Composite tunnel waterproof and drainage system

Abstract

The utility model discloses a composite tunnel waterproof and drainage system, and belongs to the technical field of tunnel waterproof and drainage. The structure comprises a waterproof plate, a geotechnical cloth layer and a longitudinal drainage blind pipe which are arranged between a primary support and a secondary lining, and is characterized in that a plurality of first annular drainage plates are arranged between the primary support and the geotechnical cloth layer, the lower ends of the first annular drainage plates are in lap joint with first longitudinal drainage plates into a whole, and the first longitudinal drainage plates are connected with a longitudinal drainage blind pipe overhaul well; pebble permeable bags are arranged above the longitudinal drainage blind pipes and are reversely wrapped by geotechnical cloth; a plurality of second annular drainage plates are arranged between the geotechnical cloth layer and the waterproof plate, and the end parts of the second annular drainage plates are positioned above the pebble permeable bags; a plurality of annular capillary permeable drainage belts are arranged between the waterproof plate and the secondary lining, the lower ends of the annular capillary permeable drainage belts are in lap joint with a second longitudinal drainage plate into a whole, and the second longitudinal drainage plate is connected with a longitudinal drainage blind pipe overhaul well; and a sand setting well is arranged at the bottom of the inner side of the longitudinal drainage blind pipe overhaul well.

Description

Technical Field

[0001] The utility model relates to a tunnel drainage system and belongs to the technical field of tunnel construction. Background Art

[0002] Water-rich mountainous terrain and urban underground tunnels are located in areas rich in groundwater or surface water, potentially providing unlimited water supply to the tunnel space. However, due to the longitudinal slope, natural drainage conditions are lacking. Furthermore, the uncertainty surrounding tunnel engineering geological surveys and detection makes tunnel leakage, water inrush, and related water-related disasters complex and severe, making prevention and control measures difficult. The drainage system faces a sharp conflict between "reducing water pressure" and "controlling drainage." As a large-scale, high-risk, and complex project, the core issues that need to be addressed are tunnel drainage design during the construction phase and leakage treatment and drainage volume control during the operation phase. This is also one of the main tasks faced throughout the entire tunnel construction and operation cycle.

[0003] Currently, the main challenges facing drill-and-blast tunnel drainage systems include: aging and failure of geotextiles, severe blockage of drainage blind pipes, and deterioration of waterproofing panels. These issues will exacerbate the performance degradation of the drainage system over the long-term operation of the tunnel, significantly weakening its drainage efficiency. This in turn can lead to a sharp rise in the water level behind the tunnel lining, increase the long-term load on the secondary lining, and induce the development and expansion of cracks in the tunnel structure, seriously threatening tunnel operation and maintenance safety. Utility Model Content

[0004] In view of the above-mentioned defects in the prior art, the utility model provides a composite tunnel drainage system which has a simple structure, is easy to construct, and has a good overall drainage effect.

