A tunnel collapse treatment process and structure

Abstract

This application relates to a tunnel collapse treatment process and structure, which includes the following steps: S1. Drainage of dripping water: Install spray pipes in the collapsed cave or at the bottom, and then use water to remotely wash the inner wall of the collapsed cave to clean the unstable rocks and soil in the collapsed cave. After the collapsed cave is stable, insert multiple flushing water pipes into the inner wall of the collapsed cave and then use water to flush, further cleaning the unstable rocks and soil in the collapsed cave; S2. Initial support: Spray concrete on the inner wall of the collapsed cave to seal and level the rock surface to form an initial support layer; S3. Secondary support: Bury multiple initial anchor rods on the inner wall of the collapsed cave. The initial anchor rods penetrate through the initial support layer, and a secondary support grid is fixedly connected to the end of the initial anchor rod that penetrates through the initial support layer, and then spray concrete twice to form a secondary support layer; S4. Backfilling of the collapsed cave: Backfill the collapsed cave with concrete. This application can effectively reduce the potential safety hazards caused by the collapsed area to subsequent construction.

Description

Technical Field

[0001] This application relates to the field of tunnel construction technology, and in particular, to a tunnel collapse treatment process and structure. Background Art

[0002] During the process of tunnel construction, due to the complex geological conditions in the mountain body, it is easy to cause a collapse when the tunnel excavation passes through a relatively loose geological area; at this time, a relatively large collapse hole will be generated at the top of the tunnel, which will have a certain impact on the subsequent tunnel lining and construction safety.

[0003] In the prior art, in order to reduce the impact of the collapse area on the subsequent construction safety, the support method is often used for treatment. The specific scheme is as follows: when supporting the collapse hole, the inner wall of the collapse hole is often consolidated by shotcreting, and the collapse hole is supported by a bracket.

[0004] However, in the actual construction process of the above technology, due to the relatively loose geology in the collapse area, although the inner wall of the collapse hole is supported by shotcreting, during the actual shotcreting process, it is still easy to cause secondary collapse of the geology in the collapse hole due to equipment vibration, etc., resulting in the failure of the initial shotcreting and relatively large potential safety hazards. Summary of the Invention

[0005] In order to reduce the potential safety hazards in the collapse area during the construction process, this application provides a tunnel collapse treatment process and structure.

[0006] A tunnel collapse treatment process and structure provided by this application adopt the following technical solutions:

[0007] In the first aspect, this application provides a tunnel collapse treatment process, adopting the following technical solutions:

[0008] A tunnel collapse treatment process includes the following steps:

[0009] S1. Drain the dripping water: Set a spray pipe in the collapse hole or at the bottom, and then use high-pressure water to remotely wash the inner wall of the collapse hole to clean the unstable rocks and soil in the collapse hole. After the collapse hole is stable, open multiple drainage holes on the inner wall of the collapse hole, insert a flushing pipe into the drainage holes, and continuously use high-pressure water to wash the drainage holes to further clean the unstable rocks and soil in the collapse hole;

[0010] S2. Initial support: Spray concrete on the inner wall of the collapse hole to close and level the rock surface to form an initial support layer, and the thickness of the initial support layer is 2 - 5 cm;

[0011] S3. Secondary support: Install multiple initial anchor rods on the inner wall of the collapsed hole. The initial anchor rods penetrate through the initial support layer, and a secondary support grid is fixedly connected to the end of the initial anchor rod that penetrates through the initial support layer. A plurality of secondary support grids are arranged in contact with the initial support layer, and then shotcrete is sprayed again to form a secondary support layer with a thickness of 8 - 10 cm;

[0012] S4. Backfilling the collapsed hole: Backfill the collapsed hole with concrete.

