Tunnel collapse rapid treatment method using assembly type self-adaptive expansion bag stent

Abstract

The invention relates to a tunnel collapse rapid treatment method using an assembly type self-adaptive expansion bag support, which comprises the following steps: reinforcing a non-collapse section around the tunnel collapse, measuring the height and the volume of each area of a tunnel collapse cavity, determining the number of required struts and the mounting positions of the struts, and then mounting the struts and expansion bags. Two-stage pore forming and chemical grouting are conducted on the reinforced section, a grout stopping layer and a consolidation layer are formed below the collapse broken body, an expansion bag and a supporting column are dismantled, a steel arch frame is built below the grout stopping layer, a pipe shed is arranged between the steel arch frame below the grout stopping layer and the steel arch frame of the reinforced section, and rapid hardening concrete is sprayed; and the inner side of the tunnel is separated from the cavity to form a protective shell, secondary lining reinforcement is conducted, and finally holes are formed in the cavity in the reinforced section and backfill is conducted. The tunnel collapse is quickly treated by using the assembly type self-adaptive expansion bag and the bracket, the collapse body in the cavity can be prevented from continuously invading the construction space, and the construction efficiency reduction caused by slow cleaning work is prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction and relates to a method for quickly processing tunnel collapse using an assembled adaptive expansion bag support. Background Art

[0002] Modern underground projects inevitably encounter fault zones. Crossing these zones can easily lead to safety issues such as landslides and the resulting water inrush and leakage, due to subjective judgment by construction workers, improper equipment operation, and a lack of comprehensive understanding of geological conditions. If these issues are not addressed quickly and effectively, construction efficiency declines and project progress is delayed.

[0003] During the subsequent construction after the collapse, temporary support structures, such as steel arch supports and protective sheds, are commonly used. Cleanup work can be carried out after adjacent sections stabilize. However, if the collapsed material within the cavity continues to intrude into the tunnel, the construction period will be significantly extended if this cannot be effectively prevented. Furthermore, fixed support structures are not adaptable to the diverse shapes of cavities.

[0004] The fracture zone is treated by grouting. Although the cost of using traditional cement-based grouting materials is low, their durability and corrosion resistance are poor. The improved cement-based materials often have too many modifiers and a small proportion of cement, which leads to increased costs. At the same time, the cement slurry takes a long time to solidify, and due to its high viscosity, it has poor fluidity and permeability, making it impossible to treat the fault fracture zone in a timely and efficient manner. In addition, cement grouting cannot fundamentally cure the water seepage caused by cracks in concrete structures. In order to solve this problem, in recent years, some people have proposed the concept of airbag grouting. For example, the Chinese invention patent with publication number CN117780392B published on March 29, 2024 discloses an airbag grouting treatment method for underground tunnel collapse. Although this method solves the problem of secondary collapse during the construction process, it assumes that the tunnel is completely buried after the collapse, and does not consider other situations. In addition, the airbag structure disclosed in this method is simple and single, and cannot fit and seal irregular cavities well. At the same time, it does not consider the possibility of sudden failure of the structure during construction, resulting in reduced safety of the construction space below the cavity. Therefore, there is an urgent need to develop a method that can quickly protect the tunnel space from continuous invasion of landslide bodies and efficiently handle broken bodies. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for quickly handling tunnel collapse using an assembled adaptive expansion bag support, which solves the problem of slow construction and low cement grouting efficiency caused by the continuous invasion of the collapsed body into the tunnel after tunnel construction collapses.

[0006] The technical solution adopted by the present invention is a method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent, comprising the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, and determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: measuring the height and volume of each area of ​​the tunnel collapse cavity; Step 3: Determine the required number of pillars and their installation locations based on the height and volume of each area of ​​the tunnel collapse cavity. Perform the first stage of slag removal on the tunnel collapse cavity, then install the pillars and expansion bladders. Fill the expansion bladders with water in different areas to ensure they fit tightly against the rock wall in the cavity. Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced area to form a grouted rock mass below the collapsed body, the grouted rock mass including a grouting layer and a consolidation layer; Step 5: Release the contents of the expansion bladder, conduct the second stage of slag removal in the tunnel, and then remove the expansion bladder and support pillars; Step 6: Build a steel arch frame under the rock mass after grouting, arrange a pipe shed and lay a steel mesh between the steel arch frame under the rock mass after grouting and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inside of the tunnel from the cavity to form a protective shell, and carry out secondary lining reinforcement. Finally, make holes into the cavity in the reinforced section and backfill.

[0007] In step 1, the uncollapsed section around the tunnel collapse is reinforced, including adding locking anchor rods on both sides of the steel arch frame in the uncollapsed section around the tunnel collapse, and welding the gaskets of the locking anchor rods to the arch frame.

[0008] In step 2, a three-dimensional laser scanner is used to scan the tunnel collapse cavity to construct a three-dimensional model of the tunnel collapse cavity, thereby obtaining the height and volume of each area of ​​the cavity.

[0009] The specific process of step 3 is as follows: Step 3.1: Calculate the impact force of the debris from the top of the tunnel collapse cavity falling to the top of the support F 1:

[0010]

[0011]

[0012] Where, M is the weight of the gravel at the top of the tunnel collapse cavity, M= ρV , ρ is the rock density at the top of the tunnel, V is the volume of the tunnel collapse cavity, v 1 is the maximum falling velocity of the gravel at the top of the tunnel collapse cavity, t 1 is the time it takes for the debris at the top of the tunnel collapse cavity to fall to the top of the support, t2 is the time when the gravel contacts the pillar, H is the average height difference between the top of the tunnel collapse cavity and the top of the pillar, and the pillar height is the height of the top of the excavated cavern; Step 3.2: Divide the tunnel collapse cavity into n regions along the length of the tunnel. The volume of the cavity in each region is V i , V i ={ V 1, V 2,……, V n}, the number of pillars required in each region is n i , the calculation formula is as follows:

[0013] Where, F 1 is the impact force of the debris from the top of the tunnel collapse cavity falling to the top of the pillar, F 2 is the bearing capacity of a single pillar, W1 is the maximum weight of the expansion bag after water injection; If calculated n i If it is a decimal, use the rounding up method; Step 3.3: Determine the number of pillars required for each area after rounding n i Is it greater than 1? n i The area with a value greater than 1 is divided again into N areas along the width of the tunnel. The corresponding cavity volume of each area is V j , V j ={ V 1, V 2,……, V N}, the number of pillars required in each region is n j , the calculation formula is as follows:

[0014] If calculated n j If it is a decimal, use the rounding up method; Step 3.4: Determine the number of pillars required for each area after rounding n j Is it greater than 1? n j The areas with a value greater than 1 are divided again until the number of pillars allocated to each area is 1; Step 3.5: Select the location for pillar installation in each area, perform the first stage of slag removal at the location for pillar installation, remove the collapsed body, and then install the pillars. After the pillars are installed, use steel bars to connect them to each other; Step 3.6: Install an expansion bladder at the top of the pillar and fill it with water in sections so that the bladder fits tightly against the rock wall in the cavity. In step 3.7, adjust the height of the pillars so that the top of each pillar fits the bottom of the expansion bag.

