Tunnel repairing method for vault collapse section

Abstract

The invention provides a tunnel repairing method for a vault collapse section, which comprises the following steps of: removing danger of the top of a collapse cavity, spraying concrete on the inner wall of the collapse cavity, respectively applying first temporary support structures for supporting an existing tunnel primary support on non-collapse sections in front of and behind the collapse section, tamping a collapse body below the collapse cavity, and repairing the collapse cavity in the collapse cavity; then concrete is sprayed on the collapse body for sealing, a second temporary supporting structure and an inclined supporting assembly are erected on the two sides of a collapse cavity opening correspondingly, a permanent supporting structure is constructed to block the collapse cavity opening, anchor rods are driven into preformed holes, an arch protection layer and a buffer layer are constructed, the second temporary supporting structure and the inclined supporting assembly are dismounted, and the collapse cavity opening is sealed; and a collapse cavity opening and an existing primary support I-shaped steel connector are cleaned, the primary support is repaired according to the original design, the first temporary support structure is dismantled, the collapse body is cleaned, and construction of the collapse section is completed. According to the method, the safety, convenience and economical efficiency of vault collapse section repairing are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnels, in particular to a method for repairing a tunnel with a collapsed arch. Background Art

[0002] Landslides often occur during tunnel construction. Depending on the diversity and complexity of the engineering geological environment in which the tunnel is located, there are various types of landslides. After the initial support is completed, landslides are prone to occur under the influence of various disturbances and surrounding rock stresses over time, resulting in damage to the initial support at local locations and the formation of collapsed cavities. In particular, when the groundwater in the tunnel is relatively developed and the surrounding rock fissure water is not effectively and fully 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 arch collapse section in the initial support section inside the tunnel, the conventional method is to spray concrete in the collapse cavity after the collapse cavity is stable, remove the damaged I-beams in the entire section, increase the lining support parameters, expand the cavern, re-build the I-beam arch frame, use a template to seal the collapse mouth on the top of the steel frame, and then spray concrete on the steel frame to form the initial support. A grouting pipe is reserved for the collapse mouth. After the treatment is completed, grouting is performed through the reserved grouting pipe to form a C25 concrete guard arch, and sand is blown or foam concrete is backfilled on the guard arch. The lining type is then adjusted, and a lining structure with a higher protection level is adopted to ensure the construction safety of the collapsed section of the tunnel.

[0004] However, the premise of this repair method is that construction can only be carried out after the collapsed cavity reaches a stable state. Otherwise, safety during the construction process cannot be guaranteed (workers and equipment are exposed under the collapsed cavity before the arch protection is installed). This further increases the construction period, delays the construction progress, and indirectly increases the construction cost. Secondly, the use of a lining structure with a higher protection level considers safety too much and ignores the convenience and period of construction. That is, if a higher level of lining type is used, it is necessary to remove the entire section of initial support including the undamaged initial support, and expand the surrounding rock. The construction is extremely inconvenient. While increasing the construction risk, it also increases the cost of treating the collapse in the tunnel.

[0005] In view of this, it is necessary to propose a tunnel repair method for the arch collapse section to solve or at least alleviate the above defects. Summary of the invention

[0006] The main purpose of the present invention is to provide a tunnel repair method for a vault collapse section to solve the technical problems that the existing repair methods have great safety risks for workers and equipment, and excessive consideration of safety while ignoring construction convenience.

[0007] To achieve the above object, the present invention provides a tunnel repair method for a vault collapse section, comprising the steps of:

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

[0009] S2, applying a first temporary support structure for supporting the initial support of the existing tunnel to the non-collapsed sections located in front of and behind the collapsed section, respectively, to ensure the stability of the non-collapsed sections;

[0010] S3, compacting the landslide body below the collapse cavity, and then spraying concrete on the landslide body to seal it, so as to ensure the stability of the landslide body;

[0011] S4, respectively erecting a second temporary support structure for supporting the initial support of the existing tunnel and an inclined brace assembly for supporting the corresponding second temporary support structure on both sides of the collapsed cavity; wherein the second temporary support structure comprises a first end and a second end which are arranged opposite to each other along its own extension direction, the first end being overlapped with the tunnel arch foot, the second end extending from the first end along the tunnel circumferential direction to the boundary of the collapsed cavity and connected to the high end of the inclined brace assembly, and the low end of the inclined brace assembly being supported on the collapsed body;