[0013] By adopting the above technical solutions, after the scouring in step S1, some unstable rocks and earthwork in the collapsed hole formed after the landslide can be cleared under the action of impact force and gravity; at the same time, the drainage holes provided can further clear some rocks and earthwork with certain potential safety hazards in the collapsed hole after preliminary scouring and cleaning. And when flushing with water, it is remotely scoured through the spray pipe, which can effectively reduce the potential safety hazards caused by the landslide during the construction process. In addition, after the scouring is completed and stabilized, through the initial support, the uneven rock surface in the collapsed hole is leveled, which is convenient for subsequent construction and further supports the surface of the collapsed hole, reducing the possibility of falling rocks during subsequent support construction, thereby further reducing the safety risks during construction and providing protection for subsequent construction. Then, through the secondary support, the secondary support layer is connected to the inner wall of the collapsed hole through the initial anchor rods to relatively comprehensively support the inner wall of the collapsed hole, thereby relatively comprehensively reducing the potential safety hazards caused by the collapse to subsequent construction, and backfilling the collapsed hole with concrete to support the geological deformation generated during subsequent construction and use.

[0014] Optionally, in step S1, the gap between the flushing pipe and the rock surface is sealed with cotton yarn, and then the drainage holes are sealed with cement mortar, and the cement mortar is sealed on the side of the cotton yarn facing the center of the collapsed hole.

[0015] By adopting the above technical solutions, after sealing with cotton yarn and then sealing the drainage holes with cement mortar, when the flushing pipe scours and cleans the inner wall of the collapsed hole, it can increase the scouring force on the unstable rock mass and earthwork, reduce the water directly discharged through the drainage holes, optimize the cleaning effect of the unstable rock layer and earthwork in the collapsed hole, and at the same time, it can also slow down the impact of water on the mortar block formed by the cement mortar sealing the drainage holes through the cotton yarn, reducing the influence of the sealing failure caused by the impact of water during scouring on the cleaning effect of the inner wall of the collapsed hole.

[0016] Optionally, in step S1, the flushing pipe is inserted into the drainage hole by 30 - 60 cm.

[0017] By adopting the above technical solutions, the water discharged through the flushing pipe can directly enter the rock mass or earthwork in the collapsed hole, so as to further optimize the cleaning effect of the collapsed hole and further reduce the potential safety hazards caused by the landslide.

[0018] Optionally, after the secondary support is completed in step S3, a plurality of arc-shaped arch frames are arranged at the entrance of the collapsed tunnel. The arch frames are arranged around the length direction of the tunnel and pass through the entrance of the collapsed tunnel. A plurality of the arch frames are fixedly connected with an arc-shaped formwork. A support plate located inside the entrance of the collapsed tunnel is formed by pouring concrete in the formwork. A plurality of guide pipes inserted into the side of the entrance of the collapsed tunnel facing the construction direction are arranged through the support plate, and the area of the support plate is smaller than the opening area of the entrance of the collapsed tunnel;

[0019] After the support plate is solidified, a guide hole is drilled through the guide pipe. The guide hole penetrates into the rock mass on the side of the collapsed tunnel facing the construction direction. A grouting pipe is inserted into the guide hole. The grouting pipe is inserted into the rock mass and the opening of the grouting pipe and the guide hole is blocked. Then, concrete is poured into the rock mass on the side of the collapsed tunnel facing the construction direction through the grouting pipe; after the concrete in the rock mass is solidified, with the support plate as the formwork, a closed formwork is fixedly connected to the edge of the support plate and the entrance of the collapsed tunnel. Finally, step S4 is completed.

[0020] By adopting the above technical solution, because the geology of the collapsed area is relatively unstable, after the inner wall support of the collapsed tunnel is completed, there is still a possibility of instability in the rock mass and soil on the side of the collapsed tunnel facing the unconstructed side of the tunnel. At this time, a support plate is formed at the entrance of the collapsed tunnel through the arch frame and the formwork, which is used as the construction platform for subsequent backfill concrete while protecting the potential safety hazards in the collapsed tunnel; and the guide pipe in the support plate can be used to insert the grouting pipe into the rock mass on the side of the collapsed tunnel located on the unconstructed side of the tunnel, and the rock mass and soil on the side of the collapsed tunnel facing the unconstructed side of the tunnel can be consolidated by grouting, so as to reinforce the unstable rock mass in the part of the collapsed tunnel located on the unconstructed side of the tunnel; thus, the unstable rock mass in the collapsed tunnel caused by the support of the mountain on the unconstructed side of the tunnel is reduced, so as to further reduce the potential safety hazards in the subsequent construction.