[0015] The support is a hydraulic support with a square base at the bottom. Ground nail holes are opened around the square base. Four rotating parts are sleeved near the top of the support. The rotating parts are rotatably connected to the support, and steel bar holes are opened on the sides of the rotating parts.

[0016] The expansion bladder is a multi-cavity expansion bladder, each cavity is independent of each other and has its own water inlet and sealing plug.

[0017] The specific process of step 4 is as follows: Step 4.1: Use a hand drill to drill the first stage of holes in the reinforced area. The drill rod is a hollow self-feeding anchor rod. The hole is drilled in one go. A connecting sleeve is used to connect the rods. The anchor rod is left in the rock mass. After the drill hole is connected to the broken body at the top of the expansion bag, the first stage grouting hole is formed. A 10cm-30cm joint is reserved. Step 4.2: Use pressurized water to flush out impurities in the first-stage grouting holes. Use seamless steel pipes to insert self-propelled anchor rods in sections. Weld the joints and use high-pressure air to blow them out. After ensuring that there is no rock debris in the steel pipe, weld the joint at the tail end of the seamless steel pipe and connect it to the grouting pump pipeline. Step 4.3: When grouting begins, prepare no more than 15 kg of slurry for the first time. Place the slurry preparation bucket in a cooling water tank to prepare the slurry. The proportion of the components is 1000:70:10:modified epoxy resin grouting liquid:curing agent:curing accelerator. Stir manually to mix the components evenly. Then, use a grouting pump to pour the slurry into the seamless steel pipe to form an arch-shaped grouting layer in the tunnel collapse debris. Step 4.4: Cut off the reserved anchor joint, seal the grouting hole, and manually seal the remaining hole with cement mortar mixed with an expansion agent. The expansion agent dosage is 3% to 3.5% of the cement dosage. Step 4.5: Use a hand drill to drill the second stage of holes in the reinforced area. After the drilled hole is connected to the broken body at the top of the stop layer, the second stage grouting hole is formed, leaving a 10cm-30cm joint. In step 4.6, grout is injected through the second-stage grouting holes to form an arch-shaped consolidation layer above the grouting layer. The reserved anchor joints are cut off, the grouting holes are closed, and the remaining sections in the holes are manually sealed with cement mortar mixed with an expansion agent.

[0018] A grouting layer with an arch-like structure is formed in the collapsed and broken body of the tunnel, with a grouting pressure of 6-8 MPa, and a consolidation layer with an arch-like structure is formed above the grouting layer, with a grouting pressure of 12-13 MPa.

[0019] In step 6, steel arch frames are built under the rock mass after grouting. The spacing between the steel arch frames is determined according to the surrounding rock grade of the construction area. For surrounding rock of grade III and above, the spacing between the steel arch frames is 120 cm. For surrounding rock between grade II and grade III, the spacing between the steel arch frames is 100 cm. For surrounding rock below grade II, the spacing between the steel arch frames is between 50 cm and 80 cm.

[0020] In step 6, holes are drilled into the cavity at the reinforced section and backfilled. The specific process is as follows: Step 6.1: Drill holes into the cavity at the bottom of the grouting layer in the reinforced section of step 1 and install backfill grouting pipes, with the holes tilted upward. Depending on the drilling angle, the height of the grouting pipe outlet on one side of the cavity is different. An exhaust hole and exhaust pipe are installed near the top of the cavity. Step 6.2: Grout the cavity layer by layer through grouting pipes at different heights. The grouting pressure is 0.3 MPa and the grouting height does not exceed 1 m each time. Grouting is continued for 5 minutes to complete the grouting of all grouting holes. Step 6.3: Clean the dirt in the grouting holes and exhaust holes, seal and smooth the entire hole with cement mortar, and cut off the embedded pipes exposed on the lining concrete surface.

[0021] The beneficial effects of the present invention are as follows: (1) The use of prefabricated adaptive expansion bags and brackets to quickly deal with tunnel collapse can prevent the collapse body in the cavity from continuously invading the construction space and prevent the slow cleaning work from reducing construction efficiency; (2) The support sleeve used in the present invention is provided with four rotating parts, which are rotatably connected to the support. A steel bar hole is provided on the side of the rotating part. Multiple supports can be connected in any triangle shape. The space occupied by the base of a single support is small. Therefore, the support can be placed at a small position where slag removal is not required or is easy to remove. A large-area working platform is not required, which reduces the possibility of the landslide in the cavity further invading the tunnel due to the long slag removal period. (3) In response to the various shapes of cavities that appear after the collapse, the hydraulic support can be adjusted in position and height to achieve higher adaptability. The expansion bladder used is a multi-cavity expansion bladder, each cavity is independent of each other, and the appropriate partition can be selected for expansion according to the shape of the tunnel collapse cavity, so that the expansion bladder can fit the rock wall as closely as possible, thereby improving the sealing efficiency; (4) Determine the required number of pillars based on the height and volume of each area of ​​the cavity, and then allocate the pillar installation positions. Increase the pillar density in areas with large impact force, and reduce the pillar density in areas with small impact force. Adjust the ability of the pillar structure to withstand accidental loads in different areas to make it more reasonable. (5) Compared with traditional cement grouting treatment, the layered chemical grouting used in the present invention has the advantages of good durability and corrosion resistance, fast consolidation effect, and less material waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic flow chart of a method for rapidly treating tunnel collapse using an assembled adaptive expansion bag stent according to the present invention; Figure 2 This is a schematic diagram of the support structure in the method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to the present invention; Figure 3 It is a schematic diagram of the process of determining the support installation position in the method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent of the present invention; Figure 4 is a structural diagram of the expansion bladder used in Example 2 of the present invention; Figure 5 It is a schematic diagram of two-stage pore creation and chemical grouting in the method for rapid treatment of tunnel collapse using an assembled adaptive expansion bag stent of the present invention; Figure 6 It is a schematic diagram of the installation of a steel arch frame in a method for quickly treating tunnel collapse using an assembled adaptive expansion bag support according to the present invention.

