Composite tunnel waterproof and drainage system and construction method thereof

Abstract

The invention discloses a composite tunnel waterproof and drainage system and a construction method thereof. The composite tunnel waterproof and drainage system comprises a waterproof plate, a geotechnical cloth layer and longitudinal drainage blind pipes 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, and the lower ends of the first annular drainage plates are in lap joint with first longitudinal drainage plates into a whole; the first longitudinal drainage plate is connected with a longitudinal drainage blind pipe overhaul well, and a pebble permeable bag is arranged above the longitudinal drainage blind pipe and is 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 present invention relates to a tunnel drainage system, belonging to the technical field of tunnel drainage, and also relates to a construction method of the tunnel drainage system. Background Art

[0002] The environment of water-rich mountains and urban underground tunnels is partly rich in groundwater or surface water, and there is unlimited water to replenish the tunnel space. Due to the limitation of longitudinal slope, there is no natural drainage condition. In addition, the uncertainty of tunnel engineering geological survey and detection makes the problems of tunnel leakage, water inrush and related water disasters and diseases complex and severe, and prevention and control measures are difficult. The contradiction between "reducing water pressure" and "controlling drainage" in the drainage system is sharp. As a large-scale, high-risk and difficult project, the core problem that needs to be solved is the tunnel drainage design during the project construction period and the treatment of leakage and drainage during the operation period. This is also one of the main tasks faced during the entire cycle from tunnel construction to operation.

[0003] At present, the main problems faced by the drilling and blasting tunnel drainage system are: aging and failure of geotextiles, serious blockage of drainage blind pipes, and deterioration of waterproof panels. These problems will aggravate the performance degradation of the drainage system in the long-term operation of the tunnel, greatly weaken its drainage efficiency, and then cause the water level behind the tunnel lining to rise sharply, increase the long-term load of the secondary lining, induce the derivation and expansion of cracks in the tunnel structure, and seriously threaten the safety of tunnel operation and maintenance. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention provides a composite tunnel drainage system which has a simple structure, is easy to construct and has good overall drainage effect.

[0005] The present invention is realized through the following technical scheme: a composite tunnel drainage system, comprising a waterproof board arranged between the initial support and the secondary lining of the tunnel, a geotextile layer arranged between the waterproof board 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 boards are fixed at intervals between the initial support and the geotextile layer, the first annular drainage board is a convex shell-type drainage board, the protrusion of the first annular drainage board faces the initial support, a first longitudinal drainage board is respectively arranged at the two arch foot positions between the initial support and the geotextile layer, the first longitudinal drainage board is a convex shell-type drainage board, the lower end of the first annular drainage board is overlapped and fixed to the first longitudinal drainage board, the first longitudinal drainage board is connected to the longitudinal drainage blind pipe inspection well through a drain port, and the first longitudinal drainage board and the drain port are both fixed on the initial support; the longitudinal drainage blind pipe is arranged at the tunnel arch foot between the geotextile layer and the waterproof board The tunnel is arranged along the longitudinal length of the tunnel, and a pebble permeable bag is arranged 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, and the second annular drainage board is a convex shell-type drainage board. The protrusion of the second annular drainage board faces the geotextile layer. The second annular drainage board is arranged at intervals with 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 permeable drainage belts are fixed at intervals between the waterproof board and the secondary lining, and the annular capillary permeable drainage belts are closely attached to the waterproof board and fixed on the waterproof board; a second longitudinal drainage board is respectively arranged at the two arch foot positions between the waterproof board and the secondary lining, and the lower end of the annular capillary permeable 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 arranged at the inner bottom of the longitudinal drainage blind pipe inspection well, and the water discharge port 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 initial 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 are used together as a tunnel drainage system to drain water. Among them, the drainage board arranged between the initial support and the geotextile layer, when the geotextile layer is blocked, the drainage board there can be used as a drainage channel to drain water, and the water is drained into the longitudinal drainage blind pipe inspection well, which can avoid the surrounding rock fissure water being retained behind the waterproof board and increasing the load of 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 timely and efficiently drain the surrounding rock fissure water retained behind the secondary lining, and drain the water into the longitudinal drainage blind pipe inspection well through the longitudinal drainage board, which can timely reduce the pressure behind the lining structure and improve the safety of the tunnel structure. By setting up a sand settling well in the longitudinal drainage blind pipe inspection well, the silt 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 silt. 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, in order to ensure the 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 present invention also provides a construction method of the composite tunnel drainage system, which adopts the following technical solution:

[0014] (i) Remove the hard objects on the exposed steel bar heads and anchor bolt 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;