[0021] Optionally, the grouting pipe includes a plurality of grouting pipe sections distributed along the axial direction. The grouting pipe sections are sequentially inserted into the guide hole, and two adjacent grouting pipe sections are threadedly connected.

[0022] By adopting the above technical solution, since the construction space in the tunnel is relatively limited and the length of the grouting pipe is relatively long, at this time, the grouting pipe sections connected by threads are sequentially inserted into the guide hole, and the installation of the grouting pipe and the consolidation of the inner wall of the collapsed tunnel can be completed in a limited space.

[0023] Optionally, the specific steps of step S4 are as follows: a strengthening formwork is hung on the initial anchor through the support plate, and then concrete is poured into the strengthening formwork to form a strengthened support plate. After the concrete is solidified, the bottom strengthening formwork is removed, and then a plurality of vertically distributed strengthened support plates are formed in the collapsed tunnel from top to bottom in sequence.

[0024] By adopting the above technical solution, the reinforcement formwork can successively form a plurality of vertically distributed reinforcement support plates. While the reinforcement support plates can support the collapsed cave, the overall weight of the concrete backfilled in the collapsed cave can be reduced, and the tensile force on the inner wall of the collapsed cave caused by the excessive weight of the support structure can be reduced, thereby reducing the potential safety hazards caused by vibration or geological deformation during the subsequent construction process.

[0025] Optionally, the specific steps of step S4 are as follows: A plurality of filling and grouting pipes are hung in the collapsed cave through a plurality of initial anchor bolts, and the plurality of filling and grouting pipes are connected to a pump pipe that penetrates out of the collapsed cave opening.

[0026] By adopting the above technical solution, the pump pipe pumps the concrete into the plurality of filling and grouting pipes, thereby realizing the layered pouring of concrete in the collapsed cave and optimizing the density of the consolidated concrete in the collapsed cave.

[0027] Optionally, in step S4, a filling valve for controlling the passage of concrete is provided between the filling and grouting pipe and the pump pipe, and the passage pressures of the filling valves connected to the plurality of filling and grouting pipes increase successively from bottom to top.

[0028] By adopting the above technical solution, since the passage pressures of the filling valves connected to the filling and grouting pipes increase successively from bottom to top, the effect of pouring concrete layer by layer from bottom to top can be achieved by controlling the pressure of the poured concrete, thereby further optimizing the density of the backfilled concrete in the collapsed cave.

[0029] In a second aspect, the present application provides a tunnel collapse treatment structure, adopting the following technical solution:

[0030] A tunnel collapse treatment structure includes initial anchor bolts, an initial support layer, and a secondary support layer inserted into the collapsed cave, and the secondary support layer is located on the side of the initial support layer facing the center of the collapsed cave.

[0031] Optionally, a backfill layer formed by concrete is filled in the collapsed cave.

[0032] In summary, the present application includes at least one of the following beneficial technical effects:

[0033] During the construction process, after the scouring by high-pressure water in step S1, the unstable rocks and soil in the collapsed cave formed after the collapse can be cleared under the impact force and gravity, so as to reduce the possibility of falling rocks or secondary collapse in the collapsed cave; at the same time, the drainage holes provided can enable the remaining unstable rocks and soil in part of the collapsed cave to be further cleared after preliminary scouring and stabilization, and when flushing water, it is remotely scoured through a spray pipe, which can effectively reduce the safety hazards caused by the collapse during the construction process; in addition, after the scouring is completed and stabilized, through the initial support, the rock surface in the uneven collapsed cave is leveled, so as to facilitate the subsequent construction and further support the surface of the collapsed cave, reducing the possibility of falling rocks during the subsequent support construction, thereby further reducing the safety during construction, providing protection for the subsequent construction, and then through the secondary support, the secondary support layer is connected to the inner wall of the collapsed cave through the initial anchor bolts, so as to support the inner wall of the collapsed cave in a relatively comprehensive manner, thereby relatively comprehensively reducing the safety hazards caused by the collapse to the subsequent construction, and through backfilling concrete to support the geological deformation generated during the subsequent construction and use of the collapsed cave;

[0034] The initial support layer and the secondary support layer can successively complete the support of the collapsed cave, reducing the safety hazards generated during the support process of the collapsed cave. At the same time, the backfill layer formed by backfilling concrete can effectively support the inner wall of the collapsed cave after the construction is completed, so as to reduce the influence of the vibration and geological deformation generated during the subsequent construction on the collapsed cave. Description of the Drawings

[0035] Figure 1 It is the process flow chart of the tunnel collapse treatment in Embodiment 1 of the present application.

