A construction method for a tunnel in a high-pressure water-rich soft rock geological environment

Abstract

This application discloses a high-pressure, water-rich, soft rock tunnel construction method. The method includes: first, pre-grouting is performed to reinforce the soil layer surrounding the tunnel; then, multiple holes are drilled circumferentially along the tunnel sidewalls for anchor rod insertion. Drainage is first achieved through the holes. After the drainage time is reached, anchor rods are driven into the holes and cement slurry is injected into the anchor rods. Drainage holes are then drilled in the rock strata on both sides of the tunnel. A water collection box is fixed to the tunnel sidewalls so that it covers the drainage holes. The water collection box is then connected to the tunnel invert drainage system. Reinforced steel mesh is then arranged circumferentially along the tunnel sidewalls and support concrete is sprayed. Blast holes are then drilled on the tunnel face. Drainage is first achieved through the holes. After the drainage time is reached, detonators are placed into the holes and blasting excavation is performed. The waste residue is then cleared to complete the excavation of a section of the tunnel. This method reduces the possibility of damage to the primary support concrete structure, thereby improving construction efficiency and safety.

Description

Technical Field

[0001] The present application relates to the technical field of tunnel construction, and in particular to a method for constructing a high-pressure, water-rich, soft rock geological tunnel. Background Art

[0002] With the rapid development of railway construction, tunnel construction through water-rich soft rock strata is inevitable. During the construction of water-rich soft rock tunnels, due to the poor self-stability of the surrounding rock, collapse, large deformation, and water leakage are prone to occur. Therefore, the choice of excavation method is a key factor in controlling surrounding rock deformation.

[0003] At present, tunnel construction in my country generally adopts drilling and blasting method, except for a few areas with poor geological conditions and some special cases where mechanized construction such as shield tunneling is used.

[0004] Currently, there is no systematic approach to deformation control in water-rich soft rock tunnels in China. Conventional construction methods are often used to control deformation in soft rock, namely, driving anchor bolts along the tunnel circumference and then spraying primary support concrete. However, this method is difficult to implement in water-rich soft rock geological areas. After spraying the primary support concrete, the surrounding rock is relatively closed, resulting in high water pressure within the soil layer. This can easily lead to excessive deformation of the primary support concrete, necessitating replacement or additional secondary support reinforcement. This seriously affects the construction schedule and poses significant safety risks. Summary of the Invention

[0005] In order to continuously drain the water in the tunnel rock layer and reduce the possibility of damage to the primary support concrete structure, thereby improving construction efficiency and improving construction safety, the present application provides a high-pressure water-rich soft rock geological tunnel construction method.

[0006] The present application provides a high-pressure, water-rich, soft rock geological tunnel construction method using the following technical solutions:

[0007] A high-pressure, water-rich, soft rock geological tunnel construction method comprises the following steps:

[0008] S1. Drive several advance grouting pipes into the rock formation along the tunnel face contour to form a pipe rack, and then inject cement slurry into the advance grouting pipes;

[0009] S2. Drill multiple holes along the tunnel sidewall for anchor rod insertion. Drain the water through the holes. After the water flow decreases or the drainage time is reached, drive the anchor rods into the holes and inject cement slurry into the anchor rods.

[0010] S3. Drill drainage holes in the rock formations on both sides of the tunnel, fix a water collection box on the tunnel sidewall so that the water collection box covers the drainage holes; set an opening on one side of the water collection box that is in contact with the tunnel sidewall, and then connect the water collection box to the tunnel invert drainage system;

[0011] S4: Arrange steel mesh along the tunnel sidewall and spray support concrete;

[0012] S5. Drill blastholes on the tunnel face and use them for drainage. When the water output from the blastholes decreases or the drainage time is reached, place detonators in the blastholes and then perform blasting excavation.

[0013] S6. Clean up waste residue;

[0014] S7. Repeat steps S1-S6 until the tunnel excavation in the water-rich soft soil section is completed.

