Drainage system and drainage method for tunnel passing through cave

Abstract

A drainage system for a tunnel passing through a karst cave belongs to the technical field of tunnel engineering construction. It comprises four parts: a tunnel main body drainage system (1), a karst cave drainage system (2), an inverted arch drainage system (3), and a support system (4). It solves the drainage problem of groundwater around the tunnel, reasonably passes through the karst cave, effectively prevents lining cracking caused by increased water pressure, effectively improves the tunnel construction quality and overall structural stability, and achieves good economic benefits.

Description

Technical field:

[0001] The invention belongs to the technical field of tunnel engineering construction, and in particular relates to a drainage system for a tunnel passing through a karst cave. Background technology:

[0002] The tunnel area is located in a complex geological environment, with an independent groundwater drainage system already forming within the tunnel body. Under such a geological background, it is common for underground karst formations of considerable size to form. During tunnel excavation, there is a high probability of encountering large caves, and the likelihood of water and sand gushing during tunnel construction is high. Therefore, it is necessary to design and formulate drainage methods for tunnels crossing caves in advance to avoid construction accidents. Since caves are typically underground water channels, the drainage of groundwater around the tunnel must be addressed during operation. Therefore, how to properly cross caves is an urgent issue for tunnel construction. Currently, drainage from tunnels crossing caves is conducted through initial support infiltration, then channeled through drainage pipes into the central ditch of the tunnel structure itself, and ultimately discharged outside the cave. However, due to the abundance of water in the surrounding area, especially during the rainy season, the main structure of the tunnel lining is subject to a large range of static and dynamic water pressures. In addition, the existing drainage pipes have limited drainage capacity and are easily blocked and cannot be drained in time, resulting in a sharp increase in water pressure, which can easily cause the lining to crack and damage, posing a major safety hazard to the tunnel. At the same time, it increases the maintenance efforts and costs of the tunnel, but cannot prevent the continued development of karst caves under the influence of groundwater, thus affecting the safety of the tunnel's later operations and increasing the uneven stress of the tunnel structure. Therefore, drainage of tunnels passing through karst caves is an urgent problem that needs to be solved in tunnel engineering. Summary of the invention:

[0003] The present invention provides a drainage method for a tunnel passing through a karst cave, the purpose of which is to overcome the above-mentioned shortcomings in the prior art, solve the problem of drainage of groundwater around the tunnel, reasonably pass through the karst cave, effectively prevent lining cracking caused by increased water pressure, effectively improve the tunnel construction quality and overall structural stability, and achieve better economic benefits.

[0004] In order to solve the above technical problems, the present invention proposes a technical solution: a drainage system for a tunnel passing through a karst cave, comprising: a tunnel main body drainage system (1), a karst cave drainage system (2), an inverted arch drainage system (3), and a support system (4).

[0005] The main body of the tunnel drainage system (1) includes primary support (1.1), waterproof board (1.2), annular drainage pipe (1.3), secondary lining (1.4), longitudinal drainage pipe (1.5), longitudinal drainage ditch (1.6), transverse drainage pipe (1.7), and central drainage ditch (1.8); from the lower surface of the upper body of the tunnel downward, the primary support (1.1), annular drainage pipe (1.3), waterproof board (1.2), secondary lining (1.4), primary support (1.1), annular drainage pipe (1.3), waterproof board (1.2) and the secondary lining (1.4) are both of the same arched structure as the main body of the upper part of the tunnel; transverse drainage pipes (1.7) are respectively provided at both ends of the annular drainage pipe (1.3) to connect with the longitudinal drainage ditch (1.6); the longitudinal drainage ditch (1.6) is along the longitudinal direction of the tunnel; the longitudinal drainage ditch (1.6) is connected with the central drainage ditch (1.8), which is located at the center of the tunnel, and the length of the central drainage ditch (1.8) is along the longitudinal direction of the tunnel, and the central drainage ditch (1.8) is located lower than the longitudinal drainage ditch (1.6);

