A method for repairing a tunnel in a section of vault collapse

Abstract

The application provides a tunnel repair method for a vault collapse section, which comprises the following steps: removing the dangerous top of the collapse cavity, spraying concrete on the inner wall of the collapse cavity, applying a first temporary support structure to the existing tunnel primary support in the non-collapse section in front of and behind the collapse section, tamping the collapse body below the collapse cavity, spraying concrete on the collapse body to seal, erecting a second temporary support structure and an inclined support assembly on both sides of the collapse cavity, applying a permanent support structure to seal the collapse cavity, inserting an anchor rod through a reserved hole, applying an arch protection layer and a buffer layer, removing the second temporary support structure and the inclined support assembly, cleaning the collapse cavity and the existing primary support I-beam joint, repairing the primary support according to the original design, removing the first temporary support structure, cleaning the collapse body, and completing the construction of the collapse section. The application greatly improves the safety, convenience and economy of the vault collapse section repair.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel, in particular to a tunnel repair method for vault collapse section. BACKGROUND

[0002] The collapse phenomenon often occurs in the tunnel construction process. According to the diversity and complexity of the engineering geological environment of the tunnel, the types of collapse are various. After the initial support is completed, the collapse phenomenon is prone to occur under the action of various disturbances and surrounding rock stress with the passage of time, which causes damage to the initial support at local positions and produces a collapse cavity. In particular, when the groundwater of the tunnel is relatively developed and the fissure water of the surrounding rock is not effectively and sufficiently discharged, it will further affect the stability of the surrounding rock and cause safety hazards to the construction of the tunnel.

[0003] Generally speaking, for the tunnel repair of the vault collapse section of the initial support section in the tunnel, the conventional method is to spray concrete in the collapse cavity after the collapse cavity is stable, to remove the damaged I-beam in the full section, to improve the lining support parameters, to expand the chamber, to re-construct the I-beam arch, to close the collapse opening with a formwork on the top surface of the steel frame, to spray concrete on the steel frame to form the initial support, to reserve a grouting pipe at the collapse opening, to form a C25 concrete arch by grouting through the reserved grouting pipe after the treatment is completed, to backfill the arch with sand blowing or foam concrete, and to adjust the lining type to adopt a higher protection level of lining structure type to ensure the construction safety of the tunnel collapse section.

[0004] However, the premise of this repair method is to wait for the collapse cavity to reach a stable state before construction, otherwise the safety of the workers and equipment cannot be guaranteed (the workers and equipment are exposed below the collapse cavity before the arch construction), which further increases the construction period, delays the construction progress, and indirectly increases the construction cost. In addition, the higher protection level of lining structure type excessively considers safety and ignores construction convenience and period. That is, if a higher level of lining type is adopted, the full section of the initial support including the undamaged initial support needs to be removed, and the surrounding rock needs to be expanded, which is extremely inconvenient for construction, increases the construction risk, and also increases the cost of the tunnel collapse treatment.

[0005] Therefore, it is necessary to provide a tunnel repair method for vault collapse section to solve or at least alleviate the above-mentioned defects. SUMMARY

[0006] The main purpose of the present application is to provide a tunnel repair method for vault collapse section to solve the technical problems that the workers and equipment face great safety risks in the existing repair method, and the safety is excessively considered and the construction convenience is ignored.

[0007] To achieve the above-mentioned purpose, the present application provides a tunnel repair method for vault collapse section, comprising the following steps:

[0008] S1, clear the top of the collapse cavity and spray concrete on the inner wall of the collapse cavity;

[0009] S2, in the non-collapsed section located in front of and behind the collapsed section, respectively, a first temporary support structure is applied to support the existing tunnel primary support, so as to ensure the stability of the non-collapsed section;

[0010] S3, tamp the collapsed body located below the collapse cavity, and then spray concrete on the collapsed body to close it, so as to ensure the stability of the collapsed body;

[0011] S4, a second temporary support structure for supporting the primary support of the existing tunnel and a diagonal support assembly for supporting the corresponding second temporary support structure are respectively erected on both sides of the collapse cavity; wherein the second temporary support structure comprises a first end and a second end oppositely arranged along the extension direction thereof, the first end is overlapped on the tunnel spring foot, and the second end extends from the first end to the boundary of the collapse cavity along the circumferential direction of the tunnel and is connected with the high end of the diagonal support assembly, and the low end of the diagonal support assembly is supported on the collapsed body;

[0012] S5, a permanent support structure is applied to close the collapse cavity; wherein the permanent support structure is connected with the corresponding second temporary support structure on both sides along the circumferential direction of the tunnel, the permanent support structure is connected with the corresponding first temporary support structure on both ends along the extension direction of the tunnel, the permanent support structure is provided with a reserved hole for the anchor rod to pass through, a first grouting hole for the first grouting pipe to pass through, and a second grouting hole for the second grouting pipe to pass through, and the length of the second grouting pipe is greater than that of the first grouting pipe;