[0005] The utility model is realized through the following technical scheme: a composite tunnel waterproofing and drainage system, comprising a waterproof plate arranged between the initial support and the secondary lining of the tunnel, a geotextile layer arranged between the waterproof plate and the initial support, a longitudinal drainage blind pipe arranged at the arch foot position, and a longitudinal drainage blind pipe inspection well connected to the longitudinal drainage blind pipe, characterized in that: a plurality of first annular drainage plates are fixed at intervals between the initial support and the geotextile layer, the first annular drainage plates are convex shell-type drainage plates, the protrusion of the first annular drainage plates faces the initial support, a first longitudinal drainage plate is respectively arranged at the two arch foot positions between the initial support and the geotextile layer, the first longitudinal drainage plates are convex shell-type drainage plates, the lower end of the first annular drainage plate is overlapped and fixed to the first longitudinal drainage plate, the first longitudinal drainage plate is connected to the longitudinal drainage blind pipe inspection well through a drain port, the first longitudinal drainage plate and the drain port are both fixed on the initial support; the longitudinal drainage blind pipe is arranged in the tunnel arch between the geotextile layer and the waterproof plate The foot portion is arranged along the longitudinal length of the tunnel, and a pebble permeable bag is set above the longitudinal drainage blind pipe. The longitudinal drainage blind pipe and the pebble permeable bag are wrapped with geotextile; a plurality of second annular drainage boards are fixed at intervals between the geotextile layer and the waterproof board. The second annular drainage board is a convex shell-type drainage board, and the bulge of the second annular drainage board faces the geotextile layer. The second annular drainage board is arranged at intervals from the first annular drainage board, and the end of the second annular drainage board is located above the pebble permeable bag; a plurality of annular capillary drainage belts are fixed at intervals between the waterproof board and the secondary lining, and the annular capillary drainage belts are closely attached to and fixed to the waterproof board; a second longitudinal drainage board is respectively provided at the two arch foot portions between the waterproof board and the secondary lining, and the lower end of the annular capillary drainage belt is overlapped and fixed to the second longitudinal drainage board, and the second longitudinal drainage board is connected to the longitudinal drainage blind pipe inspection well; a sand settling well is provided at the inner bottom of the longitudinal drainage blind pipe inspection well, and the water discharge outlet of the longitudinal drainage blind pipe inspection well is higher than the sand settling well.

[0006] In the present invention, the first annular drainage board and the first longitudinal drainage board arranged between the primary support and the geotextile layer, the second annular drainage board and the longitudinal drainage blind pipe arranged between the geotextile layer and the waterproof board, and the annular capillary drainage belt and the second longitudinal drainage board arranged between the waterproof board and the secondary lining together serve as a tunnel drainage system for drainage. Specifically, the drainage board arranged between the primary support and the geotextile layer, when the geotextile layer is blocked, can be used as a drainage channel for drainage, diverting water to the longitudinal drainage blind pipe inspection well, thereby preventing the surrounding rock fissure water from being retained behind the waterproof board and increasing the load on the secondary lining structure; the annular capillary drainage belt and the second longitudinal drainage board arranged between the waterproof board and the secondary lining can utilize the capillary and siphon effects of the capillary drainage belt to promptly and efficiently drain the surrounding rock fissure water retained behind the secondary lining, and divert the water to the longitudinal drainage blind pipe inspection well through the longitudinal drainage board, thereby promptly reducing the pressure behind the lining structure and improving the safety of the tunnel structure. By setting up a sand settling well in the longitudinal drainage blind pipe inspection well, the sediment will first settle inside the sand settling well. When the water level reaches the height of the drain hole, it will automatically flow out of the drain hole. At this time, the water flow contains almost no sediment. It only needs to clean the inspection well regularly to ensure the normal operation of the tunnel drainage system.

[0007] Furthermore, to ensure the drainage effect, the width of the first annular drainage board is 500mm, and the interval between two adjacent first annular drainage boards is 2-5m; the width of the second annular drainage board is 500mm, and the interval between two adjacent second annular drainage boards is 2-5m.

[0008] Furthermore, to ensure the drainage effect of the drainage board, the width of the first longitudinal drainage board is 250 mm, and the overlap width between the first annular drainage board and the first longitudinal drainage board is 150 mm.

[0009] Furthermore, to ensure the drainage effect, the width of the second longitudinal drainage board is 250 mm, and the overlapping length between the annular capillary drainage belt and the second longitudinal drainage board is 150 mm.

[0010] Furthermore, the longitudinal drainage blind pipe is a DN150 double-wall perforated corrugated pipe.

[0011] Furthermore, to ensure drainage effect, the width of the annular capillary drainage belt is 200mm, and the distance between two adjacent annular capillary drainage belts is 2-3m.

[0012] Furthermore, the annular capillary drainage belt is a thin strip structure and is made of PVC material.