[0006] The karst cave drainage system (2) comprises a karst cave (2.1), a diversion tunnel (2.2), mortared stone (2.3), concrete (2.4), a waterproof layer (2.5), a first drop chute (2.6), and a second drop chute (2.7); the support structure (4) comprises an anchor mechanism (4.1), a steel mesh (4.2), and a concrete support layer (4.3); in the karst cave traversed by the tunnel, according to the direction of the karst cave water flow, an entrance of the diversion tunnel (2.2) is provided upstream of the tunnel, and an exit of the diversion tunnel (2.2) is provided downstream of the tunnel, so that water in the karst cave is introduced from the upstream of the tunnel to the downstream of the tunnel through the diversion tunnel (2.2); a first drop chute (2.6) is provided on the bottom surface of the karst cave (2.1) upstream of the entrance of the diversion tunnel (2.2), and a second drop chute (2.7) is provided at the bottom surface of the karst cave (2.1) and a second drop chute (2.8) is provided at the bottom surface of the diversion tunnel (2.2). A second drop trough (2.7) is provided at the bottom of the middle water flow bend; a waterproof layer (2.5) is provided on the outer surface of the water diversion tunnel (2.2), and the water diversion tunnel (2.2) bypasses the tunnel; at the junction of the tunnel and the karst cave, the outer surface of the tunnel is filled with mortar slabs (2.3), so that the mortar slabs (2.3) fill the karst cave portion at the junction of the tunnel and the karst cave, and the mortar slabs (2.3) completely intercept the water flow in the karst cave (2.1) at the junction of the tunnel and the karst cave; the mortar slabs (2.3) are respectively provided with concrete (2.4) at both ends of the karst cave (2.1); a steel mesh (4.2) and a concrete support layer (4.3) are sequentially provided on the inner surface of the karst cave (2.1) corresponding to the mortar slabs (2.3), and a plurality of anchor rod mechanisms (4.1) are also provided to anchor to the surrounding rock of the karst cave;

[0007] The inverted arch drainage structure (3) includes an inverted arch filling layer (3.1), an inverted arch (3.2), an annular drainage pipe (3.3), a vertical water diversion pipe (3.4), and a transverse drainage pipe (3.5); the inverted arch (3.2) adopts a reinforced concrete structure and is divided into an inverted arch primary support and an inverted arch secondary lining, wherein the inverted arch primary support is at the bottom and the inverted arch secondary lining is at the top; the inverted arch filling layer (3.1) is located at the inverted arch secondary lining; the inverted arch secondary lining of the inverted arch (3.2) adopts a reinforced concrete structure and forms a whole tunnel with the secondary lining structure (1.4); A plurality of transverse drainage pipes (3.5) are provided below the filling layer (3.1), one end of the transverse drainage pipe (3.5) is connected to the central drainage ditch (1.8) and the other end is blocked, and transverse drainage pipes (3.5) are provided on both sides of the central drainage ditch (1.8); the transverse drainage pipe (3.5) is provided with a plurality of downward vertical water diversion pipes (3.4) along the length direction, and the lower end of the vertical water diversion pipe (3.4) is connected to the annular drainage pipe (3.3); the annular drainage pipe (3.3) is arranged on the outside of the lower side of the initial support of the inverted arch and forms a downward curved arch.

[0008] The tunnel main body drainage structure (1) is used to drain the tunnel seepage and the drainage of the cave, protect the main structure of the tunnel, and prevent water leakage.

[0009] The primary support (1.1) is a structural layer used to control the appropriate release and deformation of surrounding rock stress, increase structural safety and facilitate construction. The primary support (1.1) adopts the support form of shotcrete, and the surface of the primary support (1.1) is smoothly fixed with geotextile by nailing.

[0010] The waterproof sheet (1.2) is used to prevent water seepage from corroding the tunnel structure.

[0011] The annular drainage pipe (1.3) is used to drain water seeping from the primary support (1.1). The annular drainage pipe (1.3) is located between the primary support (1.1) and the waterproofing sheet (1.2), close to the primary support layer. The annular drainage pipe (1.3) is provided with a seepage port. The geotextile is used to effectively prevent the passage of soil particles while allowing water to seep through, concentrating the seepage water and draining it along the plane of the material.

[0012] Secondary lining (1.4) is used to protect the stability of the surrounding rock, prevent deformation and collapse of the surrounding rock, and ensure the safety of tunnel operation.

[0013] The longitudinal drainage pipe (1.5) is used to drain seepage water, is arranged on the surface of the tunnel primary support (1.1) layer and is connected to the annular drainage pipe (1.3).

[0014] The longitudinal drainage ditch (1.6) is used to discharge the seepage water passing through the longitudinal drainage pipe (1.5), the annular drainage pipe (1.3) and the transverse drainage pipe (1.7) out of the tunnel. The longitudinal drainage ditch (1.6) is arranged on both sides of the tunnel and is connected to the transverse drainage pipe (1.7) and the central drainage ditch (1.8).

[0015] The transverse drainage pipe (1.7) is used to drain the seepage water in the annular drainage pipe (1.3) and the longitudinal drainage pipe (1.5) into the central drainage ditch (1.8). The transverse drainage pipe (1.7) is arranged at the bottom of the tunnel, that is, above the interface between the tunnel lining and the inverted arch. The transverse drainage pipe (1.7) is connected to the annular drainage pipe (1.3) and is also connected to the longitudinal drainage ditch (1.6).

[0016] The central drainage ditch (1.8) is used to drain tunnel seepage water out of the tunnel and share the drainage pressure of the longitudinal drainage ditch (1.6). Once the end of the longitudinal drainage ditch (1.6) is blocked by sediment, the seepage water can be discharged to the central drainage ditch through the transverse drainage ditch, ensuring smooth drainage of the tunnel. The central drainage ditch (1.8) is connected to the longitudinal drainage ditch (1.6) through a transverse drainage pipe (1.7) and is set at the center bottom of the tunnel.