[0012] S5, construct a permanent support structure to block the collapsed cavity; wherein the two sides of the permanent support structure along the tunnel circumference are respectively connected to the corresponding second temporary support structure, and the two ends of the permanent support structure along the tunnel extension direction are respectively connected to the corresponding first temporary support structure, and the permanent support structure is reserved 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, driving an anchor rod through the reserved hole, applying the first grouting pipe through the first grouting hole and injecting concrete into the collapsed cavity to form an arch protection layer located on the top of the permanent support structure, and then applying the second grouting pipe through the second grouting hole and pumping foam concrete into the collapsed cavity to form a buffer layer located on the top of the arch protection layer;

[0014] S7, after the arch protection layer is formed and its strength is stable, the second temporary support structure and the diagonal brace assembly 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;

[0015] S8, dismantling the first temporary supporting structure and clearing the landslide body to complete the construction of the landslide section.

[0016] Preferably, before spraying concrete on the landslide body to seal it, step S3 also includes the steps of: clearing longitudinal working platforms on both sides of the landslide body and laying channel steels extending along the extension direction of the tunnel on the longitudinal working platforms, and the lower end of the diagonal bracing assembly is supported on the landslide body through the channel steel.

[0017] Preferably, in step S6, the first grouting pipe is constructed through the first grouting hole and concrete is injected into the collapsed cavity to form an arch protection layer located on the top of the permanent support structure, which specifically includes the steps of: constructing the first grouting pipe through the first grouting hole and injecting concrete into the collapsed cavity, and at the same time using the un-grouted first grouting pipe and the second grouting hole as the outlet pipes of the first grouting pipe 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.

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

[0019] The damaged steel arch frame section and the original steel mesh corresponding to the collapsed section are removed, and then new steel arch frame sections and new steel meshes are rebuilt; wherein, both ends of each of the new steel arch frame sections are respectively connected to the existing undamaged steel arch frame sections, and the end of each of the new steel meshes along the extension direction of the tunnel is connected to the new steel arch frame section, and the new steel meshes are sprayed 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 convexly arranged on the inner wall of the first corrugated steel plate body, 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 convexly arranged on the inner wall of the second corrugated steel plate body, 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] Wherein, the first connecting plate is connected to the third connecting plate, and the second connecting plate is connected to the fourth connecting plate.

[0024] Preferably, the first connecting plate is provided with a first long waist slot hole for bolts to pass through, the third connecting plate is provided with a second long waist slot hole arranged in a one-to-one correspondence with the first long waist slot hole, the second connecting plate is provided with a third long waist slot hole for bolts to pass through, and the fourth connecting plate is provided with a fourth long waist slot hole arranged in a one-to-one correspondence with the third long waist slot hole, the first connecting plate is connected to the third connecting plate by bolts passing through the first long waist slot hole and the second long waist slot hole, and the second connecting plate is connected to the fourth connecting plate by bolts passing through the third long waist slot hole and the fourth long waist slot hole.

[0025] Preferably, the permanent supporting structure is a third corrugated steel plate, and the wave pitch of the third corrugated steel plate corresponds to the longitudinal spacing of the initial supporting steel arch frame.

[0026] Preferably, 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 is protruding from the inner wall of the fourth corrugated steel plate body, the sixth connecting plate is connected to 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 to the fifth connecting plate, and the fourth connecting plate is connected to the sixth connecting plate.

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

[0028] Preferably, 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.

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

[0030] The present invention provides a tunnel repair method for a collapsed section of an arch. By setting up a second temporary support structure and a diagonal brace assembly, the overall stability and bearing capacity of the tunnel structure can be effectively enhanced, and the stress burden of the initial support of the existing tunnel can be reduced. The collapse can be effectively prevented from further spreading to the non-collapsed section, and the safe progress of the tunnel construction can be ensured. At the same time, it also provides favorable conditions for subsequent treatment and repair work (for example, providing a connection foundation for a permanent support structure); the construction of the permanent support structure effectively blocks the collapsed cavity, prevents the collapse from further expanding, and ensures the safety of the construction personnel and equipment below. At the same time, it also provides a locking foundation for the anchor rod, and a penetration foundation for the first grouting pipe and the second grouting pipe, and can be used as a template for constructing the arch protection layer, reducing the project cost. The permanent support structure is timely connected to the second temporary support structure in the annular direction to form a complete arch ring, and is connected to the first temporary support structure in the longitudinal direction, and cooperates with the anchor rod to form a strong overall support system, which greatly improves the safety during the construction period, and can also be used as a tunnel lining structure to permanently participate in the load-bearing in the later stage;

