Methods including shield construction, waterproofing for shield construction, and monitoring methods

Abstract

This invention discloses a method for shield tunneling and a waterproofing and monitoring method for shield tunneling, relating to the field of engineering construction. The shield tunneling method includes: hoisting the shield base into the shaft according to the baseline established by surveying and setting out, ensuring alignment with the exit section's axis during the shield base placement process; after the shield base is in place, adding a steel rear shield support between the last negative ring and the shaft wall structure; after verifying the portal position, and based on the analysis of ground monitoring information, chiseling away the portal concrete in a grid pattern, marking the positions of each section; before chiseling away the portal, removing the concrete at the joints between sections and establishing lifting points for each section; and performing synchronous grouting after the entire shield machine enters the tunnel ring. This method ensures alignment with the exit section's axis during shield base placement, guaranteeing that the shield base guides the shield machine during exit, further improving the tunneling accuracy of shield tunneling.

Description

[0001] The present application is a divisional application of the patent application No. 201910509202.1 with the title of "Method for shield construction, waterproofing and monitoring method for shield construction" filed on June 14, 2019. TECHNICAL FIELD

[0002] The present application relates to the field of engineering construction, in particular to a method for shield construction, a waterproofing and monitoring method for shield construction. BACKGROUND

[0003] Shield method is a construction method for tunnel excavation, lining and other operations by shield. Shield is a special equipment with a shield, which uses the rear installed lining block as a fulcrum to push forward, uses a cutter head to cut soil, and simultaneously discharges soil and assembles the rear prefabricated concrete lining block.

[0004] Shield is not only a construction machine, but also a strong temporary support structure. Shield machine looks like a large steel pipe machine, which is slightly larger than the tunnel part. It is designed to resist outward water pressure and ground pressure. It includes three parts: the front cutting ring, the middle support ring and the rear shield tail. Most of the shields are circular in shape, and there are also oval, semicircular, horseshoe-shaped and box-shaped and other forms. In addition, the tunneling accuracy of the existing shield construction cannot meet the demand. SUMMARY

[0005] Therefore, the present application provides a method for shield construction, a waterproofing and monitoring method for shield construction, which can ensure that the shield base is consistent with the axis of the exit section during installation, and can ensure that the shield base can guide the shield machine when it exits the hole, thereby further improving the tunneling accuracy of the shield construction.

[0006] To achieve the above object, according to an aspect of the present application, a method for shield construction is provided.

[0007] The method for shield construction comprises: lifting the shield base into the underground according to the measured baseline, and ensuring that the shield base is consistent with the axis of the exit section during installation; after the shield base is in place, adding a steel rear shield support between the last ring negative ring and the well wall structure; after rechecking the position of the portal, according to the analysis of the ground monitoring information, removing the portal concrete in block shape, and marking the block position; before removing the portal, the block joint is removed, and the block lifting point is prepared; after the shield machine enters the hole circle as a whole, synchronous grouting is performed.

[0008] Optionally, further comprising: erecting a mounting scaffold in the area of the hole ring, and installing a water-stopping device on the scaffold; and installing an arc-shaped plug plate on the hole ring as a water-stopping barrier.

[0009] Optionally, further comprising: placing two guide rails in the hole ring and at the 70cm groove wall, the guide rails extending to the shield base and being integrally installed with the two guide rails on the base, the angle and position being sequentially extended to the guide rails on the shield base.

[0010] Optionally, further comprising: arranging a grouting ball valve around the hole ring; and connecting a preset length of 1.5-inch steel pipe to the rear end of the grouting ball valve and deep into the stratum outside the hole portal.

[0011] Optionally, the step of adding a steel back shield support between the last ring and the well wall structure comprises: pouring cement mortar into the gap between the steel back shield support and the negative ring segment; and the steel back shield support uses two double 70# H steels.

[0012] Optionally, after the rechecking measurement of the hole portal position, the hole portal concrete is removed in a block shape in the form of a cross according to the analysis of the ground monitoring information, and the block position is marked; before the removal of the hole portal, the concrete at the block joint is removed, and the block lifting point is prepared; a hole is drilled in the center of the hole portal for observing the external soil condition, then the hole portal concrete is removed in a block shape in the form of a cross, and the block position is marked; the inner and outer row steels are exposed and cut off, the remaining part of the concrete on the soil-facing surface and the outer row steel therein are removed; the concrete blocks falling on the bottom of the hole ring are cleaned; the concrete at the block joint is removed before the removal of the hole portal, and the block lifting point is prepared, and the concrete blocks of the hole portal are lifted off in the order of first on top and then on the bottom.

[0013] Optionally, the steel formwork is customized according to the structure size, and the formwork is erected by using The C-shaped bones made of channel steels are used as the formwork support, the distance between the C-shaped bones is 900-1200mm, the C-shaped bones are erected on the concrete surface of the poured bottom plate, a cross-shaped steel support is added at the bottom of the C-shaped bone; a 20mm-thick wood board is added at the bottom of the C-shaped bone to prevent the bone leg from sinking; the C-shaped bones are arranged according to the centerline; in this process, the release agent is uniformly brushed on the steel formwork, and the steel formwork is installed in the order of the structure characteristics.

[0014] To achieve the above object, according to another aspect of the embodiment of the present application, a method for shield construction waterproofing is provided.

[0015] The method for shield construction waterproofing of the embodiment of the present application is used in the method for shield construction as described in any of the above, and comprises: installing a sealing device around the hole ring, the sealing device being composed of a rubber cord, a ring plate and a flap; arranging a grouting hole for hole portal water-stopping leakage; pre-burying a grouting pipe around the hole ring; and when water and soil leakage occurs in the shield portal construction, sealing and waterproofing are performed by pressing and injecting double-liquid slurry through the grouting pipe.

[0016] Optionally, after the end of the shield debugging, the shield tail grease is evenly and densely applied between the shield tail steel brushes to fill the shield tail brush grease cavity.

[0017] Optionally, an elastic sealing gasket is arranged along the periphery of the segment rib surface, wherein the elastic sealing gasket is a water-swelling rubber material.

[0018] To achieve the above object, according to a further aspect of the embodiment of the present application, a monitoring method for shield construction is provided.

[0019] The monitoring method for shield construction of the embodiment of the present application is used in the method for shield construction as described in any of the above, comprising: setting a temporary point at the bottom of the well, setting a station according to the temporary point to measure the horizontal diameter and plane coordinates of the tunnel portal ring, and obtaining the plane center coordinates of the tunnel portal ring to calculate the plane deviation value of the tunnel portal ring; using the temporary water level point at the bottom of the well to transfer the elevation to measure the bottom elevation and top elevation of the tunnel portal ring, and obtaining the ring diameter and elevation deviation value; calculating the coordinates of the center of the tunnel portal ring, the front center of the shield base and the rear center of the shield base, measuring the values of the coordinates by the instrument, and calculating the deviation of the values of the coordinates from the theoretical values; and adjusting the plane position of the base according to the deviation.

[0020] Optionally, it further comprises: pasting a piece of metal stainless steel plate on each side of the middle part of the crack, drilling a circular hole in the center of the steel plate, and the connecting direction of the circular hole is perpendicular to the crack when the crack is buried; a mark is made at each end of the crack to observe the development of the crack; gypsum sheets are arranged at both ends of the crack and are firmly bonded to the two sides of the crack.

[0021] Optionally, it further comprises: installing an abnormal gas monitor at the outlet of the shield screw machine to monitor abnormal gas.

[0022] Optionally, it further comprises: arranging ground subsidence measuring points along the tunnel axis, arranging subsidence groove observation sections at intervals, increasing the arrangement of subsidence groove observation sections when passing through important buildings and pipeline groups, using shot pins or spikes to set measurement marks on hard ground, and using steel piles to set measurement marks on soft ground; one monitoring section is arranged every 20 meters within a range of 100 meters of the shield starting section; one monitoring section is arranged every 30 meters in the remaining section; the interval between measuring points on the monitoring section is 2-5 meters, and 7-11 measuring points should be arranged in one monitoring section.

[0023] Optionally, further comprising: suspending three steel wires, the steel wires and the observation tables on the well and the well form two straight triangles in a plane; the ratio of the long side and the short side of the triangle is at least greater than 2.5 times, and the angle in the triangle is less than 2°; the end of the steel wire suspends a plummet, the plummet is immersed in an oil barrel filled with oil, and the plummet cannot contact the oil barrel; the measurement data is divided into two groups, each group of data includes one well orientation, four connection angles, and five side lengths; when solving the triangle, the simple adjustment is used to calculate the well orientation and the well control point coordinates by using the condition of the closure error of the triangle; the other group of data is calculated as above, and the obtained orientation and coordinates are checked with the first group to ensure that no error occurs.

[0024] An embodiment of the above-mentioned application has the following advantages or beneficial effects: the accuracy of the shield machine exit orientation mainly depends on the placement position of the shield base, and the shield base can guide the shield machine when the shield machine exits if the placement of the shield base is consistent with the axis of the exit section. Since there is a certain gap between the working well hole circle diameter and the shield outer diameter, in order to prevent soil loss from the gap when the shield machine exits and during construction, a sealing device composed of rubber cord belts, ring plates, and turning plates is installed around the hole circle, and a grouting hole is provided as a preventive measure for the hole waterproof plugging.

[0025] The further effects of the above-mentioned non-conventional optional mode will be described in the following combined with the specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings are used to better understand the application and do not constitute an improper limitation on the application. Among them:

[0027] Figure 1 is a schematic diagram of the main process of the shield construction method according to the embodiment of the application;

[0028] Figure 2 is a schematic diagram of the shield base according to the embodiment of the application;

[0029] Figure 3 is a schematic diagram of the interval shield starting and leaning system according to the embodiment of the application;

[0030] Figure 4 is a schematic diagram of the shield exit construction process according to the embodiment of the application;

[0031] Figure 5 is a schematic diagram of the installation of the steel pre-stressed support according to the embodiment of the application;

[0032] Figure 6 and Figure 7 is a schematic diagram of the pipe segment pulling according to the embodiment of the application;

[0033] Figure 8is a schematic diagram of a test using a SL-2 type steel ruler convergence meter according to an embodiment of the present application;

[0034] Figure 9 is a schematic diagram of a tunnel inside wire point arrangement according to an embodiment of the present application; and

[0035] Figure 10 is a schematic diagram of a directional measurement according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] Exemplary embodiments of the present application are described herein below with reference to the accompanying drawings, in which various details of embodiments of the present application are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to those skilled in the art that the embodiments described herein are merely exemplary and that the present application can be practiced in a variety of ways. Thus, the present application should not be construed as being limited to the embodiments described herein. In the following description, like reference numerals refer to like elements, and the terms "front," "rear," "top," "bottom," "upper," "lower," "inner," "outer," "right," "left," "horizontal," "vertical," "clockwise," "counter-clockwise," and the like, are used to describe the orientation of the components to each other when the device is in the use position as shown in the figures. It will be understood that these terms are not intended to limit the position of the device in its use position.

[0037] Figure 1 is a schematic diagram of the main flow of a method of shield construction according to an embodiment of the present application, as shown in Figure 1 the method of determining a shield construction according to an embodiment of the present application mainly includes:

[0038] Step S101: Hoist the shield base into the underground according to the baseline of the measurement layout, and ensure that the shield base is consistent with the axis of the exit section during the placement process.

