Waterproofing and monitoring method for shield construction

Abstract

The application discloses a shield construction method, a waterproof and monitoring method for shield construction and relates to the field of engineering construction. The shield construction method comprises the following steps: hoisting a shield base into an underground well according to a baseline of measurement and layout, and ensuring that the shield base is consistent with the axis of an exit section during the placing of the shield base; after the shield base is placed, a steel back shield support is arranged between the last ring negative ring and the well wall structure; after rechecking the position of a portal, the portal concrete is removed in a block shape according to the analysis of ground monitoring information, and the block position is marked; the block joint concrete is removed before the portal is removed, and the block lifting point is prepared; after the shield machine enters the hole circle as a whole, synchronous grouting is performed. The method can ensure that the shield base is consistent with the axis of the exit section during the placing of the shield base, can ensure that the shield base can play a guiding role when the shield machine exits the hole, and further improves the tunneling accuracy of the shield construction.

Description

[0001] This application is a divisional application of patent application No. 201910509202.1 filed on June 14, 2019, entitled "Method for Shield Tunneling Construction, Waterproofing and Monitoring Method for Shield Tunneling Construction". Technical Field

[0002] This invention relates to the field of engineering construction technology, and in particular to a method for shield tunneling and a waterproofing and monitoring method for shield tunneling. Background Technology

[0003] The shield tunneling method is a construction method that uses a shield to excavate and line tunnels. It involves using a shield to excavate tunnels in soft foundations or fractured rock formations. A shield is a specialized piece of equipment with a protective shield that uses pre-installed lining blocks at its rear as a fulcrum to advance forward, cutting the soil with a cutterhead while simultaneously excavating soil and assembling the precast concrete lining blocks at the rear.

[0004] A tunnel boring machine (TBM) is both a construction tool and a powerful temporary support structure. Externally, it resembles a large steel pipe machine, slightly larger than the tunnel itself, designed to withstand external water pressure and ground pressure. It consists of three parts: the front cutting ring, the middle support ring, and the rear tail shield. Most TBMs are circular, but elliptical, semi-circular, horseshoe-shaped, and box-shaped TBMs also exist. Furthermore, the current TBM excavation accuracy cannot consistently meet requirements. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a method for shield tunneling and a waterproofing and monitoring method for shield tunneling, which can ensure that the shield base is consistent with the axis of the exit section during the installation process, and can ensure that the shield base can play a guiding role when the shield machine exits the tunnel, thereby further improving the tunneling accuracy of shield tunneling.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for tunnel boring machine (TBM) construction is provided.

[0007] The shield tunneling method of this invention includes: hoisting the shield base into the well according to the baseline of the survey and layout, ensuring that the shield base is consistent with the axis of the exit section during the placement process; after the shield base is in place, adding a steel rear shield support between the last negative ring and the well wall structure; after verifying the position of the tunnel portal, and based on the analysis of ground monitoring information, chiseling away the concrete of the tunnel portal in a grid pattern, and marking the position of each section; before chiseling away the concrete at the joints of the sections, and preparing the lifting points for each section; and grouting simultaneously after the shield machine enters the tunnel ring as a whole.

[0008] Optionally, it also includes: erecting and installing scaffolding in the hole area, and installing a water-stopping device on the scaffolding; and installing a ring of arc-shaped inserts on the hole as a water-stopping barrier.

[0009] Optionally, it also includes: placing two guide rails inside the tunnel ring and at the location where the 70cm groove wall has been removed, the guide rails extending to the shield base and being integrated with the two guide rails on the base, the installation angle and position of which should follow the rails on the shield base.

[0010] Optionally, it also includes: installing grouting ball valves around the tunnel entrance; and connecting a 1.5-inch steel pipe of a predetermined length to the rear end of the grouting ball valves to extend into the stratum outside the tunnel entrance.

[0011] Optionally, the step of adding a steel back support between the last negative ring and the well wall structure includes: filling the gap between the steel back support and the negative ring segment with cement mortar; and the steel back support is made of two double 70#H steel bars.

[0012] Optionally, after verifying and measuring the location of the tunnel entrance, based on the analysis of ground monitoring information, the concrete of the tunnel entrance is chiseled away in a grid pattern, and the positions of the sections are marked. The steps of chiseling away the concrete at the joints of the sections before chiseling away the tunnel entrance and setting up lifting points for the sections include: chiseling a hole in the center of the tunnel entrance to observe the external soil conditions, then chiseling away the concrete of the tunnel entrance in a grid pattern and marking the positions of the sections; exposing the inner and outer reinforcing bars, cutting off the inner reinforcing bars, chiseling away the remaining concrete on the soil-facing surface and the outer reinforcing bars therein; cleaning up the concrete fragments that have fallen to the bottom of the tunnel ring; chiseling away the concrete at the joints of the sections before chiseling away the tunnel entrance, setting up lifting points for the sections, and chiseling away the concrete blocks of the tunnel entrance in a top-to-bottom order.

[0013] Optionally, steel formwork can be customized according to the structural dimensions, and vertical formwork can be used. The arch supports are made of channel steel, with a spacing of 900-1200mm. The arch supports are erected on the already poured concrete base slab, and steel cross braces are added at the bottom of the arch supports. A 20mm thick wooden board is placed under the arch support to prevent the support legs from sinking. The arch supports are installed along the center line. During this process, release agent is evenly applied to the steel formwork, and the steel formwork is installed in sequence according to the structural characteristics.

[0014] To achieve the above objectives, according to another aspect of the present invention, a method for waterproofing tunnel boring machine (TBM) construction is provided.

[0015] The method for waterproofing tunnel boring machine (TBM) construction according to embodiments of the present invention, used in the TBM construction method as described in any of the above claims, includes: installing a sealing device around the tunnel ring, the sealing device consisting of a rubber curtain strip, a ring plate, and a flap plate; setting grouting holes for waterproofing and leak sealing at the tunnel entrance, and pre-embedding grouting pipes around the tunnel ring; and, if water or soil leakage is confirmed during the TBM exit construction, injecting a double-liquid grout through the grouting pipes for sealing and waterproofing.

[0016] Optionally, after the shield tunneling is commissioned, shield tail grease is evenly and densely applied between the shield tail steel brushes to fill the shield tail brush grease chambers.

[0017] Optionally, an elastic sealing gasket is provided around the perimeter of the tube segment rib surface; wherein the elastic sealing gasket is made of water-swellable rubber material.

[0018] To achieve the above objectives, according to another aspect of the present invention, a monitoring method for tunnel boring machine (TBM) construction is provided.

[0019] The monitoring method for tunnel boring machine (TBM) construction according to this invention, used in any of the aforementioned TBM construction methods, includes: setting temporary reference points at the bottom of the shaft; measuring the transverse diameter and planar coordinates of the tunnel portal ring at the temporary reference points; calculating the planar center coordinates of the tunnel portal ring; calculating the planar deviation value of the tunnel portal ring; measuring the bottom elevation and top elevation of the tunnel portal ring using temporary leveling points transferred to the bottom of the shaft; calculating 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 coordinate values ​​using instruments; and calculating the deviation between the coordinate values ​​and the theoretical values; and adjusting the planar position of the base according to the deviation.

[0020] Optionally, it also includes: attaching a stainless steel plate to each side of the middle of the crack, with a circular hole drilled in the center of the plate, and the direction of the line connecting the circular holes being perpendicular to the crack during installation; making a mark at each end of the crack to observe the development of the crack; and placing plaster sheets at both ends of the crack, with the plaster sheets firmly bonded to both sides of the crack.

[0021] Optionally, it also includes: installing an abnormal gas monitor at the outlet of the tunnel boring machine to monitor abnormal gases.

[0022] Optionally, it also includes: setting up ground settlement measuring points along the tunnel axis, setting up settlement trough observation sections at certain intervals, adding settlement trough observation sections when crossing important buildings or pipeline groups, setting up measurement marks using nails or road spikes on hard ground, and using steel piles as measurement marks on soft ground; setting up a monitoring section every 20 meters within 100m of the shield tunneling starting section; setting up a monitoring section every 30 meters in other sections; the measuring point interval on the monitoring section is 2-5m, and 7-11 measuring points should be set up in one monitoring section.

[0023] Optionally, it also includes: suspending three steel wires, the steel wires and the observation platforms above and below ground forming two straight triangles on a plane; the ratio of the longer side to the shorter side of the triangle is at least greater than 2.5 times, and the angles in the triangle are less than 2°; a plumb bob is suspended from the end of the steel wire, the plumb bob is immersed in an oil drum filled with oil, and the plumb bob must not contact the oil drum; the measurement data is divided into two groups, each group of data includes one wellbore position, four connecting angles, and five side lengths; when solving the triangle, the wellbore position and the coordinates of the downhole control point are calculated using simple adjustment based on the condition of triangle closure error; the other group of data is calculated in the same way, and the obtained position and coordinates are checked against the first group to ensure that no errors occur.

[0024] One embodiment of the above invention has the following advantages or beneficial effects: the accuracy of the tunnel boring machine's exit orientation mainly depends on the placement of the shield base. Ensuring the shield base is aligned with the axis of the exit section during placement ensures that the shield base can guide the tunnel boring machine during exit. Since there is a certain gap between the working shaft diameter and the outer diameter of the shield, a sealing device consisting of rubber curtain strips, ring plates, and flaps is installed around the shaft to prevent soil loss during exit and construction. Grouting holes are also provided as a preventative measure for waterproofing and sealing the tunnel entrance.

[0025] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0026] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein:

[0027] Figure 1 This is a schematic diagram of the main flow of a shield tunneling construction method according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of a shield tunneling base according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the section shield tunneling starting and backing system according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the shield tunneling construction process according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the installation of a prestressed steel support according to an embodiment of the present invention;

[0032] Figure 6 and Figure 7 This is a schematic diagram of the segment being pulled apart according to an embodiment of the present invention;

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

[0034] Figure 9 A schematic diagram of the arrangement of guide points within a tunnel according to an embodiment of the present invention; and

[0035] Figure 10 This is a schematic diagram of orientation measurement according to an embodiment of the present invention. Detailed Implementation

[0036] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0037] Figure 1 This is a schematic diagram of the main flow of a tunnel boring machine (TBM) construction method according to an embodiment of the present invention, as shown below. Figure 1 As shown, the method for determining shield tunneling construction in this embodiment of the invention mainly includes:

[0038] Step S101: The shield base is hoisted into the well according to the baseline of the survey and layout, and the shield base is placed in accordance with the axis of the exit section.