[0017] The above system drains the tunnel seepage water out of the tunnel through a closed system, thus ensuring the drainage of the tunnel seepage water.

[0018] The cave drainage system (2) includes seven parts: (2.1) cave, (2.2) diversion tunnel, (2.3) mortared stone, (2.4) concrete, (2.5) waterproof layer, (2.6) ditch, and (2.7) ditch.

[0019] Karst caves (2.1) are the result of long-term groundwater dissolution in limestone areas. They affect the stability and mechanical distribution of the surrounding rock mass and thus the quality of tunnel construction.

[0020] The two openings of the diversion tunnel (2.2) are respectively connected to the karst cave (2.1). The diversion tunnel (2.2) is used to lower the water flow in the karst cave (2.1) to below the tunnel bottom elevation, and then divert the water flow from one end of the opening to the other end to drain the water in the karst cave without changing the direction of the water flow in the karst cave and without affecting the entire structure of the tunnel.

[0021] The mortared stone (2.3) is used to seal the intersection of the cave (2.1) and the tunnel, to ensure that the water flow in the cave does not affect the tunnel and to prevent the collapse of the upper part of the cave from damaging the tunnel.

[0022] Concrete (2.4) is arranged at both ends of the filling layer of the mortar-laid rubble (2.3), and has the functions of ensuring the stability of the mortar-laid rubble and blocking water flow.

[0023] The waterproof layer (2.5) is arranged on both sides of the diversion tunnel (2.2), which can effectively prevent water seepage from eroding the tunnel bottom structure.

[0024] The first drop chute (2.6) is used to buffer the water flow in the cave to prevent it from causing huge impact and damage to the main structure of the tunnel and the diversion tunnel, and is set at a suitable position away from the entrance of the diversion tunnel (2.2).

[0025] The second drop trough (2.7) is used to filter the water flow in the cave (2.1), depositing the large pieces of gravel carried by the water flow in the cave (2.1) in the second drop trough (2.7), while the small particles of sediment are discharged from the water diversion hole (2.2) along with the water flow, thereby ensuring the smooth flow of groundwater.

[0026] The cave drainage system (2) can drain the water in the cave without changing the direction of the water flow, ensuring that when the tunnel passes through the cave, the tunnel drainage pipe is not blocked and cannot be drained in time, resulting in a sharp increase in water pressure and cracking and damage to the lining, thereby reducing the maintenance effort and cost of the tunnel and ensuring the safety of the tunnel.

[0027] The inverted arch filling layer (3.1) is used to transfer the upper load to the lower inverted arch (3.2), and then the inverted arch (3.2) transfers the stratum pressure above the tunnel to the underground; the inverted arch filling layer (3.1) is arranged above the secondary lining of the tunnel inverted arch (3.2). After the secondary lining concrete of the inverted arch is finally set, an end form is set on the inverted arch concrete mix to cast the inverted arch filling concrete.

[0028] The inverted arch (3.2) is used to improve the stress conditions of the upper supporting structure, transfer the upper load to the underground, and ensure the stability of the tunnel structure; the inverted arch (3.2) adopts a reinforced concrete structure and a secondary lining structure (1.5) to form the whole of the tunnel.

[0029] The annular drainage pipe (3.3) is used to drain the groundwater at the bottom of the tunnel. The annular drainage pipe (3.3) is set outside the initial support of the tunnel invert arch. It adopts a double-wall perforated corrugated pipe and is wrapped with non-woven fabric. The non-woven fabric blocks the sediment carried by the groundwater outside the pipe, achieving the effect of filtering the groundwater and reducing the maintenance workload of the drainage system.

[0030] The vertical water diversion pipe (3.4) is used to divert the groundwater in the annular drainage pipe (3.3) to the horizontal drainage pipe (3.5) arranged in the inverted arch filling layer (3.1). The vertical water diversion pipe (3.4) is arranged at intervals along the transverse direction of the tunnel and is vertically connected to the annular drainage pipe (3.3).

[0031] The horizontal drainage pipe (3.5) is used to drain the groundwater in the vertical water diversion pipe to the central drainage ditch (1.8) and out of the tunnel. The horizontal drainage pipe (3.5) is arranged in the inverted arch filling layer, with one end blocked and the other end connected to the central drainage ditch (1.8). It is also connected to the vertical drainage pipe (3.4), so that the inverted arch drainage system becomes an integral whole.

[0032] The above system can drain the groundwater that seeps from the lower part of the tunnel, reduce the water pressure of the tunnel's lower structure, and ensure the stability of the tunnel.