[0013] S6, the anchor rod is driven through the reserved hole, the first grouting pipe is applied through the first grouting hole and concrete is injected into the collapse cavity, so as to form an arch protection layer on the top of the permanent support structure, and then the second grouting pipe is applied through the second grouting hole and foam concrete is pumped into the collapse cavity, so as to form a buffer layer on the top of the arch protection layer;

[0014] S7, after the arch protection layer is formed and the strength is stable, the second temporary support structure and the diagonal support assembly are removed, the collapse cavity and the existing primary support I-beam interface are cleaned, and the primary support is repaired according to the original design;

[0015] S8, the first temporary support structure is removed, and the collapsed body is cleaned to complete the construction of the collapsed section.

[0016] Preferably, the step S3 further comprises the steps of: cleaning out longitudinal working platforms on both sides of the collapse body and laying channel steel extending along the tunnel extension direction on the longitudinal working platforms before the concrete sealing is sprayed on the collapse body.

[0017] Preferably, the step S6 of forming the arch layer on the top of the permanent support structure by the first grouting pipe and injecting concrete into the collapse cavity comprises the steps of: forming the first grouting pipe and injecting concrete into the collapse cavity through the first grouting hole, and taking the ungrouted first grouting pipe and the second grouting hole as the air outlet pipe of the first grouting pipe during grouting; wherein the grouting speed is controlled at 50-150 L / min, and the grouting pressure is controlled at 0.5-1.5 MPa.

[0018] Preferably, the step S7 of repairing the initial support according to the original design comprises the steps of:

[0019] The damaged steel arch section and the original steel mesh corresponding to the collapse section are cut off, and then a new steel arch section and a new steel mesh are constructed; wherein the two ends of each new steel arch section are connected with the existing undamaged steel arch section, the end of each new steel mesh in the tunnel extension direction is connected to the new steel arch section, and the new steel mesh is supplemented with C25 concrete.

[0020] Preferably, the first temporary support structure is a first corrugated steel plate, and the permanent support structure is a second corrugated steel plate, wherein,

[0021] The first corrugated steel plate comprises a first corrugated steel plate body, a first connecting plate and a second connecting plate connected to the boundary of the first corrugated steel plate body, the first connecting plate is protruded on the inner wall of the first corrugated steel plate body, and the second connecting plate is connected to the bottom outer wall of the first connecting plate, and the first connecting plate and the second connecting plate form an L-shaped connecting plate.

[0022] The second corrugated steel plate comprises a second corrugated steel plate body, a third connecting plate and a fourth connecting plate connected to the boundary of the second corrugated steel plate body, the third connecting plate is protruded on the inner wall of the second corrugated steel plate body, and the fourth connecting plate is connected to the bottom outer wall of the third connecting plate, and the third connecting plate and the fourth connecting plate form an L-shaped connecting plate.

[0023] The first connecting plate and the third connecting plate are connected, and the second connecting plate and the fourth connecting plate are connected.

[0024] Preferably, the first connecting plate is provided with a first long waist slot hole for the bolt to pass through, the third connecting plate is provided with a second long waist slot hole corresponding to the first long waist slot hole, the second connecting plate is provided with a third long waist slot hole for the bolt to pass through, the fourth connecting plate is provided with a fourth long waist slot hole corresponding to the third long waist slot hole, the first connecting plate is connected with the third connecting plate by the bolt passing through the first long waist slot hole and the second long waist slot hole, and the second connecting plate is connected with the fourth connecting plate by the bolt passing through the third long waist slot hole and the fourth long waist slot hole.

[0025] Preferably, the permanent support structure is a third corrugated steel plate, and a wave distance of the third corrugated steel plate corresponds to a longitudinal distance of the initial support steel arch.

[0026] Preferably, the second temporary support structure is a fourth corrugated steel plate, the fourth corrugated steel plate comprises a fourth corrugated steel plate body, a fifth connecting plate and a sixth connecting plate connected at the boundary of the fourth corrugated steel plate body, the fifth connecting plate is protruded on the inner wall of the fourth corrugated steel plate body, the sixth connecting plate is connected at the bottom outer wall of the fifth connecting plate, and the fifth connecting plate and the sixth connecting plate form an L-shaped connecting plate; wherein the third connecting plate is connected with the fifth connecting plate, and the fourth connecting plate is connected with the sixth connecting plate.

[0027] Preferably, the length of the first corrugated steel plate along the longitudinal direction of the tunnel is 8-12 m.