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

[0040] Step S103: After verifying and measuring the location of the tunnel portal, based on the analysis of ground monitoring information, the concrete of the tunnel portal is removed in a grid pattern, and the positions of the sections are marked. Before removing the tunnel portal, the concrete at the joints between the sections is removed, and the lifting points for each section are prepared. Specifically, a hole is drilled in the center of the tunnel portal to observe the external soil conditions. Then, the concrete of the tunnel portal is removed in a grid pattern, and the positions of the sections are marked. The inner and outer reinforcing bars are exposed, and the inner reinforcing bars are cut off. The remaining concrete on the soil-facing surface and the outer reinforcing bars are removed. The concrete fragments at the bottom of the tunnel are cleaned up. Before removing the tunnel portal, the concrete at the joints between the sections is removed, and the lifting points for each section are prepared. The concrete blocks of the tunnel portal are then lifted in a top-to-bottom order.

[0041] Step S104: After the tunnel boring machine enters the tunnel ring as a whole, synchronous grouting is carried out.

[0042] The embodiments of the present invention also include: erecting and installing scaffolding in the hole area, and installing a water-stopping device on the scaffolding. A ring of arc-shaped inserts is installed on the hole as a water-stopping barrier.

[0043] The embodiments of the present invention also include: placing two guide rails inside the tunnel ring and at the location where the 70cm groove wall has been removed, the guide rails extending to the shield base and connecting with the two guide rails on the base to form a whole, the installation angle and position should follow the rails on the shield base.

[0044] The embodiments of the present invention also include: arranging grouting ball valves around the tunnel ring; and connecting a 1.5-inch steel pipe of a predetermined length to the rear end of the grouting ball valves and extending it into the stratum outside the tunnel entrance.

[0045] The steps for adding a steel back support between the last negative ring and the well wall structure include: filling the gap between the steel back support and the negative ring segment with cement mortar; and the steel back support is made of two double 70#H steel bars.

[0046] Steel formwork is customized according to structural dimensions; vertical formwork is adopted. The arch supports are made of channel steel, with a spacing of 900-1200mm. The arch supports are erected on the already poured concrete base slab, and steel cross braces are added at the bottom of the arch supports. A 20mm thick wooden board is placed under the arch support to prevent the support legs from sinking. The arch supports are installed along the center line. During this process, release agent is evenly applied to the steel formwork, and the steel formwork is installed in sequence according to the structural characteristics.

[0047] For the shield machine hoisting and transportation construction plan, the shield machine's upper shaft mainly includes the hoisting of the three major components: the front cylinder and cutterhead, and the middle cylinder. All of them are hoisted out from the working shaft opening. Among them, the front cylinder and cutterhead assembly is the heaviest, weighing about 110 tons. The shield machine dismantling and hoisting includes: (1) shield machine entering the tunnel. (2) Shield machine power off: all shield equipment is stopped in the correct position and fixed, all hydraulic cylinders are retracted to the zero position; the shield machine is powered off. (3) Pipeline removal: remove the pipelines between the bridge frame and the main machine and the frame; remove the pipelines inside the shield machine main machine; remove the pipelines between the frames. (4) Dismantling of single beams and conveyor heads: remove the conveyor belt and pull it out of the tunnel; lay the locomotive track to the bottom of the screw conveyor; use a hoist to dismantle the single beam and pull it out of the tunnel; use a hoist to dismantle the conveyor head and pull it out of the tunnel. (5) Dismantling of double beams and bridge frames: use a hoist to dismantle the double beams and pull them out of the tunnel; use a hoist to dismantle the tie rods and bridge frames and pull them out of the tunnel. (6) Welding lifting lugs: Erect a lifting lug welding platform; weld the lifting lugs of the rear cylinder, cutter head, front cylinder, and middle cylinder. (7) Lifting and dismantling the upper part of the rear cylinder: Weld steel pipes to reinforce the upper and lower parts of the rear cylinder to prevent deformation. Cut the upper part of the rear cylinder and lift it out. (8) Lifting and dismantling the assembly platform: Remove the connecting bolts of the middle assembly platform and lift it out. Remove the connecting pins and lift it out of the left assembly platform. Remove the connecting pins and lift it out of the right assembly platform. (9) Lifting and dismantling the screw conveyor: Use a crane to lift and dismantle the screw conveyor's tie rod and connecting bolts. Lift the screw conveyor and use two 5t hoists to adjust the angle. (10) Lifting and dismantling the assembly machine: Remove the assembly machine's retaining wheels. Lift the assembly machine out and turn it over. (11) Lifting and dismantling the lower part of the rear cylinder: Cut the lower part of the rear cylinder. Lift the lower part of the rear cylinder. (12) Lifting and dismantling the middle cylinder: Use a carbon planer to cut the weld between the middle cylinder and the front cylinder. Remove the connecting bolts between the middle cylinder and the front cylinder. The front cylinder is welded and fixed to the base with iron plates. The middle cylinder is lifted out and turned over. A 350t crane is used for the main crane and a 130t crane is used for the auxiliary crane; the middle cylinder is lifted into the well (first, the middle cylinder is moved horizontally to a turning radius of 9m on the underground jig with three 5t hoists and a 350t crane, and then lifted out of the well). (13) Lifting and dismantling the cutterhead and front cylinder: Cut the iron plates fixing the front cylinder and the base. Cut off the anti-tilting support. Lift out the front cylinder and cutterhead and turn over. (14) Lifting and dismantling the pedestrian gate: Remove the connecting bolts of the pedestrian gate. Lift out the pedestrian gate. (15) Lifting and dismantling the frame: Lay the track to the bottom of the well. Pull out and lift out the frame. (16) Final work: Remove the sleepers at the bottom of the well. Lift out the shield base. Clean the bottom of the well.

[0048] For determining the equipment hoisting method, the actual conditions of the construction site, the weight and size of the equipment, and the performance characteristics of the large crane can be considered. In this case, the AC350 350-ton fully hydraulic truck crane can be selected as the main hoist for mechanized construction.

[0049] Furthermore, considering lifting capacity and component dimensions, the tunnel boring machine (TBM) is disassembled into the following key components: cutterhead, cutting ring, support ring, tail ring (upper and lower halves), assembly machine, working platform, and subsequent chassis. The selection of the crane is based on the self-weight of the largest component of the TBM, the size of the working shaft, and the required placement of the TBM components. In this embodiment, a 350T crane can be selected for lifting, while a 130T crane assists the main crane in turning, erecting, or lowering the TBM components on the ground.

[0050] During the shield tunneling process, the support ring, cutting ring, cutterhead, assembly machine, and shield tail are sequentially lowered into the shaft and assembled according to the order in which the components are lowered. The shield commissioning period can be set at approximately 30 days; commissioning begins immediately after all components of the shield machine are installed underground. Specific commissioning procedures are as follows:

[0051] No-load commissioning: Check if the equipment can operate normally. The commissioning includes: calibrating the hydraulic system, lubrication system, cooling system, power distribution system, and grouting system using instruments.

[0052] Load testing: This involves checking the load capacity of various pipelines and seals, and further refining any aspects that could not be completed during no-load testing, so that all systems and auxiliary systems of the tunnel boring machine reach a working state that meets normal production requirements. The trial tunneling time is the equipment's load testing time. During load testing, strict management measures will be taken to ensure project safety, project quality, and alignment accuracy.

[0053] The shield tunneling machine (TBM) base is a prefabricated steel structure. The base's position is accurately laid out according to the design axis. During installation, it is hoisted into place and welded according to the measured baseline. The center lines of the two tracks and the shield on the base must be aligned with the center of the tunnel portal and substantially consistent with the reverse extension line of the tunnel's design axis. The base is reinforced with additional supports. The shield tunneling machine base... Figure 2 As shown.

[0054] For the fabrication of the shield support, a steel shield support is added between the last negative ring and the shaft wall structure. The steel shield support consists of two double-span 70# H steel beams, with cement mortar filling the gap between the steel shield support and the negative ring segments. A Ф609 waler is installed at the rear of the 70# H steel beams. After the shield support is installed, during shield advancement, careful observation of the shield support deformation is necessary to prevent excessive displacement and damage. Deformation observation points are set up on the shield support. Initially, measurements are taken after each section of soil is advanced, and then after each ring when the shield support deformation is relatively stable, measurements are taken until the shield support is stable before observation stops. If the shield support deformation is excessive, reinforcement measures are immediately taken. A schematic diagram of the shield launching and support system for the section is shown below. Figure 3 As shown.

[0055] For the fabrication of the guide rails, the shield support inside the tunnel ring must be able to support the weight of the shield machine when it exits the tunnel and also serve a guiding function. The support material uses 43kg / m heavy-duty rails, with a total of 2 rails arranged. The exact location is the extension of the two 43kg / m heavy-duty rails on the shield base inside the tunnel ring.

[0056] Because there is a certain gap between the diameter of the working shaft and the outer diameter of the tunnel boring machine (TBM), a sealing device consisting of rubber curtain strips, ring plates, and flaps is installed around the shaft to prevent soil loss during TBM exit and construction. Grouting holes are also provided as a preventative measure for waterproofing and sealing the tunnel entrance. The waterproofing system for this tunnel exit is designed as a waterproofing system consisting of a flap and a rubber curtain strip. During the station structure construction, grouting pipes are pre-embedded around the shaft. If water or soil leakage occurs during TBM exit construction, a double-liquid grout can be injected through these grouting pipes for sealing and waterproofing.

[0057] In addition, to ensure the sealing and waterproofing effect of the shield tail, after the shield commissioning is completed, shield tail grease is applied between the steel brushes of the shield tail. The grease should be applied evenly and densely, so as to fill the grease cavity of the shield tail brush.

[0058] For the negative ring assembly, the gap between the rear of the first ring's open end and the steel rear shield support (reaction frame) is filled with high-grade mortar to ensure uniform stress on the concrete segments and a smooth ring surface. The assembly of the first negative ring segment is the first step in controlling the quality of the segment assembly. The ring surface of the segment is aligned with the design axis according to the axial elevation and the position laid out in the plane. To ensure that the segment does not deform after exiting the shield tail, supports are added to the outer arc surface of the segment for fixation.