[0015] By adopting the above technical solution, during construction, the drill holes and blast holes are first used as drainage holes. After the water output decreases or the drainage time is reached, in order to ensure that the tunnel does not collapse and the construction progress is not affected, the anchor rods are inserted into the drill holes according to the established construction plan, and then additional drainage holes are drilled on the side walls of the tunnel to continue draining water. The drainage holes are then covered with water collection boxes. After the subsequent injection of primary support concrete, the drainage holes will not be blocked by concrete, and the water in the tunnel rock layer can still be discharged through the drainage holes, thereby effectively reducing the internal water pressure of the rock layer, making the primary support concrete less likely to be damaged or deformed, which not only helps to improve construction efficiency but also significantly improves construction safety. Detonators are then installed in the blast holes for blasting excavation. By repeating the above steps, tunnel excavation in water-rich soft soil sections can be quickly completed while ensuring construction safety.

[0016] Preferably, the anchor rod includes a spiral tube and a sleeve, an expansion tube and a fixed tube which are sequentially sleeved on the spiral tube, the sleeve and the expansion tube are both slidably connected to the spiral tube, the fixed tube is fixedly connected to the spiral tube, the fixed tube is conically arranged, the small end of the fixed tube is arranged toward the expansion tube, and the expansion tube is spliced by multiple pipe segments; when installing the anchor rod, the anchor rod is inserted into the borehole, and then the spiral tube is pulled back and the sleeve is used to support the expansion tube, the fixed tube is gradually inserted into the expansion tube and the expansion tube is expanded, and when the expansion tube is tightly pressed against the wall of the borehole, the sleeve is pulled out of the borehole, and then the sealing plate is sleeved on the spiral tube and the sealing plate is pressed against the side wall of the tunnel with a nut.

[0017] By adopting the above technical solution, due to the huge water content of water-rich soft rock geology, water will still surge out of the borehole within the predetermined construction time. If conventional anchor rods are used, there is no clamping force between the anchor rod and the borehole wall, so that in the subsequent grouting process, the anchor rod will have a tendency to fall out of the hole under high pressure, resulting in poor reinforcement effect. The present application redesigns the anchor rod for this special rock formation geology. When installing the anchor rod, first put the expansion tube and the fixed tube on the screw tube, and then insert the screw tube into the borehole. After the screw tube contacts the bottom of the borehole, pull the screw tube back out of the hole and push the sleeve into the hole to resist the expansion tube. The fixed tube gradually inserts into the expansion tube and opens the expansion tube in the process of following the movement of the screw tube. When the screw tube is difficult to pull, it means that the expansion tube has been completely expanded by the fixed tube and a large clamping force is generated between the expansion tube and the wall of the borehole, so that the anchor rod is stably inserted in the borehole, thereby keeping the anchor rod stable during the subsequent grouting process, and thus making the anchor rod have a better reinforcement effect, which is beneficial to improving construction safety.

[0018] Preferably, a plurality of through holes are provided on the fixing tube, and the through holes pass through both ends of the fixing tube.

[0019] By adopting the above technical solution, since the grouting is injected into the drill hole through the spiral tube, and the fixed tube cooperates with the expansion tube to cut off the passage of the drill hole, therefore, by opening a through hole that passes through both ends of the fixed tube on the fixed tube, the through hole is connected to the drill hole, and the cement slurry flowing out from the end of the spiral tube fills the drill hole through the through hole, thereby not affecting the reinforcement effect.

[0020] Preferably, when installing the water collecting box, multiple anchor pipes are driven into the soil layer around the drainage hole. The anchor pipes are provided with internal threads. The water inlet side of the water collecting box is provided with a convex edge along the circumferential direction. A sealing layer is adhered to the convex edge. The convex edge is pressed against the side wall of the tunnel by using a locking bolt to lock the anchor pipe.

[0021] The above technical solution facilitates the installation and removal of the water collection box. When no water or only a small amount of water is discharged from the drainage hole, the water collection box can be removed and reused, saving construction costs. The presence of the convex edge and sealing layer prevents water from escaping from the joint between the water collection box and the tunnel sidewall, thus ensuring that the primary support concrete structure is not damaged, which is conducive to improving construction safety.

[0022] Preferably, after the drainage hole is drilled, a steel cage is inserted into the drainage hole, and the length of the steel cage needs to be less than the depth of the drainage hole.

[0023] By adopting the above technical solution, due to the weak bearing capacity of the water-rich soft rock geological soil layer, the drainage holes are prone to deformation or even collapse, thus affecting drainage. To eliminate the possibility of deformation or collapse of the drainage holes, a steel reinforcement cage is inserted into the drainage holes, and the steel reinforcement cage plays a role in protecting the holes, enabling the drainage holes to maintain the drainage function, thereby reducing the possibility of damage to the primary support concrete structure, which is not only beneficial to improving the construction efficiency but also to enhancing the construction safety.