[0036] Figure 2 It is the cross-sectional view of the tunnel collapse treatment structure in Embodiment 1 of the present application.

[0037] Figure 3 It is the cross-sectional structure schematic diagram of the grouting pipe in Embodiment 1 of the present application.

[0038] Figure 4 It is the cross-sectional structure schematic diagram of the tunnel collapse treatment process in Embodiment 2 of the present application and the tunnel collapse treatment structure in Embodiment 4 of the present application.

[0039] Figure 5 It is the cross-sectional structure schematic diagram of the tunnel collapse treatment process in Embodiment 3 of the present application and the tunnel collapse treatment structure in Embodiment 5 of the present application.

[0040] Description of reference numerals: 1. Flushing pipe; 2. Primary support layer; 21. Primary bolt; 22. Secondary support grid; 3. Secondary support layer; 4. Arch frame; 41. Support plate; 42. Guide pipe; 43. Grouting pipe; 431. Grouting pipe joint; 44. Reinforced support plate; 5. Filling grouting pipeline; 51. Pump pipe; 52. Filling valve; 6. Backfill layer. Detailed implementation manners

[0041] The following further elaborates on this application Figures 1-5 in conjunction with the accompanying drawings.

[0042] An embodiment of this application discloses a tunnel collapse treatment process.

[0043] Embodiment 1:

[0044] Referring to Figure 1 and Figure 2 , a tunnel collapse treatment process includes the following steps:

[0045] S1. Drain the dripping water: Set up a spray pipe in the collapsed cave or at the bottom. Through the spray pipe, use high-pressure water to remotely flush the inner wall of the collapsed cave, clean the unstable rocks and soil in the collapsed cave, thereby reducing the possibility of secondary collapse of rocks or soil during subsequent construction, and effectively increasing the safety during subsequent construction.

[0046] After the collapsed cave is stable, that is, after the dripping water is initially infiltrated and drained, open multiple drainage holes in the inner wall of the collapsed cave, then insert a flushing pipe 1 into the drainage holes, and the flushing pipe 1 is inserted 30 - 60 cm into the top wall of the drainage holes; then pour high-pressure water into the collapsed cave through the flushing pipe 1 to further clean the inner wall of the collapsed cave and reduce potential safety hazards during subsequent construction.

[0047] S2. Primary support: Spray concrete on the inner wall of the collapsed cave to seal and supplement the rock surface in the collapsed cave and form a primary support layer 2. The thickness of the primary support layer 2 is 2 - 5 cm, and the primary support layer 2 is fixedly connected to the inner wall of the collapsed cave through part of the flushing pipe 1 staying on the inner wall of the collapsed cave to further support the inner wall of the collapsed cave and reduce potential safety hazards during subsequent tunnel lining construction and subsequent support construction.

[0048] S3. Secondary support: Bury multiple primary bolts 21 in the inner wall of the collapsed cave. One end of the primary bolt 21 is inserted into the inner wall of the collapsed cave, and the other end of the primary bolt 21 penetrates through the primary support layer 2. Fix and connect multiple secondary support grids 22 through the primary bolts 21. The secondary support grids 22 are arranged in contact with the primary support layer 2, and then spray concrete again on the surface of the primary support layer 2 to form a secondary support layer 3. The thickness of the secondary support layer 3 is 8 - 10 cm.