[0059] The process of the tunnel boring machine (TBM) exiting and reaching the construction site includes the reinforcement of the foundation for the TBM's entry and exit. Specifically, considering the soil conditions at the TBM's entry and exit points, the foundation must be pre-reinforced using ground jet grouting or a combination of jet grouting and soil mixing piles. The reinforcement length is 9m for exiting and 12m for entering; strong reinforcement is applied to the top and bottom 3m of the tunnel, and weak reinforcement is applied from the top 3m of the tunnel to the ground surface (for the right-line TBM at the south end of the Datieguan Station, weak reinforcement extends from the top 3m of the tunnel to the ventilation shaft floor). The unconfined compressive strength of the reinforced soil must be no less than 1.0 MPa, and the permeability coefficient must be less than 10⁻⁸ cm / s. The reinforced soil should have good uniformity, self-supporting properties, and sealing to prevent quicksand during TBM entry and exit. Before the TBM exits, multiple exploratory boreholes are drilled in the reinforced area. If necessary, grouting is used to reinforce the structural joints to ensure the safety of the TBM's entry and exit.

[0060] Before the tunnel boring machine (TBM) enters or exits the tunnel, the reinforcement of the external foundation is inspected and accepted. Construction can only proceed after the reinforced soil meets the requirements of the bidding drawings. If the foundation reinforcement effect does not meet the predetermined requirements, supplementary reinforcement measures are taken until it passes the test. Foundation reinforcement before the TBM is hoisted and lowered into the shaft is completed.

[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] Once the shield installation and commissioning are complete and everything is normal, it enters the exit phase. Simultaneously, clay is filled into the soil chamber in front of the shield using a reverse-rotating auger. To prevent the cutterheads on the cutterhead from damaging the tunnel entrance sealing device, grease is applied to the cutterheads and sealing device to reduce friction. The tail steel brush must be filled with tail grease. During the exit process, the sealing effect of the water-stopping device is closely monitored to prevent soil loss through gaps and ground collapse. Initially, because the shield is in a reinforced area with harder soil on its face, to control the advance axis and protect the cutterhead, the balance pressure setting should be lower than the theoretical value during construction in this area, the advance speed should not be too fast, and the shield slope can be slightly greater than the design slope. The following measures should also be noted:

[0066] (1) Technical measures for shield tunneling through reinforced areas

[0067] ① Increase the density of monitoring points and increase the monitoring frequency

[0068] ② Strictly control earth pressure

[0069] Since the tunnel boring machine (TBM) has just approached the reinforced soil, the soil pressure setting can be relatively low. Simultaneously, the settling report and other construction parameters are analyzed and adjusted, and feedback is given to the tunneling team to ensure safe exit from the tunnel.

[0070] ③ Strictly control the amount of excavated soil.

[0071] The amount of excavated soil is reasonably controlled based on the construction gap between the tunnel boring machine and the segments, as well as the characteristics of each soil layer, and is approximately 98%-100% of the construction gap. The most reasonable value is then found through analysis and adjustment.

[0072] ④ Control propulsion speed

[0073] The tunnel boring machine (TBM) advance speed should be controlled within 1-2 cm / min to ensure that the TBM jacking pressure and cutterhead torque are not too large and thus affect the performance of the TBM, and to ensure the safety of the TBM exiting the tunnel. At the same time, foaming agents or mud can be added to the front of the TBM as needed to improve the soil on the front side.

[0074] ⑤ Synchronous grouting

[0075] Strictly control the synchronous grouting volume, grout quality, and pressure. After the tunnel boring machine enters the tunnel ring, timely synchronous grouting should be carried out. The quality of the grout will ensure the reduction of secondary ground settlement in the area. The grouting pressure should not be too high to reduce disturbance to the soil and avoid ground deformation.

[0076] ⑥ Dynamic information transmission

[0077] During tunnel boring machine (TBM) construction, it is necessary to analyze ground monitoring information and combine the relationships between thrust, advance speed, excavated soil volume, and jack assembly to maintain a relatively stable advance slope, control the amount of correction required at one time, and reduce disturbance to the soil.

[0078] (2) Precautions for crossing reinforced areas

[0079] ① After the negative ring segment detaches from the shield tail, it is unrestrained and easily deformed under the action of thrust. Therefore, necessary reinforcement measures (such as adding lateral temporary supports) need to be taken.

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

[0081] ③ When the tunnel boring machine enters the tunnel ring, it is necessary to pay close attention to whether the tunnel ring water-stopping device is intact. If necessary, it is necessary to take additional reinforcement measures to ensure the sealing effect.

[0082] ④ When installing the negative ring segments, ensure a reasonable gap between the segments and the bottom of the tunnel boring machine.

[0083] ⑤ Ensure the amount and uniformity of the grease injected into the shield tail to guarantee the sealing effect of the shield tail.

[0084] ⑥ During the initial grouting, the grouting pressure setting should take into account both the ground settlement monitoring data and the pressure-bearing capacity of the tunnel portal sealing device.

[0085] After the tunnel boring machine (TBM) exits the reinforced zone, to prevent sudden "head-bumping" of the TBM due to changes in the soil conditions on the face, the balance pressure value is set slightly higher than the theoretical value. At the same time, construction parameters such as the balance pressure setting and the advance speed are adjusted in a timely manner based on feedback from information such as the amount of ground deformation.

[0086] After the first closed-ring segment exits the shield tail, the rear shield support is immediately installed. Four Ф609 steel pipes are used to transfer axial force between the transverse support of the first closed-ring segment and the two double 70#H H-beam rear supports, with the steel sections transferring the force to the station structure. This allows for a wider range of selection for the jack area and hydraulic pressure during shield tunneling, facilitating axis control during shield tunneling. After the rear shield support is installed, the deformation of the rear support should be carefully observed during shield tunneling to prevent excessive displacement and damage. Deformation observation points are set at the rear support. Initially, measurements are taken after each box of soil is advanced, and then after each ring when the rear support deformation is relatively stable, measurements are taken until the rear support is stable before observation ceases.

[0087] To prevent the shield tail from pulling apart the tunnel segments during the tunnel boring machine's entry process, causing tunnel deformation and water leakage at the joints, channel steel must be used to connect approximately 11 rings of tunnel segments into a whole before entering the tunnel. Typically, a longitudinal connecting strip is installed between the six segments of each ring.

[0088] After the tail end is a certain distance from the tunnel ring, the tunnel ring is reinforced with single-liquid grout injection.

[0089] The tunnel boring machine (TBM) advances to a point 50 meters from the receiving shaft wall, marking the entry phase of the tunnel. Before the TBM enters the tunnel, all preparations inside the receiving shaft are completed. The location of the tunnel entrance is first verified and measured, and the TBM receiving base is installed in preparation for the TBM's arrival and construction.

[0090] Based on the exact location of the tunnel portal, the placement of the shield tunneling base was accurately laid out. During installation, the base was hoisted into place and assembled and welded according to the baseline laid out in the survey. The base was placed on a level slope, and after it was in place, it was supported and reinforced to enhance its overall stability.

[0091] Scaffolding is erected in advance in the hole area to install the water-stopping device. The water-stopping device is installed, and a ring of arc-shaped inserts is installed on the hole as a water-stopping barrier.

[0092] To ensure good guidance when the tunnel boring machine (TBM) arrives for construction, guide rails are installed on the tunnel ring. Two guide rails are placed at the bottom of the tunnel ring, extending to the TBM base and connecting with two guide rails on the base.

[0093] To prevent slurry leakage when the tunnel boring machine (TBM) reaches the construction site, double-liquid grout is injected promptly at the leakage points, and six grouting ball valves are installed around the tunnel entrance. To improve the grouting effect, a 1.5-inch steel pipe of a certain length is connected to the rear end of the grouting ball valve and extends into the stratum outside the tunnel entrance.

[0094] Since the tunnel entrance water-stopping device and the arc-shaped insert plate for sealing the tunnel entrance need to be welded on the inside and outside of the tunnel ring, the tunnel ring must be cleaned to ensure that the steel tunnel ring can be firmly welded to other iron devices.

[0095] Measurements taken before the tunnel boring machine (TBM) breaks through the shield are crucial for verifying the shield's location, confirming its attitude, assessing its attitude upon arrival at the construction site, and determining the control values ​​for the construction axis, the advance slope, and the construction plan for the section the TBM reaches. This ensures that the TBM operates according to the predetermined plan during this stage of construction, arrives at the construction site in a good attitude, and is accurately positioned on the TBM receiving base.

[0096] During the tunnel boring machine (TBM) entry process, the tunnel segments should be advanced and assembled as quickly as possible upon the arrival of the TBM to shorten the TBM entry time. After the special ring of the tunnel lining detaches from the shield tail, it is immediately welded to the TBM with an arc-shaped steel plate to form a whole, and the gap between the tunnel segments and the tunnel lining is filled with grout to reduce soil erosion.

[0097] Based on the actual measured dimensions of the station end shaft ring, the shield tunneling machine's posture will be adjusted appropriately upon reaching the construction stage. When the shield tunneling machine passes through reinforced areas and retaining structures, the following precautions should be taken:

[0098] ① The advancing speed is controlled within 1 cm / min, and the frontal earth pressure is gradually reduced;

[0099] ② When crossing, pay close attention to parameters such as the cutter head torque;

[0100] ③ Assign dedicated personnel to closely monitor the deformation of the tunnel entrance and the soil and water conditions, expedite information feedback, and immediately halt progress and take appropriate countermeasures if any abnormalities are detected.

[0101] Before the tunnel boring machine (TBM) enters the tunnel, a comprehensive inspection of the main equipment of the TBM is carried out. Any problems are resolved in a timely manner to ensure that the equipment is in good operating condition. This will ensure that no engineering difficulties arise due to equipment issues when the TBM arrives at the construction site, and will also minimize the construction time.

[0102] To prevent the shield tail from pulling apart the tunnel segments during the tunnel boring machine (TBM) construction process, causing tunnel deformation and water leakage at the joints, channel steel must be used to connect about 11 rings of tunnel segments into a whole before the TBM enters the tunnel. Usually, a longitudinal connecting strip is set in the middle of 6 segments in one ring.

[0103] After the tunnel boring machine (TBM) approaches the diaphragm wall, the concrete slabs of the diaphragm wall are removed in sections and hoisted out. Throughout the entire operation, a dedicated safety officer supervises the process to eliminate potential safety hazards and ensure personal safety.

[0104] The connecting parts of the ring-shaped tunnel segments are tightened to ensure a tight connection and prevent tunnel deformation during the shield tunneling process into the receiving shaft. During the portal excavation, measures must be taken to protect the portal waterproofing device.

[0105] Depending on the progress of the tunneling construction, a second tunneling operation may be necessary. The first operation involves sealing the tunnel entrance after the tunnel boring machine (TBM) enters the tunnel ring, followed by grouting through pre-embedded grouting holes in the tunnel ring. Once the grout reaches a certain strength and the soil is stable with no leakage, the TBM continues to advance. The final segment completely detaches from the tunnel ring, and the existing fan-shaped plate is lengthened and welded to the tunnel ring segment to form a single unit. The gap between the segment and the tunnel ring is filled with hydraulic grout, and grouting continues to fill the soil gaps and maintain soil stability.