[0028] Preferably, the thickness of the arch protection layer is 0.9-1.5 m, and the arch protection layer is 2-4 m.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The application provides a tunnel repair method for a vault collapse section, through erecting a second temporary support structure and an inclined strut assembly, the overall stability and bearing capacity of the tunnel structure can be effectively enhanced, and the stress burden of the existing tunnel initial support is reduced; further spread of the collapse to the non-collapsed section can be effectively prevented, and the safety of the tunnel construction is ensured. Meanwhile, favorable conditions are provided for subsequent treatment and repair work (for example, a connecting foundation for the permanent support structure); the permanent support structure is effectively constructed to block the collapse cavity, prevent further expansion of the collapse, ensure the safety of the construction personnel and equipment below, and also provides a locking foundation for the anchor rod, a penetrating foundation for the first and second grouting pipes, and can be used as a template for the construction of the arch protection layer, reduces the engineering cost, and the permanent support structure is connected with the second temporary support structure in the circumferential direction to form a complete arch ring, and is connected with the first temporary support structure in the longitudinal direction to form a strong overall support system with the anchor rod, which greatly improves the safety during construction, and can permanently participate in stress bearing in the later period as a tunnel lining structure;

[0031] In addition, the application does not need to demolish the full-face initial support, only needs to demolish the damaged steel arch, the application can use a corrugated steel plate and an I-beam combined structure to make a temporary support structure, which can be quickly assembled, the remaining parts are connected by bolts, is convenient to assemble and disassemble, improves work efficiency, ensures the convenience of construction, saves engineering cost, and has a good popularization prospect. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can be obtained from the structures shown in the drawings without creative labor.

[0033] Figure 1 A flowchart of the tunnel repair method in an embodiment of the application;

[0034] Figure 2 A schematic view of the vault collapse in a tunnel in an embodiment of the application;

[0035] Figure 3 A schematic view of the structure after the longitudinal working platform is cleaned in an embodiment of the application;

[0036] Figure 4 A schematic view of the structure before the arch protection layer and the buffer layer are constructed in an embodiment of the application;

[0037] Figure 5 A schematic view of the structure after the arch protection layer and the buffer layer are constructed in an embodiment of the application;

[0038] Figure 6 Connection diagram of the permanent support structure and the first temporary support structure in an embodiment of the present application;

[0039] Figure 7 Structure diagram of the first connecting plate in an embodiment of the present application;

[0040] Figure 8 Connection diagram of the permanent support structure and the second temporary support structure in an embodiment of the present application;

[0041] Figure 9 Connection diagram of the second temporary support structure and the diagonal bracing assembly in an embodiment of the present application.

[0042] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings.

[0043] Explanation of the reference signs:

[0044] 10, collapse cavity; 110, collapse cavity opening; 210, first corrugated steel plate; 211, first corrugated steel plate body; 212, first connecting plate; 213, second connecting plate; 214, first long waist slot hole; 215, bolt; 30, collapse body; 310, longitudinal working platform; 320, channel steel; 40, existing tunnel initial support; 410, initial support steel arch; 510, fourth corrugated steel plate; 511, fourth corrugated steel plate body; 512, fifth connecting plate; 513, sixth connecting plate; 520, first end; 530, second end; 60, diagonal bracing assembly; 70, permanent support structure; 710, second corrugated steel plate; 711, second corrugated steel plate body; 712, third connecting plate; 713, fourth connecting plate; 810, first grouting pipe; 820, second grouting pipe; 830, arch protection layer; 840, buffer layer. DETAILED DESCRIPTION

[0045] It should be understood that the specific embodiments described herein are merely exemplary and do not limit the present application.

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0047] It should be noted that all direction indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the direction indications also change accordingly.

[0048] In addition, the description of "right part", "middle part" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance thereof or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "right part" and "middle part" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but must be based on the realization of a person skilled in the art, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0049] Please refer to the accompanying Figures 1 to 9 The tunnel repair method of the present application provides an embodiment of a vault collapse section, which comprises the following steps:

[0050] S1, the top of the collapse cavity 10 is cleared, and the inner wall of the collapse cavity 10 is sprayed with concrete; specifically, the operation is carried out according to the clearing scheme, and the loose rocks and unstable structures on the top of the collapse cavity 10 are removed by manual or mechanical means. During the operation, the changes on the top of the collapse cavity 10 should be observed at any time, and once abnormal conditions are found, the operation should be stopped immediately and the site should be evacuated. In order to ensure the spraying effect, in a preferred example, C25 concrete is used for initial spraying to ensure the stability of the collapse cavity 10, so as to ensure the safety during the treatment construction.