[0024] Preferably, a first filter screen is arranged in the water collecting box. The first filter screen is arranged vertically. The first filter screen divides the water collecting box into a filtering chamber and a clear water chamber, and the water outlet pipe is communicated with the clear water chamber.

[0025] By adopting the above technical solution, the first filter screen filters the water entering the water collecting box, thereby filtering out the gravel and sediment carried in the water, making the water outlet pipe not easily blocked.

[0026] Preferably, the first filter screen is arranged in a U shape. A second filter screen is vertically and fixedly connected to the bottom of the first filter screen. A filter cloth is slidably connected between the opposite two side walls of the first filter screen. One end of the filter cloth is fixedly connected to the second filter screen, and the top of the water collecting box is arranged to be openable and closable.

[0027] By adopting the above technical solution, initially, the filter cloth collapses, thus not hindering the water from flowing into the water collecting box. After the water collecting box works for a period of time, a certain amount of gravel and sediment will accumulate in the water collecting box and need to be cleaned in time. At this time, directly pull up the filter cloth. The filter cloth, the first filter screen, the second filter screen and the filter cloth form a filter cylinder, and then the filter cylinder can be directly taken out of the water collecting box, and the operation is relatively convenient.

[0028] Preferably, a fixing strip is fixedly connected to the end of the filter cloth far away from the second filter screen. The fixing strip is slidably connected to the first filter screen in the vertical direction. A pull rope is fixedly connected to the upper surface of the fixing strip. A cover plate is hinged to the top of the water collecting box, and the end of the pull rope far away from the fixing strip is detachably connected to the cover plate.

[0029] Since the substances accumulated in the water collecting box are basically gravel and sediment, and the filter cloth is covered by the gravel and sediment, if the filter cloth is pulled up manually, it is bound to come into contact with the gravel, thus there is a risk of scratching the hand. Therefore, by adopting the above technical solution, when the cover plate is opened, the cover plate pulls the pull rope to drag the fixing strip, and the fixing strip guides the filter cloth, enabling the filter cloth to extend in the vertical direction, thus not reducing the volume of the filter cylinder. After the cover plate is opened, the filter cloth is fully unfolded. The construction worker only needs to detach the pull rope from the cover plate and then take out the filter cylinder from the water collecting tank. The operation is simple and efficient, and eliminates the possibility of injury to the construction worker's hand. Description of the Drawings

[0030] Figure 1 is the overall structural schematic diagram of the present application;

[0031] Figure 2 is the structural schematic diagram of the anchor rod in the present application;

[0032] Figure 3 is the internal structural schematic diagram of the water collecting box in the present application;

[0033] Figure 4 is the structural schematic diagram of the water collecting box in the present application.

[0034] Explanation of reference numerals:

[0035] 1, tunnel; 2, anchor rod; 21, screw pipe; 22, sleeve; 23, expansion support pipe; 24, fixed pipe; 25, through hole; 26, cotton rope; 27, sealing plate; 28, nut; 3, water collecting box; 4, convex edge; 5, sealing layer; 6, anchor pipe; 7, pressing plate; 8, locking bolt; 9, first filter screen; 10, positioning groove; 11, water outlet pipe; 12, second filter screen; 13, filter cloth; 14, fixing strip; 15, pulling rope; 16, cover plate; 17, hook; 18, connecting ring; 19, blast hole. Specific embodiments

[0036] The following further elaborates on the present application in conjunction with the attached Figures 1-4 drawings.

[0037] The embodiment of the present application discloses a construction method for a tunnel in high-pressure water-rich soft rock geology. The method includes the following steps:

[0038] S1. A plurality of advanced grouting pipes are formed into a pipe shed in the rock stratum along the contour line of the tunnel 1 face, and then cement slurry is injected into the advanced grouting pipes.

[0039] S2. Referring to Figure 1 , a plurality of drill holes for inserting the anchor rod 2 are drilled circumferentially along the side wall of the tunnel 1. First, the drill holes are used for drainage. After the water discharge volume becomes smaller or after reaching the drainage time, the anchor rod 2 is driven into the drill holes and cement slurry is injected into the anchor rod 2.