[0106] For the normal section of shield tunneling, after a 100m trial run at the exit section, the personnel can master the operation and equipment break-in, and adjust the appropriate shield tunneling parameters and excavation volume, and then begin the normal section of shield tunneling.

[0107] The main construction parameter controls include:

[0108] (1) Principles for setting the balance pressure value

[0109] Frontal equilibrium pressure: P = k0γh

[0110] P: Balance pressure (including groundwater)

[0111] γ: Average unit weight of soil (kN / cm³) 3 )

[0112] h: Tunnel depth (m)

[0113] k0: Coefficient of lateral static equilibrium pressure of soil

[0114] During tunneling, the above method is used to obtain the set value for the balanced pressure. The specific construction set value is dynamically adjusted based on the tunnel boring machine's burial depth, the soil conditions at the location, and monitoring data.

[0115] (2) Promote the control of excavated soil volume

[0116] Theoretical soil excavation volume per ring = π / 4 × D 2 ×L=37.88m 3 / ring.

[0117] The amount of excavated soil during tunnel boring machine (TBM) operation is controlled between 98% and 100%, which is 37.12m³. 3 / ring-37.88m 3 / ring.

[0118] (3) Propulsion speed

[0119] During normal advancement, the speed should be controlled between 3-5 cm / min. When crossing underground pipelines with high settlement requirements, the advancement speed should be controlled within 2 cm / min.

[0120] (4) Control of shield axis and ground deformation

[0121] During tunnel boring machine (TBM) excavation, the deviation from the design axis shall not exceed ±50mm; ground settlement shall be controlled within (+10)-(-30mm).

[0122] Synchronous grouting during tunnel boring machine (TBM) advancement is a primary means of filling the gaps between the soil and the tunnel segments, reducing subsequent deformation, and is a crucial step in TBM construction. Timely, uniform, and sufficient grout injection is essential to ensure timely and adequate filling of the structural gaps, minimizing surface deformation and segment displacement, and preventing water leakage at segment joints. Synchronous grout can quickly and evenly fill all parts of the shield tail gap, minimizing soil disturbance during construction. The grouting volume per ring is generally 200%-250% of the structural gap (actual grouting volume adjusted based on monitoring data). Effective measures are taken promptly based on surface monitoring feedback data to control the grouting process and adjust the grout mix ratio. Grouting is a critical step, and dedicated personnel are assigned to oversee it, meticulously recording the injection location, injection volume, and pressure values, and making timely adjustments based on ground deformation monitoring information to ensure the quality of the grouting process. The transport vehicles inside the tunnel and the grout mixing system on the surface are cleaned regularly, generally once per shift. Due to the cleaning of grouting pipelines at the tunnel boring machine face, a certain amount of waste slurry will be generated, which will pollute the working environment. Therefore, soil boxes are used to transport the slurry away in a timely manner.

[0123] This invention also allows for secondary grouting behind the wall. Secondary grouting is necessary when grout leakage is severe, ground settlement alarms are triggered, or other needs arise. The secondary grouting solution used is a two-component grout, and the mixing ratio is shown in the table below:

[0124]

[0125] In actual construction, the grout ratio is adjusted according to the specific circumstances.

[0126] Due to the presence of numerous pipelines on the ground, the tail seal function is particularly crucial during tunnel excavation in this section. To ensure the safe and successful completion of the tunnel excavation, proper tail grease injection is essential. Under normal circumstances, tail grease is automatically injected via a tail grease pump, and replenishment is made as needed based on grease pressure during tunneling.

[0127] The tunnel segments transported to the site are inspected and, after confirming there are no defects such as missing corners or edges, or issues related to the curing period, are sorted and stacked. All waterproofed surfaces of the tunnel segments are cleaned. The lining joints are waterproofed using elastic rubber gaskets installed within sealing grooves. These elastic gaskets are pre-formed from EPDM rubber through extrusion vulcanization, with water-swellable rubber embedded in the top surface. Water-swellable rubber sealing rings are used to reinforce the waterproofing of bolt holes. Before assembly, the elastic gaskets on both sides of the capping block are coated with a surface lubricant to reduce friction between the gaskets when the capping block is inserted. The surface lubricant should be a water-based application agent with a viscosity of 300 cps. Since the water-swellable rubber on the gasket surface expands when exposed to water and moisture, it should be covered with a plastic film or coated with a slow-expansion agent during rainy weather.

[0128] The tunnel lining is composed of six precast reinforced concrete segments assembled in a staggered manner. The capping block is first pushed radially upwards and then inserted longitudinally. During the segment assembly process, strict control must be exercised over the flatness, lead-out amount, and ellipticity of the lining annular surface. Based on elevation and plane measurement reports and segment gaps, the segment assembly posture is adjusted promptly. Key points for segment assembly control include:

[0129] (1) Strictly control the flatness of the ring surface: start from the negative ring and check each ring. The step between adjacent segments should be less than 4mm. Each segment should not protrude from the ring surface of the adjacent segment to avoid the segment from breaking at the joint of the adjacent segment.

[0130] (2) Control of the advance of the segment ring: During construction, the perpendicularity of the segment ring ring to the tunnel design axis is frequently checked. When the advance of the segment exceeds the control amount, it is corrected by adjusting the segment assembly angle, thereby ensuring that the segment ring ring is perpendicular to the tunnel design axis.

[0131] (3) Control of the height difference between adjacent rings: The size of the height difference between adjacent rings directly affects the quality of the tunnel axis and the effective cross section of the tunnel. Therefore, the height difference between rings must be strictly controlled to not exceed the allowable range.

[0132] (4) Tunnel ellipticity control: When assembling each ring, the tunnel ellipticity should be measured in time. The horizontal and vertical diameter deviations of the lining assembled into a ring should be ≤±3mm. Any unqualified rings should be corrected in time until the ellipticity meets the requirements before proceeding to the next ring.

[0133] (5) Before assembly, remove debris from the tail section of the shield and check the segment type, appearance, and sealing material adhesion. If any damage is found, it must be repaired before assembly. The quality of the first positioning segment assembly will directly affect the overall ring segment assembly quality and its relative position to the shield. In addition to ensuring that it is aligned with the preceding ring segments without stepping on them and is centered, its perpendicularity to the tunnel axis must also be ensured.

[0134] (6) The jacks are retracted in the order of assembling the tunnel segments. After the segments are assembled, the jacks are brought close together in time to prevent the shield from retreating. After the assembly is completed, all the jacks are extended and the required jacking force is controlled before assembling the next segment. This process is carried out piece by piece to complete the assembly of each ring and prevent sudden changes in the shield's attitude.

[0135] (7) The longitudinal and circumferential bolts connecting the ring segments directly affect the overall performance and quality of the tunnel. Therefore, after the assembly of each ring lining is completed, the longitudinal and circumferential bolts connecting the lining should be tightened in time; when advancing the next ring, the longitudinal bolts should be tightened again under the action of the jack force; after the ring segment is pushed out of the frame, the longitudinal and circumferential bolts should be tightened again.

[0136] During tunnel boring machine (TBM) construction, based on different soil types and overburden thicknesses, and in conjunction with the analysis of ground monitoring information, the relationship between thrust, advance speed, and excavated soil volume is considered to maintain a relatively stable advance slope, control the amount of correction required at one time, and minimize disturbance to the soil. Simultaneously, based on monitoring data of advance speed, excavated soil volume, and ground deformation, the grouting volume is adjusted in a timely manner to keep the axis and ground deformation within allowable ranges.

[0137] (1) Reasonable control of regional oil pressure

[0138] Axis control of the tunnel boring machine (TBM) is a crucial aspect of TBM construction, as the TBM advances forward using the thrust of jacks. To facilitate axis control, the jacks are divided into different zones. During advancement, the hydraulic pressure in each zone is adjusted to ensure the TBM moves along the designed axis.

[0139] Under the premise of correctly setting the cut balance pressure, strictly control the oil pressure in each area, control the stroke of the jack, correct deviation reasonably, and make frequent corrections to reduce the amount of deviation per correction.

[0140] (2) Frontal balance pressure setting

[0141] Due to various constraints such as geological conditions and additional ground loads, the earth pressure in front of the cutterhead varies and needs to be adjusted in a timely manner.

[0142] (3) Excavated amount

[0143] During the excavation process, efforts should be made to avoid over-excavation or under-excavation, which could cause deviation of the excavation axis and ground subsidence.

[0144] (4) Balanced construction

[0145] The tunnel boring machine (TBM) should be advanced as continuously as possible to minimize unnecessary stops and prevent it from 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 construction during the shield tunneling process.

[0147] (1) Chassis sleepers: The sleepers are made of 14# channel steel and are arranged in each ring. The sleepers at the wellhead slope are made of H20 steel.

[0148] (2) Locomotive Track: Locomotive tracks (30kg / m) are laid on the sleepers for transporting materials during tunnel boring. A branch track is installed at the shaft opening to improve the utilization rate of the locomotives.

[0149] (3) Pedestrian walkway: A pedestrian walkway frame is made on the lower side of the tunnel segment, and a walkway slab (0.5×2m) is placed on it and fixed firmly.

[0150] (4) Tunnel lighting: A light frame is set up every 10m above the tunnel side, and the lighting cables and lamps are fixed on it, while the power cables are arranged below the light frame.

[0151] (5) Pipeline: Water supply and drainage pipelines are laid on one side of the tunnel and fixed with hangers every 10m.

[0152] (6) Ventilation duct: Ventilation ducts are arranged on the upper side and fixed with hangers every 10m.

[0153] (7) Cables and communication lines: Cables and tunnel boring machine communication lines are laid on the opposite side of the light frame.

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

[0155] Furthermore, the construction rules for portal shaft joints mainly include:

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

[0157] (2) Before dismantling or chiseling the segments, investigate the condition of the grouting layer outside the segments and determine whether pre-grouting is required.

[0158] (3) The cast-in-place concrete should be closely and securely connected to the tunnel and station end walls.

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

[0160] (5) Cast-in-place concrete pouring can only be carried out after obtaining approval from the supervising engineer.

[0161] (6) Take effective measures to ensure the safety of construction personnel and the safety of transport vehicles and personnel on the passage.

[0162] (7) The repair plan shall be implemented after being reviewed and approved by the supervising engineer.

