long side and the short side of the triangle should be at least 2.5 times, a: b should not be more than 1.5 times, and O ₂ ,O ₃ The spot should not be too close to the instrument. Alpha angle should be less than 2 in the triangle-shaped, and simultaneously, the steel wire end hangs the plumb bob, for preventing that the steel wire from rocking the influence and observing, soaks the plumb bob in the oil drum that holds full oil to the plumb bob must not contact with the oil drum. During observation, two 2-second total stations are required to measure the edges backwards by using the underground and aboveground connection angles and the connection triangles, the angle measurement requires 9-time measurement, the return-to-zero observation and the return-measurement difference are less than or equal to 9 ' (difference value between the maximum angle and the minimum angle), the 2C difference is less than or equal to 13 ' (difference value between a positive mirror and a negative mirror), the return-to-zero difference is less than or equal to 6 ', the edges are required to be measured for four times respectively, and the comparison difference of the observation average values is less than 3 mm. The side length measurement of the connection triangle adopts the method that a reflecting sheet is pasted on a steel wire, the side is measured by a side edge measuring mode, the three times of independent measurement are carried out every time, the difference between the three data is less than or equal to 3mm every time, and the side length measurement is carried out during the side measurementThe side length correction is calculated taking into account the temperatures above and below the well. The measurement data are divided into two groups, and each group of data comprises an aboveground position, four connecting angles and five side lengths. When the triangle is calculated, the underground direction and the coordinates of the underground control point are obtained by utilizing the condition of the triangle closure difference and calculating by using the simple adjustment difference. Then, the other group of data is calculated as above, and the obtained direction and coordinates are checked with the first group to ensure that no error occurs.

The result of each independent orientation measurement should satisfy the azimuth angle difference less than or equal to 12' and the point difference less than or equal to 20 mm.

The downhole control wire should be re-checked while geometrically oriented. A measuring lead for controlling the plane deviation of a tunnel is arranged underground and mainly comprises an underground control lead and an underground construction lead. The underground construction lead with lower precision and shorter side length is used as a common working lead, the underground control lead is used as construction first-level control and is used for accurately guiding the lead with longer side length and higher precision in the tunneling direction, the underground lead retest is synchronously carried out in coordination with each geometric orientation, the lead point is recalculated, the orientation obtained by the orientation is transmitted to a newly-arranged measuring table in the tunnel, the deviation of the construction lead is corrected, and fig. 9 is a schematic diagram of the arrangement of the lead points in the tunnel according to the embodiment of the invention. During observation, the instrument should adopt forced centering, and the measurement specification adopts the same regulation as that of the lofting measurement on the well.

The purpose of vertical shaft elevation import is to transmit the ground elevation into the bottom of a vertical shaft, and when elevation transmission is carried out, two leveling instruments are used for synchronous observation on the ground and the underground by using a steel ruler hung with 49N (tension adopted during inspection), and the elevation is transmitted to an underground fixed point. The measurements were performed three times, each time with varying instrument height. The height difference of the ground and underground leveling points measured in three times is less than 3 mm.

The above-described embodiments should not be construed as limiting the scope of the invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A shield construction method is characterized by comprising the following steps:

the method comprises the following steps that a shield base is hoisted into the underground according to a baseline for measurement lofting, the shield base is ensured to be consistent with the axis of a tunnel outlet section in the laying process, and the central lines of two tracks are aligned with a shield on the base to the center of a tunnel portal and consistent with the reverse extension line of the design axis of a tunnel; after the shield base is in place, additionally arranging a steel rear shield support between the last ring of negative rings and the well wall structure, wherein the steel rear shield support is provided with a deformation observation point, measuring once every box of soil is pushed in at the beginning, measuring once every ring when the deformation of the steel rear shield support is stable, and stopping observation until the steel rear shield support is stable;

after rechecking and measuring the position of the portal, chiseling out the portal concrete in a shape of Chinese character jing in blocks according to the analysis of ground monitoring information, and marking out the positions of the blocks; chiseling the concrete at the joint of the blocks before chiseling the door, and well preparing block hoisting points;

and (5) after the whole shield machine enters the hole ring, carrying out synchronous grouting.

2. The method of shield construction according to claim 1, further comprising:

erecting a scaffold in the hole ring area, and installing a water stopping device on the scaffold;

and a circle of arc-shaped inserting plate serving as a water-stopping barrier is arranged on the hole ring.

3. The shield construction method according to claim 1, further comprising:

two guide rails are arranged in the hole ring and at the position of a 70cm chiseled groove wall, extend to the shield base and are connected with the two guide rails on the base into a whole, and the installation angle and the position of the guide rails are arranged along the track on the shield base.

4. The method of shield construction according to claim 1, further comprising:

arranging grouting ball valves around the hole ring;

and connecting a 1.5-inch steel pipe with a preset length to the stratum outside the door at the rear end of the grouting ball valve.

5. The shield construction method according to claim 1, wherein the step of additionally arranging a steel rear shield support between the last ring negative ring and the borehole wall structure comprises the following steps:

cement mortar is poured into a gap between the steel rear shield support and the negative ring pipe sheet; and 2 double-frame 70# H steel is adopted for supporting the rear steel shield.