[0033] The anchor mechanism (4.1) is set in the surrounding rock of the cave, and forms a stable rock belt around the cave by changing the mechanical state of the cave wall itself, thereby ensuring the stability of the cave. The anchor mechanism (4.1) adopts mortar anchor rods, which are arranged in a plum blossom pattern to form a whole with the cave wall.

[0034] The steel mesh (4.2) has the function of connecting the anchor rod (4.1), is arranged in a direction perpendicular to the axis of the anchor rod mechanism (4.1), and has multiple layers along the axis of the anchor rod.

[0035] The concrete support layer (4.3) is used to fix and protect the four walls of the cave, effectively preventing the cave wall from collapsing.

[0036] The above system effectively prevents the damage caused by falling rocks in the tunnel during the construction and operation periods of the tunnel, and is conducive to the stability of the cave structure.

[0037] The annular direction refers to the circumferential direction.

[0038] The drainage method provided by the present invention has the following beneficial effects:

[0039] The drainage method of the present invention is simple, convenient to construct, and reasonably crosses the cave, thereby ensuring drainage when the tunnel passes through the cave, effectively alleviating the impact of cave seepage on the tunnel, effectively preventing lining cracking, reducing blockage of tunnel drainage channels, and increasing the safety of the tunnel structure.

[0040] The present invention includes but is not limited to the above. Description of the drawings:

[0041] Figure 1 This is a general schematic diagram of the drainage system when the tunnel passes through the cave;

[0042] Figure 2 This is a schematic diagram of the tunnel main drainage system;

[0043] Figure 3 Schematic diagram of cave drainage;

[0044] Figure 4 This is a schematic diagram of the inverted arch drainage system;

[0045] Figure annotation:

[0046] 1. Tunnel main body drainage system: including:

[0047] 1.1 Primary support, 1.2 Waterproof board, 1.3 Circumferential drain pipe, 1.4 Secondary lining, 1.5 Longitudinal drain pipe, 1.6 Longitudinal drain ditch, 1.7 Horizontal drain pipe, 1.8 Central drain ditch;

[0048] 2. Cave drainage system: including:

[0049] 2.1 Cave, 2.2 Diversion Tunnel, 2.3 Mortared Stone, 2.4 Concrete, 2.5 Waterproof Layer, 2.6 First Drop Channel,

[0050] 2.7 Second drop chute;

[0051] 3. Inverted arch drainage system: including:

[0052] 3.1 inverted arch filling layer, 3.2 inverted arch, 3.3 circular drainage pipe, 3.4 vertical water diversion pipe, 3.5 horizontal drainage pipe;

[0053] 4 Support structure: including

[0054] 4.1 Anchor mechanism, 4.2 Steel mesh, 4.3 Concrete support layer; Specific implementation method:

[0055] The specific implementation method of the present invention is now described in detail with reference to the accompanying drawings. The accompanying drawings are only schematic diagrams and only illustrate the basic structure of this patent. The examples of the present invention are developed without creativity by technicians in this field and all fall within the scope of protection of the present invention.

[0056] Principles and steps of drainage when tunneling through a cave:

[0057] like Figure 1As shown, the present invention provides a drainage method for a tunnel passing through a karst cave. Specifically, the drainage of the tunnel body is the seepage water from the initial support 1.1 of the tunnel flowing through the annular drainage pipe 1.3 and the longitudinal drainage pipe 1.5, entering the transverse drainage pipe 1.7, and then being discharged into the tunnel longitudinal drainage ditch 1.6. It can also be discharged into the central drainage ditch 1.8 through the transverse drainage pipe 1.7 to prevent the longitudinal drainage ditch from being blocked and affecting the tunnel drainage. The drainage of the tunnel bottom is to construct an annular drainage pipe 3.3 on the outside of the initial support of the tunnel invert, and to set a seepage hole on the annular drainage pipe 3.3 to connect it to the vertical water diversion pipe 3.4 above. The vertical water diversion pipe 3.4 is connected to the transverse drainage pipe 3.5. The seepage water at the bottom of the tunnel will enter the transverse drainage pipe 3.5 through the annular drainage pipe 3.3 and the vertical water diversion pipe 3.4, and then be discharged into the central drainage ditch 1.8 through the transverse drainage pipe 3.5. A diversion tunnel 2.2 is excavated within the cavern, connecting both ends of the tunnel to the cavern 2.1. A waterproof layer 2.5 is laid on the sidewalls of the diversion tunnel 2.2 to prevent erosion of the tunnel floor structure by cave water. A first drop chute 2.6 is installed at a suitable distance from the diversion tunnel entrance to buffer the flow of water in the cavern. A second drop chute 2.7 is installed below the diversion tunnel to deposit large pieces of gravel carried by the water flow into the second drop chute 2.7, preventing blockage of the diversion tunnel. Water from cavern 2.1 flows through the buffering first drop chute 2.6 before entering the diversion tunnel, where it blocks the large pieces of gravel carried by the water in the second drop chute 2.7. Smaller particles of sediment are discharged from the diversion tunnel along with the water flow, ensuring smooth groundwater flow without loss of particles, thus draining the water from the cavern. Before processing the cave, the dangerous rocks are first cleaned up, and the cave roof is supported by anchor spraying. The anchor rods use mortar anchor rods and arrange steel mesh 4.2. Then, the cave is backfilled with mortar-laid stone 2.3 to prevent the drainage in the cave from affecting the tunnel and avoid lining cracking. Concrete 2.4 is used to support both sides of the mortar-laid stone to ensure the stability of the mortar-laid stone 2.3.

