Shield tunnel segment reinforcing steel ring construction method

Abstract

The invention provides a shield tunnel segment reinforcing steel ring construction method, which comprises the following steps: carrying out on-site lofting in a tunnel, carrying out three-dimensional scanning to determine a shield segment lining cambered surface contour point cloud model, and modeling and designing data parameters of a steel ring according to the model; the steel ring is designed and divided into seven component steel plates to be machined, and anchor bolt open holes are formed in each component steel plate. Before the steel ring is reinforced, pipeline rearrangement is completed, and the types and the number of pipelines and equipment involved in the rearrangement range are investigated; the drainage ditch in the tunnel is cut and chiseled away, a steel ring and a corresponding steel pulling plate are installed, and grouting treatment is conducted after fixed welding installation; and after steel ring construction is completed, drainage ditch recovery construction is conducted according to design requirements. According to the construction method, space is saved, line invasion influences are avoided, driving risks are avoided, tunnel diseases such as large horizontal convergence deformation and serious cracks of the shield tunnel segment can be efficiently and rapidly eliminated, meanwhile, the posture of the shield tunnel segment can be kept consistent with the posture of an existing shield tunnel segment, and the normal use function of a shield tunnel is not affected.

Description

Technical Field

[0001] The present invention relates to the technical field of subway shield tunnel segment reinforcement, and in particular to a shield tunnel segment reinforcement steel ring construction method. Background Art

[0002] Since the rise of the subway industry, urban underground rail transit has crisscrossed the city. As surrounding cities continue to regenerate, the surrounding environment has been disturbed to varying degrees, leading to varying degrees of deterioration in subway tunnels and damage to some tunnel segments. Currently, the primary approach to addressing cracking in tunnel strain gauges in China is to attach vertical steel frames to the inner walls of shield segments as internal supports to reinforce and mitigate the exacerbation of tunnel deterioration.

[0003] Existing reinforcement technology not only reduces the internal space of the shield tunnel, creating the risk of line intrusion and affecting driving, but also involves more internal operations in the shield tunnel, a longer construction period, and many other risks such as increased deformation. Summary of the Invention

[0004] In view of this, the present invention proposes a method for constructing a steel ring for reinforcing a shield tunnel segment, comprising:

[0005] Cross-section measurement, on-site layout in the tunnel, 3D scanning to determine the point cloud model of the shield segment lining arc contour, and based on this, model and design the data parameters of the steel ring;

[0006] Steel ring processing: The steel ring is designed to be divided into seven component steel plates for processing, and anchor holes are set on each component steel plate;

[0007] Pipeline relocation: Complete pipeline relocation before steel ring reinforcement, and investigate the types and quantities of pipelines and equipment involved in the relocation;

[0008] The steel ring is installed, the drainage ditch in the tunnel is cut and chiseled, the steel ring and the corresponding steel pull plate are installed, fixed and welded, and then grouting is carried out.

[0009] After the pipeline is restored and the steel ring construction is completed, the drainage ditch restoration construction will be carried out in accordance with the design requirements.

[0010] Furthermore, when building a model based on the point cloud model, the misalignment relationship and out-of-roundness between the shield segments are simulated, and the curvature radius of each steel ring is designed accordingly.

[0011] Furthermore, when measuring the cross section, two cross sections were taken from each ring at a distance of 40 cm from the ring seams on both sides, located at 0.4 m and 1.1 m respectively.

[0012] Furthermore, when the steel ring is processed, grouting holes are evenly added in the circumferential direction in the middle of each component steel plate.

[0013] Furthermore, the anchor holes are arranged in three rows in the longitudinal direction on each component steel plate, and are 80mm to 100mm away from the edge of the component steel plate; the circumferential direction is adjusted according to the block size specifications, the openings are 100mm away from the weld edge, and the maximum distance is 280mm to 333mm.

[0014] Furthermore, the steel ring installation includes:

[0015] Cut and chisel out the drainage ditches on both sides of the roadbed, cut and chisel out the ditches to a depth perpendicular to the shield segments, and roughen the sides of the roadbed after cutting;

[0016] During the installation of the steel ring, the corbels are installed first, followed by the adjacent and capping steel plates.