[0039] Step S102: After the shield base is in place, add a steel back shield support between the last ring negative ring and the shaft wall structure.

[0040] Step S103: After rechecking the measurement of the portal position, according to the analysis of the ground monitoring information, remove the portal concrete in a block shape in a cross shape, and mark the block position; before removing the portal, remove the concrete at the block joint, and prepare the block lifting point. Specifically, drill a hole in the center of the portal to observe the external soil conditions, then remove the portal concrete in a block shape in a cross shape, and mark the block position; expose the inner and outer row of steel bars, and cut off the inner row of steel bars, remove the remaining part of the concrete on the soil-facing surface and the outer row of steel bars; clean the concrete debris that falls on the bottom of the portal; before removing the portal, remove the concrete at the block joint, and prepare the block lifting point, and remove the portal concrete in a first-up-and-then-down sequence.

[0041] Step S104: After the shield machine enters the portal as a whole, perform synchronous grouting.

[0042] The embodiment of the present application further includes: erecting a scaffold in the portal area, and installing a water stop device on the scaffold. An arc-shaped plugboard is installed on the portal as a water stop barrier.

[0043] The embodiment of the present application further comprises: placing two guide rails in the hole ring and at the place where the 70cm groove wall is chiseled out, the guide rails extending to the shield base and being integrally installed with the two guide rails on the base in angle and position.

[0044] The embodiment of the present application further comprises: arranging a grouting ball valve around the hole ring; and connecting a pre-set length of 1.5-inch steel pipe to the rear end of the grouting ball valve and deep into the stratum outside the hole gate.

[0045] The step of additionally setting the steel back shield support between the last ring and the well wall structure comprises: pouring cement mortar in the gap between the steel back shield support and the ring segment; and the steel back shield support adopts 2 double 70#H steels.

[0046] The steel formwork is customized according to the structure size, and the formwork is erected by The channel steel made arch bones are used as the formwork support, the distance between the arch bones is 900-1200mm, the arch bones are erected on the casted bottom plate concrete surface, a type steel cross brace is additionally arranged at the bottom of the arch bone; a layer of 20mm thick wood board is additionally arranged at the bottom of the arch bone to prevent the bone leg from sinking; the arch bones are arranged according to the centerline; in the process, the mold release agent is uniformly brushed on the steel formwork, and the steel formwork is installed according to the structure characteristics.

[0047] For the construction scheme of shield hoisting and transportation, the shield upper shaft mainly includes hoisting of the front cylinder and cutter head, middle cylinder, all of which are hoisted out of the working shaft, among which the front cylinder and cutter head assembly is the heaviest, about 110 tons. Shield disassembly and hoisting includes: (1) shield entering the hole; (2) shield machine power off: all shield equipment stops at the correct position and is fixed, all oil cylinders are retracted to zero position; the shield machine is pulled off and power off; (3) remove the pipeline: remove the pipeline between the bridge and the main machine, the pipeline in the shield main machine, and the pipeline between the carriages; (4) remove the single beam and belt machine head: remove the belt of the belt machine and pull it out from the tunnel; lay the track of the motor car to the bottom of the screw machine; remove the single beam with a hoist and pull it out from the tunnel; remove the belt machine head with a hoist and pull it out from the tunnel; (5) remove the double beam and bridge: remove the double beam with a hoist and pull it out from the tunnel; remove the pull rod and bridge with a hoist and pull it out from the tunnel; (6) weld lifting lugs: set up a lifting lug welding platform; weld the lifting lugs of the rear cylinder, cutter head, front cylinder and middle cylinder; (7) hoist and disassemble the upper part of the rear cylinder: support and reinforce the inside of the upper and lower parts of the rear cylinder with steel pipes to prevent deformation. Cut the upper part of the rear cylinder and hoist it out; (8) hoist and disassemble the assembly platform: remove the connecting bolts of the intermediate assembly platform, hoist out the intermediate assembly platform. Remove the connecting pins, hoist out the left assembly platform. Remove the connecting pins, hoist out the right assembly platform; (9) hoist and disassemble the screw machine: use a crane to hold the rear of the screw machine and remove the pull rod and connecting bolts. Hoist out the screw machine and adjust the angle with two 5t hoists; (10) hoist and disassemble the assembly machine: remove the assembly machine stop wheel. Hoist out the assembly machine and turn it over; (11) hoist and disassemble the lower part of the rear cylinder: cut the lower part of the rear cylinder. Hoist out the lower part of the rear cylinder; (12) hoist and disassemble the middle cylinder: use a carbon planer to separate the weld between the middle cylinder and the front cylinder. Remove the connecting bolts of the middle cylinder and the front cylinder. Weld the front cylinder to the base with an iron plate. Hoist out the middle cylinder and turn it over. The main hoist uses a 350t crane, and the auxiliary hoist uses a 130t crane; hoist the middle cylinder up the shaft (first use three 5t hoists to move the middle cylinder to a radius of 9m on the under-shaft bed, then hoist it out of the shaft); (13) hoist and disassemble the cutter head and the front cylinder: cut the fixed iron plate of the front cylinder and the base. Remove the anti-tilt support. Hoist out the front cylinder and the cutter head and turn them over; (14) hoist and disassemble the pedestrian gate: remove the connecting bolts of the pedestrian gate. Hoist out the pedestrian gate; (15) hoist and disassemble the carriage: lay the track to the bottom of the shaft. Pull out and hoist out the carriage; (16) final work: remove the track tie at the bottom of the shaft. Hoist out the shield base. Clean the bottom of the shaft.

[0048] For the determination of equipment hoisting method and hoisting method, according to the actual situation of the construction site conditions and the weight, external size and performance characteristics of large hoist of the equipment, the AC350 type 350T full hydraulic automobile hoist is selected as the main hoist for mechanized construction.

[0049] And, considering the lifting capacity and component size, the shield main machine is decomposed into the following key components: cutter head, cutting ring, support ring, shield tail ring (upper and lower half rings), assembling machine and working platform, and subsequent car frame. For the selection of the crane, the maximum component self-weight of the shield machine, the size of the working well and the position where the shield component needs to be placed are used as the basis. The embodiment of the present application can select a 350T crane for hoisting, and at the same time, a 130T crane is used to assist the large crane in turning over, standing up or laying down the shield component on the ground.

[0050] During the hoisting of the shield, the support ring, the cutting ring, the cutter head, the assembling machine and the shield tail are hoisted into the underground in sequence according to the sequence of the components into the well, and are assembled. In addition, the shield debugging period can be set to about 30 days, and the components of the shield machine are debugged after being installed in the well. The specific debugging content is as follows:

[0051] Empty load debugging: check whether the equipment can normally run. The debugging content is: the hydraulic system, the lubrication system, the cooling system, the power distribution system and the grouting system are corrected by using instruments.

[0052] Load debugging: check the load capacity of various pipelines and seals, and further improve the work that cannot be completed in the empty load debugging, so that each system and auxiliary system of the shield machine reaches a working state that meets the normal production requirements. The trial excavation time is the load debugging time of the equipment. Strict management measures are taken to ensure the safety of the project, the quality of the project and the line type accuracy during load debugging.

[0053] The shield base is a steel structure prefabricated into a section. The position of the shield base is accurately laid out according to the design axis. When installing, the baseline of the measurement and layout is hoisted into the well and welded in place. The center lines of the two tracks must be aligned with the shield on the base and the reverse extension line of the tunnel design axis is basically consistent, and the base is additionally supported and reinforced. The shield base is shown in Figure 2 .

[0054] For the production of the shield rear shield support, a steel rear shield support is additionally provided between the last ring negative ring and the well wall structure. The steel rear shield support adopts two double-section 70#H steels. The gap between the steel rear shield support and the negative ring segment is filled with cement mortar. A Ф609 bracing purlin is provided at the rear of the 70#H steel. After the rear shield support is set, attention is paid to the deformation of the rear shield support during the shield advancement to prevent displacement from being too large and causing damage. Deformation observation points are set on the rear shield support. At the beginning, the measurement is performed once every box of soil, and when the deformation of the rear shield support is stable, the measurement is performed once every ring, and the observation is stopped until the rear shield support is stable. If the deformation of the rear shield support is too large, reinforcement measures are immediately taken. The schematic diagram of the system of the rear shield support after the interval shield starts is shown in 3.

[0055] For the production of the guide rail, the production of the shield support in the hole circle should meet the weight of the shield body when it is out of the hole and play a guiding role. The support material is 43 kg / m heavy rail, a total of 2, the accurate position is the extension of the 2 43 kg / m heavy rail on the shield base in the hole circle.

[0056] Because there is a certain gap between the diameter of the working well hole circle and the outer diameter of the shield, in order to prevent the soil from flowing out of the gap when the shield is out of the hole and during construction, a sealing device composed of rubber cord belt, ring plate, flap and other components is installed around the hole circle, and a grouting hole is provided as a preventive measure for waterproof plugging of the hole. The waterproof device designed for this time is a waterproof system composed of one flap and one cord rubber plate. During the construction of the station structure, grouting pipes are pre-buried around the hole circle. If water and soil leakage occurs during the construction of the shield out of the hole, double liquid slurry can be injected through the grouting pipes for sealing and waterproofing.

[0057] In addition, to ensure the sealing and waterproof effect of the shield tail, after the completion of the shield debugging, shield tail grease is applied between the shield tail brushes. The grease should be evenly and densely applied to fill the shield tail brush grease cavity.

[0058] For the assembly of the negative ring, the gap between the rear part of the first ring opening ring and the steel rear shield support (counterforce frame) is filled with high-grade mortar to make the concrete segment force uniform and the ring surface flat. The assembly of the first ring negative ring segment is the first step to control the segment assembly quality. The segment ring surface is corrected to the position perpendicular to the design axis according to the axial elevation and plan layout position. To ensure that the segment does not deform after being pulled out of the shield tail, supports are added to the outer arc surface of the segment to fix it.

[0059] The process of the shield out of the hole and reaching the construction site includes the foundation reinforcement construction of the shield entering and leaving the hole. Specifically, considering the soil conditions of the shield entering and leaving the hole, the foundation of the shield entering and leaving the hole must be pre-reinforced, using ground rotary jet grouting or rotary jet grouting combined with mixing pile reinforcement method. Reinforcement length: 9m out of the hole, 12m into the hole; 3m above and below the tunnel is strongly reinforced, 3m above the tunnel to the ground is weakly reinforced (the weak reinforcement for the right line shield range of the south end well of the Tielianguan station is from the tunnel 3m above to the wind pavilion bottom plate). The unconfined compressive strength of the reinforced soil is not less than 1.0Mpa, the permeability coefficient is less than 10-8cm / s, and the reinforced soil should have good uniformity, self-standing property and sealing property to prevent the occurrence of sand flow when the shield enters and leaves the hole. Before the shield leaves the hole, the reinforced area is explored and drilled multiple times, and if necessary, grouting is used between the structure joints for additional reinforcement to ensure the safety of the shield entering and leaving the hole.