[0049] Among them, the secondary support grid 22 is a steel bar mesh or a fiberglass mesh cloth, which is used to strengthen the overall strength of the secondary support layer 3, further support the inner wall of the collapsed hole, and at the same time, through the initial anchor rod 21, the tensile force generated by the initial support layer 2 and the secondary support layer 3 due to thermal expansion and contraction and gravity on the inner wall of the collapsed hole is transmitted deep into the rock layer of the collapsed hole, reducing the external force applied to the surface layer of the collapsed hole, so as to further optimize the stability during subsequent construction.

[0050] S4. Backfilling the collapsed hole: Backfill the collapsed hole with concrete to increase the ability of the collapsed hole to bear the subsequent mountain pressure.

[0051] Specifically, in step S1, when the flushing pipe 1 is inserted into the drainage hole, after the space between the flushing pipe 1 and the rock surface is blocked with a veil, the drainage hole is then blocked with cement mortar, so as to increase the scouring effect of the water discharged from the flushing pipe 1 on the inner wall of the collapsed hole, and further optimize the effect of cleaning the unstable rock layer in the collapsed hole.

[0052] In addition, in order to further reduce the influence of the collapsed part on the subsequent tunnel construction, after step S3 is completed, a plurality of arc-shaped arch frames 4 are arranged at the entrance of the collapsed hole. The plurality of arch frames 4 are distributed along the length direction of the tunnel, and both ends of the arch frame 4 are fixedly connected to the bottom of the tunnel. The arch frame 4 passes through the entrance of the collapsed hole to serve as the support foundation for subsequent construction.

[0053] Furthermore, a plurality of arch frames 4 are fixedly connected to each other by using steel bars or the like to increase the stability during construction. Then a formwork is fixedly connected through the arch frame 4. Specifically, the inner cavity of the formwork is an arc-shaped plate structure, and the formwork is located inside the entrance of the collapsed hole. The formwork is arranged along the edge on the unconstructed side of the tunnel facing the entrance of the collapsed hole, and there is an opening between the formwork and the edge of the entrance of the collapsed hole to leave a passage for subsequent construction. And a plurality of guide pipes 42 inserted into the rock mass are fixedly connected through the arch frame 4. The guide pipes 42 are arranged obliquely upward, and the lower end of the guide pipe 42 penetrates downward through the formwork, and the upper end of the guide pipe 42 is inserted into the inner wall on the unconstructed side of the entrance of the collapsed hole.

[0054] Refer to Retreat 2 and Figure 3 , through the formwork, a support plate 41 is formed by pouring concrete at the entrance of the collapsed hole, so that the area of the support plate 41 is smaller than the opening area of the entrance of the collapsed hole. After the support plate 41 is cured, through the guidance of the guide pipe 42, a guide hole is opened in the inner wall on the unconstructed side of the entrance of the collapsed hole, then a grouting pipe 43 is inserted into the guide hole, and then mortar or concrete is poured into the collapsed hole through the grouting pipe 43 to consolidate the inner wall on the unconstructed side of the entrance of the collapsed hole, thereby reducing the possibility of secondary collapse of the rock mass near the collapsed hole area due to instability during subsequent construction. In addition, the support plate 41 can also be used for the protection of subsequent construction.

[0055] Finally, the construction of step S4 is completed as follows: Use the support plate 41 as a construction platform, place a steel mesh in the collapsed cave, and the steel mesh is fixedly connected to the initial anchor bolt 21. Then, fix and seal the formwork for blocking the opening of the collapsed cave through the support plate 41. Then, fill the collapsed cave with concrete through the formwork to block the collapsed cave and reduce the possibility of deformation or collapse of the collapsed cave caused by subsequent geological changes.

[0056] Specifically, since the construction space in the tunnel is relatively limited and the length of the grouting pipe 43 is relatively long, in order to facilitate the pouring of concrete into the area near the collapsed cave, the grouting pipe 43 includes a plurality of grouting pipe sections 431, and the plurality of grouting pipe sections 431 are axially distributed.

[0057] The plurality of grouting pipe sections 431 are sequentially inserted into the guide pipe 42 and then extended into the guide hole. When the grouting pipe section 431 is not completely extended into the guide pipe 42, the next grouting pipe section 431 is threadedly connected to the grouting pipe section 431 located in the guide pipe 42, so that while the grouting pipe section 431 can penetrate into the interior of the guide hole, it is convenient for construction.