[0023] In the figure, 1. Pillar, 2. Broken body, 3. Collapsed body, 4. Steel arch, 5. Expansion bag, 6. First stage grouting hole, 7. Second stage grouting hole, 8. Grouting stop layer, 9. Consolidation layer, 10. Tunnel collapse cavity, 11. Pipe shed, 12. Steel mesh, 13. Rock mass after grouting, 14. Steel bars, 15. Square base, 16. Rotating part, 17. Ground nail hole, 18. Steel bar hole. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 A method for quickly handling tunnel collapse using an assembled adaptive expansion bag stent, see Figure 1 , including the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, and determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: measuring the height and volume of each area of ​​the tunnel collapse cavity 10; Step 3: Determine the required number of pillars 1 and their installation locations based on the height and volume of each area of ​​the tunnel collapse cavity 10, perform the first stage of slag removal on the tunnel collapse cavity 10, and then install the pillars 1 and expansion bladders 5. Fill the expansion bladders 5 with water in different areas to ensure that the expansion bladders 5 fit tightly against the rock wall in the cavity. Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced section to form a grouted rock mass 13 below the collapsed broken body 2. The grouted rock mass 13 includes a grouting layer 8 and a consolidation layer 9. Step 5: Release the contents of the expansion bladder 5, perform the second stage of slag removal in the tunnel, and then remove the expansion bladder 5 and the support 1; Step 6: Build a steel arch frame 4 under the grouting rock mass 13, arrange a pipe shed 11 and lay a steel mesh 12 between the steel arch frame under the grouting rock mass and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and carry out secondary lining reinforcement. Finally, make holes into the cavity in the reinforced section and backfill.

[0026] Example 2 A method for quickly treating tunnel collapse using an assembled adaptive expansion bladder stent comprises the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, including applying locking anchors on both sides of the steel arch frame in the uncollapsed area around the tunnel collapse, and welding the gaskets of the locking anchors to the arch frame. Then, determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: measuring the height and volume of each area of ​​the tunnel collapse cavity 10, scanning the tunnel collapse cavity using a three-dimensional laser scanner, and constructing a three-dimensional model of the tunnel collapse cavity, thereby obtaining the height and volume of each area of ​​the cavity; Step 3: Determine the required number of pillars 1 and their installation locations based on the height and volume of each area of ​​the tunnel collapse cavity 10, perform the first stage of slag removal on the tunnel collapse cavity 10, and then install the pillars 1 and expansion bladders 5. Fill the expansion bladders 5 with water in different areas to ensure that the expansion bladders 5 fit tightly against the rock wall in the cavity. Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced section to form a grouted rock mass 13 below the collapsed broken body 2. The grouted rock mass 13 includes a grouting layer 8 and a consolidation layer 9. Step 5: Release the contents of the expansion bladder 5, perform the second stage of slag removal in the tunnel, and then remove the expansion bladder 5 and the support 1; Step 6: Build a steel arch frame 4 under the grouting rock mass 13, arrange a pipe shed 11 and lay a steel mesh 12 between the steel arch frame under the grouting rock mass and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and carry out secondary lining reinforcement. Finally, make holes into the cavity in the reinforced section and backfill.

[0027] Example 3 A method for quickly treating tunnel collapse using an assembled adaptive expansion bladder stent comprises the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, including applying locking anchors on both sides of the steel arch frame in the uncollapsed area around the tunnel collapse, and welding the gaskets of the locking anchors to the arch frame. Then, determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: measuring the height and volume of each area of ​​the tunnel collapse cavity 10, scanning the tunnel collapse cavity using a three-dimensional laser scanner, and constructing a three-dimensional model of the tunnel collapse cavity, thereby obtaining the height and volume of each area of ​​the cavity; Step 3: Determine the required number of pillars 1 and their installation locations based on the height and volume of each area of ​​the tunnel collapse cavity 10, perform the first stage of slag removal on the tunnel collapse cavity 10, and then install the pillars 1 and expansion bladders 5. Fill the expansion bladders 5 with water in different areas to ensure that the expansion bladders 5 fit tightly against the rock wall in the cavity. The specific process of step 3 is as follows: Step 3.1, calculate the impact force of the debris from the top of the tunnel collapse cavity 10 falling to the top of the pillar 1 F 1:

[0028]

[0029]

[0030] Where, M is the weight of the gravel at the top of the tunnel collapse cavity, M= ρV , ρ is the rock density at the top of the tunnel, V is the volume of the tunnel collapse cavity, v 1 is the maximum falling velocity of the gravel at the top of the tunnel collapse cavity, t 1 is the time it takes for the debris at the top of the tunnel collapse cavity to fall to the top of the support, t 2 is the time when the gravel contacts the pillar, H is the average height difference between the top of the tunnel collapse cavity and the top of the pillar, and the pillar height is the height of the top of the excavated cavern; Step 3.2: Divide the tunnel collapse cavity 10 into n regions along the length of the tunnel. The volume of the cavity corresponding to each region is Vi , V i ={ V 1, V 2,……, V n}, the number of pillars 1 required in each region is n i , the calculation formula is as follows:

[0031] Where, F 1 is the impact force of the debris from the top of the tunnel collapse cavity falling to the top of the pillar, F 2 is the bearing capacity of a single pillar, W1 is the maximum weight of the expansion bag after water injection; If calculated n i If it is a decimal, use the rounding up method; Step 3.3: Determine the number of pillars required for each area after rounding n i Is it greater than 1? n i The area with a value greater than 1 is divided again into N areas along the width of the tunnel. The corresponding cavity volume of each area is V j , V j ={ V 1, V 2,……, V N}, the number of pillars required in each region is n j , the calculation formula is as follows:

[0032] If calculated n j If it is a decimal, use the rounding up method; Step 3.4: Determine the number of pillars required for each area after rounding n j Is it greater than 1? n j The areas with a value greater than 1 are divided again until the number of pillars allocated to each area is 1; Step 3.5, selecting the installation location of the pillar 1 in each area, performing the first stage of slag removal at the pillar installation location, removing the collapsed body 3, and then installing the pillars. After the pillars are installed, they are connected to each other using steel bars 14; Step 3.6: Install the expansion bladder 5 on the top of the pillar 1 and fill the expansion bladder 5 with water in sections so that the expansion bladder 5 fits tightly against the rock wall in the cavity; Step 3.7, adjust the height of the pillars 1 so that the top of each pillar 1 fits the bottom of the expansion bag 5.

[0033] See also Figure 2 The pillar 1 used in step 3 is a hydraulic pillar. A square base 15 is provided at the bottom of the pillar 1. Ground nail holes 17 are opened around the square base 15. Four rotating parts 16 are provided near the top of the pillar 1. The rotating parts 16 are rotatably connected to the pillar 1. Steel bar holes 18 are opened on the side of the rotating parts 16.