[0060] The foundation reinforcement outside the well is accepted before the shield enters and leaves the hole. After the reinforced soil meets the requirements of the bidding drawings, the hole construction is carried out. If the foundation reinforcement effect does not meet the predetermined requirements, additional reinforcement measures will be taken until it is qualified. The foundation reinforcement out of the hole is completed before the shield is hoisted into the well.

[0061] The accuracy of the tunnel boring machine's (TBM) exit orientation largely depends on the placement of the TBM base. Therefore, it is crucial to ensure that the TBM base is aligned with the axis of the exit section during installation. The TBM base must also guide the TBM as it exits the tunnel. Furthermore, extending the base track between the base and the tunnel ring, and providing adequate support at the bottom of the guide rail, ensures the stability of the guide rail as the TBM passes.

[0062] Figure 4 This is a schematic diagram of the shield tunneling exit construction process according to an embodiment of the present invention. Figure 4 As shown, after the tunnel boring machine (TBM) has completed its commissioning, the portal excavation begins once the TBM's operational status is ensured. Steel scaffolding is erected inside the tunnel lining. A hole is drilled in the center of the portal to observe the external soil conditions. The portal concrete is then excavated in a grid pattern, with the sections marked. A pneumatic drill is used for crushing. First, the inner and outer reinforcing bars are exposed. The inner reinforcing bars are cut off, and the remaining concrete on the facing side, along with the outer reinforcing bars, is removed. Concrete fragments at the bottom of the tunnel lining are cleaned up. To ensure soil separation during the removal of the portal concrete blocks, the concrete at the joints between the sections is removed before excavating the portal, and lifting points are prepared for each section. The excavation and removal sequence is top to bottom. Portal excavation must be continuous to minimize work time and reduce soil loss. A dedicated safety officer supervises the entire process to prevent potential safety hazards and ensure personal safety. Necessary protective measures are taken for the sealing devices at the portal.

[0063] Due to the thickness of the working shaft structure and the trench wall structure, there is a certain distance between the guide rail on the shield base and the soil. In order to ensure the safe and correct exit of the shield, two guide extension steel rails are installed inside the tunnel ring and at the 70cm trench wall removal point. The installation angle and position should follow the rail on the shield base.

[0064] Furthermore, due to the construction gap between the tunnel entrance and the shield (or lining), mud and water can easily escape, leading to ground subsidence. Therefore, a sealing and water-stopping device must be installed at the tunnel entrance. This device includes a rubber curtain plate, a circular plate, a fan-shaped plate, and corresponding connecting bolts and washers. Before installation, the position and size of the bolt holes on the rubber curtain plate must be checked to ensure they match the positions of the pre-drilled bolt holes on the tunnel lining. The internal threads of the bolt holes should be cleaned with a tap. The installation sequence is rubber curtain plate → circular plate → fan-shaped plate, from top to bottom. During installation, the pressure bolts of the circular plate should be reliably tightened to ensure the rubber curtain plate is tightly attached to the tunnel entrance, preventing leakage of grout injected synchronously after the shield exits the tunnel.

[0065] When the shield installation and adjustment are completed and everything is normal, the shield enters the state of exiting the hole. At the same time, the soil in the soil chamber in front of the shield is filled by means of reverse rotation of the screw machine. In order to avoid damage to the cutter heads on the cutter head and the sealing device, butter is applied to the cutter heads and the sealing device to reduce friction. The shield tail brush must be filled with shield tail grease. During the exiting process, the sealing effect of the water stop device is observed to prevent soil from flowing out of the gap and causing the ground to collapse. When the shield exits the hole for the first time, the soil in front of the shield is hard due to the reinforced area, so the balance pressure setting value should be lower than the theoretical value, the advancing speed should not be too fast, and the shield slope can be slightly larger than the design slope. The following measures should be noted:

[0066] (1) Technical measures for the shield passing through the reinforced area

[0067] ① Increase the number of measurement points and strengthen the monitoring frequency

[0068] ② Strictly control the earth pressure

[0069] The earth pressure can be set lower due to the reinforced soil on which the shield just rests. At the same time, analyze and adjust the settlement report and other construction parameters, and feed back to the advancing team to ensure the safety of the exiting construction.

[0070] ③ Strictly control the soil output

[0071] According to the building gap between the shield and the segments and the characteristics of each soil layer, the soil output is reasonably controlled at about 98%-100% of the building gap. And through analysis and adjustment, the most reasonable value is found.

[0072] ④ Control the advancing speed

[0073] The advancing speed of the shield should be controlled within 1-2 cm / min to ensure that the shield jacking pressure and the cutter head torque are not too large to affect the performance of the shield machine, ensure the safety of the shield exiting the hole, and at the same time, add foaming agent or mud to the front of the shield as needed to improve the soil in front of the shield.

[0074] ⑤ Synchronous grouting

[0075] Strictly control the amount of synchronous grouting, the quality of the grout and the pressure. After the shield machine enters the hole circle, synchronous grouting is carried out in time, and the quality of the grout will ensure the reduction of regional ground subsidence, and the grouting pressure should not be too large to reduce the disturbance to the soil and avoid causing ground deformation.

[0076] ⑥ Dynamic information transmission

[0077] In shield construction, based on the analysis of ground monitoring information, combined with the relationship between the thrust, advancing speed and soil output, as well as the grouping of jacks, etc., the advancing slope is kept relatively stable, the amount of one-time correction is controlled, and the disturbance to the soil is reduced.

[0078] (2) Matters needing attention in crossing the reinforced area

[0079] ① After the negative annular segment is out of the tail shield, it is not constrained around and is easy to deform under the action of thrust. Therefore, necessary reinforcement measures (such as adding temporary transverse support) should be taken.

[0080] ② The total thrust of the jack should be controlled within an appropriate range (not exceeding the design load of the steel backrest).

[0081] ③ When the shield enters the tunnel ring, it is necessary to pay close attention to whether the tunnel ring sealing device is intact. If necessary, additional reinforcement measures should be taken to ensure the sealing effect.

[0082] ④ When installing the negative annular segment, the reasonable gap between the segment and the lower part of the shield should be ensured.

[0083] ⑤ The amount of pressure and uniformity of the shield tail grease should be ensured to ensure the sealing effect of the shield tail.

[0084] ⑥ When initial grouting, the setting of grouting pressure should consider the ground settlement monitoring data and the pressure bearing capacity of the portal sealing device.

[0085] After the shield exits the reinforced area, in order to prevent the shield from suddenly "kowtowing" due to changes in the front soil, the balance pressure value is set slightly higher than the theoretical value. At the same time, according to the information feedback of stratum deformation, etc., the construction parameters such as balance pressure setting value and advancing speed are adjusted in time.

[0086] After the first ring closed annular segment is out of the tail shield, the installation of the rear shield support is immediately carried out. Between the transverse support of the first ring rear seat closed annular segment and the two double-column 70# H steel backrest supports, four Ф609 steel pipes are used for axial force transmission. The steel transmits force to the station structure. In this way, the area of the jack and the oil pressure can have a larger selection range when the shield exits the tunnel, which is convenient for the control of the axis during the shield exit construction. After the rear shield support is set, attention should be paid to the deformation of the rear seat during shield advancing to prevent excessive displacement and damage. Deformation observation points are set on the rear backrest. At the beginning, the measurement is carried out once every time the shield advances one box of soil. When the deformation of the rear backrest is stable, the measurement is carried out once every ring. After the rear backrest is stable, the observation can be stopped.

[0087] In order to prevent the tail shield from pulling open the portal segment, causing tunnel deformation and joint water leakage, about 11 rings of portal segments should be connected into a whole before entering the tunnel by using channel steel. Usually, one longitudinal connecting bar is set in the middle of one ring of 6 segments.

[0088] After the tail part is a certain distance away from the tunnel ring, single-liquid slurry is used for supplemental pressure injection to reinforce the tunnel ring.

[0089] The shield advances to the distance of 50m from the well wall of the receiving well to the receiving well section, which is the construction phase of the tunneling section. Before the shield enters the tunnel, all preparations in the receiving well are completed. First, the position of the tunnel portal is rechecked and measured, and the shield receiving base is installed, ready for the shield arrival construction.

[0090] According to the exact orientation of the tunnel portal, the shield base is accurately laid out. When the base is installed, it is hoisted into place and assembled and welded underground according to the baseline of the measurement and layout. The base is placed on a flat slope, and after the base is in place, support and reinforcement are carried out to enhance the overall stability.

[0091] A scaffold for installing the water stop device is erected in the tunnel ring area in advance, and the water stop device is installed. An arc-shaped plugboard is installed on the tunnel ring as a water stop barrier.

[0092] In order to have a good guide for the shield arrival construction, a guide rail is placed on the tunnel ring. Two guide rails are placed at the bottom of the tunnel ring and extend to the shield base and are connected to the two guide rails on the base.

[0093] In order to prevent mud leakage during the shield arrival construction, double liquid slurry is injected in time at the leakage point, and six grouting ball valves are arranged around the tunnel ring. In order to make the grouting effect better, a length of 1.5-inch steel pipe is connected to the rear end of the grouting ball valve and is deep into the stratum outside the tunnel portal.

[0094] Because the tunnel portal water stop device and the arc-shaped plugboard for sealing the tunnel portal need to be welded on the inside and outside of the tunnel ring, the tunnel ring is cleaned to ensure that the steel tunnel ring can be firmly welded to other iron devices.

[0095] The measurement before the shield passes through is an important basis for reviewing the position of the shield, confirming the attitude of the shield, evaluating the attitude of the shield during the arrival construction, and formulating the construction axis of the shield arrival section, the control value of the advancing slope, and the construction scheme, so that the shield always implements the predetermined scheme during this stage of construction, and arrives at the construction with a good attitude and accurately positions on the shield receiving base.

[0096] During the shield tunneling construction, the shield is advanced as soon as possible and the segments are assembled during the shield arrival construction to shorten the time of the shield entering the tunnel. After the special ring of the tunnel ring is separated from the shield tail, an arc-shaped steel plate is immediately welded to it to form a whole, and the gap between the segment and the tunnel ring is filled with grouting liquid to reduce soil erosion.

[0097] According to the actual measurement of the size of the tunnel ring of the station end well, the attitude of the shield arrival construction stage is adjusted appropriately. When the shield passes through the reinforced area and the enclosure structure, the following matters need to be noted:

[0098] ①, the advancing speed is controlled within 1cm / min, and the front soil pressure is gradually reduced;

[0099] ②, the parameters such as cutter torque need to be closely monitored during the passing through;

[0100] 3. Arrange special person to observe the deformation of the portal and the situation of water and soil closely, accelerate the speed of information feedback, stop pushing immediately if there is abnormal situation and take corresponding countermeasures.

[0101] Before the shield enters the portal, the main equipment of the shield is checked comprehensively, the existing problems are solved in time, the equipment is kept in good running state, the engineering difficulties caused by equipment are avoided and the construction time is shortened as much as possible.

[0102] In order to prevent the shield tail from pulling open the portal segment and causing tunnel deformation and joint leakage, the portal is connected into a whole by channel steel before the shield enters the portal, usually one longitudinal connecting bar is arranged in the middle of one ring of six segments.