[0017] Steel pull plate installation, each steel ring is equipped with at least one steel pull plate;

[0018] Chemical anchor bolt installation: drilling and cleaning the hole, then gluing and installing the chemical anchor bolt;

[0019] After the steel rings are welded, the steel tie rods are installed, the brackets, adjacent and capping steel ring components and the steel tie rods on the roadbed are all installed, the steel ring components are integrally welded and the welds are treated with anti-corrosion.

[0020] Filling behind the steel ring: After the steel ring is welded into a ring and anti-corrosion treatment is carried out, the back filling operation must be carried out immediately. The steel ring is sealed with epoxy putty, and grouting holes are reserved for epoxy resin injection filling.

[0021] Furthermore, the steel ring construction and installation includes:

[0022] Installation of the corbel: The corbel is processed and transported to the site, hoisted into place, and temporarily fixed to the pipe segment with expansion bolts;

[0023] Installation of steel plates for adjacent and capping components:

[0024] 1) Loft the steel plate on site according to the installation conditions of the corbel. Install the adjacent steel plates first, then loft and install the steel plates of the capping components.

[0025] 2) Hoist the adjacent component steel plates and the capping component steel plates into place;

[0026] 3) After the adjacent and capping steel plates are hoisted into place, they are temporarily fixed with expansion bolts, which are arranged at the four corners and the middle, with 8 bolts above the arch and 6 bolts below the arch. The effective anchoring depth is greater than or equal to 125mm;

[0027] 4) The gap between the component steel plate and the shield segment is less than or equal to 20mm.

[0028] Furthermore, the installation of the chemical anchor bolt includes:

[0029] 1) Drilling, drilling diameter and hole depth are controlled within the preset range;

[0030] 2) Clean the hole. After drilling, blow the hole clean, starting from the deep end of the hole, and clean it at least 3 times until no dust is blown out of the hole. Then brush the hole wall 3 times to remove the loose concrete residue in the hole wall, and blow the hole clean again.

[0031] 3) Glueing: put the anchoring glue into the glue gun sleeve, cut the glue injection nozzle, install the mixed glue injection nozzle on the anchoring glue, install the glue gun sleeve into the glue gun, insert the retaining ring into the cleaned anchor hole, and push the glue gun into the root of the anchor hole to inject glue.

[0032] Furthermore, the steel ring welding and steel rod installation include:

[0033] 1) After the brackets, adjacent and capping steel plates and steel bars on the roadbed are all installed, the steel plates are welded as a whole, and the welds are all groove welded;

[0034] 2) Divide the weld into 5 sections, first weld sections 1, 3, and 5, and then weld sections 2 and 4 to complete the weld.

[0035] 3) Weld inspection: first inspect the appearance, then conduct ultrasonic non-destructive testing, and keep corresponding records;

[0036] 4) Steel ring anti-corrosion: The steel ring and pull rod are sprayed with polyurea elastomer for anti-corrosion before entering the site.

[0037] Furthermore, the back filling of the steel ring includes:

[0038] 1) When installing the steel ring, reserve grouting pipes and air outlet holes, arrange grouting holes in a plum blossom pattern on both sides of the steel ring, and add a grouting hole in the middle of the steel ring;

[0039] 2) Grouting epoxy resin should be carried out from bottom to top in multiple times until the resin overflows from the upper reserved hole to ensure dense filling;

[0040] 3) When using a one-way water-stop reverse pressure ring grouting nozzle, the grouting pressure should be controlled between 0.1 and 0.2 MPa. Stop pressurizing after slurry appears in the exhaust pores. Seal the exhaust pores with epoxy putty and then maintain a lower pressure for 10 minutes before ending.