[0034] Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced section to form a grouted rock mass 13 below the collapsed broken body 2. The grouted rock mass 13 includes a grouting layer 8 and a consolidation layer 9. Step 5: Release the contents of the expansion bladder 5, perform the second stage of slag removal in the tunnel, and then remove the expansion bladder 5 and the support 1; Step 6: Build a steel arch frame 4 under the grouting rock mass 13, arrange a pipe shed 11 and lay a steel mesh 12 between the steel arch frame under the grouting rock mass and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and carry out secondary lining reinforcement. Finally, make holes into the cavity in the reinforced section and backfill.

[0035] Example 4 A method for quickly treating tunnel collapse using an assembled adaptive expansion bladder stent comprises the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, including applying locking anchors on both sides of the steel arch frame in the uncollapsed area around the tunnel collapse, and welding the gaskets of the locking anchors to the arch frame. Then, determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: measuring the height and volume of each area of ​​the tunnel collapse cavity 10, scanning the tunnel collapse cavity using a three-dimensional laser scanner, and constructing a three-dimensional model of the tunnel collapse cavity, thereby obtaining the height and volume of each area of ​​the cavity; Step 3: Determine the required number of pillars 1 and their installation locations based on the height and volume of each area of ​​the tunnel collapse cavity 10, perform the first stage of slag removal on the tunnel collapse cavity 10, and then install the pillars 1 and expansion bladders 5. Fill the expansion bladders 5 with water in different areas to ensure that the expansion bladders 5 fit tightly against the rock wall in the cavity. The specific process of step 3 is as follows: Step 3.1, calculate the impact force of the debris from the top of the tunnel collapse cavity 10 falling to the top of the pillar 1 F 1:

[0036]

[0037]

[0038] Where, M is the weight of the gravel at the top of the tunnel collapse cavity, M= ρV , ρ is the rock density at the top of the tunnel, V is the volume of the tunnel collapse cavity, v 1 is the maximum falling velocity of the gravel at the top of the tunnel collapse cavity, t 1 is the time it takes for the debris at the top of the tunnel collapse cavity to fall to the top of the support, t 2 is the time when the gravel contacts the pillar, H is the average height difference between the top of the tunnel collapse cavity and the top of the pillar, and the pillar height is the height of the top of the excavated cavern; Step 3.2: Divide the tunnel collapse cavity 10 into n regions along the length of the tunnel. The volume of the cavity corresponding to each region is V i , V i ={ V 1, V 2,……, V n}, the number of pillars 1 required in each region is n i , the calculation formula is as follows:

[0039] Where, F 1 is the impact force of the debris from the top of the tunnel collapse cavity falling to the top of the pillar, F 2 is the bearing capacity of a single pillar, W1 is the maximum weight of the expansion bag after water injection; If calculated n i If it is a decimal, use the rounding up method; Step 3.3: Determine the number of pillars required for each area after rounding n i Is it greater than 1? n i The area with a value greater than 1 is divided again into N areas along the width of the tunnel. The corresponding cavity volume of each area is V j , V j ={ V 1, V 2,……, V N}, the number of pillars required in each region is n j , the calculation formula is as follows:

[0040] If calculated n j If it is a decimal, use the rounding up method; Step 3.4: Determine the number of pillars required for each area after rounding n j Is it greater than 1? n j The areas with a value greater than 1 are divided again until the number of pillars allocated to each area is 1; Step 3.5, select the installation location of the pillar 1 in each area, carry out the first stage of slag removal at the pillar installation location, remove the collapsed body 3, and then install the pillars. After the pillars are installed, use steel bars 14 to connect them to each other. Figure 3 ; Step 3.6: Install the expansion bladder 5 on the top of the pillar 1 and fill the expansion bladder 5 with water in sections so that the expansion bladder 5 fits tightly against the rock wall in the cavity; Step 3.7, adjust the height of the pillars 1 so that the top of each pillar 1 fits the bottom of the expansion bag 5.

[0041] The pillar 1 used in step 3 is a hydraulic pillar. A square base 15 is provided at the bottom of the pillar 1. Ground nail holes 17 are opened around the square base 15. Four rotating parts 16 are sleeved near the top of the pillar 1. The rotating parts 16 are rotatably connected to the pillar 1. Steel bar holes 18 are opened on the side of the rotating parts 16.

[0042] Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced section to form a grouted rock mass 13 below the collapsed broken body 2. The grouted rock mass 13 includes a grouting layer 8 and a consolidation layer 9. The specific process of step 4 is as follows: Step 4.1: Use a hand drill to drill the first stage of holes in the reinforced area. The drill rod is a hollow self-feeding anchor rod. The hole is drilled in one go. A connecting sleeve is used to connect the rods. The anchor rod is left in the rock mass. After the drill hole is connected to the broken body at the top of the expansion bag, the first stage grouting hole 6 is formed. A 10cm-30cm joint is reserved. Step 4.2: Use pressurized water to flush out impurities in the first-stage grouting hole 6. Insert the self-propelled anchor rod in sections using seamless steel pipes. Weld the joints and use high-pressure air to blow them out. After ensuring that there is no rock debris in the steel pipe, weld the joint at the tail end of the seamless steel pipe and connect it to the grouting pump pipeline. Step 4.3: Prepare the first slurry of no more than 15 kg at the start of grouting. Place the slurry preparation bucket in a cooling water tank to prepare the slurry. The proportion of the components is modified epoxy resin grouting liquid: curing agent: curing accelerator = 1000:70:10. Stir manually to mix the components uniformly. Then, use a grouting pump to pour the slurry into the seamless steel pipe to form an arch-shaped grouting layer 8 in the tunnel collapse debris 2. Step 4.4: Cut off the reserved anchor joint, seal the grouting hole, and manually seal the remaining hole with cement mortar mixed with an expansion agent. The expansion agent dosage is 3% to 3.5% of the cement dosage. Step 4.5: Use a hand drill to drill a second hole in the reinforced area. After the drill hole is connected to the broken body 2 at the top of the stop layer, a second-stage grouting hole 7 is formed, leaving a 10cm-30cm joint. Step 4.6: Inject grout through the second-stage grouting hole 7 to form an arch-shaped consolidation layer 9 above the grouting layer 8. Cut off the reserved anchor joints, close the grouting holes, and manually seal the remaining sections in the holes with cement mortar mixed with an expansion agent.

[0043] Step 5: Release the contents of the expansion bladder 5, perform the second stage of slag removal in the tunnel, and then remove the expansion bladder 5 and the support 1; Step 6: Build a steel arch frame 4 under the grouting rock mass 13, arrange a pipe shed 11 and lay a steel mesh 12 between the steel arch frame under the grouting rock mass and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and carry out secondary lining reinforcement. Finally, make holes into the cavity in the reinforced section and backfill.