[0103] After the shield is on the underground continuous wall, the underground continuous wall concrete slabs are removed and hoisted out in blocks, the whole process is supervised by full-time safety officers to eliminate safety hazards and ensure personal safety.

[0104] The connecting parts of the ring segment are retightened to ensure the tightness of the segment connection and prevent the deformation of the tunnel during the process of the shield entering the receiving well. During the portal removal process, measures must be taken to protect the portal water stop device.

[0105] According to the portal construction situation of the project, secondary portal construction will be carried out if necessary. That is, after the shield enters the portal, the portal is closed, then the pre-buried grouting hole in the portal is used for filling and grouting; when the grouting reaches a certain strength and the soil is stable without leakage, the shield continues to push forward, the last ring of segments completely separates from the portal, the original sector plate is lengthened and welded with the portal segment to form a whole, and the gap between the segment and the portal is filled with hydraulic grout, the soil gap is filled by continuing to grout the portal to maintain soil stability.

[0106] For normal segment shield pushing construction, after 100m trial pushing in the exit segment, personnel operation, equipment grinding and other aspects can be mastered skillfully, and appropriate shield construction parameters and soil removal amount are adjusted to start normal segment tunneling construction.

[0107] Among them, the main construction parameter control includes:

[0108] (1) The setting principle of balance pressure value

[0109] Front balance pressure: P = k0y h

[0110] P: balance pressure (including underground water)

[0111] y: average specific gravity of soil (KN / cm 3 )

[0112] h: tunnel depth (m)

[0113] k0: lateral static balance pressure coefficient of soil

[0114] The shield refers to the above method to obtain the set value of the balance pressure in the tunneling construction. The specific construction set value is dynamically adjusted according to the shield depth, the soil layer condition at the location and the monitoring data.

[0115] (2), the amount of earth pushed out

[0116] Theoretical amount of earth pushed out per ring = π / 4 x D 2 x L = 37.88 m 3 / ring.

[0117] The amount of earth pushed out by the shield is controlled between 98%-100%, i.e. 37.12 m 3 / ring - 37.88 m 3 / ring.

[0118] (3), the pushing speed

[0119] The speed is controlled between 3-5 cm / min in normal pushing. When passing through underground pipelines with high settlement requirements, the pushing speed is controlled within 2 cm / min.

[0120] (4), the shield axis and ground deformation control

[0121] The deviation of the shield from the design axis is not greater than ±50 mm when tunneling; the ground settlement is controlled within (+10)-(-30 mm).

[0122] Synchronous grouting in shield pushing is the main means to fill the construction gap between the soil and the segment ring and to reduce the deformation in the later period, and is also an important process in shield pushing construction. The grout pressure injection is timely, uniform and sufficient to ensure that the construction gap is filled in time and sufficient, the ground surface deformation and segment deviation are controlled to the minimum, and the segment joint leakage is prevented. The synchronous grout can quickly and uniformly fill each part of the shield tail gap, so that the disturbance to the soil is reduced to the minimum. The grouting amount per ring is generally 200%-250% of the construction gap (the actual grouting amount is adjusted according to the monitoring data). According to the feedback data of ground monitoring, effective measures are taken in time to control and adjust the grout ratio. Grouting is an important process, and a person is assigned to be responsible for it in construction, and the pressure injection position, injection amount and pressure value are well recorded, and the grouting process is adjusted in time according to the stratum deformation monitoring information to ensure the construction quality of the grouting process. The tunnel transport vehicle and the grouting system on the ground are regularly cleaned, and the cleaning time is basically controlled once per shift. Due to the cleaning of the grouting pipeline of the shield working face and other reasons, a certain amount of waste grout will be formed, which will pollute the working environment, so the soil tank is used to transport it out in time.

[0123] The embodiment of the present application can also carry out post-wall secondary grouting. Secondary grouting is needed when grouting leakage is serious or ground subsidence alarm or other needs. The post-wall secondary grouting slurry selects double-liquid slurry, and the double-liquid slurry ratio is as follows:

[0124]

[0125] In actual construction, the slurry ratio is adjusted according to specific conditions.

[0126] Due to a large number of pipelines on the ground, the shield tail sealing function is particularly important during the tunnel excavation of the interval. In order to safely and smoothly complete the tunnel excavation task of the interval, the pressure injection work of the shield tail grease must be done well. Under normal circumstances, the shield tail grease is automatically injected by the shield tail grease pump, and the grease is supplemented in time during the shield excavation process according to the grease pressure.

[0127] The segments transported to the site are accepted and classified and stacked after confirming that there are no problems such as missing corners, edges and maintenance period. The waterproof treatment surface of the segment is cleaned. The lining joint uses an elastic rubber gasket in the sealing gasket groove for waterproofing. The elastic gasket is extruded and vulcanized by ethylene-propylene-diene rubber, and the top surface is embedded with water-swelling rubber prefabricated. Water-swelling rubber sealing rings are used to strengthen the waterproofing of screw holes, and the elastic gaskets on both sides of the capping block are coated with a surface lubricant before assembly to reduce the friction between the elastic gaskets when the capping block is inserted. The surface lubricant should be a water-based coating agent with a viscosity of 300 cps. The water-swelling rubber on the surface of the gasket will swell when it comes into contact with water and moisture, so plastic film should be covered on it or a slow-swelling agent should be applied on the surface when it rains.

[0128] The tunnel lining is assembled by six prefabricated reinforced concrete segments with staggered joints. The capping block is first pushed radially and then inserted longitudinally. The flatness of the lining surface, the control of the advance amount of the surface and the ellipticity, etc. are strictly controlled during the segment assembly process. According to the elevation and plane measurement report and the segment gap, the attitude of the segment assembly is adjusted in time. The key points of segment assembly control are:

[0129] (1) Strictly control the flatness of the surface: start from the negative ring and check each ring, the step of adjacent segments should be less than 4 mm, and each segment should not protrude from the surface of the adjacent segment to prevent the adjacent segment joint from cracking.

[0130] (2) Control the advance amount of the surface: the perpendicularity of the segment ring surface to the tunnel design axis is often detected during construction. When the advance amount of the segment exceeds the control amount, the assembly angle of the segment is adjusted to correct it, so as to ensure the perpendicularity of the segment ring surface to the tunnel design axis.

[0131] (3) Control the high difference between adjacent rings: the size of the high difference between adjacent rings directly affects the quality of the tunnel axis and the effective cross section of the tunnel, so the high difference between adjacent rings must be strictly controlled within the allowed range.

[0132] (4) Tunnel ellipticity control: When assembling each ring, measure the tunnel ellipticity in time, and the horizontal and vertical diameter deviation of the lining assembled into a ring is ≤±3mm. Unqualified rings are corrected in time until the ellipticity reaches the requirement, and then the next ring is advanced.

[0133] (5) Remove the garbage at the shield tail assembly site before assembly, and check the model, appearance and adhesive condition of the sealing material of the segment. If damaged, it must be repaired before assembly. The assembly quality of the first positioning segment will directly affect the assembly quality of the whole ring segment and its relative position with the shield. In addition to the general requirements such as no stepping and centered assembly, the perpendicularity of the segment to the tunnel axis should also be ensured.

[0134] (6) The jacks are retracted according to the sequence of the assembled segments, and the jacks are closed in time after assembly to prevent the shield from retreating. After assembly is completed, all jacks are extended and controlled to the required jacking force before the assembly of the next segment is started. This process is repeated for each ring to prevent sudden changes in the attitude of the shield.

[0135] (7) The longitudinal and circumferential bolt connections of the ring segments are connected by longitudinal and circumferential bolts, and the tightness of the connection will directly affect the overall performance and quality of the tunnel. Therefore, the longitudinal and circumferential bolts connecting the lining should be tightened in time after the assembly of each ring lining is completed; when advancing the next ring, the longitudinal bolts should be retightened under the action of the jacking force of the jacks; and when the ring segment is pushed out of the carriage, the longitudinal and circumferential bolts are retightened again.

[0136] In shield construction, according to different soil and overburden thickness, combined with the analysis of ground monitoring information, the mutual relationship of thrust, advancing speed and soil volume, the advancing slope is kept relatively stable, the amount of correction is controlled, and the disturbance to the soil is reduced. At the same time, according to the monitoring data of advancing speed, soil volume and ground deformation, the grouting amount is adjusted in time, so as to control the axis and ground deformation within the allowable range.

[0137] (1) Reasonably control the regional oil pressure

[0138] The axis control of the shield is an important part of the shield construction. The shield relies on the thrust of the jacks to advance. In order to facilitate the axis control, the jacks are divided into different regions. By adjusting the regional oil pressure during advancement, the shield is advanced along the designed axis direction.

[0139] Under the premise of correct setting of the incision balance pressure, strictly control the oil pressure of each region, and control the stroke of the jacks at the same time. Reasonably correct, correct frequently, and reduce the amount of single correction.

[0140] (2) Front balance pressure setting

[0141] Due to the different geological conditions, ground load and other factors, the soil pressure in front of the cutter head is different, which needs to be adjusted in time.

[0142] (3) The amount of earth

[0143] During the advancing process, over-excavation or under-excavation should be avoided to prevent the deviation of the advancing axis and ground subsidence.

[0144] (4) Balanced construction

[0145] Shield advancing should be as continuous as possible to reduce unnecessary pauses to prevent shield sinking.

[0146] Under the premise of ensuring safe construction, the tunnel cross-section layout mainly considers the rational use of space, which is conducive to the convenience of shield advancing during construction.

[0147] (1) Rail sleeper: The rail sleeper is made of 14# channel steel, and is arranged every ring. The rail sleeper at the wellhead is made of H20 steel.

[0148] (2) Electric locomotive track: The electric locomotive track (30kg / m) is arranged on the rail sleeper for shield tunneling material transportation. A turnout is arranged at the wellhead to improve the utilization rate of the electric locomotive.

[0149] (3) Pedestrian walkway: The pedestrian walkway frame is made on the tunnel side below the segment, and the walkway board (0.5×2m) is placed on it.

[0150] (4) Tunnel lighting: A lamp frame is arranged every 10m on the top of the tunnel side, and the lighting cable and lamp are fixed on it. The power cable is arranged below the lamp frame.

[0151] (5) Pipe: The water supply and drainage pipe is arranged on one side of the tunnel, and is fixed every 10m with a hanger.

[0152] (6) Ventilation pipe: The ventilation pipe is arranged on the side above, and is fixed every 10m with a hanger.

[0153] (7) Cable and communication line: The cable and shield machine communication line are arranged on the opposite side of the lamp frame.

[0154] (8) A fire extinguisher is arranged every 100m in the tunnel, and an electric box and telephone are arranged every 200m.

[0155] Further, the construction rules of the portal shaft joint mainly include:

[0156] (1) The construction of the portal shaft joint should not delay the progress of the main tunnel project at any time.

[0157] (2) Before removing or drilling the segment, the condition of the segment external grouting layer should be investigated to determine whether pre-grouting is needed.

[0158] (3) The cast-in-situ concrete should be closely attached to the tunnel and station end wall and stably connected.

[0159] (4) All measures should be taken to ensure the waterproof construction quality.

[0160] (5) The cast-in-situ concrete can be implemented only after the approval of the supervising engineer.