[0041] The shield tunnel segment reinforcement steel ring construction method provided by the present invention has the following advantages: the present invention adopts steel rings instead of previous reinforcement methods, and can design appropriate steel rings according to the current status of existing shield segments in subway tunnels, which not only saves space, but also does not cause line invasion and avoids driving risks. It can efficiently and quickly eliminate tunnel diseases such as large horizontal convergence deformation and serious cracks of shield tunnel segments, and at the same time maintain consistency with the posture of existing shield tunnel segments, without affecting the normal use function of the shield tunnel and taking up shield tunnel space. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0043] Figure 1 A schematic diagram of a construction method according to an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the structure of a cross-sectional measurement scan provided by an embodiment of the present invention;

[0045] Figure 3 A schematic structural diagram of a steel ring provided in an embodiment of the present invention;

[0046] Figure 4 A schematic structural diagram of a steel ring provided in an embodiment of the present invention divided into seven components;

[0047] Figure 5 Schematic diagram of the structure of the reinforced steel plate assembly provided by the embodiment of the present invention

[0048] Figure 6 A schematic structural diagram of a steel ring cross section provided in an embodiment of the present invention

[0049] Figure 7 Schematic diagram of the structure of the weld and groove provided by the embodiment of the present invention

[0050] Figure 8 Schematic diagram of the structure of the chemical anchor bolt provided by the embodiment of the present invention

[0051] Figure 9 Schematic diagram of the large-scale structure of the corbel provided by the embodiment of the present invention

[0052] Figure 10 Schematic diagram of the structure of the pipeline rearrangement in the tunnel provided by the embodiment of the present invention Figure 1 ;

[0053] Figure 11A schematic diagram of the structure of a bilaterally symmetrical steel bracket provided by an embodiment of the present invention, anchored by bolts;

[0054] Figure 12 A schematic diagram of the structure of the bilaterally symmetrical side wall anchor bolts, steel plates, capping steel plates, and steel plate walls filled with epoxy resin provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, unless there is a conflict, the embodiments of the present disclosure and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0056] See also Figure 1-12 As shown, a shield tunnel segment reinforcement steel ring construction method provided by an embodiment of the present invention includes:

[0057] Cross-section measurement, on-site layout in the tunnel, 3D scanning to determine the point cloud model of the shield segment lining arc contour, and based on this, model and design the data parameters of the steel ring;

[0058] Steel ring processing: The steel ring is designed to be divided into seven component steel plates for processing, and anchor holes are set on each component steel plate;

[0059] Pipeline relocation: Complete pipeline relocation before steel ring reinforcement, and investigate the types and quantities of pipelines and equipment involved in the relocation;

[0060] The steel ring is installed, the drainage ditch in the tunnel is cut and chiseled, the steel ring and the corresponding steel pull plate are installed, fixed and welded, and then grouting is carried out.

[0061] After the pipeline is restored and the steel ring construction is completed, the drainage ditch restoration construction will be carried out in accordance with the design requirements.

[0062] Furthermore, when building a model based on the point cloud model, the misalignment relationship and out-of-roundness between the shield segments are simulated, and the curvature radius of each steel ring is designed accordingly.

[0063] Furthermore, when measuring the cross section, two cross sections were taken from each ring at a distance of 40 cm from the ring seams on both sides, located at 0.4 m and 1.1 m respectively.

[0064] Furthermore, when the steel ring is processed, grouting holes are evenly added in the circumferential direction in the middle of each component steel plate.

[0065] Furthermore, the anchor holes are arranged in three rows in the longitudinal direction on each component steel plate, and are 80mm to 100mm away from the edge of the component steel plate; the circumferential direction is adjusted according to the block size specifications, the openings are 100mm away from the weld edge, and the maximum distance is 280mm to 333mm.

[0066] Furthermore, the steel ring installation includes:

[0067] Cut and chisel out the drainage ditches on both sides of the roadbed, cut and chisel out the ditches to a depth perpendicular to the shield segments, and roughen the sides of the roadbed after cutting;

[0068] During the installation of the steel ring, the corbels are installed first, followed by the adjacent and capping steel plates.

[0069] Steel pull plate installation, each steel ring is equipped with at least one steel pull plate;

[0070] Chemical anchor bolt installation: drilling and cleaning the hole, then gluing and installing the chemical anchor bolt;

[0071] After the steel rings are welded, the steel tie rods are installed, the brackets, adjacent and capping steel ring components and the steel tie rods on the roadbed are all installed, the steel ring components are integrally welded and the welds are treated with anti-corrosion.

[0072] Filling behind the steel ring: After the steel ring is welded into a ring and anti-corrosion treatment is carried out, the back filling operation must be carried out immediately. The steel ring is sealed with epoxy putty, and grouting holes are reserved for epoxy resin injection filling.