[0031] In addition, the present invention does not need to dismantle the initial support of the entire section, but only needs to dismantle the damaged part of the steel arch frame. The present application can use a combined structure of corrugated steel plates and I-beams as a temporary support structure, which can be quickly assembled, and the remaining parts are connected by bolts, which is convenient for installation and disassembly, improves work efficiency, ensures the convenience of construction, and saves project costs. It has a good promotion prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 is a schematic flow chart of a tunnel repair method in one embodiment of the present invention;

[0034] Figure 2 A schematic diagram of a tunnel vault collapse in one embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the structure after the longitudinal working platform is cleared out in one embodiment of the present invention;

[0036] Figure 4 It is a schematic diagram of the structure before the arch protection layer and the buffer layer are applied in one embodiment of the present invention;

[0037] Figure 5 It is a schematic diagram of the structure after the arch protection layer and the buffer layer are applied in one embodiment of the present invention;

[0038] Figure 6 is a schematic diagram of the connection between the permanent supporting structure and the first temporary supporting structure in one embodiment of the present invention;

[0039] Figure 7 is a schematic structural diagram of a first connecting plate in one embodiment of the present invention;

[0040] Figure 8 A schematic diagram of the connection between a permanent supporting structure and a second temporary supporting structure in one embodiment of the present invention;

[0041] Fig. 9 It is a schematic diagram of the connection between the second temporary supporting structure and the diagonal bracing assembly in one embodiment of the present invention.

[0042] The purpose of the present invention is achieved, and the functional features and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

[0043] Description of Figure Numbers:

[0044] 10. Collapse cavity; 110. Collapse cavity mouth; 210. First corrugated steel plate; 211. First corrugated steel plate body; 212. First connecting plate; 213. Second connecting plate; 214. First long waist slot; 215. Bolt; 30. Collapse body; 310. Longitudinal working platform; 320. Channel steel; 40. Initial support of existing tunnel; 410. Initial support steel arch frame; 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 brace 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 only used to explain the present invention, and are not used to limit the present invention.

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the descriptions of "right part", "middle part" and the like in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "right part" and "middle part" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the realization of ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be realized, it should be deemed that such combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0049] Please see attached Figures 1 to 9 In one embodiment of the present invention, a method for repairing a tunnel of a vault collapse section comprises the following steps:

[0050] S1, clear the top of the collapsed cavity 10, and spray concrete on the inner wall of the collapsed cavity 10; specifically, according to the clearing plan, the loose rocks and unstable structures on the top of the collapsed cavity 10 are removed manually or mechanically. During the operation, the changes on the top of the collapsed cavity 10 should be observed at any time. Once an abnormal situation is found, the operation should be stopped immediately and the site should be evacuated. To ensure the spraying effect, in the preferred example, the initial spraying of C25 concrete is used to ensure the stability of the collapsed cavity 10 to ensure safety during the treatment construction.

[0051] S2, in the non-collapsed sections located in front and behind the collapsed section, a first temporary support structure (not shown in the figure) for supporting the initial support 40 of the existing tunnel is respectively applied to ensure the stability of the non-collapsed section; as a preferred example, the first temporary support structure adopts corrugated steel plates, which are transported to the work site, and in the non-collapsed sections 10m before and after the collapsed section, 8mm thick 400mm*150mm corrugated steel plates are used to form a temporary support structure, which is closely attached to the initial support of the tunnel, to ensure the stability of the adjacent sections of the collapsed section, and to minimize the impact of the repair of the collapsed section on the adjacent non-collapsed section.

[0052] S3, compact the landslide body 30 located below the collapse cavity 10, and then spray concrete on the landslide body 30 to seal it, so as to ensure the stability of the landslide body 30; the compaction operation can significantly improve the compactness of the landslide body 30, thereby enhancing its stability and preventing it from further collapsing or sliding. By spraying concrete to seal the surface of the landslide body 30, a safer working environment can be provided for construction workers. Specifically, the landslide bodies 30 on both sides of the projected landslide mouth can be compacted, a working platform can be cleared, and C25 concrete can be initially sprayed on the landslide body 30 to seal it, so as to ensure the stability of the landslide body 30.