[0058] The tunnel main body drainage system 1 can discharge the seepage of the tunnel initial support 1.1 out of the tunnel, reduce the water pressure on the outside of the tunnel initial support, ensure the safety of tunnel operation, reduce the treatment of defects, and effectively avoid the waste of manpower and material resources caused by defect treatment. Among them, the initial support 1.1 should deal with the seepage of the initial support surface, the leaking protrusions and the uneven surface before laying the waterproof layer. The waterproof board 1.2 is laid by a waterproof board operation trolley, which is carried out from both sides of the arch. During the construction of the circumferential weld, the waterproof board in the downhill direction presses the waterproof board in the uphill direction, and the longitudinal weld is pressed by the lower waterproof board on the upper waterproof board. The waterproof board 1.2 is fixed to the surface of the geotextile by ultrasonic hot melt welding, so that the waterproof board and the thermoplastic gasket are melted and bonded into one. The circumferential drainage pipe 1.3 is set between the waterproof layer and the initial support, and adopts a double-wall perforated corrugated pipe. The geotextile is smoothly fixed to the surface of the initial support 1.1 by nailing. The longitudinal drainage pipe 1.5 is arranged circumferentially along the surface of the initial support of the tunnel and is connected to the annular drainage pipe 1.3. The longitudinal drainage ditch 1.6 is cast with concrete and connected to the transverse drainage pipe 1.7. The transverse drainage pipe 1.8 is set in the arch filling layer using PVC pipes and is connected to the annular drainage pipe 1.3 and the longitudinal drainage ditch 1.7. The central drainage ditch 1.8 is set longitudinally at the bottom of the center of the tunnel and is connected to the transverse drainage pipe 1.8. The above system forms a main drainage system, which ensures the discharge of tunnel seepage and solves the problem of groundwater drainage around the tunnel.

[0059] The cave diversion and drainage system 2 can drain the water in the cave without changing the original drainage system of the cave, ensuring that the tunnel passes through the cave safely and reasonably. A diversion tunnel 2.2 is excavated so that both ends of the diversion tunnel 2.2 are connected to the cave 2.1. A drop chute 2.6 is set at a certain distance from the entrance of the diversion tunnel, and a drop chute 2.7 is set at the bottom of the diversion tunnel. Then, a waterproof layer 2.5 is laid on the side wall of the diversion tunnel 2.2 to prevent the cave water from eroding the tunnel bottom structure. Before processing the cave, the dangerous rocks are cleaned up first, and the top plate of the cave is supported by anchor spraying. The anchor rods use mortar anchor rods and arrange steel mesh. Then, mortar-laid stone 2.3 is used to backfill the cave to prevent the drainage in the cave from affecting the tunnel and avoid cracking of the lining. Concrete 2.4 is used to support both sides of the mortar-laid stone to ensure the stability of the mortar-laid stone 2.3. The above system can realize the drainage of the cave when the tunnel passes through the cave without changing the original drainage system of the cave, ensuring that the tunnel is not affected by the drainage of the cave 2.1, while avoiding the blockage of the drainage pipe and ensuring the reasonable passage of the tunnel through the cave.

[0060] The inverted arch drainage system 3 is used to drain groundwater from the lower portion of the tunnel. The inverted arch filling layer 3.1 is arranged above the inverted arch secondary lining and filled with concrete to ensure that the upper load is transferred to the inverted arch 3.2 below. The inverted arch 3.2 is constructed of reinforced concrete and located below the inverted arch filling layer 3.1. It is divided into primary support and secondary lining. The upper load transferred from the inverted arch filling layer 3.1 is transferred to the underground rock mass through the inverted arch 3.2. The annular drain pipe 3.3 is arranged outside the inverted arch primary support and is constructed of double-walled perforated corrugated pipe. The annular drain pipe 3.3 has a seepage port and is connected to a vertical water diversion pipe 3.4. The vertical water diversion pipe 3.4 is spaced apart horizontally along the tunnel. It connects to the annular drain pipe 3.3 below, which passes through the tunnel's secondary lining and primary support, and to the lateral drain pipe 3.5 above. Transverse drainage pipes 3.5 are arranged within the tunnel invert filling layer. One end, near the tunnel's secondary lining, is sealed, while the other end connects to the central drainage ditch 1.8. The middle connects to the vertical water diversion pipe 3.4, arranged symmetrically across the tunnel. This system drains groundwater from the tunnel floor, ensuring stability in the lower portion.