[0040] Referring to Figure 2The anchor rod 2 includes a screw tube 21, one end of which is sequentially sleeved with a sleeve 22, an expansion tube 23, and a fixed tube 24. The sleeve 22 and the expansion tube 23 are slidably sleeved with the screw tube 21, and the fixed tube 24 is fixedly connected to the screw tube 21. The fixed tube 24 is located at the end of the screw tube 21. The fixed tube 24 is arranged in a cone shape, with the small end of the fixed tube 24 facing the expansion tube 23. The fixed tube 24 is provided with a plurality of through holes 25, which are circumferentially distributed on the fixed tube 24, and each through hole 25 passes through both ends of the fixed tube 24. The expansion tube 23 is composed of multiple pipe segments, which are tied together by cotton ropes 26. There is a gap between the inner wall of the expansion tube 23 and the outer wall of the screw tube 21 for the small end of the fixed tube 24 to be inserted. The other end of the screw tube 21 is sequentially sleeved with a sealing plate 27 and a nut 28, which is locked and connected to the screw tube 21.

[0041] When installing the anchor rod 2, first remove the sealing plate 27 and nut 28, insert a gasket between the expansion tube 23 and the screw tube 21 to make the expansion tube 23 coaxial with the screw tube 21. Then insert the screw tube 21 into the borehole. When the end of the screw tube 21 reaches the bottom of the borehole, pull the screw tube 21 back and use the sleeve 22 to support the expansion tube 23. The fixed tube 24 is gradually inserted into the expansion tube 23 and the cotton rope 26 is broken. The expansion tube 23 is gradually expanded by the fixed tube 24. When the screw tube 21 is difficult to pull, it means that the expansion tube 23 is tightly against the wall of the borehole. Then, pull the sleeve 22 out of the borehole, then put the sealing plate 27 on the screw tube 21 and use the nut 28 to press the sealing plate 27 against the side wall of the tunnel 1 to complete the installation of the anchor rod 2. The anchor rod 2 in the present application can generate a large pressing force against the hole wall, so that during the subsequent grouting process into the spiral tube 21, the anchor rod 2 will not be displaced under the action of high pressure, which is beneficial to improving the reinforcement effect of the anchor rod 2 on the soil layer.

[0042] Then, cement slurry is injected into the anchor rod 2. When slurry overflow is observed at the sealing plate 27, the grouting is stopped and the pressure is maintained for a period of time to complete the grouting.

[0043] S3. Reference Figure 1 Drain holes are drilled in the rock formations on both sides of Tunnel 1, located adjacent to the drilled holes. Once the holes are rotated, a steel cage is inserted into the holes to protect them from deformation or collapse. A water collection box 3 is then installed over the outlet of the drainage holes and secured to the sidewalls of Tunnel 1. The box is then connected to the inverted arch drainage system of Tunnel 1.

[0044] Reference Figure 3 and Figure 4, the water collecting box 3 is provided with an opening on one side close to the side wall of the tunnel 1. A convex edge 4 is circumferentially convexly provided on one side of the water collecting box 3 close to the side wall of the tunnel 1. The convex edge 4 is located on two opposite outer side walls and the outer bottom wall of the water collecting box 3. A sealing layer 5 is adhered to one side of the convex edge 4 close to the side wall of the tunnel 1, and the sealing layer 5 can be made of a rubber sheet. When installing the water collecting box 3, a plurality of anchor pipes 6 are driven into the surrounding rock layer around the drainage hole. One end of the anchor pipe 6 inserted into the rock layer is closed. The anchor pipe 6 is provided with internal threads, and then a locking bolt 8 with a pressing plate 7 is connected to the anchor pipe 6. During locking, the convex edge 4 is pressed tightly against the side wall of the tunnel 1 by the pressing plate 7.

[0045] A first filter screen 9 is arranged in the water collecting box 3. The first filter screen 9 is arranged in a U shape and is vertically placed in the water collecting box 3. A positioning groove 10 for inserting the first filter screen 9 is recessed on the side wall of the water collecting box 3. The first filter screen 9 and the positioning groove 10 are slidably inserted along the vertical direction. After the first filter screen 9 is inserted into the positioning groove 10, the first filter screen 9 divides the water collecting box 3 into a filtering chamber and a clear water chamber. The filtering chamber is communicated with the drainage hole, and a water outlet pipe 11 is communicated with the bottom of the clear water chamber. The water outlet pipe 11 is used for connecting with the invert drainage system of the tunnel 1.