[0053] S4, a second temporary support structure (not shown) for supporting the existing tunnel initial support 40 and a diagonal brace assembly 60 for supporting the corresponding second temporary support structure are respectively set up on both sides of the collapsed cavity 110; wherein the second temporary support structure includes a first end 520 and a second end 530 which are arranged opposite to each other along its own extension direction, the first end 520 is overlapped with the tunnel arch foot, the second end 530 extends from the first end 520 along the tunnel circumferential direction to the boundary of the collapsed cavity 110 and is connected to the high end of the diagonal brace assembly 60, and the low end of the diagonal brace assembly 60 is supported on the collapsed body 30;

[0054] Specifically, Figure 4 As shown, the second temporary support structure can be made of rigid materials such as I-beams or steel pipes, extending along the tunnel circumferentially, with one end lapped at the tunnel arch foot and the other end extending to the boundary of the collapsed cavity 110. The second temporary support structure is closely fitted with the existing tunnel initial support 40 to form an effective support system. By erecting the second temporary support structure and the diagonal brace assembly 60, the overall stability and bearing capacity of the tunnel structure can be effectively enhanced, and the force burden of the existing tunnel initial support 40 can be reduced; it can effectively prevent the collapse from further spreading to the non-collapsed section, and ensure the safe progress of the tunnel construction. At the same time, it also provides favorable conditions for subsequent treatment and repair work (for example, providing a connection foundation for the permanent support structure 70).

[0055] As a preferred example, a temporary support structure of 8mm thick 400mm*150mm corrugated steel plates is erected within the range from the boundaries of both sides of the collapse section to the tunnel arch foot. One side is overlapped on the tunnel arch foot, and the other side is supported by I20 I-beams. One end of the I-beam can be connected to the corrugated steel plate through a pad, and the other end is supported on the collapse body 30.

[0056] S5, construct a permanent support structure 70 to block the collapsed cavity 110; wherein the permanent support structure 70 is connected to the corresponding second temporary support structure at both sides along the tunnel circumference, and the permanent support structure 70 is connected to the corresponding first temporary support structure at both ends along the tunnel extension direction, and the permanent support structure 70 is reserved with a reserved hole (not shown) for the anchor rod to pass through, a first grouting hole (not shown) for the first grouting pipe 810 to pass through, and a second grouting hole (not shown) for the second grouting pipe 820 to pass through, and the length of the second grouting pipe 820 is greater than the first grouting pipe 810;

[0057] Specifically, the construction of the permanent support structure 70 effectively blocks the collapse cavity 110, prevents the collapse from further expanding, ensures the safety of the construction personnel and equipment below, and provides a locking foundation for the anchor rod, provides a penetration foundation for the first grouting pipe 810 and the second grouting pipe 820, and can be used as a template for the construction of the arch protection layer 830, reducing the project cost. The permanent support structure 70 is connected to the second temporary support structure in a timely manner in the circumferential direction to form a complete arch ring, and is connected to the first temporary support structure in the longitudinal direction. It cooperates with the anchor rod to form a strong overall support system, which greatly improves the safety during the construction period. In the later stage, it can also be used as a tunnel lining structure to permanently participate in the load bearing. Along both sides of the tunnel circumferential direction, the permanent support structure 70 is reliably connected to the corresponding second temporary support structure, which is usually achieved by welding, bolt 215 connection or other methods to ensure a firm connection. For ease of disassembly and assembly, it is preferably connected by bolt 215; 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 collapsed area is sealed with a 1cm thick 500mm*400mm corrugated steel plate, and the 500mm*400mm corrugated steel plate is connected to a 400mm*150mm corrugated steel plate on all sides; the corrugated steel plate specification can be 8mm thick 400mm*150mm, and the wave pitch of the corrugated steel plate used to seal the collapsed area should correspond to the 410 spacing of the initial support steel arch frame. For example, the initial support adopts 26cm thick I20 I-beams, and the spacing between I-beams is 50cm, then the wave pitch of the corrugated steel plate is 50cm, for example Figure 6 shown.