[0073] Furthermore, the steel ring construction and installation includes:

[0074] Installation of the corbel: The corbel is processed and transported to the site, hoisted into place, and temporarily fixed to the pipe segment with expansion bolts;

[0075] Installation of steel plates for adjacent and capping components:

[0076] 1) Loft the steel plate on site according to the installation conditions of the corbel. Install the adjacent steel plates first, then loft and install the steel plates of the capping components.

[0077] 2) Hoist the adjacent component steel plates and the capping component steel plates into place;

[0078] 3) After the adjacent and capping steel plates are hoisted into place, they are temporarily fixed with expansion bolts, which are arranged at the four corners and the middle, with 8 bolts above the arch and 6 bolts below the arch. The effective anchoring depth is greater than or equal to 125mm;

[0079] 4) The gap between the component steel plate and the shield segment is less than or equal to 20mm.

[0080] Furthermore, the installation of the chemical anchor bolt includes:

[0081] 1) Drilling, drilling diameter and hole depth are controlled within the preset range;

[0082] 2) Clean the hole. After drilling, blow the hole clean, starting from the deep end of the hole, and clean it at least 3 times until no dust is blown out of the hole. Then brush the hole wall 3 times to remove the loose concrete residue in the hole wall, and blow the hole clean again.

[0083] 3) Glueing: put the anchoring glue into the glue gun sleeve, cut the glue injection nozzle, install the mixed glue injection nozzle on the anchoring glue, install the glue gun sleeve into the glue gun, insert the retaining ring into the cleaned anchor hole, and push the glue gun into the root of the anchor hole to inject glue.

[0084] Furthermore, the steel ring welding and steel rod installation include:

[0085] 1) After the brackets, adjacent and capping steel plates and steel bars on the roadbed are all installed, the steel plates are welded as a whole, and the welds are all groove welded;

[0086] 2) Divide the weld into 5 sections, first weld sections 1, 3, and 5, and then weld sections 2 and 4 to complete the weld.

[0087] 3) Weld inspection: first inspect the appearance, then conduct ultrasonic non-destructive testing, and keep corresponding records;

[0088] 4) Steel ring anti-corrosion: The steel ring and pull rod are sprayed with polyurea elastomer for anti-corrosion before entering the site.

[0089] Furthermore, the back filling of the steel ring includes:

[0090] 1) When installing the steel ring, reserve grouting pipes and air outlet holes, arrange grouting holes in a plum blossom pattern on both sides of the steel ring, and add a grouting hole in the middle of the steel ring;

[0091] 2) Grouting epoxy resin should be carried out from bottom to top in multiple times until the resin overflows from the upper reserved hole to ensure dense filling;

[0092] 3) When using a one-way water-stop reverse pressure ring grouting nozzle, the grouting pressure should be controlled between 0.1 and 0.2 MPa. Stop pressurizing after slurry appears in the exhaust pores. Seal the exhaust pores with epoxy putty and then maintain a lower pressure for 10 minutes before ending.

[0093] An embodiment of the present invention provides a preferred construction method, referring to Figure 1-12 As shown below:

[0094] Step 1: Cross-section measurement, 3D scanning

[0095] Reference Figure 2As shown, the specific size of the steel ring needs to be determined based on the on-site layout of each ring. The pipe segment to be equipped with the steel ring is scanned in three dimensions to form a point cloud model of the arc surface contour of the pipe segment lining. Then, modeling is performed based on the point cloud model to simulate the misalignment relationship and out-of-roundness between the pipe segments. The curvature radius of each steel ring is designed based on the modeled pipe segment, and the distance from the busbar to the arch is measured to ensure that the steel ring maintains a safe insulation distance from the contact network after installation.

[0096] Two sections were taken from each ring at 40 cm from the annular seam on both sides, located at 0.4 m and 1.1 m respectively, for use in making the steel ring model. During the processing, construction errors were taken into account, and the tolerance for the steel lining processing dimensions was ±2 mm.

[0097] Step 2: Steel ring processing

[0098] 2.1 Position and Block

[0099] Reference Figure 3-4 As shown, the steel ring plate is 1.2m wide (1.5m for shield segments) and 30mm thick. The steel ring is bent from Q355 steel plate. A single ring design consists of seven components joined together, secured to the segments with chemical anchors. The ring is groove welded, and the contact surface is sandblasted (shot treated), achieving a friction coefficient of 0.45.