[0046] A second filter screen 12 is vertically and fixedly connected to the bottom of the first filter screen 9. The second filter screen 12 is located in the filtering chamber and seals the bottom of the first filter screen 9.

[0047] A filter cloth 13 is slidably connected between two opposite side walls of the first filter screen 9. The lower end of the filter cloth 13 is fixedly connected to the second filter screen 12. The upper end of the filter cloth 13 is fixedly connected to a fixing strip 14. The fixing strip 14 is slidably connected to the first filter screen 9 along the vertical direction. A pull rope 15 is fixedly connected to the top of the fixing strip 14. The pull rope 15 is made of a chain, a steel wire rope, etc.

[0048] The top of the water collecting box 3 is provided with an opening and is hinged with a cover plate 16. The cover plate 16 can cover the opening at the top of the water collecting box 3. One end of the pull rope 15 away from the fixing strip 14 is detachably connected to one end of the cover plate 16 away from its hinge axis with the water collecting box 3. Specifically, one end of the pull rope 15 away from the fixing strip 14 is fixedly connected with a hook 17, and a connecting ring 18 is fixedly connected to the lower surface of the cover plate 16. The hook 17 is hooked with the connecting ring 18.

[0049] The first filter screen 9, the second filter screen 12, and the filter cloth 13 form a filter cylinder. When the filter cylinder is placed in the filter cavity and the cover plate 16 is closed, the filter cloth 13 is kneaded together, enabling the water discharged from the drain hole to enter the filter cylinder for filtration. After the water collection box 3 has been working for a period of time, the filter cylinder collects a certain amount of gravel and sediment, which needs to be cleaned in a timely manner. At this time, the cover plate 16 can be opened. During the opening process of the cover plate 16, the pull rope 15 is pulled, thereby lifting the fixing strip 14. During the rising process of the fixing strip 14, the filter cloth 13 is pulled, causing the filter cloth 13 to gradually unfold in the vertical direction, thus holding the gravel and sediment in the filter cylinder. After the cover plate 16 is completely opened, the filter cylinder can be directly taken out of the water collection box 3. The operation is simple and efficient, and there is no need for manual hands to pass through the gravel and sediment layer to pull the filter cloth 13, eliminating the risk of hand scratches.

[0050] S4. After the water collection box 3 is installed, a steel mesh is arranged circumferentially along the side wall of the tunnel 1 and shotcrete is sprayed.

[0051] S5. According to the construction drawings, blast holes 19 are drilled on the tunnel face of the tunnel 1. The drilling depth of the blast holes 19 needs to be greater than the single - excavation depth of the tunnel 1. After the blast holes 19 are drilled, first use the blast holes 19 for drainage. After the water discharge volume becomes smaller or reaches the drainage time, a plugging rod is inserted into the blast holes 19. The length of the plugging rod is the same as the over - excavation depth of the blast holes 19. Then, detonators are placed into the blast holes 19, and then blasting excavation is carried out. By over - excavating the blast holes 19, the water pressure in the rock formation of the next - section tunnel 1 can be released in advance, so that after blasting, the rock formation of the next - section tunnel 1 will not collapse. And the existence of the plugging rod can limit the installation depth of the detonators, avoiding the phenomenon of incomplete blasting caused by the too - deep burial of the detonators.

[0052] S6. After blasting is completed, the waste residue is cleaned.

[0053] S7. Repeat steps S1 - S6 until the excavation of the tunnel 1 in the water - rich soft soil geological section is completed.

[0054] The implementation principle of the construction method for a high - pressure water - rich soft rock geological tunnel in this application example is as follows: When constructing the excavation of the tunnel 1 in the water - rich soft rock geology in this application, first, the drill holes and the blast holes 19 are used as drainage holes to initially drain the water in the rock formation. After reaching the specified drainage time, the anchor bolts 2 are inserted into the drill holes. Then, additional drainage holes are drilled on the side wall of the tunnel 1, and the water collection box 3 is used to cover the drainage holes, so that during the spraying of the primary support concrete, the drainage holes will not be blocked by the concrete, enabling the water in the rock formation of the tunnel 1 to continuously drain through the drainage holes, effectively reducing the internal water pressure of the rock formation, thereby reducing the possibility of the collapse of the primary support concrete. This not only improves the construction efficiency but also significantly improves the construction safety.