[0013] The beneficial effects of the present invention are as follows: the composite tunnel waterproofing and drainage system of the present invention has a simple structure; by arranging a drainage board between the initial support and the geotextile layer, drainage can be carried out together with the original tunnel drainage system, which can reduce the drainage load of the tunnel drainage system and slow down the deterioration of the tunnel waterproofing and drainage system; and when the geotextile layer is blocked, the drainage board there can be used as a drainage channel for drainage, which can avoid the surrounding rock fissure water being retained behind the waterproof board and increasing the load of the secondary lining structure; by arranging an annular capillary drainage belt and a second longitudinal drainage board between the waterproof board and the secondary lining, the capillary and siphon effects of the capillary drainage belt can be utilized to timely and efficiently drain the water. The invention discloses a composite tunnel drainage system with a simple structure, convenient construction and good overall drainage effect. The composite tunnel drainage system has the advantages of simple structure, convenient construction and good overall drainage effect. Moreover, when the tunnel leaks, the water seepage point on the secondary lining surface can be directly blocked. Since there is a drainage channel behind the secondary lining, the seepage water will enter the drainage system through the drainage channel, which can reduce the difficulty and cost of tunnel leakage control. In addition, during the construction process, the drainage and waterproofing system of the present invention can select appropriate sections for layout according to the hydrogeological conditions and reasonably adjust the layout spacing of the drainage plates; during operation, when the longitudinal drainage blind pipe is blocked, the high-pressure nozzle is extended into the longitudinal drainage blind pipe through the maintenance joint and cleaned by a high-pressure water jet. After the maintenance is completed, the bolts can be closed. Therefore, the drainage and waterproofing system constructed by the present invention is adjustable, anti-blocking and easy to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural layout diagram of the composite tunnel drainage system in the present utility model;

[0015] Figure 2 This is a schematic diagram of the overlap between the first annular drainage board and the first longitudinal drainage board in the present invention;

[0016] Figure 3 It is a schematic diagram of the drain port in the utility model;

[0017] Figure 4 It is a schematic diagram of fixing the geotextile layer in the present utility model;

[0018] Figure 5 This is a schematic diagram of the waterproof layer reverse drainage blind pipe in the utility model;

[0019] Figure 6 This is a schematic diagram of fixing the waterproof board in the utility model;

[0020] Figure 7 This is a schematic diagram of the welding of the overlapping parts of the waterproofing plates in the present invention;

[0021] Figure 8 This is a schematic diagram of the overlap between the annular capillary drainage belt and the second longitudinal drainage board in the utility model;

[0022] Figure 9 This is a structural diagram of a longitudinal drainage blind pipe inspection well in the utility model;

[0023] Figure 10 It is a three-dimensional schematic diagram of the composite tunnel waterproofing and drainage system in the utility model;

[0024] In the figure, 1. initial support, 2. secondary lining, 3. geotextile layer, 4. waterproof board, 5. first annular drainage board, 6. second annular drainage board, 7. annular capillary drainage belt, 8. first longitudinal drainage board, 9. surrounding rock, 10. hot-melt pad, 11. nails, 12. second longitudinal drainage board, 13. longitudinal drainage blind pipe, 14. longitudinal drainage blind pipe inspection well, 15. sand well, 16. horizontal drain pipe, 17. pebble permeable bag, 18. geotextile wrapping, 19. drain outlet. DETAILED DESCRIPTION

[0025] The present invention will be further described below by way of non-limiting embodiments and in conjunction with the accompanying drawings:

[0026] As shown in the accompanying drawings, a composite tunnel waterproofing and drainage system includes a waterproof board 4 arranged between the initial support 1 and the secondary lining 2 of the tunnel, a geotextile layer 3 arranged between the waterproof board 4 and the initial support, a longitudinal drainage blind pipe 13 arranged at the arch foot, and a longitudinal drainage blind pipe inspection well 14. The longitudinal drainage blind pipe 13 is connected to the longitudinal drainage blind pipe inspection well 14. The system is characterized in that: a plurality of first annular drainage boards 5 are fixed at intervals between the initial support 1 and the geotextile layer 3, the first annular drainage boards 5 are fixed to the initial support by nailing, the first annular drainage boards 5 are convex shell-type drainage boards, and the bulge of the first annular drainage boards 5 is toward the initial support 1. A first longitudinal drain board 8 is installed at each of the two arch footings between the primary support 1 and the geotextile layer 3. These first longitudinal drain boards 8 are convex shell-shaped, covered with geotextile and secured to the primary support surface with nails. The lower end of the first circumferential drain board 5 overlaps the first longitudinal drain board 8 and is welded together by heat fusion. The first longitudinal drain board 5 is connected to the longitudinal drainage blind pipe inspection well 14 via a drain port 19, which is secured to the primary support with expansion screws. Drain port 19 is made of steel plate and has an outlet for draining water. The first longitudinal drain board 5 is inserted into drain port 19. A longitudinal drainage blind pipe 13 is installed at the tunnel arch footing between the geotextile layer 3 and the waterproofing sheet 4, running the entire length of the tunnel. The longitudinal drainage blind pipe 13 is preferably a DN150 double-wall perforated corrugated pipe. A pebble permeable bag 17 is placed above the longitudinal drainage blind pipe 13. Both the longitudinal drainage blind pipe 13 and the pebble permeable bag are covered with geotextile. Multiple second annular drain panels 6 are fixed at intervals between the geotextile layer 3 and the waterproofing sheet 4. The second annular drain panels 6 are convex shell-shaped drain panels with their protrusions facing the geotextile layer 3. The second annular drain panels 6 are spaced apart from the first annular drain panels 5, and the ends of the second annular drain panels 6 are located above the pebble permeable bags 17. Multiple annular capillary drainage strips 7 are fixed at intervals between the waterproofing sheet 4 and the secondary lining 2. The annular capillary drainage strips 7 are tightly attached to and fixed to the waterproofing sheet 4. A second longitudinal drain panel 12 is provided at each of the two arch foot portions between the waterproofing sheet 4 and the secondary lining 2. The lower ends of the annular capillary drainage strips 7 overlap and are fixed to the second longitudinal drain panel 12 as a whole. Strong adhesive can be used to overlap the annular capillary drainage strips 7 and the second longitudinal drain panel 12. The second longitudinal drain panel 12 is connected to a longitudinal drainage blind pipe inspection well 14. A sand trap 15 is provided at the inner bottom of the longitudinal drainage blind pipe inspection well 14, and the drain port of the longitudinal drainage blind pipe inspection well is higher than the sand trap 15. The second longitudinal drainage board 12 can also be a convex shell type drainage board.

[0027] The convex shell drainage board used in this utility model is prior art and commercially available. The capillary drainage strip 7 used in this utility model is also prior art and commercially available. The capillary drainage strip is a thin, strip-like material made of high-density PVC polymer with good toughness. Installed within the soil or building structure, it draws water back into the capillary pores under the action of "gravity capillary force," rapidly filling them. The surface tension of the water forms a closed structure, and the installation height difference generates a "siphon force." The three forces combine to collect, transport, and discharge groundwater.

[0028] To ensure the drainage effect, it is preferred that the width of the first annular drainage board 5 is 500 mm, and the interval between two adjacent first annular drainage boards 5 is 2-5 m; the width of the second annular drainage board 6 is 500 mm, and the interval between two adjacent second annular drainage boards 6 is 2-5 m.

[0029] To ensure the drainage effect, it is preferred that the width of the first longitudinal drain plate 8 is 250 mm, and the overlap width between the first annular drain plate 5 and the first longitudinal drain plate 8 is 150 mm.