[0100] 2.2 Layout of reserved holes in steel plates

[0101] Reference Figure 6 As shown, the anchor holes are 25mm in diameter, with three rows in the longitudinal direction and a distance of 80mm to 100mm from the edge of the steel plate. The circumferential direction is adjusted according to the size of the block, with the hole distance from the weld edge being 100mm, and the maximum distance between 280mm and 333mm.

[0102] Grouting holes with a diameter of 14 mm are evenly added in the middle of the divided steel plates in an circumferential direction, including 3 holes in block one, 6 holes in block two, 4 holes each in blocks three, four and five, 3 holes in block six and 2 holes in block seven.

[0103] Step 3: Pipeline Rerouting

[0104] Before formally carrying out steel ring reinforcement, the pipeline rearrangement should be completed first, and the types and quantities of pipelines and equipment involved in the rearrangement should be fully investigated; the pipelines mainly involved are pipeline supports, overhead ground wire cables, fire water pipes, fire fighting facilities, signs and signs, high and low voltage, monitoring facilities, etc. Other special equipment such as video surveillance, monitoring prisms, total stations, etc. are also included.

[0105] Step 4: Steel ring installation

[0106] 4.1 Cutting and chiseling of drainage ditches

[0107] To minimize the impact of construction on existing line equipment and facilities, only the ditches on both sides of the trackbed will be cut and chiseled out to a depth perpendicular to the shield segments. The sides of the trackbed will be roughened after cutting. Damage to the sleepers and tracks is strictly prohibited.

[0108] After the drainage ditch is chiseled and cleaned, the gap between the pipe segment and the roadbed needs to be grouted.

[0109] 4.2 Steel ring installation and construction

[0110] Before formally reinforcing the steel ring, the damaged segments within the steel ring are checked and counted, and the damaged segments are repaired. This mainly involves repairing damage, cracks, caulking the longitudinal joints of the segments, and performing handhole and grouting treatments.

[0111] 1. Corbel installation

[0112] 1) According to the track bed cutting size, the corbels are processed after on-site setting out, refer to Figure 9 、 11 , as shown in 12;

[0113] 2) Use a special flatbed truck to transport it to the site and use a monorail beam to hoist the bracket into place;

[0114] 3) The corbel is temporarily fixed to the pipe segment using two 125mm M16 bottom-expanded expansion bolts embedded in concrete.

[0115] 2. Installation of adjacent and capping steel plates

[0116] 1) Loft, process adjacent and capping steel plates on site according to the installation conditions of the corbel (install adjacent steel plates first and then loft, process and install capping steel plates);

[0117] 2) Use a special flatbed truck to transport it to the site, and use a robotic arm to lift the adjacent and capping steel plates into place;

[0118] 3) After the adjacent and capping steel plates are hoisted into place, temporary fastening shall be performed using 8.8-grade M16 expanded-bottom expansion bolts. These bolts shall be placed at the four corners and in the middle, with eight bolts above the arch and six bolts below the arch. The effective anchorage depth shall be no less than 125 mm. Main reinforcement, segment joints, and pipelines shall be avoided. (For temporary fastening force calculations, see Chapter 9 Force Calculations.)

[0119] 4) The gap between the steel plate and the segment should not exceed 20mm. If there are any problems such as segment misalignment, adjustments can be made based on the actual situation on site. In principle, the gap between the steel plate and the segment should be minimized as much as possible.

[0120] 4.3 Steel plate installation

[0121] 1) The cross section of each pull plate is 20mm×100mm, and the length is determined according to on-site layout.

[0122] 2) Each steel ring should be equipped with at least one pull plate. If the deviation between a single pull plate and the center of the steel corbel is greater than 100mm, two pull plates should be installed, and the total area of ​​the pull plates should not be less than 3000mm. 2 .