[0051] S2, the first temporary support structure (not marked in the figure) for supporting the existing tunnel primary support 40 is applied to the non-collapse section located in front of and behind the collapse section, respectively, to ensure the stability of the non-collapse section; as a preferred example, the first temporary support structure uses corrugated steel plate, the corrugated steel plate is transported to the work site, and in the non-collapse section 10m in front of and behind the collapse section, 8mm thick 400mm*150mm corrugated steel plate is used to form a temporary support structure, which is closely attached to the tunnel primary support, so as to ensure the stability of the adjacent section of the collapse section and reduce the impact of repairing the collapse section on the adjacent non-collapse section as much as possible.

[0052] S3, compacting the collapse body 30 below the collapse cavity 10, and then spraying concrete to seal the collapse body 30 to ensure the stability of the collapse body 30; the compaction operation can significantly improve the compactness of the collapse body 30, thereby enhancing the stability of the collapse body 30 and preventing further collapse or sliding of the collapse body 30; spraying concrete to seal the surface of the collapse body 30 can provide a safer working environment for the construction personnel. Specifically, the collapse body 30 on both sides of the collapse opening can be compacted, a working platform can be cleaned, and C25 concrete can be sprayed on the collapse body 30 to ensure the stability of the collapse body 30.

[0053] S4, erecting a second temporary support structure (not shown in the figure) for supporting the existing tunnel primary support 40 and a diagonal strut assembly 60 for supporting the corresponding second temporary support structure on both sides of the collapse cavity opening 110; the second temporary support structure includes a first end 520 and a second end 530 arranged opposite to each other along the extension direction of the second temporary support structure, the first end 520 is overlapped on the tunnel spring foot, and the second end 530 extends from the first end 520 to the boundary of the collapse cavity opening 110 along the circumferential direction of the tunnel and is connected with the high end of the diagonal strut assembly 60, and the low end of the diagonal strut assembly 60 is supported on the collapse body 30;

[0054] Specifically, as shown in Figure 4 the second temporary support structure can be made of rigid materials such as I-shaped steel or steel pipes, and extends along the circumferential direction of the tunnel, one end is overlapped on the tunnel spring foot, and the other end extends to the boundary of the collapse cavity opening 110; the second temporary support structure is closely combined with the existing tunnel primary support 40 to form an effective support system; by erecting the second temporary support structure and the diagonal strut assembly 60, the overall stability and bearing capacity of the tunnel structure can be effectively enhanced, and the stress burden of the existing tunnel primary support 40 is reduced; further spread of the collapse to the non-collapsed section can be effectively prevented, and the safety of the tunnel construction is ensured. At the same time, favorable conditions are provided for subsequent treatment and repair work (for example, providing a connection base for the permanent support structure 70).

[0055] As a preferred example, within the range from the boundary of the collapse opening on both sides of the collapse section to the tunnel spring foot, a 8mm-thick 400mm*150mm corrugated steel plate temporary support structure is erected, one side of which is overlapped on the tunnel spring foot, and the other side is supported by an I20 I-shaped steel, one end of the I-shaped steel can be connected with the corrugated steel plate through a pad, and the other end is supported on the collapse body 30.

[0056] S5, the permanent support structure 70 is applied to seal the cavity opening 110; wherein the permanent support structure 70 is connected with the corresponding second temporary support structure along the two sides of the tunnel in the circumferential direction, and the permanent support structure 70 is connected with the corresponding first temporary support structure along the two ends of the tunnel in the extension direction, the permanent support structure 70 is provided with a reserved hole (not shown in the figure) for the anchor rod to pass through, a first grouting hole (not shown in the figure) for the first grouting pipe 810 to pass through, and a second grouting hole (not shown in the figure) for the second grouting pipe 820 to pass through, the length of the second grouting pipe 820 is greater than that of the first grouting pipe 810;

[0057] Specifically, the application of the permanent support structure 70 effectively seals the cavity opening 110, prevents the further expansion of the collapse, ensures the safety of the construction personnel and equipment below, and also provides a locking foundation for the anchor rod, a passing-through foundation for the first grouting pipe 810 and the second grouting pipe 820, and can serve as a template for the application of the arch protection layer 830, thereby reducing the engineering cost. The permanent support structure 70 is connected with the second temporary support structure in the circumferential direction to form a complete arch ring, and is connected with the first temporary support structure in the longitudinal direction, thereby forming a strong overall support system with the anchor rod, greatly improving the safety during construction, and participating in stress bearing as a permanent tunnel lining structure in the later period. On both sides of the tunnel in the circumferential direction, the permanent support structure 70 is reliably connected with the corresponding second temporary support structure, which is usually achieved by welding, bolt connection or other means to ensure firm connection. For easy disassembly, bolt connection is preferably adopted. One end of the anchor rod is anchored into the surrounding rock, and the other end is locked on the permanent support structure 70 to provide sufficient anchoring force.