[0030] To ensure the drainage effect, it is preferred that the width of the second longitudinal drainage board 12 is 250 mm, and the overlapping length of the annular capillary drainage belt 7 and the second longitudinal drainage board 12 is 150 mm.

[0031] To ensure the drainage effect, it is preferred that the width of the annular capillary drainage belt 7 is 200 mm, and the distance between two adjacent annular capillary drainage belts 7 is 2-3 m.

[0032] In the utility model, the first annular drainage board 5 and the first longitudinal drainage board 8 serve as drainage channels between the initial support 1 and the geotextile layer 3, and the seepage water can be drained into the longitudinal drainage blind pipe inspection well 14 through the first longitudinal drainage board 8; the second annular drainage board 5 and the longitudinal drainage blind pipe serve as drainage channels between the geotextile layer 3 and the waterproof board 4, and the seepage water is discharged into the longitudinal drainage blind pipe inspection well 14 through the longitudinal drainage blind pipe 13; the annular capillary drainage belt 7 and the second longitudinal drainage board 12 serve as drainage channels between the waterproof board 4 and the secondary lining 2, and the seepage water is drained into the longitudinal drainage blind pipe inspection well 14 through the second longitudinal drainage board 12.

[0033] The construction of the composite tunnel drainage system includes the following steps:

[0034] (1) Remove the exposed steel bar heads and anchor rod heads on the initial support surface, smooth them with cement mortar, and trim the uneven parts to ensure that the initial support surface is flat.

[0035] (II) The first ring-shaped drainage plate 5 is laid from the arch to the arch foot by the trolley, the interval of the first ring-shaped drainage plate 5 is 5 meters, the interval is adjusted to 2-3 meters in the area where the surrounding rock has a large amount of water seepage, and the first ring-shaped drainage plate 5 is fixed by using the shot pin. The first ring-shaped drainage plate 5 should avoid overlapping at the arch wall position, if overlapping is needed, the overlapping length should not be less than 100 mm, the overlapping position needs to be below the haunch and fixed; and the lower drainage plate is located outside the upper drainage plate, and hot melt welding is used at the joint of the drainage plate.

[0036] (III) At the arch foot position, the first longitudinal drainage plate 8 is arranged along the longitudinal direction of the tunnel, the first ring-shaped drainage plate 5 and the first longitudinal drainage plate 8 are constructed by overlapping, hot melt welding is used at the joint, and the first ring-shaped drainage plate 5 is located on the side close to the primary support 1, as shown in the accompanying drawings. Figure 2 The first longitudinal drainage plate 8 is wrapped with geotextile and fixed on the surface of the primary support 1 by using the shot pin, and the first longitudinal drainage plate 8 is connected to the longitudinal drainage blind pipe maintenance well 14 through a water outlet 19. The first longitudinal drainage plate 8 is inserted into the water outlet 19, and then the water outlet 19 is fixed on the primary support 1 by using the expansion screw.

[0037] (IV) The geotextile layer is laid by using the trolley, the geotextile layer uses non-woven geotextile, and the geotextile is fixed on the primary support 1 by using the shot pin 11 and the heated melting pad 10, as shown in the accompanying drawings. Figure 4 The interval and arrangement of the fixed points are according to the design requirements, the fixed points are firm, the geotextile should be laid flat, stretched, smooth and smooth, and has a certain degree of slack. When the geotextile needs to be overlapped, the overlapping width should not be less than 100 mm.