[0059] S6, driving an anchor rod (not shown) through the reserved hole, applying the first grouting pipe 810 through the first grouting hole and injecting concrete into the collapsed cavity 10 to form an arch protection layer 830 located on the top of the permanent support structure 70, and then applying the second grouting pipe 820 through the second grouting hole and pumping foamed concrete into the collapsed cavity 10 to form a buffer layer 840 located on the top of the arch protection layer 830;

[0060] Specifically, the anchor rod is driven into the anchor rod at an angle of 15° to enhance stability; a grouting pipe is installed at the first grouting hole position, and the sealing between the grouting pipe and the hole wall is ensured; concrete is prepared according to the design requirements to ensure that the strength, fluidity and other indicators of the concrete meet the construction requirements; the grouting equipment is started, and concrete is injected into the collapsed cavity 10 through the grouting pipe; during the grouting process, the grouting pressure and grouting amount need to be controlled to ensure that the concrete can evenly and densely fill the collapsed cavity 10 space; as the concrete is injected and solidified, a solid arch layer 830 is gradually formed on the top of the permanent support structure 70; this arch layer 830 can effectively disperse and bear the pressure of the rock and soil above, and improve the stability of the tunnel structure; a grouting pipe is installed at the second grouting hole position; since the length of the second grouting pipe 820 is greater than that of the first grouting pipe 810, it can penetrate into a higher collapsed cavity 10 area; foam concrete is prepared according to the design requirements. Foam concrete has the advantages of light weight, high strength, thermal insulation, etc., and is suitable as a buffer layer 840 material; the pumping equipment is started, and foam concrete is pumped into the collapsed cavity 10 through the grouting pipe. During the pumping process, the pumping speed and pumping volume need to be controlled to ensure that the foamed concrete can evenly and densely fill the collapsed cavity 10 space. As the foamed concrete is pumped and solidified, a light buffer layer 840 is gradually formed on the top of the arch protection layer 830. This buffer layer 840 can effectively absorb and disperse the impact energy of the rock and soil above, 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 the foamed concrete is pumped to form a 3m thick buffer layer 840.

[0061] As a preferred embodiment, the step S6 of applying the first grouting pipe 810 through the first grouting hole and injecting concrete into the collapsed cavity 10 to form the arch protection layer 830 located at the top of the permanent support structure 70 specifically includes the following steps: applying the first grouting pipe 810 through the first grouting hole and injecting concrete into the collapsed cavity 10, and at the same time using the un-grouted first grouting pipe 810 and the second grouting hole as the air outlet pipe of the first grouting pipe 810 during the grouting process; wherein the grouting speed is controlled at 50 to 150 L / min, and the grouting pressure is controlled at 0.5 to 1.5 MPa. Similarly, the un-grouted second grouting hole is used as an exhaust hole during the grouting of the second grouting hole, and the exhaust hole is used to exhaust air and seepage during the concrete pouring process.

[0062] Preferably, the first grouting pipe 810 is set to be 10-20 cm higher than the arch protection layer 830, and the second grouting hole is set to be 10-20 cm higher than the buffer layer 840. 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 of the termination 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 of the termination of grouting.

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

[0064] As a preferred implementation, the step S7 of repairing the initial support according to the original design specifically includes the following steps: cutting off the damaged steel arch frame section and the original steel mesh corresponding to the collapsed section, and then re-constructing a new steel arch frame section and a new steel mesh; wherein, the two ends of each of the new steel arch frame sections are respectively connected to the existing undamaged steel arch frame sections, and the end of each of the new steel meshes along the extension direction of the tunnel is connected to the new steel arch frame section, and the new steel meshes are sprayed with C25 concrete.

[0065] By cutting off the damaged part and re-constructing new steel arch sections and steel mesh, the repaired initial support structure is more complete and stable. The strong connection between the new steel arch section and the existing steel arch section, as well as the laying of the new steel mesh and shotcrete, have jointly improved the overall strength and stability of the support structure, and 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 construction, it can proceed more smoothly, reducing construction difficulties and quality problems caused by support structure problems.

[0066] As a preferred example, after the guard arch is formed and its strength is stable, the 500mm*400mm corrugated steel plate in the collapsed area is removed, the collapsed area 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, and C25 concrete is sprayed. If there is water seepage in the collapsed cavity 10, a drainage pipe is reserved in the initial support to discharge it.

[0067] S8, dismantling the first temporary supporting structure and clearing the landslide body 30 to complete the landslide section construction.

[0068] As a preferred embodiment, the step S3 also includes the steps of clearing out longitudinal working platforms 310 on both sides of the landslide body 30 and laying channel steels 320 extending along the extension direction of the tunnel on the longitudinal working platforms 310 before spraying concrete on the landslide body 30 to seal it, and the lower end of the diagonal bracing assembly 60 is supported on the landslide body 30 through the channel steel 320.