[0015] (ii) The first annular drainage board is laid from the arch to the arch foot using a trolley. The spacing of the first annular drainage board is 5 meters. The spacing is adjusted to 2-3 meters in areas with large water seepage in the surrounding rock. The first annular drainage board is fixed with nails;

[0016] (III) At the arch foot, the first longitudinal drain plate is set along the longitudinal direction of the tunnel. The first annular drain plate and the first longitudinal drain plate are constructed by overlapping. The first annular drain plate is located close to the side of the initial support. The first longitudinal drain plate is reversed with geotextile and fixed to the surface of the initial support with nails. The first longitudinal drain plate is connected to the longitudinal drainage blind pipe inspection well through a drain port. The first longitudinal drain plate is inserted into the drain port, and then the drain port is fixed to the initial support with expansion screws;

[0017] (iv) Use a trolley to lay the geotextile layer, and fix the geotextile to the initial support by nailing and heating the fusion pad;

[0018] (V) Install the longitudinal drainage blind pipe at the tunnel arch foot. The longitudinal drainage blind pipe is arranged along the longitudinal length of the tunnel. The longitudinal drainage blind pipe and the pebble permeable bag are covered with geotextile and fixed with nails;

[0019] (VI) Use a trolley to lay the second annular drainage board between the geotextile layer and the waterproof board. The spacing between the second annular drainage boards is 5 meters. The spacing is adjusted to 2-3 meters in areas with large surrounding rock seepage. The second annular drainage board is fixed to the initial support with nails. The second annular drainage board is arranged at intervals from the first annular drainage board;

[0020] (VII) The waterproof panels are laid using a special platform vehicle, and the waterproof panels are laid in the entire circumferential direction, and hot-melt welding is used between the waterproof panels;

[0021] (VIII) Lay the circumferential capillary drainage tape with a circumferential spacing of 2-3m, apply glue on the surface of the waterproof board, and after the glue is air-dried, glue the capillary drainage tape to the surface of the waterproof board;

[0022] (IX) The second longitudinal drainage board is laid at the arch foot. The annular capillary drainage belt and the second longitudinal drainage board are constructed by overlapping. The overlapping ends of the annular capillary drainage belt and the second longitudinal drainage board are cold-bonded together by strong glue;

[0023] (10) A sand settling well shall be set at the inner bottom of the longitudinal drainage blind pipe inspection well.

[0024] The beneficial effects of the present invention are as follows: the composite tunnel drainage system of the present invention has a simple structure, and 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 drainage system. Moreover, 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 discharge the water. The surrounding rock fissure water trapped behind the secondary lining can timely reduce the pressure behind the lining structure and improve the safety of the tunnel structure; by setting a pebble permeable bag above the longitudinal drainage blind pipe, and using geotextile to reverse the longitudinal drainage blind pipe and the pebble permeable bag, the drainage blind pipe can be effectively prevented from being blocked, and it is convenient to clean and maintain the longitudinal drainage blind pipe in the later stage; by setting a sand settling well in the inspection well of the longitudinal drainage blind pipe, the silt will first settle inside the sand settling well, and when the water level reaches the height of the drainage hole, it will automatically flow out of the drainage hole. At this time, the water flow contains almost no silt, and only the inspection well needs to be cleaned regularly to ensure the normal operation of the tunnel drainage system. The composite tunnel drainage system of the present invention has the advantages of simple structure, easy construction, and good overall drainage effect. In addition, by using the composite tunnel drainage system of the present invention, when the tunnel leaks, the water seepage point on the surface of the secondary lining can be directly blocked. Since there is a drainage channel behind the secondary lining, the seepage will enter the drainage system through the drainage channel, which can reduce the difficulty and cost of the current tunnel leakage treatment. In addition, during the construction process, the drainage 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 the operation process, 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 system constructed by the present invention is adjustable, anti-blocking, and easy to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural layout diagram of the composite tunnel drainage system in the present invention;

[0026] Figure 2 It is a schematic diagram of the overlap between the first annular drainage board and the first longitudinal drainage board in the present invention;

[0027] Figure 3 It is a schematic diagram of the drain port in the present invention;

[0028] Figure 4 It is a schematic diagram of fixing the geotextile layer in the present invention;

[0029] Figure 5This is a schematic diagram of a drainage blind pipe with a waterproof layer wrapped around it in the present invention;

[0030] Figure 6 It is a schematic diagram of fixing the waterproof board in the present invention;

[0031] Figure 7 It is a schematic diagram of welding at the overlapping part of the waterproof board in the present invention;