[0055] The above are all preferred embodiments of this application, and the protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A construction method for a tunnel in a high-pressure water-rich soft rock geological formation, characterized in that: The following steps are involved: S1, driving a plurality of advance grouting pipes into the rock formation along the contour line of the tunnel face (1) to form a pipe rack, and then injecting cement slurry into the advance grouting pipes; S2. Drilling a plurality of holes along the side wall of the tunnel (1) for inserting anchor rods (2), first using the holes for drainage, and after the water output decreases or the drainage time is reached, driving the anchor rods (2) into the holes and injecting cement slurry into the anchor rods (2); S3, drilling drainage holes in the rock formations on both sides of the tunnel (1), fixing the water collecting box (3) on the side wall of the tunnel (1) so that the water collecting box (3) covers the drainage holes; setting an opening on one side of the water collecting box (3) that is in contact with the side wall of the tunnel (1), and then connecting the water collecting box (3) with the inverted arch drainage system of the tunnel (1); S4, arranging a steel mesh along the side wall of the tunnel (1) in a circumferential direction and spraying supporting concrete; S5. Drilling blastholes (19) on the tunnel (1) face, first using the blastholes (19) for drainage, and after the water output becomes smaller or the drainage time is reached, placing detonators into the blastholes (19), and then blasting excavation is carried out; S6. Clean up waste residue; S7, repeating steps S1-S6 until the excavation of the tunnel (1) in the water-rich soft soil section is completed; The anchor rod (2) comprises a coil (21) and a sleeve (22), an expansion tube (23) and a fixed tube (24) which are sequentially sleeved on the coil (21); the sleeve (22) and the expansion tube (23) are both slidably connected to the coil (21); the fixed tube (24) is fixedly connected to the coil (21); the fixed tube (24) is conically arranged, and the small end of the fixed tube (24) is arranged toward the expansion tube (23); the expansion tube (23) is formed by splicing a plurality of tube segments; When installing the anchor rod (2), the anchor rod (2) is inserted into the borehole, and then the screw tube (21) is pulled back and the sleeve (22) is used to press against the expansion tube (23), and the fixed tube (24) is gradually inserted into the expansion tube (23) and the expansion tube (23) is opened. When the expansion tube (23) is tightly pressed against the wall of the borehole, the sleeve (22) is pulled out from the borehole, and then the sealing plate (27) is sleeved on the screw tube (21) and the sealing plate (27) is pressed against the side wall of the tunnel (1) using a nut (28); A first filter screen (9) is provided in the water collection box (3), the first filter screen (9) being vertically arranged, and the first filter screen (9) divides the water collection box (3) into a filter chamber and a clean water chamber, and the bottom of the clean water chamber is connected to a water outlet pipe (11); The first filter screen (9) is arranged in a U-shape, the bottom of the first filter screen (9) is vertically fixedly connected to the second filter screen (12), a filter cloth (13) is provided between the two opposite side walls of the first filter screen (9) and is slidably connected, one end of the filter cloth (13) is fixedly connected to the second filter screen (12), and the top of the water collection box (3) can be opened and closed; One end of the filter cloth (13) away from the second filter screen (12) is fixedly connected with a fixing strip (14). A pull rope (15) is fixedly connected to the upper surface of the fixing strip (14). A cover plate (16) is hinged to the top of the water collecting box (3). One end of the pull rope (15) away from the fixing strip (14) is detachably connected to the cover plate (16).

2. The construction method of a high-pressure water-rich soft rock geological tunnel according to claim 1, characterized in that: A plurality of through holes (25) are formed in the fixed pipe (24), and the through holes (25) penetrate through both ends of the fixed pipe (24).

3. A construction method for a tunnel in a high-pressure water-rich soft rock geological formation according to claim 1, characterized in that: When installing the water collecting box (3), drive a plurality of anchor pipes (6) into the soil layer around the drainage holes. The anchor pipes (6) are provided with internal threads. A convex edge (4) is circumferentially convex on one side of the water collecting box (3) for water inlet. A sealing layer (5) is adhered to the convex edge (4). The convex edge (4) is pressed against the side wall of the tunnel (1) by using a locking bolt (8) to be locked and connected with the anchor pipe (6).

4. A construction method for a tunnel in high-pressure water-rich soft rock geology according to claim 1, characterized in that: After the drainage holes are drilled, insert the steel reinforcement cage into the drainage holes. The length of the steel reinforcement cage should be less than the depth of the drainage holes.

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