[0058] As a preferred example, the collapse opening range is sealed by a 1cm thick 500mm*400mm corrugated steel plate, and the 500mm*400mm corrugated steel plate is connected with a 400mm*150mm corrugated steel plate around. The specification of the corrugated steel plate can be 8mm thick 400mm*150mm. The corrugated steel plate for sealing the collapse opening should have a wave distance corresponding to the spacing of the initial support steel arch 410, for example, if the initial support is a 26cm thick I20 I-shaped steel, the spacing of the I-shaped steel is 50cm, then the wave distance of the corrugated steel plate is 50cm, for example Figure 6 As shown.

[0059] S6, the anchor rod is driven through the reserved hole (not shown in the figure), the first grouting pipe 810 is applied through the first grouting hole, and concrete is injected into the cavity 10 to form an arch protection layer 830 on the top of the permanent support structure 70, and then the second grouting pipe 820 is applied through the second grouting hole and foamed concrete is pumped into the cavity 10 to form a buffer layer 840 on the top of the arch protection layer 830;

[0060] Specifically, the anchor rod is obliquely inserted at an angle of 15° to enhance stability; the grouting pipe is installed at the position of the first grouting hole, and the sealing between the grouting pipe and the hole wall is ensured; the concrete is prepared according to the design requirements, and the strength, fluidity and other indicators of the concrete are ensured to meet the construction requirements; the grouting equipment is started, and the concrete is injected into the collapsed cavity 10 through the grouting pipe; the grouting pressure and the grouting amount need to be controlled during the grouting process to ensure that the concrete can uniformly and densely fill the space of the collapsed cavity 10; as the concrete is injected and solidified, a layer of solid arch protection layer 830 is gradually formed on the top of the permanent support structure 70; this layer of arch protection layer 830 can effectively disperse and bear the pressure of the overlying rock-soil mass, thereby improving the stability of the tunnel structure; the grouting pipe is installed at the position of the second grouting hole; since the length of the second grouting pipe 820 is greater than that of the first grouting pipe 810, the second grouting pipe 820 can penetrate into a higher collapsed cavity 10 area; the foam concrete is prepared according to the design requirements. The foam concrete has the advantages of light weight, high strength, heat preservation and insulation, etc., and is suitable for being used as the buffer layer 840 material; the pumping equipment is started, and the foam concrete is pumped into the collapsed cavity 10 through the grouting pipe. The pumping speed and the pumping amount need to be controlled during the pumping process to ensure that the foam concrete can uniformly and densely fill the space of the collapsed cavity 10; as the foam concrete is pumped and solidified, a layer of light buffer layer 840 is gradually formed on the top of the arch protection layer 830. This layer of buffer layer 840 can effectively absorb and disperse the impact energy of the overlying rock-soil mass, thereby further improving the stability and safety of the tunnel structure; preferably, C25 concrete is injected to form a 1m-thick arch protection layer 830, and then foam concrete is pumped to form a 3m-thick buffer layer 840.

[0061] As a preferred embodiment, the step S6 of injecting the concrete through the first grouting hole to form the arch protection layer 830 on the top of the permanent support structure 70 specifically includes the steps of: injecting the concrete through the first grouting hole and the first grouting pipe 810 and the second grouting hole into the collapsed cavity 10, while the first grouting pipe 810 and the second grouting hole that are not used for grouting serve as the air outlet pipe for the first grouting pipe 810 during the grouting process; wherein the grouting speed is controlled at 50-150 L / min, and the grouting pressure is controlled at 0.5-1.5 MPa. Similarly, the second grouting hole that is not used for grouting serves as the air vent during the grouting of the second grouting hole, and the air vent is used to discharge air and bleeding water during the concrete pouring process.

[0062] Preferably, the height of the first grouting pipe 810 above the arch protection layer 830 is set to be 10-20 cm, and the height of the second grouting hole above the buffer layer 840 is set to be 10-20 cm; when the grouting height of the arch protection layer 830 reaches the height of the first grouting pipe 810, the grouting pressure will increase accordingly, which can be used as a judgment for the end of grouting; similarly, when the grouting height of the buffer layer 840 reaches the height of the second grouting pipe 820, the grouting pressure will increase accordingly, which can be used as a judgment for the end of grouting.

[0063] S7, after the arch protection layer 830 is formed and stable in strength, the second temporary support structure and the inclined support assembly 60 are removed, the collapsed cavity opening 110 and the existing initial support I-beam interface are cleaned, and the initial support is repaired according to the original design;

[0064] As a preferred embodiment, the step S7 of repairing the initial support according to the original design specifically includes the steps of cutting off the damaged steel arch section corresponding to the collapsed section and the original steel mesh, and then newly applying a new steel arch section and a new steel mesh; wherein the two ends of each new steel arch section are respectively connected with the existing undamaged steel arch section, the end of each new steel mesh extending along the tunnel direction is connected on the new steel arch section, and the new steel mesh is supplemented with C25 concrete.