[0038] (V) The longitudinal drainage blind pipe 13 is installed at the arch foot position of the tunnel, the longitudinal drainage blind pipe 13 is arranged along the longitudinal direction of the tunnel, the stone permeable bag 17 is arranged above the longitudinal drainage blind pipe 13, the original rock is a non-soluble material, and the longitudinal drainage blind pipe 13 and the stone permeable bag 17 are wrapped with geotextile and fixed by using the shot pin, as shown in the accompanying drawings. Figure 5

[0039] (VI) The second ring-shaped drainage plate 6 between the geotextile layer 3 and the waterproof plate 4 is laid by using the trolley, the interval of the second ring-shaped drainage plate 6 is 5 meters, the interval is adjusted to 2-3 meters in the area where the surrounding rock has a large amount of water seepage, the second ring-shaped drainage plate 6 is fixed on the primary support 1 by using the shot pin, and the second ring-shaped drainage plate 6 is arranged at intervals with the first ring-shaped drainage plate 5. The second ring-shaped drainage plate 6 should avoid overlapping at the arch wall position, if overlapping is needed, the overlapping length should not be less than 100 mm, the overlapping position needs to be below the haunch and fixed at the overlapping position, and the lower drainage plate is located outside the upper drainage plate, and hot melt welding is used at the joint of the drainage plate.

[0040] ​(VII) The waterproof board 4 is laid by a special gantry truck. The waterproof board 4 is laid in the entire ring, and there is no longitudinal overlap between the arch and the side wall. The length of the waterproof board is reasonably cut according to the size of the laid ring to minimize the joints. The waterproof boards are automatically hot-melt welded by an automatic double-seam hot-melt welding machine; the effective weld width of a single weld is not less than 15mm, and the overlap width of the waterproof board should be greater than 150mm. The edge of the waterproof board laid in sections should reserve an overlap margin of at least 600mm, and the reserved area should be effectively protected. The waterproof board is fixed to the initial support 1 with nails. As shown in the attached Figure 6 and Figure 7 shown.

[0041] (8) Lay the circumferential capillary drainage tape 7. The circumferential spacing of the circumferential capillary drainage tape 7 is 2-3m. In order to avoid damaging the capillary drainage tape during the fixing process and to avoid damaging the waterproof board, the circumferential capillary drainage tape 7 and the waterproof board 4 are fixed by cold bonding with strong glue. First, apply glue on the surface of the waterproof board 4. After the glue is air-dried, the capillary drainage tape 7 is firmly bonded to the surface of the waterproof board 4. When the tunnel cross-section is uneven, use hard rubber strips for auxiliary fixation by hot welding. Align the left and right ends of the hard rubber strips with the two side edges of the capillary drainage tape, and use an electric hot air blower to melt and bond them. The capillary drainage tape should avoid overlapping in the circumferential direction. If overlapping is required, the overlapping length must be greater than 50mm and the lower drainage tape must include the upper drainage tape. The overlapping position is below the arch waist, and a fixed position is set at the overlapping position.

[0042] (IX) The second longitudinal drainage board 12 is laid at the arch foot. The annular capillary drainage belt 7 and the second longitudinal drainage board 12 are constructed by overlapping. The overlapping length is 100mm. Figure 8 To avoid damaging the capillary drainage strip, the overlapping ends of the annular capillary drainage strip 7 and the second longitudinal drainage board 12 are cold-bonded together using strong glue. The second longitudinal drainage board 12 is secured to the waterproofing board 4 using hard rubber strips with auxiliary hot welding. The edges of the second longitudinal drainage board 12 are covered with non-woven fabric to prevent clogging during subsequent secondary lining construction. The second longitudinal drainage board 12 is connected to the longitudinal drainage blind pipe inspection well 14.

[0043] (10) A sand settling well 15 is set at the inner bottom of the longitudinal drainage blind pipe inspection well 14, as shown in the attached Figure 9 shown.

[0044] The utility model has the advantages of simple structure, convenient construction and good overall drainage effect. It can solve the problems faced by the current drilling and blasting tunnel drainage system, such as aging and failure of geotextiles, blockage of drainage blind pipes, and deterioration of waterproof boards. It can improve the tunnel drainage capacity and improve the safety of the tunnel structure.

[0045] The other parts of this embodiment are all existing technologies and will not be described in detail here.