[0032] Figure 8 It is a schematic diagram of the overlap between the annular capillary drainage belt and the second longitudinal drainage board in the present invention;

[0033] Fig. 9 It is a structural schematic diagram of a longitudinal drainage blind pipe inspection well in the present invention;

[0034] Fig.10 It is a three-dimensional schematic diagram of the composite tunnel waterproofing and drainage system of the present invention;

[0035] 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 drainage pipe, 17. pebble permeable bag, 18. geotextile outer package, 19. drainage outlet. DETAILED DESCRIPTION

[0036] The present invention will be further described below by way of non-limiting embodiments and in conjunction with the accompanying drawings:

[0037] As shown in the accompanying drawings, a composite tunnel 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, and 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 board 5 is fixed to the initial support by nailing, the first annular drainage board 5 is a convex shell type drainage board, and the bulge of the first annular drainage board 5 faces the initial support 1. A first longitudinal drainage board 8 is respectively arranged at the two arch foot positions between the initial support 1 and the geotextile layer 3. The first longitudinal drainage board 8 is a convex shell type drainage board. The first longitudinal drainage board 8 is reversed with geotextile and fixed to the surface of the initial support by nailing. The lower end of the first annular drainage board 5 overlaps with the first longitudinal drainage board 8 and is integrated by hot-melt welding. The first longitudinal drainage board 5 is connected to the longitudinal drainage blind pipe inspection well 14 through a drainage port 19. The drainage port 19 is made of steel plate and has an outlet for drainage. The first longitudinal drainage board 5 is inserted into the drainage port 19. The longitudinal drainage blind pipe 13 is arranged at the tunnel arch foot position between the geotextile layer 3 and the waterproof board 4, and is arranged along the longitudinal length of the tunnel. The longitudinal drainage blind pipe 13 preferably adopts a DN150 double-wall perforated corrugated pipe. A pebble permeable bag 17 is arranged above the longitudinal drainage blind pipe 13. The longitudinal drainage blind pipe 13 and the pebble permeable bag are reversed with geotextile. Multiple second annular drainage boards 6 are fixed at intervals between the geotextile layer 3 and the waterproof board 4. The second annular drainage boards 6 are convex shell-type drainage boards. The protrusions of the second annular drainage boards 6 face the geotextile layer 3. The second annular drainage boards 6 are arranged at intervals from the first annular drainage boards 5, and the ends of the second annular drainage boards 6 are located above the pebble permeable bags 17. Multiple annular capillary drainage belts 7 are fixed at intervals between the waterproof board 4 and the secondary lining 2. The annular capillary drainage belts 7 are closely attached to the waterproof board 4 and fixed on the waterproof board 4. A second longitudinal drainage board 12 is respectively arranged at the two arch foot parts between the waterproof board 4 and the secondary lining 2. The lower ends of the annular capillary drainage belts 7 overlap and are fixed as a whole with the second longitudinal drainage board 12. The annular capillary drainage belts 7 and the second longitudinal drainage board 12 can be overlapped and bonded with strong glue. The second longitudinal drainage board 12 is connected to the 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 may also be a convex shell type drainage board.

[0038] The convex shell type drainage board used in the present invention is an existing technology and can be purchased. The capillary drainage belt used in the annular capillary drainage belt 7 of the present invention is also an existing technology and can be purchased. The capillary drainage belt is a thin layer of strip material, which is a PVC high-density polymer material with good toughness. It is installed in the soil or building structure. Under the action of "gravity capillary force", the water flow is sucked back into the capillary pore groove and quickly filled. Under the action of the surface tension of water, a closed state is formed. The installation drop is used to generate "siphon force". The three forces are combined to collect, transport and discharge the groundwater flow.

[0039] 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.

[0040] To ensure the drainage effect, preferably, 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.

[0041] 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.

[0042] To ensure the drainage effect, preferably, 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.

[0043] In the present invention, 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 infiltrated 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 infiltrated 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 infiltrated water can be drained into the longitudinal drainage blind pipe inspection well 14 through the second longitudinal drainage board 12.

[0044] The construction method of the composite tunnel drainage system comprises the following steps:

[0045] (I) Remove the hard objects on the exposed steel bar heads and anchor 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.

[0046] (II) The first annular drainage board 5 is laid from the arch to the arch foot using a trolley. The spacing of the first annular drainage board 5 is 5 meters. The spacing is adjusted to 2-3 meters in areas with large water seepage in the surrounding rock. The first annular drainage board 5 is fixed with nails. The first annular drainage board 5 should avoid overlapping at the arch wall. If overlapping is required, the overlapping length should not be less than 100mm. The overlapping position should be located below the arch waist and fixed; and the lower drainage board is located outside the upper drainage board, and the drainage board joints are hot-melt welded.