[0065] By cutting off the damaged part and newly applying a new steel arch section and a steel mesh, the repaired initial support structure is more complete and stable. The firm connection of the new steel arch section with the existing steel arch section and the laying and concrete spraying of the new steel mesh together improve the overall strength and stability of the support structure, which can better resist the surrounding rock pressure and groundwater pressure. The repaired initial support provides a strong guarantee for subsequent construction. In the subsequent secondary lining, drainage system and other constructions, it can be carried out more smoothly, reducing the construction difficulties and quality problems caused by the support structure problems.

[0066] As a preferred example, after the arch protection is formed and stable in strength, the collapsed opening range 500mm*400mm corrugated steel plate is removed, the collapsed opening and the original initial support I-beam interface are cleaned, and the initial support is repaired according to the original design, the damaged I-beam in the initial support is replaced, the steel mesh is hung, the C25 concrete is supplemented, and if water seeps out of the collapsed cavity 10, a drainage pipe is reserved in the initial support for drainage.

[0067] S8, the first temporary support structure is removed, and the collapsed body 30 is cleaned to complete the construction of the collapsed section.

[0068] As a preferred embodiment, the step S3 further includes the steps of cleaning out longitudinal working platforms 310 on both sides of the collapsed body 30 and laying channel steels 320 extending along the tunnel direction on the longitudinal working platforms 310 before the collapsed body 30 is sprayed with concrete to seal.

[0069] This embodiment provides a stable support foundation for the inclined support assembly 60 by setting longitudinal working platforms 310 on both sides of the collapsed body 30 and laying channel steels 320, effectively enhancing the stability of the inclined support assembly 60, preventing it from shifting or collapsing during construction, and thus ensuring the stability of the entire support structure.

[0070] As a preferred embodiment, the first temporary support structure is a first corrugated steel plate 210, and the permanent support structure 70 is a second corrugated steel plate 710, wherein the first corrugated steel plate 210 comprises a first corrugated steel plate body 211, a first connecting plate 212 connected to the boundary of the first corrugated steel plate body 211, and a second connecting plate 213 connected to the boundary of the first corrugated steel plate body 211, the first connecting plate 212 is protruded on the inner wall of the first corrugated steel plate body 211, and the second connecting plate 213 is connected to the bottom outer wall of the first connecting plate 212, and the first connecting plate 212 and the second connecting plate 213 form an L-shaped connecting plate.

[0071] The second corrugated steel plate 710 comprises a second corrugated steel plate body 711, a third connecting plate 712 connected to the boundary of the second corrugated steel plate body 711, and a fourth connecting plate 713 connected to the boundary of the second corrugated steel plate body 711, the third connecting plate 712 is protruded on the inner wall of the second corrugated steel plate body 711, and the fourth connecting plate 713 is connected to the bottom outer wall of the third connecting plate 712, and the third connecting plate 712 and the fourth connecting plate 713 form an L-shaped connecting plate; wherein the first connecting plate 212 and the third connecting plate 712 are connected, and the second connecting plate 213 and the fourth connecting plate 713 are connected.

[0072] Specifically, the connection of the plugging and collapsing corrugated steel plate and other corrugated steel plates should consider grouting sealing and installation errors, therefore, in the design, the L-shaped steel plate is used as the flange plate at the connection of the corrugated steel plates, a single-side open screw hole is provided at the bottom edge of the L-shaped steel plate during connection, the flange plate of the plugging corrugated steel plate is wrapped outside the bottom edge of the flange plate of the other corrugated steel plate, and then the bolt 215 is tightened. The design of the L-shaped connecting plate significantly enhances the connection strength between the first corrugated steel plate 210 and the second corrugated steel plate 710 by increasing the connection area and providing additional support points. The design of the L-shaped connecting plate makes the installation process of the first corrugated steel plate 210 and the second corrugated steel plate 710 more convenient and fast, and reduces the installation time and labor cost. The first corrugated steel plate 210 as a temporary support structure provides preliminary stability during the tunnel construction process.

[0073] Preferably, the third connecting plate 712 needs to be designed to be lengthened, so that the initial support repair space can be reserved, and after the plugging corrugated steel plate is removed, the cleaning work of the initial support interface can be reduced, and the initial support repair is facilitated.