[0123] 4.4 Chemical anchor installation

[0124] Reference Figure 8 As shown, bolt installation holes are reserved on the surface of the steel plate lining for installing chemical anchor bolts. Chemical anchor bolts should avoid controlled and longitudinal joints, with a minimum margin of 150mm. If the chemical anchor bolt collides with the steel bars of the pipe segment, the bolt position can be adjusted appropriately, with an adjustment distance of no more than 50mm. The anchor bolts use special inverted cone adhesive anchor bolts with a diameter of 16mm. The anchor bolt adhesive should comply with the "Code for Design of Reinforcement of Concrete Structures" (GB50367-2013). The anchor bolts use grade 8.8, the anchoring depth is not less than 16cm, and the anchor bolt length is calculated as 25cm. The anchoring must meet the monitoring requirements of relevant specifications. The construction department adjusts the length according to the gap between the steel ring and the pipe segment, but the anchoring depth must be met. The length of the steel plate at the capping block should ensure that there are at least two rows of anchor bolts with a total of 6 anchors at the position overlapped on the two adjacent blocks.

[0125] (1) Drilling: The drilling diameter is 18 mm, the hole depth is 160 mm, and the drill rod length is not more than 250 mm.

[0126] (2) Hole cleaning: After drilling, clean the hole three times with an air blower, starting from the deep end of the hole and continuing for at least three times until no more dust is blown out of the hole. Then, brush the hole wall three times with a steel brush to remove the loose concrete residue inside the hole wall. The brush diameter should be the same as the hole diameter. Clean the hole again with an air blower three times.

[0127] (3) Gluing:

[0128] ①Put the anchoring glue into the glue gun sleeve (do not use the anchoring glue with damaged packaging or unclean glue gun sleeve).

[0129] ② Cut the injection nozzle (including the extension tube) approximately 10mm shorter than the drilled hole depth to ensure injection can be performed from the very top of the anchor hole. Also, wrap tape around the base of the injection nozzle to ensure it is large enough to block the anchor hole. Do not cut into the mixer area.

[0130] ③Install the mixed glue injection nozzle on the anchoring glue.

[0131] ④Insert the glue gun sleeve into the glue gun.

[0132] ⑤ Discard the anchoring colloid that flows out from the first three times the trigger is pulled.

[0133] ⑥ Insert the retaining ring into the cleaned anchor hole.

[0134] ⑦ Push the glue gun into the root of the anchor hole to inject glue, keep the glue gun still until no more glue can be injected, and ensure that the glue fills the anchor hole.

[0135] ⑧Wrap the exposed part of the screw below the burial depth line with paper or tape in advance to prevent the flowing colloid from sticking to the screw and causing the nut to be unable to be screwed on.

[0136] ⑨ Press the retaining ring into the glue injection hole by hand and remove the glue injection gun.

[0137] 4.5 Steel ring welding and steel tie rod installation

[0138] 1) After the brackets, adjacent and capping steel plates and steel tie bars on the roadbed are all installed, the steel plates are welded as a whole to ensure that a good force-bearing whole is formed to play a role in strengthening and supporting the tunnel; all welds are groove welded and gas shielded welded, and the weld grade is level 2.

[0139] 2) Due to the excessive length of the weld, to prevent deformation, the weld should be welded in five sections. First, weld sections 1, 3, and 5, then weld sections 2 and 4 to complete the weld. Each section should be welded three times. Multi-layer welding should be performed continuously. After each weld pass, clean the weld slag and surface spatter promptly. If defects that affect weld quality are found, remove them before re-welding. If welding is interrupted, appropriate post-heating and insulation measures should be implemented. The re-preheat temperature should be higher than the initial preheat temperature when welding again.

[0140] 3) Weld inspection

[0141] First, the appearance is inspected. Defects such as incomplete welds, root shrinkage, undercuts, and poor joints are not allowed. Surface defects such as pores, slag inclusions, cracks, and arc scratches are also not allowed. Finally, if the appearance is qualified, ultrasonic non-destructive testing is performed and the corresponding records are kept.

[0142] 4) Steel ring anti-corrosion

[0143] Before delivery, the steel rings and tie bars are treated with a spray-coated polyurea elastomer (SPUR) for corrosion protection. The steel surface is sandblasted or shot-blasted to Sa2.5, with a surface roughness of Rz40-70μm. Then, one coat of epoxy zinc-rich primer is applied, followed by two coats of epoxy micaceous iron intermediate. After curing, three coats of chlorinated rubber topcoat are applied. The coating thickness is uniform, with a firm and tight bond. Defects such as peeling, cracking, holes, and loose joints are not permitted. The back of the steel is not treated for corrosion, only for rust removal. Welds require additional corrosion protection.