[0044] Example 5 A method for quickly treating tunnel collapse using an assembled adaptive expansion bladder stent comprises the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, including applying locking anchors on both sides of the steel arch frame in the uncollapsed area around the tunnel collapse, and welding the gaskets of the locking anchors to the arch frame. Then, determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: measuring the height and volume of each area of ​​the tunnel collapse cavity 10, scanning the tunnel collapse cavity using a three-dimensional laser scanner, and constructing a three-dimensional model of the tunnel collapse cavity, thereby obtaining the height and volume of each area of ​​the cavity; Step 3: Determine the required number of pillars 1 and their installation locations based on the height and volume of each area of ​​the tunnel collapse cavity 10, perform the first stage of slag removal on the tunnel collapse cavity 10, and then install the pillars 1 and expansion bladders 5. Fill the expansion bladders 5 with water in different areas to ensure that the expansion bladders 5 fit tightly against the rock wall in the cavity. The specific process of step 3 is as follows: Step 3.1, calculate the impact force of the debris from the top of the tunnel collapse cavity 10 falling to the top of the pillar 1 F 1:

[0045]

[0046]

[0047] Where, M is the weight of the gravel at the top of the tunnel collapse cavity, M= ρV , ρ is the rock density at the top of the tunnel, V is the volume of the tunnel collapse cavity, v 1 is the maximum falling velocity of the gravel at the top of the tunnel collapse cavity, t 1 is the time it takes for the debris at the top of the tunnel collapse cavity to fall to the top of the support, t 2 is the time when the gravel contacts the pillar, H is the average height difference between the top of the tunnel collapse cavity and the top of the pillar, and the pillar height is the height of the top of the excavated cavern; Step 3.2: Divide the tunnel collapse cavity 10 into n regions along the length of the tunnel. The volume of the cavity corresponding to each region is V i , V i ={ V 1, V 2,……, V n}, the number of pillars 1 required in each region is n i , the calculation formula is as follows:

[0048] Where, F 1 is the impact force of the debris from the top of the tunnel collapse cavity falling to the top of the pillar, F 2 is the bearing capacity of a single pillar, W1 is the maximum weight of the expansion bag after water injection; If calculated n i If it is a decimal, use the rounding up method; Step 3.3: Determine the number of pillars required for each area after rounding n i Is it greater than 1? n i The area with a value greater than 1 is divided again into N areas along the width of the tunnel. The corresponding cavity volume of each area is V j , V j ={ V 1, V 2,……, V N}, the number of pillars required in each region is n j , the calculation formula is as follows:

[0049] If calculatedn j If it is a decimal, use the rounding up method; Step 3.4: Determine the number of pillars required for each area after rounding n j Is it greater than 1? n j The areas with a value greater than 1 are divided again until the number of pillars allocated to each area is 1; Step 3.5, selecting the installation location of the pillar 1 in each area, performing the first stage of slag removal at the pillar installation location, removing the collapsed body 3, and then installing the pillars. After the pillars are installed, they are connected to each other using steel bars 14; Step 3.6: Install an expansion bladder 5 on the top of the pillar 1. The expansion bladder 5 is a multi-cavity expansion bladder, each cavity of which is independent of the others and has its own water inlet and sealing plug. Fill the expansion bladder 5 with water in different areas so that the expansion bladder 5 fits tightly against the rock wall in the cavity. Step 3.7, adjust the height of the pillars 1 so that the top of each pillar 1 fits the bottom of the expansion bag 5.

[0050] The pillar 1 used in step 3 is a hydraulic pillar. A square base 15 is provided at the bottom of the pillar 1. Ground nail holes 17 are opened around the square base 15. Four rotating parts 16 are sleeved near the top of the pillar 1. The rotating parts 16 are rotatably connected to the pillar 1. Steel bar holes 18 are opened on the side of the rotating parts 16.

[0051] Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced section to form a grouted rock mass 13 below the collapsed broken body 2. The grouted rock mass 13 includes a grouting layer 8 and a consolidation layer 9. The specific process of step 4 is as follows: Step 4.1: Use a hand drill to drill the first stage of holes in the reinforced area. The drill rod is a hollow self-feeding anchor rod. The hole is drilled in one go. A connecting sleeve is used to connect the rods. The anchor rod is left in the rock mass. After the drill hole is connected to the broken body at the top of the expansion bag, the first stage grouting hole 6 is formed. A 10cm-30cm joint is reserved. Step 4.2: Use pressurized water to flush out impurities in the first-stage grouting hole 6. Insert the self-propelled anchor rod in sections using seamless steel pipes. Weld the joints and use high-pressure air to blow them out. After ensuring that there is no rock debris in the steel pipe, weld the joint at the tail end of the seamless steel pipe and connect it to the grouting pump pipeline. Step 4.3: Prepare the first slurry of no more than 15 kg at the start of grouting. Place the slurry preparation bucket in a cooling water tank to prepare the slurry. The proportion of the components is modified epoxy resin grouting liquid: curing agent: curing accelerator = 1000:70:10. Stir manually to mix the components uniformly. Then, use a grouting pump to pour the slurry into the seamless steel pipe at a grouting pressure of 6-8 MPa to form an arch-shaped grouting layer 8 in the tunnel collapse fragment 2. Step 4.4: Cut off the reserved anchor joint, seal the grouting hole, and manually seal the remaining hole with cement mortar mixed with an expansion agent. The expansion agent dosage is 3% to 3.5% of the cement dosage. Step 4.5: Use a hand drill to drill a second hole in the reinforced area. After the drill hole is connected to the broken body 2 at the top of the stop layer, a second-stage grouting hole 7 is formed, leaving a 10cm-30cm joint. Step 4.6: Inject slurry through the second-stage grouting hole 7 at a grouting pressure of 12-13 MPa to form an arch-shaped consolidation layer 9 above the stop layer 8. Cut off the reserved anchor joints, close the grouting holes, and manually seal the remaining sections in the holes with cement mortar mixed with an expansion agent.

[0052] Step 5: Release the contents of the expansion bladder 5, perform the second stage of slag removal in the tunnel, and then remove the expansion bladder 5 and the support 1; Step 6: Build a steel arch frame 4 under the grouting rock mass 13, arrange a pipe shed 11 and lay a steel mesh 12 between the steel arch frame under the grouting rock mass 13 and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and carry out secondary lining reinforcement. Finally, make holes into the cavity in the reinforced section and backfill.