[0161] (6) Effective measures should be taken to ensure the safety of the construction personnel and the transport vehicles and personnel on the passage.

[0162] (7) The repair scheme should be implemented after the examination and approval of the supervising engineer.

[0163] The construction method of the shaft joint of the portal mainly includes:

[0164] (1) Removal of the zero ring segment

[0165] First, the gap between the standard block and the bottom block is chiseled with a wind pick to loosen the standard block for easy removal. Two φ12 double-strand steel wires are passed through the outside longitudinal screw holes of the standard block at the lifting point. In order to prevent the danger of segment shaking after lifting, the inside longitudinal screw holes and the outside longitudinal screw holes of the +1 ring are bound and pulled with steel wires after lifting, and then moved smoothly to the vertical lifting position, and then lifted. In this way, the adjacent blocks, the top blocks, the adjacent blocks and the standard blocks are removed in turn.

[0166] (2) Steel bar forming and welding

[0167] The length of the steel bar is determined according to the actual size on site, and the steel bar is pasted and bent and positioned with single-component chlorobutyl-phenolic adhesive, and the water-swelling rubber waterstop is fixed, and the outside is coated with a slow-expanding agent. The ring-shaped steel bars are evenly arranged, the steel bar framework is welded and fixed, and whether the steel bars are connected with the pre-buried steel plates of the segment and the pre-buried steel plates of the station lining portal is tested by electric bridge, and those that are not connected are welded.

[0168] (3) Formwork making

[0169] Wooden formwork is adopted, the inner arc is lofted according to the inner diameter size of the tunnel ring, and after lofting, 10 circular arc wooden formworks are used to form the inner ring. The outer ring is lofted according to the outer diameter size of the tunnel ring, and after lofting, 23 pieces of 20mm plywood are used as the closure head. The railings for fixing the formwork are welded on the steel tunnel ring with φ12 round steel, and φ12 pull rod screws are connected, and are fixed with three-shaped clamps and 1.5 inch steel pipes.

[0170] (4) Concrete pouring and vibrating

[0171] Commercial concrete is adopted for self-unloading and string barrel construction method, and a 1.5m long chute is connected to the string barrel on the ground, and the length of the string barrel can be adjusted according to the depth of the caisson. The string barrel is directly connected to the formwork opening, and an insertion type vibrator is used for vibrating and compacting.

[0172] For tunnel waterproofing construction, the interval tunnel waterproofing level is two, the roof is not allowed to seep water, the structure is not allowed to leak, and the structure surface can have a small amount of wet spots. The total wet spot area should not be greater than 6 / 1000 of the waterproof area, and any 100m 2 The wet spot on the waterproof area is not more than 4, and the maximum area of a single wet spot is not greater than 0.2m 2 . The pipe concrete strength is C50, the impermeability level is not less than P10, the crack width is not greater than 0.2mm, and when the groundwater has corrosion on the concrete, the corrosion resistance coefficient of the concrete is required to be greater than 0.8. The tunnel top is not allowed to drip water, the side is allowed to have a small amount of wet spots, the joint is not allowed to leak mud and drip, and the bottom block of the arch is not allowed to have seepage after the caulking operation. The method for measuring the amount of leakage and the amount of wet spots is to use the method of calculating the accumulated water in the dam for one day and night, and the method of measuring the wet spot area with a ruler to calculate the amount of leakage and the wet spot area (measured when the tunnel is not yet connected).

[0173] The interval tunnel structure waterproofing is based on the self-waterproofing of the pipe concrete, the waterproofing of the pipe joint, and the waterproofing of the joint between the interval tunnel and the station or working well, and the connection of the contact channel, to ensure the overall waterproofing performance of the interval tunnel. The main structure of the tunnel adopts waterproof concrete, the concrete adopts "double-doped technology", and 20% of high-quality fly ash and anti-cracking additive are added. The permeability coefficient K of the pipe is ≤5×10 -13 m / s, the chloride ion diffusion coefficient is ≤8×10 -9 cm 2 / s. When the tunnel is in an erosive medium, the corresponding erosion-resistant concrete or erosion-resistant waterproof coating should be used on the outer surface of the lining structure, and the permeability coefficient K of the concrete is ≤5×10 -14 m / s, and the ion diffusion coefficient is ≤2×10 -9 cm 2 / s.

[0174] The pipe joint is equipped with an elastic rubber sealing pad (referred to as a sealing pad) as the main measure for joint waterproofing, and caulking and post-grouting are auxiliary measures. The pipe longitudinal joint needs to be provided with a force transmission pad to disperse concentrated stress.

[0175] (1) Elastic sealing pad (shield pipe joint waterproof strip)

[0176] The method of setting elastic sealing pads along the rib surface of the pipe is used for pipe joint waterproofing. The sealing pads used ensure that the waterproofing requirements are met even with construction errors. The approved adhesive is used to firmly bond the sealing pads to the pipe according to the operating method. When water-swelling rubber waterproof materials are used, moisture-proof measures must be taken during transportation and storage, and a special warehouse must be provided for storage.

[0177] The elastic sealing pad should meet the relevant performance indicators. The performance indicator test method should comply with the relevant provisions of the national standard.

[0178] (2) Caulking

[0179] Caulking operation can only be started after the end of shield jacking and the thorough cleaning of the tunnel. Caulking operation is allowed to be carried out on slightly permeable and damp segments. If there is water leakage, caulking operation can only be carried out after the completion of plugging. If the segment caulking groove has large defects, it should be repaired before use. The strength of the repair material should be close to that of the original concrete, and the approval of the supervising engineer should be obtained before use.

[0180] (3) Force transfer pad

[0181] The force transfer pad made of neoprene rubber should be processed according to the design drawing and pasted on the construction site. Before pasting, use a steel wire brush to remove dust and sludge, and ensure that after pasting, it does not shift, fall off, and all adhesives and gaskets are the same.

[0182] The process of waterproof construction mainly includes:

[0183] 1. Segment longitudinal and ring joint caulking

[0184] Remove dirt and garbage from the longitudinal and ring joints, apply interface agent, insert closed-cell foam polyethylene strips, and make polyurethane sealant protective layer.

[0185] 2. Corrosion protection of bolts

[0186] Check and tighten the nut, remove metal rust and dirt, apply anti-rust material, and cover the high-pressure polyethylene plastic cup containing quick-setting and slightly-expanding cement.

[0187] 3. Segment hand hole filling

[0188] Remove garbage and debris from the hand hole, clean dust and sludge, apply interface agent, and fill the hand hole with slightly-expanding cement.

[0189] 4. Waterproof method

[0190] (1) Segment external grouting waterproofing

[0191] During shield tunneling construction, the gap between the shield and the segment is filled by synchronous grouting and post-wall secondary grouting to form an external waterproof layer, which is beneficial to the waterproofing of the section tunnel.

[0192] (2) Segment self-waterproofing

[0193] The segment uses high-performance self-waterproofing concrete with good durability. Through reasonable mix design, standard material selection, and strict production control, the impermeability grade of the segment is ensured. The impermeability grade of the concrete segment is not less than P10.

[0194] (3) Segment joint waterproofing

[0195] In order to meet the waterproof requirements of the joint, a frame-shaped elastic sealing pad and a caulking are provided at the joint of the segment ring and the longitudinal joint, and the elastic sealing pad is the main waterproof measure.

[0196] (4) Waterproofing by elastic sealing pad

[0197] 1) The elastic sealing pad is the main measure for waterproofing the lining joint, which is extruded and vulcanized from ethylene-propylene-diene rubber and has a water-swelling rubber embedded on the top surface thereof.

[0198] 2) Before the sealing pad is pasted, the segments transported to the site shall be inspected to confirm that there are no problems such as missing corners, edges and maintenance period, and shall be classified and stacked, and then the floating dust and dirt in the grooves of the segments shall be brushed off with a steel wire brush, and the sealing pad shall be pasted with a neoprene-phenolic adhesive.

[0199] The sealing pad must be firmly pasted in the groove, and cannot be dropped, peeled off or displaced.

[0200] If the lining with the pasted sealing pad is not used temporarily or in rainy days, it must be tightly covered with plastic film or tarpaulin, and at the same time, a slow-expanding agent shall be applied, and a movable rain shelter shall be provided on site.

[0201] 3) In order to strengthen the waterproofing of the corner part of the elastic sealing pad, a self-adhesive rubber sheet is pasted on the outer corner part of the sealing pad.

[0202] 4) The waterproof sealing pads on both sides of the adjacent blocks and the capping blocks shall be coated with a water-based surface lubricant (a water-based coating agent with a viscosity of 300 CP) before assembly, so as to reduce the frictional resistance between the elastic sealing pads when the capping blocks are inserted, thereby preventing misalignment or damage.

[0203] 5) When the shield curve is advanced or the attitude needs to be adjusted for other reasons, the adjustment amount of one time (one ring) should not be too large, so as to prevent the shield tail steel plate from being damaged, the sealing pad from being damaged, and the waterproof effect from being affected.

[0204] (5) Water-swelling rubber water-blocking strip

[0205] In order to ensure the waterproof effect of the tunnel, a 20x4mm water-swelling rubber water-blocking strip is pasted on the outside of the elastic sealing pad of the segment, and a 3mm thick water-swelling rubber strip shall also be pasted on the elastic sealing pad at the deformation joint of the tunnel.

[0206] The overlapping part of the water-blocking strip should avoid the corner part, the overlapping joint should be butt-jointed at an angle of 45 degrees, and the adhesive should be fixed.

[0207] (6) Waterproofing by caulking

[0208] The caulking is the second line of defense for joint waterproofing. After the service life of the sealing pad expires, the caulking material as the inner waterproof line can be easily removed and refilled.

[0209] 1) The sealing material for the joint groove is polymer cement (such as neoprene latex cement mortar), and the interface between the material and the concrete is treated with an interface treatment agent.

[0210] 2) The joint range: the lining ring section with large deformation at the portal section of 30 m, the contact passage on both sides of 8-10 m, etc. is filled with jointing, and the remaining sections are the arch top of 45° and the arch bottom of 90°.

[0211] (7) Waterproofing of bolt holes and lifting holes (grouting holes)

[0212] Bolt hole waterproofing: water-swelling rubber sealing rings are used as bolt hole sealing rings, and the dual effects of compaction and swelling are used to enhance waterproofing.

[0213] Lifting hole (grouting hole) waterproofing: when lifting holes and grouting holes are used together, in order to reduce the grouting holes as a weak link of tunnel water seepage, a 50 mm plain concrete is left on the outside of the segment of the lifting hole, and when secondary grouting behind the lining is needed, the plain concrete of the lifting hole is broken to be used as a grouting hole. A water-swelling bolt sealing ring is provided to enhance waterproofing.

[0214] (8) Waterproofing when the shield enters and exits the portal

[0215] When the shield enters and exits the portal, due to the reduction of thrust, the segment elastic sealing pad is difficult to compress, and measures should be taken to tighten the segment during construction, and comprehensive waterproofing is carried out by combining with guide pipe grouting and reinforcing the soil layer when the shield enters and exits the portal.

[0216] (9) Anti-corrosion

[0217] The lining bolts, other metal connecting parts and exposed parts must be treated with hot-dip zinc or zinc-based chromate coating.