[0144] According to process requirements, steel rings were prefabricated in the factory and shipped to the site after painting. The steel plates were welded together to ensure a well-balanced structure, providing support for the tunnel. All welds were groove welded using gas shielded arc welding, achieving a Class II weld grade.

[0145] 4.6 Filling behind the steel ring

[0146] After the steel ring is welded into a ring and anti-corrosion treatment is carried out, the back filling operation must be carried out immediately. The steel ring is sealed with epoxy putty, and grouting holes are reserved for epoxy resin injection filling.

[0147] (1) When installing the steel ring, reserve grouting pipes and vents. Grouting holes are arranged in a plum blossom pattern on both sides of the steel ring, and a φ14mm grouting hole is added in the middle of the steel ring. The number of holes varies from 2 to 6 depending on the size of the steel plate. Before grouting, first use epoxy putty to seal both sides of the steel ring to prevent a large amount of epoxy resin from being lost.

[0148] (2) Use a mobile flat plate to set up a movable working platform, and use a small electric grouting pump to inject epoxy resin. The grouting should be carried out from bottom to top in multiple times until the resin overflows from the upper reserved hole to ensure dense filling.

[0149] (3) When using a one-way water-stop reverse pressure ring grouting nozzle, the grouting pressure is controlled between 0.1 and 0.2 MPa. Stop pressurizing after slurry appears in the exhaust pores. Seal the exhaust pores with epoxy putty and then maintain a lower pressure for 10 minutes before ending.

[0150] Step 5: Pipeline recovery

[0151] (1) Permanently restore the original drainage pipelines in the tunnel according to design requirements.

[0152] (2) After the steel ring construction is completed, the drainage ditch restoration construction shall be carried out in accordance with the design requirements.

[0153] To sum up, the shield tunnel segment reinforcement steel ring construction method provided by the embodiment of the present invention has the following interesting technical effects: the present invention adopts steel rings instead of previous reinforcement methods, and can design suitable steel rings according to the current status of existing shield segments in subway tunnels, which not only saves space, but also does not cause line invasion and avoid driving risks. It can efficiently and quickly eliminate tunnel diseases such as large horizontal convergence deformation and serious cracks of shield tunnel segments, and at the same time maintain consistency with the posture of existing shield tunnel segments, without affecting the normal use function of the shield tunnel and taking up shield tunnel space.

[0154] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0155] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0156] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for constructing a steel ring for reinforcing a shield tunnel segment, characterized in that: include: Cross-section measurement, on-site layout in the tunnel, 3D scanning to determine the point cloud model of the shield segment lining arc contour, and based on this, model and design the data parameters of the steel ring; Steel ring processing: The steel ring is designed to be divided into seven component steel plates for processing, and anchor holes are set on each component steel plate; Pipeline relocation: Complete pipeline relocation before steel ring reinforcement, and investigate the types and quantities of pipelines and equipment involved in the relocation; Installation of steel rings: Cut and chisel out the drainage ditch in the tunnel, install the steel rings and corresponding steel pull plates, fix and weld them, and then perform grouting. After the pipeline is restored and the steel ring construction is completed, the drainage ditch restoration construction will be carried out in accordance with the design requirements.

2. The shield tunnel segment reinforcement steel ring construction method according to claim 1 is characterized in that: When modeling based on the point cloud model, the misalignment relationship and out-of-roundness between the shield segments are simulated, and the curvature radius of each steel ring is designed accordingly.

3. The shield tunnel segment reinforcement steel ring construction method according to claim 1, characterized in that: When measuring the cross section, two cross sections were taken from each ring at a distance of 40 cm from the ring seams on both sides, located at 0.4 m and 1.1 m respectively.

4. The shield tunnel segment reinforcement steel ring construction method according to claim 1, characterized in that: When the steel ring is processed, grouting holes are evenly added in the circumferential direction in the middle of each component steel plate.

5. The shield tunnel segment reinforcement steel ring construction method according to claim 1 is characterized in that: The anchor holes are arranged in three rows in the longitudinal direction on each component steel plate, and are 80mm to 100mm away from the edge of the component steel plate; the circumferential direction is adjusted according to the block size specifications, the openings are 100mm away from the weld edge, and the maximum distance is 280mm to 333mm.