[0058] Embodiment 2:

[0059] Refer to Figure 4 In this embodiment, the difference from Embodiment 1 is that the specific steps of step S4 are as follows: When backfilling the collapsed cave with the support plate 41 as the construction platform, a plurality of filling and grouting pipes 5 are arranged in the collapsed cave and distributed in sequence from top to bottom. The filling and grouting pipes 5 are annular and are respectively fixedly connected to different initial anchor bolts 21, and the filling and grouting pipes 5 are horizontally arranged. The grouting pipe 5 can be a common concrete grouting guide pipe, or a grouting pipe 5 is formed by opening grouting holes on the side wall of the pipe.

[0060] Furthermore, a plurality of filling and grouting pipes 5 are communicated with a pump pipe 51 passing through the opening of the collapsed cave for pouring concrete into the filling and grouting pipes 5. A filling valve 52 for controlling the passage of concrete is arranged between the filling and grouting pipes 5 and the pump pipe 51. The filling valve 52 is a safety valve, and the passing pressures of the filling valves 52 connected to the plurality of filling and grouting pipes 5 increase sequentially from bottom to top, so that when grouting, the concrete can be poured into the collapsed cave in layers through the plurality of filling and grouting pipes 5, increasing the density of the concrete without additional electrical control.

[0061] Embodiment 3:

[0062] Refer to Figure 5, the difference between this embodiment and Embodiment 1 lies in that the specific steps of Step S4 are as follows: Inside the collapsed cave, the support plate 41 serves as a construction platform. A reinforcement formwork is hung on the initial anchor bolt 21 at the top, and concrete is poured into the reinforcement formwork to form the reinforced support plate 44. After the reinforced support plate 44 is cured, the reinforcement formwork below is removed.

[0063] A reinforcement formwork is hung again below the formed reinforced support plate 44, and the next reinforced support plate 44 is formed through the reinforcement formwork, so that a plurality of reinforced support plates 44 are formed in sequence from top to bottom inside the collapsed cave opening. Finally, the opening formed between the support plate 41 and the edge of the collapsed cave opening is blocked. Thus, while achieving the support for the inside of the collapsed cave, it reduces the possibility of geological deformation of the collapsed cave caused by the pressure generated by the relatively large gravity of the solidified concrete filled in the collapsed cave on the inner wall of the collapsed cave; at the same time, it can effectively reduce the concrete used for the support of the collapsed cave.

[0064] Embodiment 4:

[0065] This application embodiment also discloses a tunnel collapse treatment structure. Refer to Figure 4 , the tunnel collapse treatment structure includes a plurality of initial anchor bolts 21 inserted into the collapsed cave, an initial support layer 2, and a secondary support layer 3. The secondary support layer 3 is located on the central side of the initial support layer 2 facing the collapsed cave, and a backfill layer 6 is formed by filling concrete inside the collapsed cave. Among them, a plurality of vertically distributed filling grouting pipes 5, pump pipes 51, and filling valves 52 are arranged inside the collapsed cave, specifically arranged as in Embodiment 2.

[0066] A support plate 41 is formed at the opening of the collapsed cave. A plurality of guide pipes 42 arranged around the tunnel center are preset inside the support plate 41, and a grouting pipe 43 inserted into the rock mass penetrates through the guide pipe 42. The grouting pipe 43 is used to pour concrete for consolidating the rock mass on the unconstructed side of the opening of the collapsed cave.

[0067] Embodiment 5:

[0068] Refer to Figure 5 , the difference between this embodiment and Embodiment 4 lies in that a plurality of vertically distributed reinforced support plates 44 are formed inside the collapsed cave, and the steel mesh inside the reinforced support plates 44 is fixedly connected to the initial anchor bolts 21 for supporting the collapsed cave.