6. The shield construction method according to claim 1, wherein after rechecking the portal position, the portal concrete is chiseled in a # -shape and marked out according to the analysis of the ground monitoring information; chiseling the concrete at the joint of the blocks before chiseling the door with the holes, wherein the step of making the block hoisting points comprises the following steps:

drilling a hole in the center of the portal for observing the condition of an external soil body, then dividing the hole into blocks in a # -shape, chiseling out portal concrete, and marking the dividing positions;

exposing the inner and outer steel bars, cutting off the inner steel bars, and chiseling the remaining concrete on the soil facing surface and the outer steel bars;

cleaning concrete fragments falling on the bottom of the tunnel ring;

chiseling concrete at the joint of the blocks before chiseling the tunnel door, making block hoisting points, and hoisting the tunnel door concrete blocks sequentially from top to bottom.

7. The method of shield construction according to claim 1, further comprising:

The arch bones made of 16 channel steel are used as template supports, the distance between the arch bones is 900-1200mm, and the arch bones are vertically arranged on the concrete surface of the poured bottom plateOn the upper part, a section steel cross brace is added at the bottom foot of the arch bone; the arch foot bottom is padded with a 20mm thick wood plate to prevent the bone legs from sinking;

the arch is arranged according to the middle waist line; in the process, a mold release agent is uniformly coated on the steel template, and the steel template is installed according to the structural characteristic sequence.

8. A method for shield construction waterproofing according to any one of claims 1 to 7, comprising:

installing a sealing device around the hole ring, wherein the sealing device consists of a rubber curtain cloth belt, a ring plate and a turning plate;

arranging grouting holes for preventing water and leaking stoppage at the hole, and embedding grouting pipes around the hole ring;

when water and soil leakage during shield tunneling construction is confirmed, double-liquid slurry is injected through the grouting pipe for sealing and water proofing,

wherein the double-liquid slurry is injected at the leakage point by pressure, 6 grouting ball valves are arranged around the hole ring so as to prevent the shield from leaking slurry when reaching the construction, and the rear end of the grouting ball valve is connected with a 1.5-inch steel pipe with a specific length and extends into the stratum outside the hole door so as to ensure that the grouting effect is better.

9. The method of shield construction waterproofing according to claim 8, further comprising:

and after the shield is debugged, uniformly and densely smearing shield tail grease between the shield tail steel brushes to fill a grease cavity of the shield tail brushes.

10. The method for shield construction waterproofing according to claim 8, further comprising:

elastic sealing gaskets are arranged along the periphery of the rib surface of the duct piece; wherein, the elastic sealing gasket is made of water-swelling rubber material.

11. A method of monitoring shield construction for use in a method of shield construction according to any one of claims 1 to 7, comprising:

setting a temporary point location at the bottom of the well, measuring the transverse diameter and the plane coordinate of the door ring according to the temporary point location station, calculating the plane center coordinate of the door ring, and calculating the plane deviation value of the door ring;

measuring the bottom elevation and the top elevation of the portal ring by using a temporary level point transmitted to the bottom of the well by the elevation, and solving the ring diameter and elevation deviation value;

calculating the coordinates of the portal ring center, the shield base front center and the shield base rear center, actually measuring the value of the coordinates by using an instrument, and calculating the deviation of the value of the coordinates and a theoretical value; adjusting the position of the base plane according to the deviation,

wherein the method further comprises: hanging three steel wires, wherein the steel wires and the above-well and underground observation platforms form two straight triangles on the plane; the ratio of the long sides and the short sides of the triangle is at least more than 2.5 times, and the angle in the triangle is less than 2 degrees;

hanging a drop ball at the tail end of the steel wire, wherein the drop ball is immersed in an oil drum filled with oil and cannot be contacted with the oil drum;

dividing the measurement data into two groups, wherein each group of data comprises an aboveground position, four connecting angles and five side lengths; when the triangle is calculated, the condition of the triangle closure difference is utilized, and the simple adjustment difference is used for calculation to obtain the coordinates of the underground position and the underground control point; the other set of data is calculated as above and the orientation and coordinates found are checked against the first set to ensure that no errors occur.

12. The method for monitoring shield construction according to claim 11, further comprising:

respectively sticking a metal stainless steel plate on two sides of the middle part of the monitored crack, drilling a round hole in the center of the steel plate, enabling the connecting line direction of the round hole to be vertical to the crack during embedding, and respectively marking two ends of the crack so as to observe the development condition of the crack;

and arranging gypsum sheets at two ends of the crack, wherein the gypsum sheets are firmly bonded with two sides of the crack.

13. The method for monitoring shield construction according to claim 11, further comprising:

and an abnormal gas monitor is arranged at the outlet of the shield spiral machine to monitor abnormal gas.

14. The method for monitoring shield construction according to claim 11, further comprising:

laying ground settlement measuring points along the axis of the tunnel, laying a settlement tank observation section at certain intervals, increasing the distribution of the settlement tank observation section when passing through important buildings and pipeline groups, setting a measurement mark on a hard ground by using a shooting nail or a spike, and using a reinforced pile as the measurement mark on a soft ground;

arranging a monitoring section every 20 meters within the range of 100m of the shield starting section; arranging a monitoring section every 30 meters in other sections; the interval of the measuring points on the monitoring section is 2-5m, and 7-11 measuring points are arranged in one monitoring section.