6. The shield tunnel segment reinforcement steel ring construction method according to claim 1, characterized in that: The steel ring installation includes: Cut and chisel out the drainage ditches on both sides of the roadbed, cut and chisel out the ditches to a depth perpendicular to the shield segments, and roughen the sides of the roadbed after cutting; During the installation of the steel ring, the corbels are installed first, followed by the adjacent and capping steel plates. Steel pull plate installation, each steel ring is equipped with at least one steel pull plate; Chemical anchor bolt installation: drilling and cleaning the hole, then gluing and installing the chemical anchor bolt; After the steel rings are welded, the steel tie rods are installed, the brackets, adjacent and capping steel ring components and the steel tie rods on the roadbed are all installed, the steel ring components are integrally welded and the welds are treated with anti-corrosion. Filling behind the steel ring: After the steel ring is welded into a ring and anti-corrosion treatment is carried out, the back filling operation must be carried out immediately. The steel ring is sealed with epoxy putty, and grouting holes are reserved for epoxy resin injection filling.

7. The shield tunnel segment reinforcement steel ring construction method according to claim 6, characterized in that: The steel ring construction and installation includes: Corbel installation: The processed corbel is transported to the site, hoisted into place, and temporarily fixed to the pipe segment with expansion bolts; Installation of steel plates for adjacent and capping components: 1) Loft the steel plate on site according to the installation conditions of the corbel. Install the adjacent steel plates first, then loft and install the steel plates of the capping components. 2) Hoist the adjacent component steel plates and the capping component steel plates into place; 3) After the adjacent and capping steel plates are hoisted into place, they are temporarily fixed with expansion bolts, which are arranged at the four corners and the middle, with 8 bolts above the arch and 6 bolts below the arch. The effective anchoring depth is greater than or equal to 125mm; 4) The gap between the component steel plate and the shield segment is less than or equal to 20mm.

8. The shield tunnel segment reinforcement steel ring construction method according to claim 6, characterized in that: The installation of the chemical anchor bolt includes: 1) Drilling, drilling diameter and hole depth are controlled within the preset range; 2) Clean the hole. After drilling, blow the hole clean, starting from the deep end of the hole, and clean it at least 3 times until no dust is blown out of the hole. Then brush the hole wall 3 times to remove the loose concrete residue in the hole wall, and blow the hole clean again. 3) Glueing: put the anchoring glue into the glue gun sleeve, cut the glue injection nozzle, install the mixed glue injection nozzle on the anchoring glue, install the glue gun sleeve into the glue gun, insert the retaining ring into the cleaned anchor hole, and push the glue gun into the root of the anchor hole to inject glue.

9. The shield tunnel segment reinforcement steel ring construction method according to claim 6, characterized in that: The steel ring welding and steel tie rod installation include: 1) After the brackets, adjacent and capping steel plates and steel bars on the roadbed are all installed, the steel plates are welded as a whole, and the welds are all groove welded; 2) Divide the weld into 5 sections, first weld sections 1, 3, and 5, and then weld sections 2 and 4 to complete the weld. 3) Weld inspection: first inspect the appearance, then conduct ultrasonic non-destructive testing, and keep corresponding records; 4) Steel ring anti-corrosion: The surface of the steel ring and the pull rod is sprayed with polyurea elastomer for anti-corrosion before entering the site.

10. The shield tunnel segment reinforcement steel ring construction method according to claim 6, characterized in that: The back filling of the steel ring includes: 1) When installing the steel ring, reserve grouting pipes and air outlet holes, arrange grouting holes in a plum blossom pattern on both sides of the steel ring, and add a grouting hole in the middle of the steel ring; 2) Grouting epoxy resin should be carried out from bottom to top in multiple times until the resin overflows from the upper reserved hole to ensure dense filling; 3) When using a one-way water-stop reverse pressure ring grouting nozzle, the grouting pressure should be controlled between 0.1 and 0.2 MPa. Stop pressurizing after slurry appears in the exhaust pores. Seal the exhaust pores with epoxy putty and then maintain a lower pressure for 10 minutes before ending.

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