Claims

1. A composite tunnel drainage system, comprising a waterproof plate (4) disposed between the primary support and the secondary lining of the tunnel, a geotextile layer (3) disposed between the waterproof plate (4) and the primary support, a longitudinal drainage blind pipe (13) disposed at the arch foot, and a longitudinal drainage blind pipe inspection well (14) connected to the longitudinal drainage blind pipe, wherein: A plurality of first annular drainage plates (5) are fixed at intervals between the initial support and the geotextile layer (3). The first annular drainage plates (5) are convex shell drainage plates. The convexity of the first annular drainage plates (5) faces the initial support. A first longitudinal drainage plate (8) is respectively provided at the two arch foot positions between the initial support and the geotextile layer (3). The first longitudinal drainage plate (8) is a convex shell drainage plate. The lower end of the first annular drainage plate (5) is overlapped with the first longitudinal drainage plate (8) and fixed as a whole. The first longitudinal drainage plate ( 8) A longitudinal drainage blind pipe inspection well (14) is connected via a drain port, wherein the first longitudinal drainage board (8) and the drain port are both fixed on the initial support; the longitudinal drainage blind pipe (13) is arranged at the tunnel arch foot portion between the geotextile layer (3) and the waterproof board (4), and is arranged along the longitudinal length of the tunnel; a pebble permeable bag (17) is arranged above the longitudinal drainage blind pipe (13), and the longitudinal drainage blind pipe (13) and the pebble permeable bag are wrapped with geotextile; a fixed spacer is provided between the geotextile layer (3) and the waterproof board (4); There are multiple second annular drainage boards (6), which are convex shell-type drainage boards. The bulge of the second annular drainage board (6) faces the geotextile layer (3). The second annular drainage board (6) is arranged at intervals from the first annular drainage board (5). The end of the second annular drainage board (6) is located above the pebble permeable bag (17); multiple annular capillary drainage belts (7) are fixed at intervals between the waterproof board (4) and the secondary lining. The annular capillary drainage belts (7) are closely attached to the waterproof board (4) and fixed to the On the waterproof board (4); a second longitudinal drainage board (12) is respectively provided at the two arch foot positions between the waterproof board (4) and the secondary lining; the lower end of the annular capillary drainage belt (7) is overlapped and fixed to the second longitudinal drainage board (12); the second longitudinal drainage board (12) is connected to the longitudinal drainage blind pipe inspection well (14); a sand settling well (15) is provided at the inner bottom of the longitudinal drainage blind pipe inspection well (14); the drain port of the longitudinal drainage blind pipe inspection well (14) is higher than the sand settling well (15).

2. The composite tunnel drainage system according to claim 1 is characterized by: The width of the first annular drainage plate (5) is 500 mm, and the interval between two adjacent first annular drainage plates (5) is 2-5 m; the width of the second annular drainage plate (6) is 500 mm, and the interval between two adjacent second annular drainage plates (6) is 2-5 m.

3. The composite tunnel drainage system according to claim 2 is characterized by: The width of the first longitudinal drain plate (8) is 250 mm, and the overlap width between the first annular drain plate (5) and the first longitudinal drain plate (8) is 150 mm.

4. The composite tunnel drainage system according to claim 2 is characterized by: The width of the second longitudinal drainage plate (12) is 250 mm, and the overlapping length between the annular capillary drainage belt (7) and the second longitudinal drainage plate (12) is 150 mm.

5. The composite tunnel drainage system according to claim 1 is characterized by: The longitudinal drainage blind pipe (13) is a DN150 double-wall perforated corrugated pipe.

6. The composite tunnel drainage system according to claim 1, 2, 3, 4 or 5, characterized in that: The width of the annular capillary drainage belt (7) is 200 mm, and the distance between two adjacent annular capillary drainage belts (7) is 2-3 m.

7. The composite tunnel drainage system according to claim 6 is characterized by: The annular capillary drainage belt (7) is a thin strip structure and is made of PVC material.

Images