[0053] The specific process of step 6 is as follows: Step 6.1: Build steel arches 4 below the grouting layer 8. Determine the spacing between the steel arches 4 based on the surrounding rock grade of the construction area. For rock grade III and above, the spacing between the steel arches 4 is 120 cm. For rock grade II to III, the spacing between the steel arches 4 is 100 cm. For rock grade below II, the spacing between the steel arches 4 is between 50 cm and 80 cm. Step 6.2: Arrange a pipe shed and lay a steel mesh between the steel arch frame below the grouting layer 8 and the steel arch frame in the reinforced section. Then, spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and perform secondary lining reinforcement. Step 6.3: Drill holes into the cavity at the bottom of the grouting layer in the reinforced section of step 1 and install backfill grouting pipes, with the holes tilted upward. Depending on the drilling angle, the height of the grouting pipe outlet on one side of the cavity is different. An exhaust hole and exhaust pipe are installed near the top of the cavity. Step 6.4: Grout the cavity layer by layer through grouting pipes at different heights. The grouting pressure is 0.3 MPa and the grouting height does not exceed 1 m each time. Grouting is continued for 5 minutes to complete the grouting of all grouting holes. Step 6.5: Clean the dirt in the grouting holes and exhaust holes, seal and smooth the entire hole with cement mortar, and cut off the embedded pipes exposed on the lining concrete surface.

[0054] Example 6 A method for quickly treating tunnel collapse using an assembled adaptive expansion bladder stent comprises the following steps: Step 1: Reinforce the uncollapsed area around the tunnel collapse, including applying locking anchors on both sides of the steel arch frame in the uncollapsed area around the tunnel collapse. The anchors are Φ18 threaded steel bars with a length L of 1.5m, and the gaskets of the locking anchors are welded to the arch frame. Then, determine whether water gushing occurs at the tunnel collapse site. If water gushing occurs, drain the tunnel and then proceed to step 2. If water gushing does not occur, proceed directly to step 2. Step 2: Measure the height and volume of each area of ​​the tunnel collapse cavity 10, use a three-dimensional laser scanner to scan the tunnel collapse cavity, and construct a three-dimensional model of the tunnel collapse cavity to obtain the height and volume of each area of ​​the cavity. In this embodiment, the volume of the tunnel collapse cavity is 28.68m 3 ; Step 3: Determine the required number of pillars 1 based on the height and volume of each area of ​​the tunnel collapse cavity 10, perform the first stage of slag removal on the tunnel collapse cavity 10, and then install the pillars 1 and expansion bladders 5. Fill the expansion bladders 5 with water in different areas so that the expansion bladders 5 fit tightly against the rock wall in the cavity. See also Figure 3 , Figure 3 The middle tunnel collapse cavity 10 is a schematic cross-sectional view of the tunnel collapse cavity at the height of the top of the pillar 1. The specific process of step 3 is as follows: Step 3.1, calculate the impact force of the debris from the top of the tunnel collapse cavity 10 falling to the top of the pillar 1 F 1:

[0055]

[0056]

[0057] Where, M is the weight of the gravel at the top of the tunnel collapse cavity, M= ρV , ρ is the density of the rock mass at the top of the tunnel, V is the volume of the tunnel collapse cavity. In this embodiment, the rock mass at the top of the tunnel is gabbro with a density of 3.1 g / cm3. Then, the weight of the debris that may fall from the top of the tunnel collapse cavity is M, which is 8.8908 × 104 kg. H is the average height difference from the top of the tunnel collapse cavity to the top of the pillar. The height of the pillar is the height of the top of the excavated cavern. In this embodiment, the height of the top of the excavated cavern is 2.2 m, and H is 2.669 m. t 1 is the time it takes for the debris at the top of the tunnel collapse cavity to fall to the top of the support, which is calculated to be 0.738s. v1 is the maximum falling velocity of the gravel at the top of the tunnel collapse cavity, which is calculated to be 7.2327m / s. t 2 is the time when the gravel contacts the pillar, which is 0.2s. The impact force F1 is calculated to be 3215.2kN; Step 3.2: Divide the tunnel collapse cavity 10 into three regions along the length of the tunnel. The volume of each region is V i , V i ={ V 1, V 2, V 3}, V 1=7.32m 3 , V 2=11.25 m 3 , V 3=10.11 m 3 , the number of pillars 1 required in each region is n i , the calculation formula is as follows:

[0058] Where, F 1 is the impact force of the debris from the top of the collapsed tunnel cavity falling to the top of the pillar, F 2 is the bearing capacity of a single pillar. F 2 is 150kN, W1 is the maximum weight of the expansion bag after water injection, the required number of expansion bags is determined according to the volume of the collapsed cavity of the tunnel and the maximum volume of a single expansion bag, and then the maximum weight of the expansion bag after water injection is determined. The maximum volume of a single expansion bag used in this embodiment is 52m 3 The volume of the tunnel collapse cavity is 28.68m 3 , which is smaller than the maximum volume of a single expansion bladder, so one expansion bladder is sufficient. The weight of the expansion bladder after filling with water is 30kg, so the maximum gravity after filling with water is 0.294kN; If calculated n i If it is a decimal, use the rounding up method; After calculation, n 1=5.47, rounded up to 6 using the round-up method. n 2=8.41, rounded up to 9 using the round-up method. n 3=7.56, rounded up to 8 using the round-up method.

[0059] Step 3.3: Determine the number of pillars required for each area after rounding n i Is it greater than 1? n iThe area with a value greater than 1 is divided again into N areas along the width of the tunnel. The corresponding cavity volume of each area is V j , V j ={ V 1, V 2,……, V N}, the number of pillars required in each region is n j , the calculation formula is as follows:

[0060] If calculated n j If it is a decimal, use the rounding up method; Step 3.4: Determine the number of pillars required for each area after rounding n j Is it greater than 1? n j The areas with a value greater than 1 are divided again until the number of pillars allocated to each area is 1; Step 3.5, selecting the installation location of the pillar 1 in each area, performing the first stage of slag removal at the pillar installation location, removing the collapsed body 3, and then installing the pillars. After the pillars are installed, they are connected to each other using steel bars 14; Step 3.6, install the expansion bladder 5 on the top of the pillar 1. The expansion bladder 5 is a multi-cavity expansion bladder. Each cavity is independent of each other and has its own water inlet and sealing plug. In this embodiment, the expansion bladder is a 5-cavity expansion bladder. The expansion bladder 5 is divided into sections and filled with water so that the expansion bladder 5 fits tightly to the rock wall in the cavity. Figure 4 ; Step 3.7, adjust the height of the pillars 1 so that the top of each pillar 1 fits the bottom of the expansion bag 5.

[0061] The pillar 1 used in step 3 is a hydraulic pillar. A square base 15 is provided at the bottom of the pillar 1. Ground nail holes 17 are opened around the square base 15. Four rotating parts 16 are sleeved near the top of the pillar 1. The rotating parts 16 are rotatably connected to the pillar 1. Steel bar holes 18 are opened on the side of the rotating parts 16.