[0163] The main construction methods for portal shaft joints include:

[0164] (1) Remove the zero-ring segment

[0165] First, use a pneumatic hammer to widen the gap between the bottom block and the standard block, loosening the standard block for easier removal. At the lifting point, thread two φ12 double-strand steel wire ropes through the outer longitudinal bolt holes of the standard block. To prevent the segment from swaying after lifting, the inner longitudinal bolt holes and the outer longitudinal bolt holes of the +1 ring are tied together with steel wire ropes for traction, then the block is smoothly moved to the vertical lifting position before lifting. Using this construction method, the adjacent blocks, capping blocks, adjacent blocks, and standard blocks are removed sequentially.

[0166] (2) Steel bar forming and welding

[0167] The length of the reinforcing bars is determined according to the actual dimensions on site. The reinforcing bars are adhered to and bent using a single-component chloroprene-phenolic adhesive, and then used to fix the water-swellable rubber waterstop strip. A slow-expansion agent is applied externally. Ring-shaped reinforcing bars are evenly distributed, and the reinforcing bar skeleton is welded and fixed. An electrical bridge is used to check whether the reinforcing bars are connected to the pre-embedded steel plates of the tunnel segments and the pre-embedded steel plates of the station lining openings; any disconnections are repaired by welding.

[0168] (3) Template creation

[0169] Wooden molds were used. The inner arc was laid out according to the inner diameter of the hole ring, and 10 round wooden molds were used to form the inner ring. The outer ring was laid out according to the outer diameter of the hole ring, and 23 pieces of 20mm plywood were used as end caps. The railings for fixing the template were made of φ12 round steel welded to the steel hole ring, with φ12 tie rod screws attached to the outside, and fixed with triangular clips and 1.5-inch steel pipes.

[0170] (4) Concrete pouring

[0171] The construction method employs self-unloading of commercial concrete and chute construction. A chute approximately 1.5 meters long connects to the chute on the ground, and the length of the chute can be adjusted according to the depth of the caisson. The chute extends directly to the opening in the formwork, where an immersion vibrator is used to compact the concrete.

[0172] For tunnel waterproofing and caulking construction, the waterproofing level of the tunnel section is Class II. Water seepage is not allowed in the roof slab, and water leakage is not allowed in the structure. A small amount of dampness is permissible on the structural surface. The total dampness area should not exceed 6 / 1000 of the waterproofed area, and any 100m²... 2 There should be no more than four wet stains on the waterproof area, and the largest area of ​​any single wet stain should not exceed 0.2m². 2 The concrete strength of the tunnel segments is C50, the impermeability grade is not less than P10, the crack width is not greater than 0.2mm, and when groundwater corrodes the concrete, the erosion resistance coefficient of the concrete is required to be greater than 0.8. No dripping water is allowed at the tunnel roof, a small amount of dampness is allowed on the sides, no leakage of mud or sand or dripping is allowed at the mortar joints, and no seepage is allowed in the arch base blocks after caulking. The methods for determining leakage and dampness are as follows: Leakage and dampness are estimated by measuring the accumulated water in a water-storage earthen dam over one day, and by measuring the dampness area using a scale (measured before the tunnel is completed).

[0173] The waterproofing of the tunnel structure focuses on the self-waterproofing of the segment concrete, the waterproofing of segment joints, and the waterproofing of the joints between the tunnel and stations or working shafts, as well as the joints of connecting passages, to ensure the overall waterproofing performance of the tunnel. The main tunnel structure uses waterproof concrete, employing a "double-admixture technology," adding 20% ​​high-quality fly ash and crack-resistant admixtures. The segment permeability coefficient K ≤ 5 × 10⁻⁶. -13 m / s, chloride ion diffusion coefficient ≤ 8 × 10 -9 cm 2 / s. When the tunnel is in a corrosive medium, appropriate corrosion-resistant concrete should be used, or a corrosion-resistant waterproof coating should be applied to the outer surface of the lining structure. The permeability coefficient of the concrete should be K≤5×10. -14 m / s, ion diffusion coefficient ≤2×10 -9 cm 2 / s.

[0174] The joint of the tunnel segment is equipped with an elastic rubber gasket (referred to as a gasket) as the main measure for joint waterproofing. Cementing and backfilling are auxiliary measures. The longitudinal joint of the tunnel segment needs to be equipped with a force transmission pad to disperse the concentrated stress.

[0175] (1) Elastic sealing gasket (waterstop strip for tunnel segment)

[0176] Waterproofing of segment joints is achieved by setting elastic sealing gaskets around the perimeter of the segment ribs. The sealing gaskets used are guaranteed to meet waterproofing requirements even in the event of construction errors. The approved adhesives are used to firmly bond the sealing gaskets to the segments according to the operating procedures. When water-swellable rubber waterproofing materials are used, moisture-proof measures must be taken during transportation and storage, and a special warehouse must be set up for storage.

[0177] The elastic sealing gasket shall meet the relevant performance indicators. The test methods for the performance indicators shall comply with the relevant national standards.

[0178] (2) Caulking

[0179] The caulking work can only begin after the shield tunneling is completed and the tunnel has been thoroughly cleaned. Caulking is permitted on slightly seeping and damp segments; however, if leakage occurs, it should only be carried out after the leak has been plugged. Large defects in the segment caulking grooves should be repaired before use. The strength of the repair material should be close to that of the original concrete, and its use must be approved by the supervising engineer.

[0180] (3) Force transmission pad

[0181] The nitrile cork rubber force transmission gasket should be processed according to the design drawings and pasted on the construction site. Before pasting, use a wire brush to remove floating dust and mud, and ensure that it will not shift or fall off after pasting. All adhesives are the same as those used for the sealing gasket.

[0182] The waterproofing construction process mainly includes:

[0183] 1. Seam filling of longitudinal and circumferential joints of tunnel segments

[0184] Remove mud, sand, and debris from the longitudinal and circumferential joints – apply interface agent – ​​embed closed-cell polyethylene foam strips – create a polyurethane sealant protective layer.

[0185] 2. Bolt corrosion protection treatment

[0186] Inspect and tighten the nuts – remove surface rust and dirt from metal parts – apply rust-preventive material – place the high-pressure polyethylene plastic cup containing fast-setting micro-expansion cement inside.

[0187] 3. Segment hand hole filling

[0188] Remove debris and impurities from the manhole, clean away dust and mud, apply a bonding agent, and fill the manhole with micro-expansion cement.

[0189] 4. Waterproofing method

[0190] (1) External grouting waterproofing of pipe segments

[0191] During the shield tunneling process, synchronous grouting and secondary grouting behind the tunnel wall are used to fill the gap between the shield and the tunnel segments, forming an outer waterproof layer, which is beneficial for waterproofing the tunnel section.

[0192] (2) Self-waterproofing of pipe segments

[0193] The tunnel segments are made of high-performance self-waterproof concrete characterized by good durability. The impermeability grade of the tunnel segments is ensured through reasonable mix design, standardized material selection, and strict production control. The impermeability grade of the concrete tunnel segments is not less than P10.

[0194] (3) Waterproofing of segment joints

[0195] To meet the waterproofing requirements of the joints, two waterproofing measures were installed at the segment ring and longitudinal joints: a frame-shaped elastic sealing gasket and caulking, with the elastic sealing gasket being the primary waterproofing measure.

[0196] (4) Waterproof elastic sealing gasket

[0197] 1) Elastic sealing gaskets are the main measure for waterproofing lining joints. They are made of EPDM rubber through extrusion and vulcanization, with water-swellable rubber embedded on their top surface.

[0198] 2) Before pasting the sealing gasket, the pipe segments transported to the site must be inspected to confirm that there are no missing corners, broken edges, or problems with the curing period. The segments should be sorted and stacked. Then, use a wire brush to remove the floating dust and dirt in the grooves of the pipe segments and paste them with neoprene-phenolic adhesive.

[0199] It is essential to ensure that the sealing gasket is firmly bonded in the groove, and there should be no falling off, peeling, or displacement.

[0200] If the lining with the sealing gasket is not used temporarily or in rainy weather, it must be tightly covered with plastic film or tarpaulin and coated with a swelling inhibitor. A movable rain shelter should be provided on site.

[0201] 3) To enhance waterproofing at the corners of the elastic sealing gasket, a self-adhesive rubber sheet is applied to the outer corners of the sealing gasket.

[0202] 4) Before assembly, the waterproof sealing gaskets on both sides of the capping block and adjacent blocks should be coated with a water-based surface lubricant (water-based coating with a viscosity of 300 CP) to reduce the frictional resistance between the elastic sealing gaskets when the capping block is inserted, which may cause misalignment or damage.

[0203] 5) When the shield tunneling machine advances in a curved manner or needs to adjust its attitude for other reasons, the adjustment amount at one time (one ring) should not be too large, so as to avoid the tail steel plate of the shield tearing the segments, damaging the sealing gasket, and affecting the water-stopping effect.

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

[0205] To ensure the waterproofing effect of the tunnel, a 20×4mm water-swellable rubber strip is added to the outside of the elastic sealing gasket of the tunnel segment. At the tunnel deformation joint, a 3mm thick water-swellable rubber strip should also be added to the elastic sealing gasket.

[0206] The overlapping parts of the water-blocking strip should avoid corners, and the overlapping joints should be butted at a 45-degree angle and fixed with adhesive.

[0207] (6) Sealing and waterproofing

[0208] Joint caulking is the second line of defense for waterproofing joints. After the gasket reaches the end of its lifespan, the caulking material, which serves as the inner waterproofing layer, is easy to remove and re-fill.

[0209] 1) The joint sealant is made of polymer cement (such as chloroprene latex cement mortar), and the interface between the material and the concrete is treated with an interface treatment agent.

[0210] 2) Cementing range: The lining rings with large deformation, such as the 30m section of the tunnel portal and the 8-10m sections on both sides of the connecting passage, are filled in the whole ring. The remaining sections are the 45° range of the arch top and the 90° range of the arch bottom.

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

[0212] Bolt hole waterproofing: Water-swellable rubber sealing rings are used as bolt hole sealing rings, which enhance waterproofing through the dual effects of compression and expansion.

[0213] Waterproofing of lifting holes (grouting holes): When lifting holes and grouting holes are used in combination, to reduce the vulnerability of the grouting holes as weak points for tunnel water seepage, a 50 mm layer of plain concrete is left on the outside of the segments of the lifting hole. When secondary grouting is required behind the lining, the plain concrete of the lifting hole is broken up and used as a grouting hole. A water-expanding bolt sealing ring is installed in the grouting hole to enhance waterproofing.