[0061] The support system 4 is used to support the cave wall and maintain the stability of the cave structure. First, the dangerous rocks in the cave are cleared, and the top plate of the cave where the tunnel and the cave intersect is supported by anchor spraying. The anchor rod mechanism uses mortar anchor rods, which are inserted into the surrounding rock in a plum blossom arrangement to form a whole with the cave wall. Construction is carried out from bottom to top to ensure the stability of the cave 2.1. A steel mesh is set on the axis of the anchor rod perpendicular to the anchor rod mechanism 4.1, and a multi-layer steel mesh 4.2 is set along the axis of the anchor rod, and the steel mesh is fixed on the anchor rod mechanism. Concrete is also sprayed on the tunnel cave wall to form a concrete support layer 4.3 to increase the stability of the cave top surface. The above system ensures the stability of the cave.

Claims

1. A drainage system for a tunnel passing through a cave, characterized in that: include: The tunnel consists of four parts: the main body drainage system (1), the cave drainage system (2), the inverted arch drainage system (3), and the support system (4); The main body of the tunnel drainage system (1) includes the initial support (1.1), waterproof board (1.2), the first annular drainage pipe (1.3), the secondary lining (1.4), the longitudinal drainage pipe (1.5), the longitudinal drainage ditch (1.6), the first transverse drainage pipe (1.7), and the central drainage ditch (1.8); from the lower surface of the upper body of the tunnel downward, the initial support (1.1), the first annular drainage pipe (1.3), the waterproof board (1.2), the secondary lining (1.4), the initial support (1.1), the first annular drainage pipe (1.3), the waterproof board (1.2), the secondary lining (1.4), the initial support (1.1), the first annular drainage pipe (1.3), the waterproof board (1.5), the longitudinal drainage ditch (1.6), the first transverse drainage pipe (1.7), and the central drainage ditch (1.8); 2) The secondary lining (1.4) is of the same arched structure as the main body of the upper part of the tunnel; first transverse drainage pipes (1.7) are respectively provided at both ends of the first annular drainage pipe (1.3) and connected to the longitudinal drainage ditch (1.6); the longitudinal drainage ditch (1.6) is along the longitudinal direction of the tunnel; the longitudinal drainage ditch (1.6) is connected to the central drainage ditch (1.8), and the central drainage ditch (1.8) is located at the center of the tunnel. The length of the central drainage ditch (1.8) is along the longitudinal direction of the tunnel, and the central drainage ditch (1.8) is located lower than the longitudinal drainage ditch (1.6); The primary support (1.1) has a geotextile fixed on the surface by nailing smoothly; The karst cave drainage system (2) includes a karst cave (2.1), a diversion tunnel (2.2), mortared stone (2.3), concrete (2.4), a waterproof layer (2.5), a first drop trough (2.6), and a second drop trough (2.7); the support system (4) includes an anchor mechanism (4.1), a steel mesh (4.2), and a concrete support layer (4.3); in the karst cave traversed by the tunnel, according to the direction of the karst cave water flow, an entrance of the diversion tunnel (2.2) is provided at the upstream of the tunnel, and an exit of the diversion tunnel (2.2) is provided at the downstream of the tunnel, so that water in the karst cave is introduced from the upstream of the tunnel to the downstream of the tunnel through the diversion tunnel (2.2); a karst cave (2.1) is provided upstream of the entrance of the diversion tunnel (2.2), a first drop trough (2.6) is provided on the bottom surface, and an exit of the diversion tunnel (2.2) is provided at the bottom surface of the diversion tunnel (2.2). ) is provided with a second drop trough (2.7) at the bottom of the water flow bend; a waterproof layer (2.5) is provided on the outer surface of the water diversion tunnel (2.2), and the water diversion tunnel (2.2) bypasses the tunnel; at the junction of the tunnel and the karst cave, the outer surface of the tunnel is filled with mortar slabs (2.3), so that the mortar slabs (2.3) fill the karst cave portion at the junction of the tunnel and the karst cave, and the mortar slabs (2.3) completely intercept the water flow in the karst cave (2.1) at the junction of the tunnel and the karst cave; the mortar slabs (2.3) are provided with concrete (2.4) at both ends of the karst cave (2.1); on the inner surface of the karst cave (2.1) corresponding to the mortar slabs (2.3), a steel mesh (4.2) and a concrete support layer (4.3) are provided outward in sequence, and a plurality of anchor rod mechanisms (4.1) are also provided to anchor to the surrounding rock of the karst cave; The inverted arch drainage system (3) includes an inverted arch filling layer (3.1), an inverted arch (3.2), a second annular drainage pipe (3.3), a vertical water diversion pipe (3.4), and a second transverse drainage pipe (3.5); the inverted arch (3.2) adopts a reinforced concrete structure and is divided into an inverted arch primary support and an inverted arch secondary lining, wherein the inverted arch primary support is at the bottom and the inverted arch secondary lining is at the top; the inverted arch filling layer (3.1) is located at the inverted arch secondary lining; the inverted arch secondary lining of the inverted arch (3.2) adopts a reinforced concrete structure and forms a whole tunnel with the secondary lining (1.4); ... filling layer (3.1) is located at the inverted arch secondary lining; the inverted arch secondary 1) is provided with a plurality of second transverse drainage pipes (3.5), one end of the second transverse drainage pipe (3.5) is connected to the central drainage ditch (1.8), and the other end is blocked. Second transverse drainage pipes (3.5) are provided on both sides of the central drainage ditch (1.8); the second transverse drainage pipe (3.5) is provided with a plurality of downward vertical water diversion pipes (3.4) along the length direction, and the lower ends of the vertical water diversion pipes (3.4) are connected and communicated with the second annular drainage pipe (3.3); the second annular drainage pipe (3.3) is provided on the outside of the lower side of the initial support of the inverted arch and forms a downwardly curved arch; The anchor mechanism (4.1) is set in the surrounding rock of the cave, and by changing the mechanical state of the cave wall itself, the cave is formed into a stable rock belt to ensure the stability of the cave. The anchor mechanism (4.1) uses mortar anchors, which are arranged in a plum blossom pattern to form an integral whole with the cave wall. The steel mesh (4.2) has the function of connecting the anchor rod mechanism (4.1), is arranged in a direction perpendicular to the axis of the anchor rod mechanism (4.1), and has multiple layers along the axis of the anchor rod; The concrete support layer (4.3) is used to fix and protect the four walls of the cave, effectively preventing the cave wall from collapsing.