[0062] Step 4: Perform two-stage pore drilling and chemical grouting in the reinforced section to form a grouted rock mass 13 below the collapsed broken body 2. The grouted rock mass 13 includes a grouting layer 8 and a consolidation layer 9. See also Figure 5 , the specific process of step 4 is as follows: Step 4.1: Use a hand drill to drill the first stage of holes in the reinforced area. The drill rod is a φ25 hollow self-feeding anchor rod. The hole is drilled in one go. A connecting sleeve is used to connect the rods. The anchor rod is left in the rock mass. After the drill hole is connected to the broken body at the top of the expansion bag, the first stage grouting hole 6 is formed. A 10cm-30cm joint is reserved. Step 4.2: Use pressurized water to flush out impurities in the first-stage grouting hole 6. Use φ13 seamless steel pipes to insert self-feeding anchor rods in sections. Weld the joints and use high-pressure air to blow them out. After ensuring that there is no rock debris in the steel pipe, weld the joint at the tail end of the seamless steel pipe and connect it to the grouting pump pipeline. Step 4.3: When grouting begins, the first slurry preparation shall not exceed 15 kg. The slurry preparation bucket shall be placed in a cooling water tank for slurry preparation. The proportion of each component shall be modified epoxy resin grouting liquid: curing agent: curing accelerator = 1000:70:10. The mixing order shall be as follows: first weigh the modified epoxy resin grouting liquid, then weigh and add the curing accelerator and stir for 1 to 3 minutes, then weigh and add the curing agent and stir for 1 to 3 minutes, and then use a grouting pump to pour the slurry into the seamless steel pipe. The grouting pressure shall be 6-8 MPa, and an arch-shaped grouting stop layer 8 shall be formed in the tunnel collapse crushed body 2 to prevent the second-stage slurry from flowing back into the tunnel; Step 4.4: Cut off the reserved anchor joint, seal the grouting hole, and manually seal the remaining hole with cement mortar mixed with an expansive agent. The cement mortar has a composition ratio of water:cement:sand = 0.3:1:1, and the expansive agent content is 3% to 3.5% of the cement content. The expansive agent is light-burned MgO. Step 4.5: Perform the second stage of hole grouting according to the first stage hole grouting steps. Use a hand drill to drill the second stage hole in the reinforced area. After the drilled hole is connected to the broken body 2 at the top of the stop layer, the second stage grouting hole 7 is formed, leaving a 10cm-30cm joint. In step 4.6, slurry is injected through the second-stage grouting hole 7. The slurry used is the same as that used for the stop-grouting layer. The grouting pressure is 12-13 MPa. An arch-shaped consolidation layer 9 is formed above the stop-grouting layer 8 to bond the loose bodies and prevent the loose bodies from sliding and damaging the tunnel support structure.

[0063] Cut off the reserved anchor joints, close the grouting holes, and manually seal the remaining sections in the holes with cement mortar mixed with expansion agent.

[0064] Step 5: Release the contents of the expansion bladder 5, perform the second stage of slag removal in the tunnel, and then remove the expansion bladder 5 and the support 1; Step 6, see Figure 6A steel arch frame 4 is built under the grouting rock mass 13, a pipe shed 11 is arranged between the steel arch frame under the grouting rock mass 13 and the steel arch frame in the reinforced section, and a steel mesh 12 is laid. Then, quick-setting concrete is sprayed to separate the inner side of the tunnel from the cavity to form a protective shell, and secondary lining reinforcement is carried out. Finally, holes are made into the cavity in the reinforced section and backfilled.

[0065] The specific process of step 6 is as follows: Step 6.1: Build steel arches 4 below the grouting layer 8. According to the surrounding rock grade of the construction area, the spacing between the steel arches 4 is determined to be 120 cm. Step 6.2: Arrange a pipe shed and lay a steel mesh between the steel arch frame below the grouting layer 8 and the steel arch frame in the reinforced section. Then, spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and perform secondary lining reinforcement. Step 6.3: Drill holes into the cavity at the bottom of the grouting layer in the reinforced section of step 1 and install backfill grouting pipes, with the holes tilted upward. Depending on the drilling angle, the height of the grouting pipe outlet on one side of the cavity is different. Vent holes and vent pipes are installed near the top of the cavity. The number of holes is determined by the size of the cavity. Step 6.4: Grout the cavity layer by layer through grouting pipes at different heights. The grouting pressure is 0.3 MPa, and the grouting height does not exceed 1 m each time to ensure that no excessive pressure is exerted on the inner protective shell of the tunnel. Continue grouting for 5 minutes until the grouting holes stop absorbing grout. This completes the grouting of all grouting holes. Step 6.5: Clean the dirt in the grouting holes and exhaust holes, seal and smooth the entire hole with cement mortar, and cut off the embedded pipes exposed on the lining concrete surface.

Claims

1. A method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent, characterized in that: The following steps are involved: Step 1, reinforce the non-collapsed area around the tunnel collapse, determine whether water gushing occurs at the tunnel collapse, if water gushing occurs, drain the tunnel, and then proceed to step 2, if no water gushing occurs, directly proceed to step 2; Step 2, measuring the height and volume of each area of ​​the tunnel collapse cavity (10); Step 3, determining the number of pillars (1) required and their installation positions according to the height and volume of each area of ​​the tunnel collapse cavity (10), performing the first stage of slag removal on the tunnel collapse cavity (10), and then installing the pillars (1) and the expansion bag (5), and filling the expansion bag (5) with water in different areas so that the expansion bag (5) fits tightly against the rock wall in the cavity; Step 4, performing two-stage pore making and chemical grouting in the reinforced section to form a grouted rock mass (13) below the collapsed broken body (2), wherein the grouted rock mass (13) includes a grouting stop layer (8) and a consolidation layer (9); Step 5, releasing the material inside the expansion bag (5), carrying out the second stage of slag removal in the tunnel, and then removing the expansion bag (5) and the support (1); Step 6, build a steel arch frame (4) below the grouting rock mass (13), arrange a pipe shed (11) and lay a steel mesh (12) between the steel arch frame below the grouting rock mass (13) and the steel arch frame in the reinforced section, then spray quick-setting concrete to separate the inner side of the tunnel from the cavity to form a protective shell, and perform secondary lining reinforcement, and finally make a hole into the cavity in the reinforced section and backfill it.

2. The method for rapidly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 1, characterized in that: In the step 1, the non-collapsed section around the tunnel collapse is reinforced, including adding locking anchor rods on both sides of the steel arch frame in the non-collapsed section around the tunnel collapse, and welding the gaskets of the locking anchor rods to the arch frame.

3. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 1, characterized in that: In the step 2, a three-dimensional laser scanner is used to scan the tunnel collapse cavity (10) to construct a three-dimensional model of the tunnel collapse cavity (10), thereby obtaining the height and volume of each region of the cavity.

4. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 3 is characterized in that: The specific process of step 3 is as follows: Step 3.1, calculate the impact force of the debris from the top of the tunnel collapse cavity (10) falling to the top of the support (1) F 1: Where, M is the weight of the gravel at the top of the collapsed cavity of the tunnel, M= ρV , ρ is the rock mass density at the top of the tunnel, V is the volume of the collapsed cavity of the tunnel, v 1 is the maximum falling speed of the gravel at the top of the tunnel collapse cavity, t 1 is the time it takes for the debris at the top of the collapsed cavity of the tunnel to fall to the top of the pillar, t 2 is the time when the gravel contacts the pillar, H is the average height difference from the top of the tunnel collapse cavity to the top of the pillar, and the pillar height is the height of the top of the excavated cavern; Step 3.2: Divide the tunnel collapse cavity (10) into n regions along the length of the tunnel. The corresponding cavity volume of each region is V i , V i ={ V 1, V 2,……, V n }, the number of pillars (1) required in each region is n i , the calculation formula is as follows: In the formula, F 1 is the impact force of the debris from the top of the collapsed tunnel cavity falling to the top of the pillar, F 2 is the bearing capacity of a single pillar, W1 is the maximum weight of the expansion bag after water injection; If calculated n i If it is a decimal, use the rounding up method; Step 3.3: Determine the number of pillars required for each area after rounding n i Is it greater than 1? n i The area with >1 is divided again into N areas along the width of the tunnel. The corresponding cavity volume of each area is V j , V j ={ V 1, V 2,……, V N }, the number of pillars required in each region is n j , the calculation formula is as follows: If calculated n j If it is a decimal, use the rounding up method; Step 3.4: Determine the number of pillars required for each area after rounding n j Is it greater than 1? n j The areas with a value greater than 1 are divided again until the number of pillars allocated to each area is 1; Step 3.5, selecting a location for installing the pillars (1) in each area, performing a first-stage slag removal on the location for installing the pillars, removing the collapsed body (3), and then installing the pillars. After the pillars are installed, they are connected to each other using steel bars (14); Step 3.6, installing an expansion bag (5) at the top of the pillar (1), and filling the expansion bag (5) with water in different areas, so that the expansion bag (5) fits tightly against the rock wall in the cavity; Step 3.7, adjusting the height of the pillars (1) so that the top of each pillar (1) fits the bottom of the expansion bag (5).

5. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 4 is characterized in that: The support (1) is a hydraulic support. A square base (15) is provided at the bottom of the support (1). Ground nail holes (17) are provided around the square base (15). Four rotating parts (16) are sleeved near the top of the support (1). The rotating parts (16) are rotatably connected to the support (1). Steel bar holes (18) are provided on the sides of the rotating parts (16).

6. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 4, characterized in that: The expansion bladder (5) is a multi-cavity expansion bladder, each cavity is independent of each other and has its own water inlet and sealing plug.

7. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 1, characterized in that: The specific process of step 4 is as follows: Step 4.1, use a hand-held pneumatic drill to drill the first stage of holes in the reinforced area. The drill rod is a hollow self-advancing anchor rod. The hole is drilled in one go. A connecting sleeve is used to connect the rods. The anchor rod is left in the rock mass. After the drill hole is connected to the broken body at the top of the expansion bag, the first stage grouting hole (6) is formed. A 10cm-30cm joint is reserved. Step 4.2, use pressurized water to flush out impurities in the first-stage grouting hole (6), use seamless steel pipes to insert self-propelled anchor rods in sections, weld the joints, and use high-pressure air to blow to ensure that there is no rock slag in the steel pipe, then weld the joint at the tail end of the seamless steel pipe and connect it to the grouting pump pipeline; Step 4.3, when grouting is started, the first grouting liquid is prepared in an amount not exceeding 15 kg, and the grouting bucket is placed in a cooling water tank for grouting, and the proportion of each component is modified epoxy resin grouting liquid: curing agent: curing accelerator = 1000:70:10, and each component is mixed evenly by manual stirring, and then the grouting liquid is poured into the seamless steel pipe by a grouting pump to form a grouting stop layer (8) of an arched structure in the tunnel collapse fragments (2); Step 4.4, cut off the reserved anchor joint, close the grouting hole, and manually seal the remaining section in the hole with cement mortar mixed with expansion agent, the expansion agent dosage is 3% to 3.5% of the cement dosage; Step 4.5, use a hand drill to drill a second stage hole in the reinforced area, and after the drill hole is connected with the broken body (2) at the top of the stop layer, a second stage grouting hole (7) is formed, leaving a 10cm-30cm joint; Step 4.6, inject grout through the second-stage grouting hole (7) to form a consolidation layer (9) with an arch-shaped structure above the stop layer (8), cut off the reserved anchor joint, close the grouting hole, and manually seal the remaining section in the hole with cement mortar mixed with an expansion agent.

8. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 7, characterized in that: A grouting stop layer (8) with an arch-shaped structure is formed in the tunnel collapse fragments (2), and the grouting pressure is 6-8 MPa. A consolidation layer (9) with an arch-shaped structure is formed above the grouting stop layer (8), and the grouting pressure is 12-13 MPa.

9. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 1, characterized in that: In the step 6, a steel arch frame (4) is built below the grouting rock mass (13). The spacing between the steel arch frames (4) is determined according to the surrounding rock grade of the construction area. For surrounding rock of grade III or above, the spacing between the steel arch frames (4) is 120 cm. For surrounding rock between grade II and grade III, the spacing between the steel arch frames (4) is 100 cm. For surrounding rock below grade II, the spacing between the steel arch frames (4) is between 50 cm and 80 cm.

10. The method for quickly treating tunnel collapse using an assembled adaptive expansion bag stent according to claim 1, characterized in that: In step 6, holes are made inside the cavity in the reinforced section and backfilled. The specific process is as follows: Step 6.1, drilling a hole in the bottom cavity of the stop grout layer (8) in the reinforced section of step 1 and setting a backfill grouting pipe, so that the hole is inclined upward, and the height of the outlet of the grouting pipe on one side of the cavity is different according to the different drilling angles, and an exhaust hole and an exhaust pipe are set near the top of the cavity; Step 6.2, grouting the cavity in layers through grouting pipes at different heights, with a grouting pressure of 0.3 MPa and a grouting height of no more than 1 m each time, until the grouting hole stops absorbing grout, and grouting is terminated after continuing to grout for 5 minutes, completing the grouting of all grouting holes; Step 6.3: clean the dirt in the grouting holes and exhaust holes, seal and smooth the entire hole with cement mortar, and cut off the embedded pipes exposed on the surface of the lining concrete.

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