[0074] As another preferred embodiment, the first connecting plate 212 is provided with a first long slot hole 214 through which the bolt 215 passes, the third connecting plate 712 is provided with a second long slot hole (not shown in the figure) corresponding to the first long slot hole 214, the second connecting plate 213 is provided with a third long slot hole (not shown in the figure) through which the bolt 215 passes, and the fourth connecting plate 713 is provided with a fourth long slot hole (not shown in the figure) corresponding to the third long slot hole. The first connecting plate 212 is connected to the third connecting plate 712 by the bolt 215 passing through the first long slot hole 214 and the second long slot hole, and the second connecting plate 213 is connected to the fourth connecting plate 713 by the bolt 215 passing through the third long slot hole and the fourth long slot hole.

[0075] The design of the long slot hole allows for some adjustment space when the bolt 215 passes through, and the position of the connecting plate can be fine-tuned as needed during installation to ensure accurate alignment and tight connection between them. Once the position is adjusted, tightening the bolt 215 can achieve a firm fastening effect, ensuring the overall stability of the support structure.

[0076] Further, the second temporary support structure is a fourth corrugated steel plate 510, which includes a fourth corrugated steel plate body 511, a fifth connecting plate 512 connected to the boundary of the fourth corrugated steel plate body 511, and a sixth connecting plate 513 connected to the fifth connecting plate 512. The fifth connecting plate 512 is protruded on the inner wall of the fourth corrugated steel plate body 511, and the sixth connecting plate 513 is connected to the bottom outer wall of the fifth connecting plate 512. The fifth connecting plate 512 and the sixth connecting plate 513 form an L-shaped connecting plate. The third connecting plate 712 is connected to the fifth connecting plate 512, and the fourth connecting plate 713 is connected to the sixth connecting plate 513.

[0077] By designing the fourth corrugated steel plate 510 to include an L-shaped connecting plate (composed of the fifth connecting plate 512 and the sixth connecting plate 513) and tightly connecting it with the second corrugated steel plate 710 (through the third connecting plate 712 and the fourth connecting plate 713) of the permanent support structure 70, a more stable support system is formed, enhancing the overall rigidity and stability of the support structure. The design of the L-shaped connecting plate simplifies the installation process, allowing the fourth corrugated steel plate 510 to be connected to the permanent support structure 70 more quickly, reducing construction time and improving construction efficiency, which helps to speed up the tunnel construction progress.

[0078] As a preferred example, the length of the first corrugated steel plate 210 along the longitudinal direction of the tunnel is 8-12 m.

[0079] As a preferred example, the thickness of the arch protection layer 830 is set to 0.9-1.5 m, and the arch protection layer 830 is set to 2-4 m.

[0080] The above merely illustrates the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which is made by using the content of the present application specification and drawings, is also included in the patent protection scope of the present application.

Claims

1. A method for repairing a tunnel with a collapsed arch section, characterized in that, Including the following steps: S1, clear the top of the collapsed cavity and spray concrete on the inner wall of the collapsed cavity; S2, in the uncollapsed sections located in front of and behind the collapsed section, the first temporary support structure is applied to support the initial support of the existing tunnel to ensure the stability of the uncollapsed section; S3, compact the collapsed body located below the collapsed cavity, and then spray concrete on the collapsed body to seal it, so as to ensure the stability of the collapsed body; S4, a second temporary support structure for supporting the existing tunnel initial support and a diagonal brace assembly for supporting the corresponding second temporary support structure are respectively erected on both sides of the collapse opening; wherein, the second temporary support structure includes a first end and a second end arranged opposite to each other along its own extension direction, the first end overlaps the tunnel arch foot, the second end extends from the first end along the tunnel circumferential direction to the boundary of the collapse opening and connects with the high end of the diagonal brace assembly, and the low end of the diagonal brace assembly is supported on the collapse body; S5, Construct a permanent support structure to seal the collapsed cavity; wherein, the permanent support structure is connected to the corresponding second temporary support structure on both sides along the tunnel circumferential direction, and the permanent support structure is connected to the corresponding first temporary support structure at both ends along the tunnel extension direction; the permanent support structure is reserved with reserved holes for anchor rods to pass through, a first grouting hole for a first grouting pipe to pass through, and a second grouting hole for a second grouting pipe to pass through, the length of the second grouting pipe being greater than that of the first grouting pipe; S6, drive anchor bolts through the reserved holes, install the first grouting pipe through the first grouting hole and inject concrete into the collapsed cavity to form an arch protection layer on top of the permanent support structure, and then install the second grouting pipe through the second grouting hole and pump foamed concrete into the collapsed cavity to form a buffer layer on top of the arch protection layer. S7. After the arch support layer is formed and its strength is stable, the second temporary support structure and diagonal brace components are removed, the collapsed cavity and the existing initial support I-beam interface are cleaned, and the initial support is repaired according to the original design. S8, dismantle the first temporary support structure and clear the collapsed body to complete the construction of the collapsed section.