[0047] (III) At the arch foot, a first longitudinal drainage board 8 is arranged along the longitudinal direction of the tunnel. The first annular drainage board 5 and the first longitudinal drainage board 8 are constructed by overlapping, and the joints are welded by hot melt. The first annular drainage board 5 is located close to the side of the initial support 1. Figure 2 The first longitudinal drainage board 8 is reversed with geotextile and fixed to the surface of the initial support 1 with nails. The first longitudinal drainage board 8 is connected to the longitudinal drainage blind pipe inspection well 14 through a drainage port 19. The first longitudinal drainage board 8 is inserted into the drainage port 19, and then the drainage port 19 is fixed to the initial support 1 with expansion screws.

[0048] (IV) The geotextile layer is laid using a trolley. The geotextile layer is made of non-woven geotextile. The geotextile is fixed to the initial support 1 by means of nails 11 and heated fusion pads 10. Figure 4 As shown. The spacing and arrangement of the fixing points shall be carried out in accordance with the design requirements, and the fixing shall be reliable. The geotextile shall be laid flat, stretched, smooth, and have a certain degree of looseness. When the geotextile needs to be overlapped, the overlap width shall not be less than 100mm.

[0049] (V) Install the longitudinal drainage blind pipe 13 at the tunnel arch foot. The longitudinal drainage blind pipe 13 is arranged along the longitudinal length of the tunnel. A pebble permeable bag 17 is set above the longitudinal drainage blind pipe 13. The original rock is used as a non-soluble material. The longitudinal drainage blind pipe 13 and the pebble permeable bag 17 are reversed with geotextiles and fixed with nails. Figure 5 shown.

[0050] (VI) Use a trolley to lay the second annular drain board 6 between the geotextile layer 3 and the waterproof board 4. The spacing between the second annular drain boards 6 is 5 meters. The spacing is adjusted to 2-3 meters in areas with large water seepage in the surrounding rock. The second annular drain board 6 is fixed to the initial support 1 by nailing. The second annular drain board 6 is arranged at intervals from the first annular drain board 5. The second annular drain board 6 should avoid overlapping at the arch wall. If overlapping is required, the overlapping length should not be less than 100mm. The overlapping position should be located below the arch waist and fixed at the overlapping position. The lower drain board is located outside the upper drain board, and the drainage board joints are hot-melt welded.

[0051] (VII) The waterproof board 4 is laid by a special gantry vehicle. The waterproof board 4 is laid in the whole width of the ring. 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. At least 600mm of overlap margin should be reserved at the edge of the waterproof board laid in sections, 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.

[0052] (VIII) Lay the circumferential capillary drainage belt 7. The circumferential spacing of the circumferential capillary drainage belt 7 is 2-3m. In order to avoid damage to the capillary drainage belt during the fixing process and to avoid damage to the waterproof board, the circumferential capillary drainage belt 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 belt 7 is butted and firmly bonded to the surface of the waterproof board 4. When the tunnel section is uneven, use hard rubber strip hot welding to assist in fixing. Align the left and right ends of the hard rubber strip with the edges of the two sides of the capillary drainage belt, and use an electric hot blower to melt and bond. The capillary drainage belt should avoid overlapping in the circumferential direction. If overlapping is required, the overlapping length must be greater than 50mm and the lower drainage belt contains the upper drainage belt. The overlapping position is below the arch waist, and a fixed position is set at the overlapping position.

[0053] (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, and the overlapping length is 100mm. Figure 8 As shown. To avoid damaging the capillary drainage belt, the overlapping ends of the annular capillary drainage belt 7 and the second longitudinal drainage board 12 are cold-bonded together with strong glue. The second longitudinal drainage board 12 and the waterproof board 4 are fixed by hard rubber strip hot welding. The edge of the second longitudinal drainage board 12 is covered with non-woven fabric to prevent the drainage board from being blocked during the subsequent secondary lining construction. The second longitudinal drainage board 12 is connected to the longitudinal drainage blind pipe inspection well 14.

[0054] (10) A sand settling well 15 is provided at the inner bottom of the longitudinal drainage blind pipe inspection well 14, as shown in the attached Fig. 9 shown.

[0055] The present invention 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, deterioration of waterproof boards, etc. It can improve the tunnel drainage capacity and improve the safety of the tunnel structure.