[0069] The above are all the preferred embodiments of this application. The protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A tunnel collapse treatment process, characterized in that: It includes the following steps: S1. Exclude water spraying: Set a spray pipe in the collapsed cave or at the bottom, then use high-pressure water to remotely wash the inner wall of the collapsed cave, clean the unstable rocks and earthwork in the collapsed cave. After the collapsed cave is stable, open multiple drainage holes in the inner wall of the collapsed cave, insert a flushing water pipe (1) into the drainage hole, the flushing water pipe (1) is inserted into the drainage hole by 30 - 60 cm, the space between the flushing water pipe (1) and the rock surface is sealed with cotton yarn, then seal the drainage hole with cement mortar, the cement mortar is sealed on the side of the cotton yarn facing the center of the collapsed cave, and continuously use high-pressure water to wash the drainage hole to further clean the unstable rocks and earthwork in the collapsed cave; S2. Initial support: Spray concrete on the inner wall of the collapsed cave to close and level the rock surface to form an initial support layer (2), and the thickness of the initial support layer (2) is 2 - 5 cm; S3. Secondary support: Bury multiple initial anchor rods (21) in the inner wall of the collapsed cave, the initial anchor rods (21) penetrate through the initial support layer (2), fixedly connect a secondary support grid (22) to the end of the initial anchor rod (21) that penetrates through the initial support layer (2), multiple secondary support grids (22) are arranged in contact with the initial support layer (2), then spray concrete for the second time to form a secondary support layer (3), the thickness of the secondary support layer (3) is 8 - 10 cm. After the secondary support is completed, set multiple arc-shaped arch frames (4) at the entrance of the collapsed cave, the arch frames (4) are arranged around the length direction of the tunnel and pass through the entrance of the collapsed cave, multiple of the arch frames (4) are fixedly connected with an arc-shaped formwork, and a support plate (41) located inside the entrance of the collapsed cave is cast and formed in the formwork. Multiple guide pipes (42) inserted into the side of the collapsed cave entrance facing the construction direction are arranged on the support plate (41), and the area of the support plate (41) is smaller than the opening area of the collapsed cave entrance; After the support plate (41) is cured, drill a guide hole through the guide pipe (42), the guide hole penetrates into the rock mass on the side of the collapsed cave facing the construction direction, insert a grouting pipe (43) into the guide hole, the grouting pipe (43) is inserted into the rock mass and the opening of the grouting pipe (43) and the guide hole is sealed, then pour concrete into the rock mass on the side of the collapsed cave facing the construction direction through the grouting pipe (43); After the concrete in the rock mass is cured, use the support plate (41) as a formwork, and fixedly connect a closed formwork to the support plate (41) and the edge of the entrance of the collapsed cave; S4. Backfill the collapsed cave: Backfill the collapsed cave with concrete, hang multiple filling grouting pipes (5) distributed in sequence from top to bottom in the collapsed cave through multiple initial anchor rods (21), multiple filling grouting pipes (5) are communicated with a pump pipe (51) that penetrates through the entrance of the collapsed cave, a filling valve (52) for controlling the passage of concrete is arranged between the filling grouting pipe (5) and the pump pipe (51), and the passing pressure of the filling valves (52) connected to multiple filling grouting pipes (5) increases sequentially from bottom to top.

2. The tunnel collapse treatment process according to claim 1, characterized in that: The grouting pipe (43) includes multiple grouting pipe sections (431) distributed along the axial direction, the grouting pipe sections (431) are sequentially inserted into the guide hole, and adjacent two grouting pipe sections (431) are threadedly connected.

3. A tunnel collapse treatment process according to claim 1, characterized in that: The specific steps of step S4 are as follows: Hang a strengthening formwork on the initial bolt (21) through the support plate (41), then pour concrete into the strengthening formwork to form a strengthened support plate (44). After the concrete is cured, remove the bottom strengthening formwork, and then successively form a plurality of vertically distributed strengthened support plates (44) in the collapsed cave from top to bottom.

4. A collapse treatment structure applying the tunnel collapse treatment process described in any one of claims 1-3, characterized in that: It includes an initial bolt (21) inserted into the collapsed cave, an initial support layer (2) and a secondary support layer (3), and the secondary support layer (3) is located on the side of the initial support layer (2) facing the center of the collapsed cave.

5. A landslide treatment structure according to claim 4, characterized in that: The collapsed cave is filled with a backfill layer (6) formed by concrete.

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