[0218] (10) Waterproofing of the contact passage

[0219] The contact passage and the pump station use flexible waterproofing layer (non-woven fabric + EVA waterproof board), and the joint between the section tunnel and the contact passage uses water-swelling rubber strip for waterproofing.

[0220] Joint waterproofing treatment measures include:

[0221] ① Clean the joint, brush off the dirt and debris in the joint, and rinse it clean with water.

[0222] ② Insert the closed-cell foam polyethylene strip. When the joint produces steps, the insertion depth of the sealing glue is at least 12 mm, and after insertion, it can reach the predetermined depth and tightly fit.

[0223] ③ After the closed-cell foam polyethylene strip is inserted, the surface should be smooth.

[0224] ④ The closed-cell foam polyethylene strip at the joint should be connected.

[0225] 5. Apply interface agent YJ-302 (two components). Pour the interface agent into a container in a ratio of A:B:cement = 1:3:4, and mix well. The mixing should be completed within 2 hours.

[0226] 6. The interface agent should be applied to the inner wall of the slot, both sides of the longitudinal joint within a range of 15 mm, and both sides of the ring joint within a range of 16 mm.

[0227] 7. Apply a protective layer of polyurethane sealant. The sealant should be applied before the interface agent dries.

[0228] For the range of the joint, the inlet and outlet holes 20 are ringed, and the longitudinal joint is jointed. The steel pipe piece ring center joint is jointed for 5 rings before and after the ring joint (including the ring longitudinal joint). The deformation joint ring joint is jointed (only the ring joint). The other areas are jointed within the range of 45° of the arch top and 90° of the arch bottom.

[0229] The corrosion protection treatment of the exposed part of the assembly bolt includes: the exposed bolt, nut, and washer within the upper 180-degree range are subjected to corrosion protection treatment. The construction requirements are:

[0230] 1) Remove rust and loose rust.

[0231] 2) Apply water-based anti-rust paint.

[0232] 3) Seal the head tightly with quick-setting cement and cover it with a plastic protective sleeve.

[0233] 4) The head and plastic protective sleeve should be perpendicular to the wall surface of the hole, and the nut and washer should not be exposed.

[0234] For the waterproofing of the interval tunnel and the station end well, the joint, and the contact joint of the contact channel, mainly include:

[0235] (1) Tunnel and end well

[0236] The joint waterproofing of the tunnel and the vertical well includes the waterproofing of the temporary joint during construction and the permanent joint after completion.

[0237] a. The temporary joint is mainly composed of a rubber ring and its fastening device, supplemented by well ring grouting.

[0238] b. The permanent joint is a reinforced concrete well ring, which should be pre-set with a full-section grouting pipe and a single-component polyurethane sealant and other flexible waterproofing materials.

[0239] (2) Tunnel and contact channel

[0240] The connection channel and the shield section joint are the weak links of waterproof. The waterproof plate should be closed at the joint with the shield segment. The water stop strip and the external water stop belt are used, and the surrounding stratum is grouted through the grouting pipe.

[0241] For the connection channel, pump room soil excavation and support, the soil excavation should have some conditions, such as:

[0242] 1) Temperature measurement hole inspection

[0243] According to the measured data of the temperature measurement hole, the frozen soil development speed can be calculated, the freezing time can be calculated, and the frozen soil development radius under the freezing time can be calculated, so as to calculate the thickness of the frozen soil curtain. Then, the average temperature of the frozen soil curtain is obtained by formula method or drawing method. If the thickness and average temperature of the frozen soil curtain of each layer and each part meet the design requirements, excavation can be carried out.

[0244] 2) Pressure relief hole inspection

[0245] During the active freezing process, the pressure relief hole has two functions. One is to unload the frost heaving pressure, and the other is to show the pressure which can be used as an important basis for judging whether the frozen soil curtain is closed. Generally speaking, in the early stage of freezing, the pressure of the pressure relief hole is the original stratum pressure. With the gradual expansion of the frozen soil, the water migrates continuously. After the freezing, the frozen soil forms a closed soil body, and the frost heaving pressure cannot be released and gradually increases. The external manifestation is that the pressure of the pressure relief hole increases sharply, and it can gradually return to the original value after the pressure relief valve is opened, unloaded and closed. The difference between the values of the pressure relief hole before and after the freezing is 0.15-0.3Mpa.

[0246] 3) Salt water inlet and outlet temperature difference

[0247] Because the cooling consumption after the freezing is less than that before the freezing, the temperature difference between the salt water inlet and outlet before the freezing is larger than that after the freezing. If the temperature difference between the salt water inlet and outlet (other freezing parameters remain unchanged) suddenly becomes smaller at a certain period, it is likely that the freezing has been closed. However, this phenomenon is only a reference for judging the freezing. To determine the excavation, it is necessary to consider the temperature measurement hole data, the pressure of the pressure relief hole, the exploration hole condition and other aspects comprehensively.

[0248] Before the soil excavation construction of the connection channel and the pump room, the following should be included:

[0249] 1) Exploration hole inspection

[0250] The exploration hole inspection should be carried out before the formal excavation. The exploration hole should be drilled at the weak part of the frozen soil curtain. There is no sand gushing and water inrush phenomenon at the exploration hole. The stratum is stable, the frozen soil curtain is normal, and the temperature measurement effect is good. Then the formal excavation can be carried out.

[0251] 2) Tunnel working platform erection

[0252] According to the size of the connecting passage outlet and the needs of construction, an intermediate working platform is set up at the opening of the connecting passage, mainly used for the change of handcart for material transportation, and a material equipment platform is set up for the temporary storage of construction materials.

[0253] 3) Installation of emergency safety door

[0254] The emergency safety door is used to ensure the safety of the tunnel in case of a large amount of sand and water gushing out of the reinforced soil or displacement deformation exceeding the value during excavation and construction, and other rescue measures are ineffective. The safety door installation must be firm and reliable, and the door leaf opening and closing should be convenient and safe. The emergency safety door is installed before the active freezing of the connecting passage, and is equipped with an air compressor with an air volume of not less than 6m 3 / min to provide air for safety door pressure test. The safety door can be removed after the completion of the connecting passage.

[0255] In addition, considering that the stress of the connecting passage opening lining ring is redistributed after the steel pipe segment at the portal is pulled open, affecting the safety of the main tunnel structure, a steel pre-stressed tunnel support is set up in the tunnel segment opening ring at the opening of the connecting passage before the excavation of the trumpet mouth, to reduce the adverse effects of the excavation and construction of the connecting passage on the tunnel. A single steel support is composed of a central rectangular closed steel support, 5 pre-stressed jacks, 2 fixed supports, and support protection plates, as shown in Figure 5 . The installation method is as follows: two sets of steel supports are erected on both sides of the connecting passage opening in the interval tunnel, with a distance of 2m between the two sets of steel supports, and symmetrically arranged along the tunnel direction at both ends of the connecting passage. The two sets of supports are combined by welding 67x67mm equal angle steel. Each set of support has seven support points, and the pre-stress is provided by 5 50t screw jacks. Each jack should be slowly and smoothly pressurized at the same time when applying pre-stress, and the compaction support point is preferred for each jack. A person in charge should be responsible for directing during erection, and the bolts must be tightened during assembly. The high jacks should be fixed on the main frame to prevent falling. The pressure condition of the jacks should be checked regularly, and any abnormal conditions such as looseness should be treated in time.

[0256] 4) Installation of air pressure facilities

[0257] To ensure the safety of soil excavation and construction, a 20m 3 air compressor and related pipelines are equipped, which can be connected with the safety door compressed air valve. In case of serious water leakage in the connecting passage, air pressure should be added in the connecting passage to balance the external water pressure, reduce the water inflow, and ensure the safety of the tunnel. In emergency situations, the air pressure can be increased to 180Kpa.

[0258] 5) Reserve of emergency materials

[0259] In order to deal with the frozen hole construction and the possible emergency in the process of excavation construction, in addition to formulating feasible emergency measures, a certain amount of emergency materials, such as liquid nitrogen, emergency sand bags, clay bags, wooden wedges, cement, hemp, wooden back plates and the like, are needed to be stacked in the construction site to ensure the safety of the connection channel construction. The emergency materials should be stacked in order and prominent signboards should be set up. The emergency materials should be special and cannot be moved at will, and a special person should be arranged to guard and store the emergency materials and the emergency materials should be checked regularly.

[0260] After the strength of the reinforced soil body reaches the design requirement and the construction preparation work is ready, the soil body excavation work can be formally started. Before the pipe segment is opened, two 5t jacks and one 5t and one 2t hand-operated hoist are prepared. The method for opening the pipe segment includes: the two jacks are placed on both sides of the pipe segment to be opened, a cross beam of a section steel is directly connected with the steel pipe segment in the middle, the cross beam is pushed outwards by the jacks, as shown in Figs. Figure 6 、 Figure 7 When the pipe segment is operated, the stress and displacement of the pipe segment should be observed carefully, the local blocking factors should be eliminated, and the deformation of the pipe segment should be prevented.

[0261] The 5t hoist is used as an auxiliary pipe segment pulling device, one end of the 5t hoist is hung on the pipe segment to be pulled out, and the other end of the 5t hoist is tied to the pipe segment of the opposite tunnel, and the pipe segment is pulled outwards (in the tunnel) in the horizontal direction with a little force, and the operation of the 5t hoist should be coordinated with the operation of the jacks. The 2t hoist is hung above the pipe segment to be pulled out, and one end of the 2t hoist is hooked on the pipe segment to be pulled out, so that the pipe segment is prevented from falling on the working platform when the pipe segment is pulled out. During the pulling operation of the jacks and the 5t hoist, the outward movement of the pipe segment should be observed, and the pulling degree and direction of the 2t hoist should be adjusted in time. When the pulling is difficult, the reasons for the difficulty should be checked and handled. If the difficulty is caused by the rust of the pipe segment, a big hammer is used to vibrate the pipe segment to reduce the pulling resistance.

[0262] According to the structural characteristics of the project, the excavation cycle footage of the connection channel is controlled to be 0.5m or 0.6m, and two-stage bench excavation is adopted. The upper bench is excavated first, the excavation height is 1.6m, the steel arch support is erected, then the lower bench soil body is excavated, the height is 1.65m, the side wall steel arch support connecting leg and the inverted arch steel arch support are installed, and the interval between the two-stage bench excavation surfaces is kept to be about 2m. In order to reduce the influence of excavation on the deformation of the tunnel, the excavation step distance is controlled to be 0.5m. After the connection channel is excavated through, the water collecting well of the drainage pump house is excavated, and the drainage pump house is excavated in the form of lower bench, and the excavation is carried out in layers, and each layer is 0.5m.

[0263] As another aspect, the application also provides a method for waterproofing in shield construction.

[0264] The method for shield construction waterproofing of the embodiment of the present application, for the method for shield construction as described in any of the above, comprises: installing a sealing device around the hole ring, the sealing device being composed of a rubber cord, a ring plate and a turning plate; setting a grouting hole for hole waterproofing plugging; and when water and soil leakage occurs in the shield hole construction, injecting double-liquid slurry through the grouting pipe to seal and waterproof.