2. A drainage system for a tunnel passing through a cave according to claim 1, characterized in that: The drainage of the tunnel body is that the seepage water of the tunnel initial support (1.1) flows through the first annular drainage pipe (1.3) and the longitudinal drainage pipe (1.5), enters the first transverse drainage pipe (1.7), and then is discharged into the tunnel longitudinal drainage ditch (1.6); or is discharged into the central drainage ditch (1.8) through the first transverse drainage pipe (1.7), so as to avoid the longitudinal drainage ditch from being blocked and affecting the tunnel drainage; the drainage of the tunnel bottom is that the second annular drainage pipe (3.3) is constructed outside the initial support of the tunnel invert, and the drainage pipe (3. 3) is provided with a seepage hole connected to the vertical water diversion pipe (3.4) above, and the vertical water diversion pipe (3.4) is connected to the second horizontal drainage pipe (3.5). The seepage water at the bottom of the tunnel will enter the second horizontal drainage pipe (3.5) through the second annular drainage pipe (3.3) and the vertical water diversion pipe (3.4), and then be discharged into the central drainage ditch (1.8) through the second horizontal drainage pipe (3.5); at the karst cave, a water diversion tunnel (2.2) is excavated so that both ends of the water diversion tunnel (2.2) are connected to the karst cave (2.1). 2.2) A waterproof layer (2.5) is laid on the side wall to prevent the karst cave water from eroding the tunnel bottom structure. A first drop trough (2.6) is set at a suitable location away from the diversion tunnel entrance to buffer the water flow in the karst cave. A second drop trough (2.7) is set below the diversion tunnel to deposit large pieces of gravel carried by the water flow in the second drop trough (2.7) to prevent the diversion tunnel from being blocked. The water flow in the karst cave (2.1) passes through the buffer of the first drop trough (2.6) and enters the diversion tunnel, blocking the large pieces of gravel carried by the water in the second drop trough (2.7). ) in the tunnel, small particles of sediment are discharged from the diversion tunnel along with the water flow, ensuring smooth groundwater flow without loss of particles, and then draining the water flow in the cave; before treating the cave, the dangerous rocks are cleaned and the cave roof is supported by anchor spraying nets. The anchor mechanism uses mortar anchors and arranges steel mesh (4.2). Then, mortar-laid stone (2.3) is used to backfill the cave to prevent the drainage in the cave from affecting the tunnel and avoid cracking of the lining. Concrete (2.4) is used to support both sides of the mortar-laid stone to ensure the stability of the mortar-laid stone (2.3); The tunnel main body waterproofing and drainage system (1) can discharge the seepage of the tunnel initial support (1.1) out of the tunnel, reduce the water pressure outside the tunnel initial support, ensure the safety of tunnel operation, reduce the treatment of diseases, and effectively avoid the waste of manpower and material resources caused by disease treatment; wherein the initial support (1.1) should be treated for the seepage of the initial support surface, the protrusions and the uneven surface before laying the waterproof layer; the waterproof board (1.2) is laid by a waterproof board operation trolley, and is carried out from both sides of the arch. When constructing the circumferential weld, the waterproof board in the downhill direction presses the waterproof board in the uphill direction, and the longitudinal weld is constructed by the lower waterproof board pressing the upper waterproof board. The waterproof board (1.2) is fixed to the surface of the geotextile by ultrasonic hot melt welding, so that the waterproof board The first annular drainage pipe (1.3) is arranged between the waterproof layer and the initial support and adopts a double-wall perforated corrugated pipe; the geotextile is smoothly fixed on the surface of the initial support (1.1) by nailing; the longitudinal drainage pipe (1.5) is arranged annularly along the surface of the initial support of the tunnel and is connected to the first annular drainage pipe (1.3); the longitudinal drainage ditch (1.6) is cast with concrete and connected to the first transverse drainage pipe (1.7); the first transverse drainage