[0214] (8) Waterproofing during shield tunneling entry and exit

[0215] When the shield tunnel enters and exits the tunnel, the thrust decreases and the elastic sealing gasket of the tunnel segment is difficult to tighten. During construction, measures should be taken to tighten the tunnel segment, and comprehensive waterproofing should be carried out in combination with grouted duct and reinforced soil layer when the shield tunnel enters and exits the tunnel.

[0216] (9) Corrosion protection

[0217] Lining bolts, other metal connectors, and exposed parts must be treated with hot-dip galvanizing or zinc-based chromate coating.

[0218] (10) Waterproofing of connecting passages

[0219] The connecting passage and pumping station use a flexible waterproof layer (non-woven fabric + EVA waterproof membrane), and the joint between the tunnel and the connecting passage is waterproofed with water-swellable rubber strips.

[0220] Joint sealing and waterproofing measures include:

[0221] ① Clean the seams: brush away the mud, sand and debris inside the seams, and rinse with clean water.

[0222] ② Embedded closed-cell polyethylene foam strips. When steps are formed at the joint, the sealant should be embedded to a depth of at least 12mm, ensuring that it reaches the predetermined depth and adheres tightly after embedding.

[0223] ③ After the closed-cell foam polyethylene strips are installed, the surface should be flat.

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

[0225] ⑤ Apply interface agent YJ-302 (two-component). Pour the interface agent into a container with a mixing ratio of component A: component B: cement = 1:3:4 and mix well. Each batch of mixing should be used up within 2 hours.

[0226] ⑥ The interface agent should be applied to the inner wall of the groove, within 15mm on both sides of the longitudinal joint, and within 16mm on both sides of the circumferential joint.

[0227] ⑦ Apply a protective layer of polyurethane sealant. Seal with polyurethane sealant before the interface agent dries.

[0228] For the caulking area, the 20 rings of the entrance and exit openings should be caulked in a full ring and longitudinal joint. The 5 rings before and after the central circumference of the connecting passage steel segment should be caulked in a full ring (including the longitudinal joints). The expansion joint circumference should be caulked in a full ring (circumference only). Caulking should be applied within the 45° range of the segment crown and the 90° range of the segment base in other areas.

[0229] Corrosion protection treatment for exposed bolt parts includes: corrosion protection treatment of exposed bolts, nuts, and washers within the upper 180-degree range. Construction requirements are as follows:

[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 cover;

[0233] 4) The end cap and plastic protective sleeve should be perpendicular to the wall of the hole, and the nuts and washers should not be exposed.

[0234] Waterproofing of the joints between tunnel sections and station end shafts, as well as connecting passages, mainly includes:

[0235] (1) Tunnel and End Shaft

[0236] Waterproofing of tunnel and shaft joints includes waterproofing of temporary joints during construction and permanent joints after completion.

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

[0238] b. The permanent joint is a reinforced concrete well ring. The joint between it and the well wall and the pipe segments should be pre-installed with a grouting pipe with full-section grout discharge and multiple layers of flexible waterproof materials such as single-component polyurethane sealant.

[0239] (2) Tunnels and connecting passages

[0240] The joint between the connecting passage and the shield tunnel section is a weak point in waterproofing. The waterproofing membrane should be sealed at the joint with the shield tunnel segments. Water-swellable rubber waterstops and externally applied waterstops should be used, and grouting should be applied to the surrounding strata at the joint through grouting pipes for waterproofing.

[0241] For the excavation and support of connecting passages and pump rooms, certain conditions must be met for soil excavation, such as:

[0242] 1) Temperature measuring hole inspection

[0243] The rate of permafrost development can be calculated based on the measured data from the temperature measuring holes, the time of fusion can be calculated, and then the radius of permafrost development under that freezing time can be calculated, thereby calculating the thickness of the permafrost curtain. Based on this thickness, the average temperature of the permafrost curtain can be obtained by formula or graphical method. If the thickness and average temperature of the permafrost curtain at each layer and at each part meet the design requirements, excavation can be carried out.

[0244] 2) Inspection of pressure relief holes

[0245] During active freezing, the pressure relief orifice serves two purposes: firstly, it unloads frost heave pressure; secondly, the pressure it displays can serve as an important indicator of whether the frozen soil curtain has formed a closed loop. Generally, in the early stages of freezing, the pressure in the pressure relief orifice is the original ground pressure. As the frozen soil gradually expands and moisture migrates, the frozen soil forms a closed loop, preventing the frost heave pressure from being released. Instead, the pressure gradually increases, manifesting as a sharp increase in the pressure of the pressure relief orifice. Moreover, opening and closing the pressure relief valve gradually returns the pressure to its original value. The difference in pressure before and after the loop formation is 0.15-0.3 MPa.

[0246] 3) Temperature difference in the brine return loop

[0247] Since the cooling loss after the ring is less than before the ring, the temperature difference between the brine inlet and outlet before the ring is greater than after the ring. If the temperature difference between the brine inlet and outlet (with other freezing parameters unchanged) suddenly decreases at a certain period, the ring may have already been formed. However, this phenomenon is only used as a reference for judging the ring. To determine the excavation, it is necessary to consider the data from the temperature measurement holes, the pressure of the pressure relief holes, the condition of the exploration holes, and other factors.

[0248] Before the excavation and construction of the connecting passage and pump house, the following should be included:

[0249] 1) Hole inspection

[0250] Before formal excavation, exploratory boreholes should be drilled in weak areas of the frozen soil curtain. If there is no sand or water inrush at the borehole location, the strata are stable, the frozen soil curtain is normal, and the temperature measurement results are good, then formal excavation can begin.

[0251] 2) Construction of working platform inside the tunnel

[0252] Based on the dimensions of the connecting passage exit and construction needs, an intermediate working platform will be erected at the opening of the connecting passage. This platform will primarily serve as a route for changing the direction of material transport trolleys and will also be used for temporary storage of construction materials.

[0253] 3) Installation of emergency safety doors

[0254] Emergency safety doors are used to ensure tunnel safety in cases where, during excavation and construction, a large amount of sand or water gushes out of the reinforced soil, or when displacement and deformation exceed limits, and other rescue measures are ineffective. The safety doors must be installed firmly and reliably, and the doors should open and close easily. Emergency safety doors must be installed before the connecting passages freeze and must be equipped with ventilation of no less than 6 m³ / h. 3 An air compressor with a capacity of / min supplies air for the safety gate pressure test. The safety gate can be removed after the connecting passage is completed.

[0255] Furthermore, considering the stress redistribution in the lining ring of the connecting passage after the steel segments at the tunnel entrance are pulled apart, which could affect the structural safety of the main tunnel, a prestressed steel tunnel support is installed in the tunnel segment opening ring at the passage opening before excavation of the funnel opening. This is to mitigate the adverse effects of the connecting passage excavation and construction on the tunnel. A single steel support consists of a central rectangular closed steel support, five prestressed jacks, two fixed supports, and a support protection plate, etc. Figure 5 As shown. Installation method: Two steel supports are erected on each side of the opening of the tunnel connecting passage, with a 2m gap between them. These supports are symmetrically arranged along the tunnel direction at both ends of the connecting passage. The supports are joined by welding 67×67mm equilateral angle steel. Each support has seven support points, prestressed by five 50t screw jacks. When applying prestress, each jack should be applied slowly and steadily simultaneously, ensuring each jack compacts the support point. A designated person must be in charge of directing the erection. Bolts must be tightened during assembly, and jacks at higher positions should be fixed to the main frame to prevent them from falling off. The pressure of the jacks should be checked regularly, and any loosening or other abnormalities should be addressed promptly.

[0256] 4) Installation of pneumatic equipment

[0257] To ensure the safety of earthwork excavation, a 20m [unit / equipment] is considered. 3 An air compressor and related piping are provided, which can be connected to the compressed air valve of the safety door. In the event of a serious water leak in the connecting passage, air pressure must be increased in the connecting passage to balance the external water pressure, reduce the amount of water flowing in, and ensure the safety of the tunnel. In an emergency, the air pressure can be increased to 180 kPa.

[0258] 5) Reserves of emergency supplies

[0259] To address potential emergencies during the construction and excavation of freezing holes, in addition to developing practical emergency measures, a certain amount of emergency supplies needs to be stockpiled at the construction site: liquid nitrogen, emergency sandbags, clay bags, wooden wedges, cement, hemp fiber, wooden backing boards, etc., to ensure the safety of the connecting passage construction. Emergency supplies should be stacked in an orderly manner and clearly marked. These supplies must be used for their designated purpose and not be misappropriated. They should be guarded and stored by designated personnel and inspected regularly.

[0260] After the soil reinforcement strength reaches the design requirements and the construction preparation work is completed, the excavation work can officially begin. Before opening the tunnel segments, prepare two 5t jacks and one 5t and one 2t hand chain hoist. The method for opening the tunnel segments includes: placing the two jacks on both sides of the segment to be opened, with a steel beam directly connected to the steel segment in the middle. The steel segment is pushed outward by pushing the beam with the jacks. Figure 6 , Figure 7 As shown. During operation, it is essential to carefully observe the stress and displacement of the tunnel segments, eliminate local obstructions, and prevent segment deformation.

[0261] The 5-ton hoist is used as an auxiliary tool for pulling out the tunnel segments. One end is hooked onto the segment to be removed, and the other end is tied to the segment in the opposite tunnel. A slight horizontal force is applied to pull the segment outwards (inside the tunnel), requiring coordination with jacks. A 2-ton hoist is suspended above the segment to be removed, with one end hooked onto it to prevent it from suddenly falling onto the work platform during pull-out. While using jacks and the 5-ton hoist, it is important to observe the outward movement of the segment and adjust the tension and direction of the 2-ton hoist as needed. If pulling becomes difficult, the cause of the obstruction should be checked and addressed. If it is caused by segment corrosion, a sledgehammer should be used to vibrate the segment to reduce pulling resistance.

[0262] Based on the structural characteristics of the project, the excavation cycle advance of the connecting passage was controlled at 0.5m or 0.6m, employing a two-step excavation method. The upper step was excavated first, with a height of 1.6m, and the steel arch frame for the arch was erected. Subsequently, the soil of the lower step was excavated, with a height of 1.65m, and the side wall steel arch frame extensions and the invert steel arch frame were installed. The distance between the two steps of the excavation was maintained at approximately 2m. To mitigate the impact of excavation on tunnel deformation, the excavation step distance was controlled at 0.5m. After the connecting passage was completed, the drainage pump house sump was excavated. The drainage pump house excavation was carried out in a step-by-step manner, with each layer excavated in 0.5m increments.

[0263] In another aspect, the present invention also provides a method for waterproofing during tunnel boring machine (TBM) construction.