[0265] After the shield debugging is completed, shield tail grease is evenly and densely applied between the shield tail brushes to fill the shield tail brush grease cavity, and an elastic sealing pad is arranged around the rib surface of the pipe segment. The elastic sealing pad is made of water-swelling rubber material.

[0266] As another aspect, the present application also provides a monitoring method for shield construction. The monitoring method for shield construction of the embodiment of the present application, for the method for shield construction as described in any of the above, comprises: setting a temporary point at the bottom of the well, measuring the horizontal diameter and plane coordinates of the hole ring according to the temporary point, and calculating the plane center coordinates of the hole ring to calculate the plane deviation value of the hole ring; measuring the bottom elevation and top elevation of the hole ring by using the temporary water level point at the bottom of the well, and calculating the diameter and elevation deviation value; calculating the coordinates of the center of the hole ring, the front center of the shield base and the rear center of the shield base, measuring the values of the coordinates by using an instrument, and calculating the deviation between the values of the coordinates and the theoretical values; and adjusting the plane position of the base according to the deviation.

[0267] The monitoring method for shield construction of the embodiment of the present application further comprises: pasting a piece of metal stainless steel plate on each side of the middle part of the crack, drilling a round hole in the center of the steel plate, and burying the round hole in a direction perpendicular to the crack; and making a mark at each end of the crack to observe the development of the crack; and setting a gypsum sheet at each end of the crack, and firmly bonding the gypsum sheet with the two sides of the crack.

[0268] The monitoring method for shield construction of the embodiment of the present application further comprises: installing an abnormal gas monitor at the outlet of the shield screw machine to monitor abnormal gas.

[0269] The monitoring method for shield construction of the embodiment of the present application further comprises: arranging ground subsidence measuring points along the tunnel axis, arranging subsidence groove observation sections at intervals, increasing the arrangement of subsidence groove observation sections when important buildings and pipeline groups are crossed, setting measurement markers by using nails or spikes on hard ground, and setting measurement markers by using steel piles on soft ground; arranging one monitoring section every 20 meters within a range of 100 meters of the shield starting section; arranging one monitoring section every 30 meters in the remaining sections; the interval between measuring points on the monitoring section is 2-5 meters, and 7-11 measuring points should be arranged in one monitoring section.

[0270] The shield construction monitoring method of the embodiment of the application further comprises: suspending three steel wires, the steel wires and the observation tables on the well and the observation tables below the well form two straight triangles on a plane; the ratio of the long side to the short side of the triangle is at least greater than 2.5 times, and the angle in the triangle is less than 2°; a plummet is suspended at the end of the steel wire, the plummet is immersed in an oil barrel filled with oil, and the plummet cannot contact the oil barrel; the measurement data is divided into two groups, each group of data includes one well orientation, four connection angles, and five side lengths; when solving the triangle, the well orientation and the well control point coordinates are obtained by using the condition of the closure error of the triangle and by using simple adjustment to calculate; the other group of data is calculated as above, and the obtained orientation and coordinates are checked with those of the first group to ensure that no error occurs.

[0271] The shield construction is a disturbance process to the soil body, and the ground will change in heave and settlement due to the extrusion of the soil body or the loss of the soil body and the consolidation of the soil body, which is related to the following factors: shield sealing bin balance pressure; soil removal speed; shield posture; shield shell tow belt effect; pipe piece lining joint sealing degree; building gap; tunnel lining deformation; soil body consolidation and secondary consolidation settlement; grouting filling material solidification shrinkage settlement, etc. In addition, the monitoring considers the shield construction design and the surrounding environmental conditions, and the following factors need to be considered:

[0272] (1) Shield construction depth and soil layer crossing, estimating the possible range and degree of disturbance;

[0273] (2) Structures such as buildings, structures, drainage box culverts, and pile foundations crossed by the shield and adjacent structures, and the distance relationship with the tunnel;

[0274] (3) Distribution and characteristics of pipelines adjacent to shield construction;

[0275] (4) During tunnel construction, soil deformation and ground vertical displacement monitoring and deformation monitoring of ground buildings, structures, and underground pipelines should be performed, and appropriate measures should be taken to ensure that ground settlement is controlled within a specified range and to ensure the safety of roads, pipelines, and buildings.

[0276] The monitoring items are: underground comprehensive pipeline vertical and horizontal displacement monitoring; surrounding building (structure) vertical displacement, inclination, and crack monitoring; shield tunnel settlement and ground surface settlement profile monitoring along the line; tunnel convergence monitoring; and soil body internal displacement.

[0277] Adopt convergent meter (if have condition, can choose TCRA1200 series total station instrument) measurement method carries out convergence deformation measurement, and sets up two convergent measurement hooks on both sides of the upper and lower part of the tunnel ring, when the measuring point is buried, first, punch a hole slightly larger than the diameter of the expansion bolt at the measuring point position, then screw the expansion bolt with screw hole on the top, and then screw the hook made of stainless steel into the expansion bolt. Before testing, the ambient temperature needs to be read first in order to make temperature correction. The temperature correction formula is as follows:

[0278] ΔL C = K x ΔT x L

[0279] Where: ΔLc temperature correction value (mm)

[0280] K correction coefficient (this instrument is 12*10-6mm / ℃)

[0281] ΔT the difference between the temperature and the initial temperature (℃)

[0282] L the distance between the two measuring points (mm)

[0283] In high temperature and severe winter season, after entering the tunnel, the convergent meter should be stabilized for more than 15 minutes. When testing the distance between any two points, it needs to be measured and read continuously for more than 3 times, and the average value is taken as the current reading. The difference between the current convergence value after temperature correction and the last convergence value is the current convergence change. The symbol "+" represents elongation, and the symbol "-" represents shortening. The cross section of the convergence monitoring point is shown in the following figure, A, B, C and D are monitoring points, and the distance of AB, AC, BD, BC, BD and CD is measured by using convergent meter: Figure 8 The schematic diagram of using SL-2 type steel ruler convergent meter for testing according to the embodiment of the present application.

[0284] There may be harmful gases such as methane in the engineering soil layer, in order to ensure the smooth progress of the project, the soil harmful gas super strong monitoring must also be carried out, and the abnormal gas monitor is installed at the outlet of the shield screw machine, and the alarm will sound immediately once the abnormal gas is found. The interval tunnel construction monitoring items of the embodiment of the present application are as follows:

[0285]

[0286] In order to monitor the influence degree and range of the interval tunnel on the surrounding ground surface when pushing forward, the ground surface settlement profile monitoring point needs to be arranged for vertical displacement monitoring, which is arranged as follows:

[0287] The ground settlement measuring points are generally arranged along the axis with a point distance of 4-5 m. The density of the points is increased appropriately when entering the hole and encountering important buildings. The settlement tank observation sections are arranged at a certain distance (about 30 m). When crossing important buildings and pipeline groups, the settlement tank observation sections are increased. The measuring marks are set by using the nails or spikes on the hard ground and the reinforced piles on the soft ground.

[0288] A monitoring section is arranged every 20 m within a range of 100 m from the shield starting section, and a monitoring section is arranged every 30 m in the remaining sections. The measuring points on the cross section are generally spaced 2-5 m apart, and 7-11 measuring points should be arranged in one monitoring section. After entering the site, the ground surface settlement monitoring points are arranged according to the actual situation of the section line.

[0289] The convergence monitoring sections are arranged in the tunnel. The convergence sections are arranged on the tunnel structures of the left line and the right line at an interval of 10 m, and the convergence sections and the settlement points are on the same cross section.

[0290] In order to make the shield propulsion parameter setting more scientific and accurate, the monitoring information communication network is established on site, and the purpose of controlling the ground settlement is finally achieved.

[0291] Due to the different constraints of geological conditions, ground additional load and many other factors, the soil pressure in front of the cutterhead will be different, and therefore it needs to be adjusted in time. At the same time, the settlement report is analyzed, adjusted in time, and fed back to the propulsion team. If the ground settlement is in front of the shield cutout, the balance pressure setting value needs to be adjusted higher, and vice versa. If the ground settlement is behind the shield tail, the synchronous grouting amount needs to be increased, and vice versa.

[0292] According to the building gap between the shield and the segment and the characteristics of each soil layer, the reasonable control of the amount of excavated soil is controlled by the along-line settlement monitoring data, and the most reasonable value is found through analysis and adjustment.

[0293] The reasonable propulsion speed is controlled to make the shield construction balanced and uniform, and to reduce the soil deformation caused by the shield. The purpose of controlling the ground deformation is achieved.

[0294] During the shield propulsion process, other grouting pipelines are opened synchronously according to the actual situation. The synchronous grouting amount and the quality of the slurry are strictly controlled. The building gap is filled in time through synchronous grouting, and the soil deformation in the construction process is reduced. The synchronous grouting amount is generally 140%-200% of the building gap. Since there may be a certain gap when the slurry of the synchronous grouting fills the building gap during the shield propulsion, and the shrinkage deformation of the slurry also has the potential risk of ground settlement, therefore, the secondary post-wall grouting is necessary when necessary. The slurry is injected into the stratum through the grouting holes of the segment, and the push and grouting linkage is adopted during the construction. If the grouting does not meet the requirements, the shield is stopped to prevent soil deformation. According to the deformation monitoring situation in the construction, the grouting amount and the grouting parameters are adjusted in time, and the post-wall secondary grouting is adjusted in time according to the ground monitoring situation, so as to stabilize the stratum deformation.

[0295] Each time the results of the measurement are timely summarized to the construction technology department, so that the construction technical personnel can timely understand the construction status and the deformation of the pipeline in the corresponding area, determine the new construction parameters and grouting quantity, etc. and pass the information and instructions to the shield advancing face, so that the advancing construction face can be timely adjusted, and finally the effect is determined through monitoring, so as to repeatedly circulate, verify and improve, and ensure the tunnel construction quality

[0296] In order to ensure the safety of the tunnel structure and the surrounding environment, strengthen the structure monitoring and environmental monitoring, achieve information management, make the monitoring data timely feedback, and guide the construction. In addition to the convergence deformation monitoring, the preventive monitoring of frozen soil temperature should also be carried out for the excavation of the soil body reinforced by the freezing method, so as to master the development state of the frozen soil body and provide construction safety warning. The construction measurement and monitoring contents include: 1. Monitoring contents of the freezing pipe drilling construction: drilling length, freezing pipe laying length, freezing pipe deflection monitoring, freezing equipment sealing performance, and supply liquid pipe laying length; 2. Monitoring contents of the freezing system: freezing equipment return circuit brine temperature, cooling circulating water inlet and outlet temperature, salt water pump working pressure, freezing machine suction and exhaust pressure, freezing machine suction and exhaust pressure, refrigeration system condensing pressure, and refrigeration system vaporization pressure; 3. Monitoring contents of the freezing wall: freezing wall inside and outside temperature measuring hole temperature, freezing wall pressure relief hole monitoring, excavation after freezing wall well side temperature, and frost heaving pressure monitoring; 4. Monitoring contents of the main tunnel and the connecting passage structure: support structure and structure deformation monitoring, and tunnel deformation monitoring (intermittent tunnel radial deformation < 15 mm; horizontal and vertical displacement ≤ 10 mm).