[0069] This embodiment provides a stable support foundation for the diagonal bracing assembly 60 by setting a longitudinal working platform 310 and laying channel steel 320 on both sides of the landslide body 30, effectively enhancing the stability of the diagonal bracing assembly 60 and preventing it from shifting or collapsing during the construction process, thereby 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 includes a first corrugated steel plate body 211, a first connecting plate 212 and a second connecting plate 213 connected to the boundary of the first corrugated steel plate body 211, the first connecting plate 212 is convexly arranged on the inner wall of the first corrugated steel plate body 211, 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 includes a second corrugated steel plate body 711, a third connecting plate 712 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 from the inner wall of the second corrugated steel plate body 711, 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 is connected to the third connecting plate 712, and the second connecting plate 213 is connected to the fourth connecting plate 713.

[0072] Specifically, the connection between the corrugated steel plate for sealing the collapsed opening and other corrugated steel plates should take into account the grouting seal and installation error. Therefore, the L-shaped steel plate is used as the flange at the connection of the corrugated steel plate in the design. When connecting, a single-sided open screw hole is set at the bottom edge of the L-shaped steel plate, and the flange of the sealing corrugated steel plate is wrapped around the bottom edge of the flange of other corrugated steel plates, and then tightened by bolts 215. 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 simpler and faster, reducing installation time and labor costs. The first corrugated steel plate 210 serves as a temporary support structure to provide initial stability during tunnel construction.

[0073] Preferably, the third connecting plate 712 needs to be lengthened so that space for initial support repair can be reserved. After the sealing corrugated steel plate is removed, the cleaning work of the initial support interface can be reduced, thereby facilitating initial support repair.

[0074] As another preferred embodiment, the first connecting plate 212 is provided with a first long waist slot 214 for the bolt 215 to pass through, the third connecting plate 712 is provided with a second long waist slot (not shown) arranged in a one-to-one correspondence with the first long waist slot 214, the second connecting plate 213 is provided with a third long waist slot (not shown) for the bolt 215 to pass through, the fourth connecting plate 713 is provided with a fourth long waist slot (not shown) arranged in a one-to-one correspondence with the third long waist slot, the first connecting plate 212 is connected to the third connecting plate 712 by the bolt 215 passing through the first long waist slot 214 and the second long waist slot, and the second connecting plate 213 is connected to the fourth connecting plate 713 by the bolt 215 passing through the third long waist slot and the fourth long waist slot.

[0075] The design of the long waist slot allows a certain amount of adjustment space when the bolt 215 is inserted, and the position of the connecting plate can be fine-tuned as needed during the installation process to ensure accurate alignment and tight connection between them. Once the position adjustment is completed, a firm fastening effect can be achieved by tightening the bolt 215, ensuring the overall stability of the support structure.

[0076] Furthermore, the second temporary support structure is a fourth corrugated steel plate 510, and the fourth corrugated steel plate 510 includes a fourth corrugated steel plate body 511, a fifth connecting plate 512 and a sixth connecting plate 513 connected to the boundary of the fourth corrugated steel plate body 511, the fifth connecting plate 512 is protruded from 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, and the fifth connecting plate 512 and the sixth connecting plate 513 form an L-shaped connecting plate; wherein 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 as a structure including an L-shaped connecting plate (composed of a fifth connecting plate 512 and a sixth connecting plate 513), and closely connecting it with the second corrugated steel plate 710 of the permanent support structure 70 (through the third connecting plate 712 and the fourth connecting plate 713), a more stable support system is formed, which enhances 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, improving construction efficiency, and helping to speed up the progress of tunnel construction.