2. The tunnel repair method for the collapsed section of the arch as described in claim 1, characterized in that, Before spraying concrete to seal the collapsed body in step S3, the method further includes the following steps: clearing longitudinal working platforms on both sides of the collapsed body and laying channel steel extending along the tunnel extension direction on the longitudinal working platforms, with the lower end of the inclined bracing assembly supported on the collapsed body by the channel steel.

3. The tunnel repair method for the collapsed section of the arch as described in claim 1, characterized in that, Step S6, which involves constructing the first grouting pipe through the first grouting hole and injecting concrete into the collapsed cavity to form a protective arch layer at the top of the permanent support structure, specifically includes the following steps: The first grouting pipe is installed through the first grouting hole and concrete is injected into the collapsed cavity. At the same time, the first grouting pipe and the second grouting hole that are not grouted are used as the air outlet pipes of the first grouting pipe during the grouting process. The grouting speed is controlled at 50-150 L / min and the grouting pressure is controlled at 0.5-1.5 MPa.

4. The tunnel repair method for the collapsed section of the arch as described in claim 1, characterized in that, The specific steps for repairing the initial support according to the original design in step S7 include: The damaged steel arch frame segment and the original steel reinforcement mesh corresponding to the collapsed section were removed, and then a new steel arch frame segment and a new steel reinforcement mesh were constructed. The two ends of each new steel arch frame segment were connected to the existing undamaged steel arch frame segment, and the end of each new steel reinforcement mesh along the tunnel extension direction was connected to the new steel arch frame segment. C25 concrete was sprayed onto the new steel reinforcement mesh.

5. The tunnel repair method for the collapsed section of the arch as described in claim 1, characterized in that, The first temporary support structure is a first corrugated steel plate, and the permanent support structure is a second corrugated steel plate, wherein... The first corrugated steel plate includes a first corrugated steel plate body, a first connecting plate and a second connecting plate connected to the boundary of the first corrugated steel plate body. The first connecting plate protrudes from the inner wall of the first corrugated steel plate body, and the second connecting plate is connected to the bottom outer wall of the first connecting plate. The first connecting plate and the second connecting plate form an L-shaped connecting plate. The second corrugated steel plate includes a second corrugated steel plate body, a third connecting plate and a fourth connecting plate connected to the boundary of the second corrugated steel plate body. The third connecting plate protrudes from the inner wall of the second corrugated steel plate body, and the fourth connecting plate is connected to the bottom outer wall of the third connecting plate. The third connecting plate and the fourth connecting plate form an L-shaped connecting plate. The first connecting plate is connected to the third connecting plate, and the second connecting plate is connected to the fourth connecting plate.

6. The tunnel repair method for the collapsed section of the arch as described in claim 5, characterized in that, The first connecting plate has a first elongated slot hole for bolts to pass through. The third connecting plate has a second elongated slot hole arranged in a one-to-one correspondence with the first elongated slot hole. The second connecting plate has a third elongated slot hole for bolts to pass through. The fourth connecting plate has a fourth elongated slot hole arranged in a one-to-one correspondence with the third elongated slot hole. The first connecting plate is connected to the third connecting plate by bolts passing through the first elongated slot hole and the second elongated slot hole. The second connecting plate is connected to the fourth connecting plate by bolts passing through the third elongated slot hole and the fourth elongated slot hole.

7. The tunnel repair method for the collapsed section of the arch as described in claim 1, characterized in that, The permanent support structure is a third corrugated steel plate, and the corrugation of the third corrugated steel plate corresponds to the longitudinal spacing of the initial support steel arch frame.

8. The tunnel repair method for the collapsed section of the arch as described in claim 5, characterized in that, The second temporary support structure is a fourth corrugated steel plate, which includes a fourth corrugated steel plate body, a fifth connecting plate and a sixth connecting plate connected to the boundary of the fourth corrugated steel plate body. The fifth connecting plate protrudes from the inner wall of the fourth corrugated steel plate body, and the sixth connecting plate is connected to the bottom outer wall of the fifth connecting plate. The fifth connecting plate and the sixth connecting plate form an L-shaped connecting plate. The third connecting plate is connected to the fifth connecting plate, and the fourth connecting plate is connected to the sixth connecting plate.

9. The tunnel repair method for the collapsed section of the arch as described in claim 5, characterized in that, The length of the first corrugated steel plate along the longitudinal direction of the tunnel is set to 8 to 12 meters.

10. The tunnel repair method for the collapsed section of the arch as described in claim 5, characterized in that, The thickness of the arch protection layer is set to 0.9–1.5 m, and the thickness of the arch protection layer is set to 2–4 m.

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