pipe (1.7) is arranged in the inverted arch filling layer using a PVC pipe and is connected to the first annular drainage pipe (1.3) and the longitudinal drainage ditch (1.6); the central drainage ditch (1.8) is arranged longitudinally at the center bottom of the tunnel and is connected to the first transverse drainage pipe (1.7); The cave diversion and drainage system (2) can drain the water flow in the cave without changing the original drainage system of the cave, ensuring that the tunnel passes through the cave safely and reasonably; excavating the diversion tunnel (2.2) so that both ends of the diversion tunnel (2.2) are connected to the cave (2.1); setting a first drop trough (2.6) at a certain distance from the entrance of the diversion tunnel; setting a second drop trough (2.7) at the bottom of the diversion tunnel; and then laying a waterproof layer (2.5) on the side wall of the diversion tunnel (2.2) to prevent the cave water from eroding the tunnel bottom structure; before processing the cave, clean up the dangerous rocks and The cave roof is supported by shotcrete anchors. The anchor mechanism uses mortar anchors and a steel mesh. Then, mortar-laid stone (2.3) is used to backfill the cave to prevent drainage from the cave from affecting the tunnel and avoid lining cracking. Concrete (2.4) is used on both sides of the mortar-laid stone to ensure the stability of the mortar-laid stone (2.3). This allows drainage of the cave when the tunnel passes through it without changing the original drainage system of the cave, ensuring that the tunnel is not affected by drainage from the cave (2.1). At the same time, blockage of the drainage pipe is avoided, ensuring that the tunnel passes through the cave in a reasonable manner. The inverted arch drainage system (3) is used to drain the groundwater in the lower part of the tunnel, wherein the inverted arch filling layer (3.1) is arranged above the inverted arch secondary lining and is filled with concrete to ensure that the upper load is transferred to the lower inverted arch (3.2); the inverted arch (3.2) is a reinforced concrete structure, located below the inverted arch filling layer (3.1), and is divided into primary support and inverted arch secondary lining. The upper load transferred by the inverted arch filling layer (3.1) is transferred to the underground rock mass through the inverted arch (3.2); the second annular drainage pipe (3.3) is arranged outside the inverted arch primary support and adopts double-wall perforated corrugated concrete structure. The second annular drainage pipe (3.3) is provided with a seepage port and is connected to the vertical water diversion pipe (3.4); the vertical water diversion pipe (3.4) is arranged at intervals along the tunnel transverse direction, and is connected to the second annular drainage pipe (3.3) at the bottom through the secondary lining and initial support of the tunnel invert, and is connected to the second transverse drainage pipe (3.5) at the top; the second transverse drainage pipe (3.5) is arranged in the filling layer of the tunnel invert, and is sealed at one end close to the secondary lining of the tunnel, and is connected to the central drainage ditch (1.8) at the other end, and is connected to the vertical water diversion pipe (3.4) in the middle, and is arranged symmetrically in the transverse direction of the tunnel; The above system drains the groundwater at the bottom of the tunnel, ensuring the stability of the lower part of the tunnel; The support system (4) is used to support the cave wall and maintain the stability of the cave structure. First, the dangerous rocks in the cave are cleared, and the cave roof at the intersection of the tunnel and the cave is supported by anchor spraying. The anchor rod mechanism uses mortar anchor rods, which are inserted into the surrounding rock in a plum blossom arrangement to form a whole with the cave wall. The construction is carried out from bottom to top to ensure the stability of the cave (2.1). A steel mesh is set on the axis of the anchor rod perpendicular to the anchor rod mechanism (4.1), and multiple layers of steel mesh (4.2) are set along the axis of the anchor rod. The steel mesh is fixed to the anchor rod mechanism. Concrete is sprayed on the tunnel cave wall to form a concrete support layer (4.3) to increase the stability of the cave roof.

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