[0056] The other parts of this embodiment are all prior art and will not be described in detail here.

Claims

1. A composite tunnel drainage system, comprising a waterproof board (4) arranged between the primary support and the secondary lining of the tunnel, a geotextile layer (3) arranged between the waterproof board (4) and the primary support, a longitudinal drainage blind pipe (13) arranged 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 fixedly arranged between the initial support and the geotextile layer (3), the first annular drainage plates (5) being convex shell-shaped drainage plates, the bulge of the first annular drainage plates (5) facing the initial support, and a first longitudinal drainage plate (8) is respectively arranged at the two arch foot positions between the initial support and the geotextile layer (3), the first longitudinal drainage plate (8) being a convex shell-shaped drainage plate, the lower end of the first annular drainage plate (5) overlaps and is fixedly integrated with the first longitudinal drainage plate (8), and the first longitudinal drainage plate (8) is provided at the two arch foot positions between the initial support and the geotextile layer (3). 8) A longitudinal drainage blind pipe inspection well (14) is connected via a drain port, 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 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); A plurality of second annular drainage plates (6) are provided, the second annular drainage plates (6) are convex shell-type drainage plates, the bulges of the second annular drainage plates (6) face the geotextile layer (3), the second annular drainage plates (6) are arranged at intervals from the first annular drainage plates (5), and the ends of the second annular drainage plates (6) are located above the pebble permeable bags (17); a plurality of annular capillary permeable drainage belts (7) are fixed at intervals between the waterproof plate (4) and the secondary lining, the annular capillary permeable drainage belts (7) are closely attached to the waterproof plate (4) and fixed on the On the waterproof board (4); a second longitudinal drainage board (12) is respectively arranged at the two arch foot positions between the waterproof board (4) and the secondary lining; the lower end of the annular capillary permeable 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 arranged 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 in that: 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 in that: The width of the first longitudinal drainage plate (8) is 250 mm, and the overlap width between the first annular drainage plate (5) and the first longitudinal drainage plate (8) is 150 mm.

4. The composite tunnel drainage system according to claim 2 is characterized in that: 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 layer strip structure and is made of PVC material.

8. The construction method of the composite tunnel drainage system according to any one of claims 1 to 7, characterized in that: The steps include: (i) Remove the hard objects on the exposed steel bar heads and anchor bolt 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; (ii) The first annular drainage board is laid from the arch to the arch foot using a trolley. The spacing of the first annular drainage board is 5 meters. The spacing is adjusted to 2-3 meters in areas with large water seepage in the surrounding rock. The first annular drainage board is fixed with nails; (III) At the arch foot, the first longitudinal drain plate is set along the longitudinal direction of the tunnel. The first annular drain plate and the first longitudinal drain plate are constructed by overlapping. The first annular drain plate is located close to the side of the initial support. The first longitudinal drain plate is reversed with geotextile and fixed to the surface of the initial support with nails. The first longitudinal drain plate is connected to the longitudinal drainage blind pipe inspection well through a drain port. The first longitudinal drain plate is inserted into the drain port, and then the drain port is fixed to the initial support with expansion screws; (iv) Use a trolley to lay the geotextile layer, and fix the geotextile to the initial support by nailing and heating the fusion pad; (V) Install the longitudinal drainage blind pipe at the tunnel arch foot. The longitudinal drainage blind pipe is arranged along the longitudinal length of the tunnel. The longitudinal drainage blind pipe and the pebble permeable bag are covered with geotextile and fixed with nails; (VI) Use a trolley to lay the second annular drainage board between the geotextile layer and the waterproof board. The spacing between the second annular drainage boards is 5 meters. The spacing is adjusted to 2-3 meters in areas with large surrounding rock seepage. The second annular drainage board is fixed to the initial support with nails. The second annular drainage board is arranged at intervals from the first annular drainage board; (VII) The waterproof panels are laid using a special platform vehicle, and the waterproof panels are laid in the entire circumferential direction, and hot-melt welding is used between the waterproof panels; (VIII) Lay the circumferential capillary drainage tape with a circumferential spacing of 2-3m, apply glue on the surface of the waterproof board, and after the glue is air-dried, glue the capillary drainage tape to the surface of the waterproof board; (IX) The second longitudinal drainage board is laid at the arch foot. The annular capillary drainage belt and the second longitudinal drainage board are constructed by overlapping. The overlapping ends of the annular capillary drainage belt and the second longitudinal drainage board are cold-bonded together by strong glue; (10) A sand settling well shall be set at the inner bottom of the longitudinal drainage blind pipe inspection well.

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