[0264] The method for waterproofing tunnel boring machine (TBM) construction according to embodiments of the present invention, used in the TBM construction method as described in any of the above claims, includes: installing a sealing device around the tunnel ring, the sealing device consisting of a rubber curtain strip, a ring plate, and a flap plate; setting grouting holes for waterproofing and leak sealing at the tunnel entrance, and pre-embedding grouting pipes around the tunnel ring; and, if water or soil leakage is confirmed during the TBM exit construction, injecting a double-liquid grout through the grouting pipes for sealing and waterproofing.

[0265] After the tunnel boring machine (TBM) commissioning is completed, tail grease is evenly and densely applied between the tail grease brushes to fill the grease cavities. Additionally, elastic sealing gaskets are installed around the perimeter of the tunnel segment ribs. These elastic sealing gaskets are made of water-swellable rubber.

[0266] In another aspect, the present invention also provides a monitoring method for shield tunneling construction. This monitoring method, used for shield tunneling construction as described in any of the above embodiments, includes: setting temporary reference points at the bottom of the shaft; measuring the transverse diameter and planar coordinates of the tunnel portal ring based on these temporary reference points; determining the planar center coordinates of the tunnel portal ring; and calculating the planar deviation value of the tunnel portal ring; using temporary leveling points transferred to the bottom of the shaft to measure the bottom elevation and top elevation of the tunnel portal ring; determining 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 these coordinates using instruments; and determining the deviation between the calculated coordinate values ​​and the theoretical values; and adjusting the planar position of the base based on the deviation.

[0267] The monitoring method for tunnel boring machine construction in this embodiment of the invention further includes: attaching a metal stainless steel plate to each side of the middle of the crack, with a circular hole drilled in the center of the plate, and the direction of the line connecting the circular holes being perpendicular to the crack during installation; making a mark at each end of the crack to observe the development of the crack; and setting plaster sheets at both ends of the crack, with the plaster sheets firmly bonded to both sides of the crack.

[0268] The monitoring method for tunnel boring machine (TBM) construction in this embodiment of the invention further includes: installing an abnormal gas monitor at the exit of the TBM auger to monitor abnormal gases.

[0269] The monitoring method for shield tunneling in this embodiment of the invention further includes: setting up ground settlement measuring points along the tunnel axis, setting up settlement trough observation sections at certain intervals, adding settlement trough observation sections when crossing important buildings or pipeline groups, setting up measurement marks using nails or road spikes on hard ground, and using steel piles as measurement marks on soft ground; setting up a monitoring section every 20 meters within 100m of the shield launching section; setting up a monitoring section every 30 meters in other sections; the measuring point interval on the monitoring section is 2-5m, and 7-11 measuring points should be set up in one monitoring section.

[0270] The monitoring method for tunnel boring machine (TBM) construction in this embodiment of the invention further includes: suspending three steel wires, which, together with the observation platforms above and below ground, form two straight triangles on a plane; the ratio of the length of the triangle to the length of the short side is at least 2.5 times, and the angles in the triangle are less than 2°; a plumb bob is suspended from the end of the steel wire, immersed in an oil drum filled with oil, and the plumb bob must not contact the oil drum; the measurement data is divided into two groups, each group including one azimuth position above ground, four connecting angles, and five side lengths; when solving the triangles, the azimuth position below ground and the coordinates of the control points below ground are calculated using simple adjustment based on the condition of triangle closure error; the azimuth and coordinates of the other group of data are calculated in the same way, and then checked against the first group to ensure that no errors occur.

[0271] Shield tunneling involves disturbing the soil, causing ground heave and settlement due to soil compression, loss, and consolidation. This is related to factors such as: the balance pressure within the shield's sealing chamber; the excavation speed; the shield's attitude; the dragging effect of the shield's outer shell; the sealing degree of the segment lining joints; construction gaps; tunnel lining deformation; soil consolidation and secondary consolidation settlement; and the settling and shrinkage settlement of the grouting material. Furthermore, monitoring must consider the shield construction design and the surrounding environment, with a focus on the following factors:

[0272] (1) Shield tunneling depth and soil layers penetrated, estimate the possible range and extent of disturbance impact;

[0273] (2) The structural characteristics of the buildings (structures) that are traversed by the shield tunnel and adjacent buildings (structures), drainage culverts and pile foundations, and their distance relationship with the tunnel;

[0274] (3) The distribution and characteristics of pipelines adjacent to shield tunneling construction;

[0275] (4) During tunnel construction, soil deformation and vertical displacement monitoring of the ground, as well as deformation monitoring of ground buildings, structures and underground pipelines, should be carried out. Appropriate measures should be taken to ensure that ground settlement is controlled within the prescribed range and to ensure the safety of roads, pipelines and buildings.

[0276] The monitoring items are: vertical and horizontal displacement monitoring of underground integrated pipelines; vertical displacement, tilt and crack monitoring of surrounding buildings and structures; settlement monitoring of shield tunnels and surface settlement profiles along the route; tunnel convergence monitoring; and internal displacement of soil.

[0277] Convergence deformation was measured using a convergence meter (TCRA1200 series total station, if available). Two convergence measurement hooks were installed on each side of the upper and lower sections of the tunnel annulus. When installing the measuring points, a hole slightly larger than the diameter of the expansion bolt was first drilled at the measuring point location using an impact drill. Then, the expansion bolt with a threaded hole at the top was tightened, and finally, one end of the stainless steel hook was screwed into the expansion bolt. Before testing, the ambient temperature must be read for temperature correction. The temperature correction formula is as follows:

[0278] ΔL C =K×ΔT×L

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

[0280] K is the correction factor (12*10⁻⁶ mm / ℃ for this instrument).

[0281] ΔT is the difference between the current temperature and the initial temperature (°C).

[0282] L is the distance between the two measuring points in this reading (mm).

[0283] In high temperatures and severe winters, after entering the tunnel, the convergence meter should be kept stable for at least 15 minutes. When testing the distance between any two points, at least three consecutive readings must be taken, and the average value is used as the current reading. The difference between the current convergence value (after temperature correction) and the previous convergence value is the change in convergence. The symbol "+" indicates elongation, and the symbol "-" indicates shortening. The following is a schematic diagram of the convergence monitoring point profile, where A, B, C, and D are monitoring points. During the convergence test, the convergence meter is used to measure the distances along the six sides AB, AC, BD, BC, BD, and CD. Figure 8 This is a schematic diagram of a test using an SL-2 type steel ruler convergence meter according to an embodiment of the present invention.

[0284] Harmful gases such as methane may exist in the soil layers of the project. To ensure the smooth progress of this project, it is necessary to conduct intensive monitoring of harmful gases in the soil. An abnormal gas detector will be installed at the exit of the tunnel boring machine, and an alarm will be triggered immediately upon detection of any abnormal gas. The monitoring items for tunnel construction in this embodiment are summarized in the table below:

[0285]

[0286] To monitor the degree and extent of the impact on the surrounding ground surface during tunnel construction, surface settlement profile monitoring points need to be set up for vertical displacement monitoring. The specific setup is as follows:

[0287] Ground settlement monitoring points are generally laid out along the axis, with a spacing of 4-5m. The spacing is appropriately increased when entering or exiting tunnels or encountering important buildings. Settlement trough observation sections are set up at certain intervals (about 30m). When crossing important buildings or pipeline groups, additional settlement trough observation sections are set up. On hard ground, measurement marks are set up using nails or road spikes, and on soft soil ground, steel piles are used as measurement marks.

[0288] Within the initial 100m section of the tunnel boring machine (TBM), a monitoring section is set up every 20 meters; in other sections, a monitoring section is set up every 30 meters. The interval between measuring points on the cross section is generally 2-5m, and 7-11 measuring points should be set up within one monitoring section. After the site is opened, surface settlement monitoring points along the line will be set up according to the actual conditions of the section.

[0289] Convergence monitoring sections will be set up inside the tunnel. It is planned to set convergence sections on the tunnel structure of the left and right lines at intervals of 10m. The convergence sections and settlement points will be on the same cross section.

[0290] To make the setting of tunnel boring machine propulsion parameters more scientific and accurate, a monitoring information exchange and communication network was established on site to ultimately control ground subsidence.

[0291] Due to varying geological conditions, ground loads, and other factors, the earth pressure in front of the cutterhead will differ, necessitating timely adjustments. Simultaneously, settlement reports should be analyzed, adjustments made promptly, and feedback relayed to the propulsion team. If ground settlement occurs before the shield cutterhead, the balance pressure setting should be increased; conversely, it should be decreased. If ground settlement occurs behind the shield tail, the synchronous grouting volume should be increased; conversely, it should be decreased.

[0292] The amount of excavated soil is reasonably controlled based on the construction gap between the tunnel boring machine and the segments and the characteristics of each soil layer. The control is based on the settlement monitoring data along the line, and the most reasonable value is found through analysis and adjustment.

[0293] Controlling the advance speed to ensure balanced and uniform tunneling reduces the shield's deflection on the soil, thereby controlling ground deformation.

[0294] During tunnel boring machine (TBM) advancement, other grouting pipelines are simultaneously activated based on actual conditions. Strict control is maintained over the synchronous grouting volume and grout quality. Synchronous grouting promptly fills voids in the structure, reducing soil deformation during construction. The synchronous grouting volume is generally 140%-200% of the void space. Because gaps may exist in the grout used for synchronous grouting during TBM advancement, and the shrinkage and deformation of the grout pose a risk of ground settlement, secondary backwall grouting is performed when necessary. Grout is injected into the stratum through the grouting holes in the tunnel segments. During construction, advancement and grouting are linked; if grouting does not meet requirements, TBM advancement is paused to prevent soil deformation. Based on deformation monitoring during construction, the grouting volume and parameters are adjusted continuously. Secondary backwall grouting is adjusted as needed based on ground monitoring data to stabilize ground deformation.

[0295] Each measurement result is promptly summarized and sent to the construction technology department so that construction technicians can understand the current construction status and pipeline deformation in the corresponding areas, determine new construction parameters and grouting volumes, and transmit information and instructions to the tunnel boring machine (TBM) face for timely adjustments. Finally, the effectiveness is confirmed through monitoring, and this process of repeated iteration, verification, and improvement ensures the quality of tunnel construction.