[0078] As a preferred example, the length of the first corrugated steel plate 210 along the longitudinal direction of the tunnel is set to 8 to 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 are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for repairing a tunnel with a collapsed vault, characterized in that: Includes steps: S1, clear the top of the collapsed cavity and spray concrete on the inner wall of the collapsed cavity; S2, applying a first temporary support structure for supporting the initial support of the existing tunnel to the non-collapsed sections located in front of and behind the collapsed section, respectively, to ensure the stability of the non-collapsed sections; S3, compacting the landslide body below the collapse cavity, and then spraying concrete on the landslide body to seal it, so as to ensure the stability of the landslide body; S4, respectively erecting a second temporary support structure for supporting the initial support of the existing tunnel and an inclined brace assembly for supporting the corresponding second temporary support structure on both sides of the collapsed cavity; wherein the second temporary support structure comprises a first end and a second end which are arranged opposite to each other along its own extension direction, the first end being overlapped with the tunnel arch foot, the second end extending from the first end along the tunnel circumferential direction to the boundary of the collapsed cavity and connected to the high end of the inclined brace assembly, and the low end of the inclined brace assembly being supported on the collapsed body; S5, construct a permanent support structure to block the collapsed cavity; wherein the two sides of the permanent support structure along the tunnel circumference are respectively connected to the corresponding second temporary support structure, and the two ends of the permanent support structure along the tunnel extension direction are respectively connected to the corresponding first temporary support structure, and the permanent support structure is reserved 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; S6, driving an anchor rod through the reserved hole, applying the first grouting pipe through the first grouting hole and injecting concrete into the collapsed cavity to form an arch protection layer located on the top of the permanent support structure, and then applying the second grouting pipe through the second grouting hole and pumping foam concrete into the collapsed cavity to form a buffer layer located on the top of the arch protection layer; S7, after the arch protection layer is formed and its strength is stable, the second temporary support structure and the diagonal brace assembly 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, dismantling the first temporary supporting structure and clearing the landslide body to complete the construction of the landslide section.

2. The method for repairing a tunnel with a collapsed vault according to claim 1, characterized in that: The step S3 also includes the following steps before spraying concrete on the landslide body for sealing: longitudinal working platforms are respectively cleared on both sides of the landslide body and channel steels extending along the extension direction of the tunnel are laid on the longitudinal working platforms, and the lower end of the diagonal bracing assembly is supported on the landslide body by the channel steels.

3. The method for repairing a tunnel with a collapsed vault according to claim 1, characterized in that: The step S6 of applying the first grouting pipe through the first grouting hole and injecting concrete into the collapsed cavity to form an arch protection layer located on the top of the permanent support structure specifically includes the following steps: The first grouting pipe is constructed through the first grouting hole and concrete is injected into the collapsed cavity. At the same time, the un-grouted first grouting pipe and the second grouting hole are used as air outlet pipes of the first grouting pipe during the grouting process. The grouting speed is controlled at 50-150L / min, and the grouting pressure is controlled at 0.5-1.5MPa.

4. The tunnel repair method for a vault collapse section according to claim 1, characterized in that: The step S7 specifically includes the following steps: The damaged steel arch frame section and the original steel mesh corresponding to the collapsed section are removed, and then new steel arch frame sections and new steel meshes are rebuilt; wherein, both ends of each of the new steel arch frame sections are respectively connected to the existing undamaged steel arch frame sections, and the end of each of the new steel meshes along the extension direction of the tunnel is connected to the new steel arch frame section, and the new steel meshes are sprayed with C25 concrete.

5. The method for repairing a tunnel with a collapsed vault according to 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 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 convexly arranged on the inner wall of the first corrugated steel plate body, 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; 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 convexly arranged on the inner wall of the second corrugated steel plate body, 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; Wherein, 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 method for repairing a tunnel with a collapsed vault according to claim 5, characterized in that: The first connecting plate is provided with a first long waist slot hole for bolts to pass through, the third connecting plate is provided with a second long waist slot hole which is arranged in a one-to-one correspondence with the first long waist slot hole, the second connecting plate is provided with a third long waist slot hole for bolts to pass through, and the fourth connecting plate is provided with a fourth long waist slot hole which is arranged in a one-to-one correspondence with the third long waist slot hole. The first connecting plate is connected to the third connecting plate by bolts passing through the first long waist slot hole and the second long waist slot hole, and the second connecting plate is connected to the fourth connecting plate by bolts passing through the third long waist slot hole and the fourth long waist slot hole.

7. The method for repairing a tunnel with a collapsed vault according to claim 1, characterized in that: The permanent support structure is a third corrugated steel plate, and the wave pitch of the third corrugated steel plate corresponds to the longitudinal spacing of the initial support steel arch frame.

8. The method for repairing a tunnel with a collapsed vault according to 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 is protruding from the inner wall of the fourth corrugated steel plate body, the sixth connecting plate is connected to 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 to the fifth connecting plate, and the fourth connecting plate is connected to the sixth connecting plate.

9. The method for repairing a tunnel with a collapsed vault according to 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 a vault collapse section according to claim 5, characterized in that: The thickness of the arch protection layer is set to 0.9-1.5m, and the thickness of the arch protection layer is set to 2-4m.

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