[0297] For the connecting passage constructed by the freezing method, different monitoring methods and means are adopted for different parts and different stages, including:

[0298] 1. For the return circuit brine temperature of the freezing system, temperature sensors are arranged on the pipeline, and all are included in the computer monitoring system for management.

[0299] 2. For the freezing effect of the frozen soil curtain, temperature sensors are arranged in the temperature measuring hole, and pressure sensors are arranged in the pressure relief hole. The method is also included in the computer monitoring system for collection and management.

[0300] 3. For the structure deformation monitoring of the tunnel, monitoring points are arranged on the pipe piece within 30 meters of the connecting passage, and total station and precise level are used to measure the planar and elevation deformation and settlement.

[0301] 4. Other conventional monitoring items need to collect monitoring data in time according to the specification requirements and record and summarize.

[0302] An important work in construction is to control the plane by the geometric orientation method of the triangle connected with the surface and the underground, and to correct the axis of the shield advancing. During the construction, the directional measurement is carried out several times according to the specific situation of each interval, generally for the first time after advancing about 150-200 meters, and for the last time about 100 meters away from the advancing hole. The directional measurement of the connecting triangle is to transmit the coordinates and the azimuth by three steel wires. In the specific implementation, three steel wires are hung, and the steel wires and the observation stations on the surface and the underground form two straight triangles. The side view is shown in Fig. 10.

[0303] When laying, the ratio of the long side and the short side of the triangle should be at least greater than 2.5 times, and a:b should not be greater than 1.5 times, and O2 and O3 should not be too close to the instrument. The angle a in the triangle should be less than 2°. Meanwhile, the end of the steel wire is hung with a vertical ball. In order to prevent the steel wire from shaking and affecting the observation, the vertical ball is immersed in an oil barrel full of oil, and the vertical ball should not contact the oil barrel. During the observation, the connecting angle and the connecting triangle observation on the surface and the underground require two 2-second level total stations to measure the side and the angle. The angle measurement requires 9 measurement returns, the zero return observation, and the measurement return difference is less than or equal to 9″ (the maximum angle and the minimum angle difference). The 2C difference is less than or equal to 13″ (the difference between the normal mirror and the inverted mirror). The zero return difference is less than or equal to 6″. The side measurement requires four times in the normal and inverted states, and the average value comparison difference should be less than 3mm. The connecting triangle side length measurement adopts the reflection sheet on the steel wire, and the side is measured by the opposite side mode. Each time, three independent measurements are carried out, and the difference between the three data is less than or equal to 3mm. When measuring the side, the temperature on the surface and the underground is considered to calculate the side length correction. The above measurement data is divided into two groups. Each group of data includes one surface azimuth, four connecting angles, and five side lengths. When solving the triangle, the closed difference of the triangle is used to calculate by simple adjustment to obtain the underground azimuth and the underground control point coordinates. Then, the above calculation is carried out on the other group of data to obtain the azimuth and the coordinates, which are checked with the first group to ensure that there is no error.

[0304] The result of each independent directional measurement should satisfy that the azimuth angle difference is less than or equal to 12″, and the point position difference is less than or equal to 20mm.

[0305] At the same time of the geometric orientation, the underground control line should be checked. The underground control line is arranged to control the plane deviation of the tunnel, which is mainly divided into the underground control line and the underground construction line. The underground construction line has low precision and short side length, which is used as the general working line. The underground control line has long side length and high precision, which is used as the first control of the construction to accurately guide the advancing direction. The underground line re-measurement is carried out synchronously with each geometric orientation, the line points are re-calculated, the azimuth obtained by the orientation is transmitted to the latest measurement station in the tunnel, and the deviation of the construction line is corrected. Figure 9 The schematic diagram of the tunnel line point arrangement according to the embodiment of the application. The instrument should be forced to be centered during the observation, and the measurement specification adopts the same regulation as the surface lofting measurement.

[0306] The purpose of the shaft elevation introduction is to transmit the ground elevation into the shaft bottom. When transmitting the elevation, the steel ruler with a hanging force of 49N (the pulling force used in the test) is used, and two levels are synchronously observed on the shaft and the shaft bottom to transmit the elevation to the fixed point on the shaft bottom. The measurement is performed three times, and the height of the instrument should be changed each time. The difference of the height difference of the ground and underground level points measured three times should be less than 3mm.

[0307] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can occur depending on design requirements and other factors. Any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method comprising a shield construction, a waterproofing method for shield construction, and a monitoring method, characterized in that, the method of shield construction comprises: hoisting a shield base into a shaft according to a measured baseline of a layout, ensuring consistency with an axis of an exit section during placement of the shield base, wherein two track centerlines are aligned with a shield on the base, a portal center, and a reverse extension line of a tunnel design axis; after the shield base is in place, adding a steel back shield support between a last ring negative ring and a shaft wall structure, wherein a deformation observation point is provided on the steel back shield support, and the observation is measured once at the beginning of each box of soil, and then once per ring when the deformation of the steel back shield support is relatively stable, until the observation stops after the steel back shield support is stable; after rechecking the position of the portal, according to the analysis of ground monitoring information, the portal concrete is removed in a block shape in a cross shape, and the block position is marked; before removing the portal, the concrete at the block joint is removed, and the block lifting point is prepared; after the shield machine as a whole enters the portal ring, synchronous grouting is performed, wherein the method for waterproofing shield construction comprises: installing a sealing device around the portal ring, the sealing device being composed of a rubber cord belt, a ring plate, and a turning plate; providing a grouting hole for waterproof plugging of the portal, and pre-burying a grouting pipe around the portal ring; if water and soil leakage occurs during shield exit construction, sealing and waterproofing are performed by pressure injection of double-liquid slurry through the grouting pipe, and wherein the monitoring method for shield construction comprises: setting a temporary point at the bottom of the shaft, measuring the horizontal diameter and plane coordinates of the portal ring based on the temporary point, and calculating the plane center coordinates of the portal ring to calculate the plane deviation value of the portal ring; using a temporary water level point transferred to the bottom of the shaft to measure the bottom elevation and top elevation of the portal ring, and calculating the ring diameter and elevation deviation value; calculating the coordinates of the center of the portal ring, the front center of the shield base, and the rear center of the shield base, measuring the values of the coordinates with an instrument, and calculating the deviation of the values of the coordinates from the theoretical values; adjusting the plane position of the base according to the deviation.

2. The method comprising a tunneling, a waterproofing for tunneling, and a monitoring method according to claim 1, characterized in that, The method of shield construction further comprises: erecting a scaffold around the portal ring, and installing a water stop device on the scaffold; installing an arc-shaped plug plate as a water stop barrier on the portal ring.

3. The method comprising a tunneling, a waterproofing for tunneling, and a monitoring method according to claim 1, characterized in that, The method of shield construction further comprises: placing two guide rails in the portal ring and at the removed 70cm slot wall, the guide rails extending to the shield base and being integrally installed with the two guide rails on the base in terms of angle and position, which should be sequentially extended to the tracks on the shield base.

4. The method comprising a tunneling, a waterproofing for tunneling, and a monitoring method according to claim 1, characterized in that, The method of shield construction further comprises: arranging grouting ball valves around the portal ring; connecting a pre-set length of 1.5-inch steel pipe to the rear end of the grouting ball valve and deep into the ground formation outside the portal.

5. The method comprising a tunneling, a waterproofing for tunneling, and a monitoring method according to claim 1, characterized in that, The step of adding a steel back shield support between the last ring negative ring and the shaft wall structure comprises: filling cement mortar in the gap between the steel back shield support and the negative ring segment; and the steel back shield support adopts 2 double 70#H steel.

6. The method comprising a tunneling, a waterproofing for tunneling, and a monitoring method according to claim 1, characterized in that, The step of rechecking the position of the portal, according to the analysis of ground monitoring information, removing the portal concrete in a block shape in a cross shape, and marking the block position; before removing the portal, removing the concrete at the block joint, and preparing the block lifting point comprises: A hole is drilled in the center of the portal to observe the external soil, and the portal concrete is removed in blocks in the shape of a cross, and the block positions are marked; The inner and outer rows of reinforcement are exposed, and the inner row of reinforcement is cut off, and the remaining concrete on the soil-facing surface and the outer row of reinforcement are removed; The concrete blocks that fall on the bottom of the hole are cleaned up; The concrete at the block joints is removed before the portal is removed, and the block lifting points are prepared, and the portal concrete blocks are lifted in the order of first up and then down.

7. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The method for shield construction further comprises: Steel formwork is customized according to structural size, and formwork is erected The formwork is supported by the channel steel made arch bones with a distance of 900-1200mm, and the arch bones are erected on the surface of the poured bottom plate concrete, and a type steel cross brace is added at the bottom of the arch bone; a 20mm thick wooden board is added at the bottom of the arch bone to prevent the sinking of the bone leg; The arch bones are arranged according to the centerline; during the process, the release agent is uniformly applied on the steel formwork, and the steel formwork is installed in the order of structural characteristics.

8. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The waterproof method for shield construction further comprises: After the shield debugging is completed, shield tail grease is uniformly and densely applied between the shield tail steel brushes to fill the shield tail grease cavity.

9. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The waterproof method for shield construction further comprises: An elastic sealing gasket is arranged around the rib surface of the segment; the elastic sealing gasket is made of water-swelling rubber material.

10. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The monitoring method for shield construction further comprises: A metal stainless steel plate is pasted on each side of the middle part of the crack, a round hole is drilled in the center of the steel plate, the connecting line direction of the round hole is perpendicular to the crack when the steel plate is buried, and a mark is made at each end of the crack to observe the development of the crack; Gypsum sheets are arranged at the two ends of the crack and are firmly bonded to the two sides of the crack.

11. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The monitoring method for shield construction further comprises: An abnormal gas monitor is installed at the outlet of the shield screw machine to monitor abnormal gas.

12. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The monitoring method for shield construction further comprises: Ground subsidence measuring points are arranged along the tunnel axis, subsidence groove observation sections are arranged at intervals, more subsidence groove observation sections are arranged when important buildings and pipeline groups are crossed, and measuring marks are set by using nails or spikes on hard ground and by using steel piles on soft ground; One monitoring section is arranged every 20 meters within a range of 100 meters of the shield starting section, and one monitoring section is arranged every 30 meters in the remaining sections; the measuring points on the monitoring sections are spaced 2-5 meters apart, and 7-11 measuring points should be arranged in one monitoring section.

13. The method comprising a tunneling, a waterproofing and a monitoring method for tunneling according to claim 1, characterized in that, The monitoring method for shield construction further comprises: Three steel wires are hung, and the steel wires and the observation tables on the well and the observation tables on the well form two straight triangles in the plane; the ratio of the long side to the short side of the triangle is at least greater than 2.5 times, and the angle in the triangle is less than 2°; A plummet is hung at the end of the steel wire, the plummet is immersed in an oil barrel filled with oil, and the plummet cannot contact the oil barrel; The measurement data is divided into two groups, each group of data includes one well orientation, four connection angles, and five side lengths; when solving the triangle, the well orientation and the well control point coordinates are calculated by using the condition of the closure error of the triangle and by using simple adjustment; the orientation and the coordinates obtained by calculating the other group of data are checked with the first group to ensure that no errors occur.

Images