[0296] To ensure the safety of the tunnel structure and surrounding environment, structural and environmental monitoring should be strengthened, and information-based management should be implemented to ensure timely feedback of monitoring data and guide construction. For excavation of soil reinforced by the freezing method, in addition to monitoring convergence deformation, preventative monitoring of frozen soil temperature should also be conducted to understand the development status of the frozen soil and provide early warnings for construction safety. The construction surveying and monitoring content includes: 1. Monitoring of freezing pipe drilling construction: drilling length, length of frozen pipe laid, monitoring of freezing pipe deviation, sealing performance of freezing equipment, and length of liquid supply pipe laid; 2. Monitoring of freezing system: temperature of brine returning to freezing equipment, temperature of cooling circulating water inlet and outlet, working pressure of brine pump, suction and exhaust pressure of chiller, condensing pressure of refrigeration system, and vaporization pressure of refrigeration system; 3. Monitoring of frozen wall: temperature of temperature measuring holes on the inner and outer sides of frozen wall, monitoring of pressure relief holes of frozen wall, temperature of frozen wall well sides after excavation, and monitoring of frost heave pressure; 4. Monitoring of main tunnel and connecting passage structure: deformation monitoring of support structure and structures, and tunnel deformation monitoring (radial deformation of tunnel section <15mm; horizontal and vertical displacement ≤10mm).

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

[0298] 1. The temperature of the brine in the return loop of the freezing system is monitored by installing temperature sensors on the pipelines and integrating them into a computer monitoring system.

[0299] 2. To assess the freezing effect of the frozen soil curtain, temperature sensors are installed in the temperature measurement holes and pressure sensors are installed in the pressure relief holes. This data is also collected and managed by a computer monitoring system.

[0300] 3. For monitoring the structural deformation of the tunnel, monitoring points are set up on the segments within a 30-meter range of the connecting passage, and total stations and precision levels are used to measure the deformation and settlement of the plane and elevation.

[0301] 4. For other routine monitoring items, monitoring data should be collected in a timely manner in accordance with the specifications, and recorded and summarized.

[0302] A crucial task during construction is controlling the horizontal plane and correcting the tunnel boring machine's (TBM) axis using the connecting triangle geometric orientation method between the surface and underground sections. During construction, several orientation measurements are conducted for each section, typically the first around 150-200 meters into the tunnel, and the last approximately 100 meters from the entrance. The connecting triangle orientation uses three steel wires to transmit coordinates and orientation. In practice, these three wires are suspended, forming two straight triangles on the horizontal plane with the observation platforms above and below ground. A side view diagram is shown below. Figure 10 As shown.

[0303] When setting up the triangle, the ratio of the longer side to the shorter side should be at least 2.5 times, while the ratio of a to b should not exceed 1.5 times. Points O2 and O3 should not be too close to the instrument. Angle α in the triangle should be less than 2°. A plumb bob should be suspended from the end of the wire. To prevent the wire from swaying and affecting observation, the plumb bob should be immersed in an oil drum filled with oil, ensuring that the plumb bob does not touch the oil drum. During observation, the connecting angles above and below ground and the connecting triangles require two 2-second total stations to measure the sides in both directions. Nine rounds of angle measurement are required, with a zeroing observation and a round-trip difference ≤ 9″ (difference between the maximum and minimum angles), a 2C difference ≤ 13″ (difference between the upright and inverted mirrors), and a zeroing difference ≤ 6″. Four upright and four inverted mirror measurements are required for each side measurement, and the difference between the average observations should be less than 3mm. For measuring the side lengths of the connecting triangles, reflectors are attached to a steel wire, and the side lengths are measured using the opposite-side mode. Three independent measurements are taken each time, with the difference between these three measurements ≤ 3mm. Temperatures above and below ground are considered during side measurement, and side length corrections are calculated. The measurement data are divided into two groups, each including one azimuth, four connecting angles, and five side lengths. When solving the triangle, the conditions for triangle closure error are used, and simple adjustment is employed to calculate the azimuth and coordinates of the control points below ground. Then, the same calculation is performed on the other group of data, and the azimuth and coordinates are checked against the first group to ensure no errors occur.

[0304] The results of each independent orientation measurement should meet the following requirements: azimuth difference ≤ 12″, position difference ≤ 20mm.

[0305] Simultaneously with geometric orientation, the underground control traverse should be verified. Underground surveying traverses, used to control tunnel horizontal deviations, are mainly divided into underground control traverses and underground construction traverses. The underground construction traverses, with lower precision and shorter side lengths, serve as general working traverses. The underground control traverses, serving as the primary control during construction, are longer and more precise, accurately guiding the excavation direction. They should be re-measured synchronously with each geometric orientation, recalculating the traverse points, and transmitting the obtained orientation azimuth to the newly installed surveying station inside the tunnel to correct any deviations in the construction traverses. Figure 9 This is a schematic diagram of the layout of traverse points inside the tunnel according to an embodiment of the present invention. During observation, the instrument should be forced to center, and the measurement specifications should follow the same rules as those for surface surveying.

[0306] The purpose of shaft elevation transfer is to transmit the ground elevation to the bottom of the shaft. During elevation transfer, a steel tape with a tension of 49N (used for verification) is suspended, and two levels are used simultaneously above and below the shaft to transfer the elevation to a fixed point below. A total of three measurements are taken, with the instrument height adjusted each time. The difference between the three measurements of the ground and underground leveling points should be less than 3mm.

[0307] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for waterproofing during tunnel boring machine (TBM) construction, comprising: A sealing device is installed around the hole ring, the sealing device consisting of a rubber curtain belt, a ring plate, and a flap plate; Set up grouting holes for waterproofing and sealing the opening, and pre-embed grouting pipes around the opening; If water or soil leakage is confirmed during the tunnel boring machine's exit construction, a dual-component grout will be injected through the grouting pipe to seal and waterproof the area. The shield tunneling construction includes the following steps: The shield tunneling base is hoisted into the shaft according to the baseline laid out by surveying. During the placement of the shield tunneling base, it is ensured to be consistent with the axis of the exit section. The center lines of the two tracks are aligned with the center of the shield on the base and are consistent with the reverse extension line of the tunnel design axis. After the shield tunneling base is in place, a steel rear shield support is added between the last negative ring and the shaft wall structure. Deformation observation points are set on the steel rear shield support. Initially, measurements are taken after each box of soil is advanced. Once the deformation of the steel rear shield support is relatively stable, measurements are taken for each ring until the steel rear shield support is stable before observation can be stopped. After verifying and measuring the location of the tunnel entrance, based on the analysis of ground monitoring information, the concrete of the tunnel entrance was removed in sections in a grid pattern, and the positions of the sections were marked. Before removing the tunnel entrance, the concrete at the joints of the sections was removed, and the lifting points for each section were prepared. as well as After the tunnel boring machine enters the tunnel ring as a whole, grouting is carried out simultaneously.

2. The method for waterproofing shield tunneling construction according to claim 1, characterized in that, Also includes: After the tunnel boring machine (TBM) is commissioned, apply grease evenly and densely between the tail steel brushes to fill the grease chambers of the tail brushes.

3. The method for waterproofing shield tunneling construction according to claim 1, characterized in that, Also includes: An elastic sealing gasket is provided around the perimeter of the tube segment rib surface; wherein, the elastic sealing gasket is made of water-swellable rubber material.

4. The method for waterproofing tunnel boring machine (TBM) construction according to claim 1, wherein the TBM construction further includes: Two guide rails are placed inside the tunnel and at the point where the 70cm groove wall is removed. The guide rails extend to the shield base and are integrated with the two guide rails on the base. The installation angle and position should follow the rails on the shield base.

5. A monitoring method for tunnel boring machine (TBM) construction, characterized in that, include: A temporary point is set at the bottom of the well. The transverse diameter and planar coordinates of the portal ring are measured based on the temporary point. The planar center coordinates of the portal ring are then calculated, and the planar deviation value of the portal ring is calculated. Using the temporary leveling point transferred to the bottom of the well, measure the bottom elevation and top elevation of the portal ring, and calculate the ring diameter and elevation deviation. The coordinates of the portal ring center, the front center of the shield base, and the rear center of the shield base were calculated, and the values ​​of these coordinates were measured using instruments. The deviations between these coordinate values ​​and the theoretical values ​​were also calculated. The plane position of the base was adjusted based on these deviations. The shield tunneling construction includes the following steps: The shield tunneling base is hoisted into the shaft according to the baseline laid out by surveying. During the placement of the shield tunneling base, it is ensured to be consistent with the axis of the exit section. The center lines of the two tracks are aligned with the center of the shield on the base and are consistent with the reverse extension line of the tunnel design axis. After the shield tunneling base is in place, a steel rear shield support is added between the last negative ring and the shaft wall structure. Deformation observation points are set on the steel rear shield support. Initially, measurements are taken after each box of soil is advanced. Once the deformation of the steel rear shield support is relatively stable, measurements are taken for each ring until the steel rear shield support is stable before observation can be stopped. After verifying and measuring the location of the tunnel entrance, based on the analysis of ground monitoring information, the concrete of the tunnel entrance was removed in sections in a grid pattern, and the positions of the sections were marked. Before removing the tunnel entrance, the concrete at the joints of the sections was removed, and the lifting points for each section were prepared. as well as After the tunnel boring machine enters the tunnel ring as a whole, grouting is carried out simultaneously.

6. The monitoring method for tunnel boring machine construction according to claim 5, characterized in that, Also includes: A stainless steel plate is attached to each side of the middle of the crack. A round hole is drilled in the center of the plate. When the plate is installed, the line connecting the round holes is perpendicular to the crack. A mark is also made at each end of the crack to observe the development of the crack. Plaster sheets are placed at both ends of the crack, and the plaster sheets are firmly bonded to both sides of the crack.

7. The monitoring method for shield tunneling construction according to claim 5, characterized in that, Also includes: An abnormal gas monitor is installed at the exit of the tunnel boring machine to monitor abnormal gases.

8. The monitoring method for tunnel boring machine construction according to claim 5, characterized in that, Also includes: Ground settlement measuring points are set up along the tunnel axis, and settlement trough observation sections are set up at certain intervals. When passing through important buildings and pipeline groups, additional settlement trough observation sections are set up. On hard ground, nails or road spikes are used to set up measurement marks, and on soft ground, steel piles are used as measurement marks. Within 100m of the shield tunneling starting section, a monitoring section is set up every 20 meters; in other sections, a monitoring section is set up every 30 meters; the interval between measuring points on the monitoring section is 2-5m, and 7-11 measuring points should be set up in one monitoring section.

9. The monitoring method for tunnel boring machine (TBM) construction according to claim 5, wherein the TBM construction further includes: Two guide rails are placed inside the tunnel and at the point where the 70cm groove wall is removed. The guide rails extend to the shield base and are integrated with the two guide rails on the base. The installation angle and position should follow the rails on the shield base.

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