An underground tunnel drainage system suitable for rainy season

Abstract

The application discloses a kind of underground tunnel drainage systems suitable for rainy season, including by inside to outside sequentially arranged secondary lining, waterproof layer, drainage layer and initial support, and drainage ditch being arranged in the both sides of tunnel driving surface;Drainage layer inside is along the direction of tunnel axis and is laid with several inner layer annular drainage blind pipes, the outer surface of initial support is along the direction of tunnel axis and is laid with several outer layer annular drainage blind pipes, the bottom of the both sides of inner layer annular drainage blind pipe and outer layer annular drainage blind pipe is communicated with the both sides drainage ditch by connecting pipe respectively, drainage ditch includes variable cross section drainage ditch and side drainage ditch;Variable cross section drainage ditch is connected with several jet pumps, jet pump is connected with high-pressure water mechanism, and variable cross section drainage ditch and side drainage ditch are communicated by cross pipe.The drainage system of the application is connected with jet pump and high-pressure water mechanism by setting variable cross section drainage ditch, so that passive drainage becomes active pumping, significantly improves the drainage efficiency of underground tunnel in rainy season, and is suitable for tunnel engineering technical field.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering technology, and in particular relates to an underground tunnel drainage system suitable for the rainy season. Background Technology

[0002] As critical transportation or water conveyance structures traversing mountains, waterways, or cities, the safety and stability of tunnels during both construction and operation are of paramount importance. Groundwater infiltration is a common phenomenon throughout the tunnel's entire lifespan. However, during the rainy season (flood season), this routine problem worsens dramatically, becoming one of the core risk factors threatening tunnel engineering safety, construction schedule, and operational efficiency.

[0003] The water environment problems faced by urban underground tunnels during the rainy season are mainly manifested in the risk of waterlogging, overflow pollution and infrastructure safety pressure: (1) Traditional drainage pipe network standards are low, and surface water accumulation is serious during heavy rainfall, making the tunnel a disaster area for waterlogging. (2) Combined sewer overflows during the rainy season, and the first rain washes surface pollutants directly into the river. (3) Infrastructure challenges, shallow underground space is occupied by pipelines, making expansion difficult. (4) Long-term structural impact: Continuous and high-pressure groundwater seepage will aggravate the erosion and seepage damage to the lining structure, affecting the long-term durability and waterproof performance of the tunnel structure. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a drainage system for underground tunnels suitable for the rainy season. This drainage system, by setting up inner and outer circumferential drainage blind pipes and connecting them to a variable cross-section drainage ditch, allows groundwater from the initial support layer and seepage water from inside the tunnel to ultimately drain into the variable cross-section drainage ditch. Combined with a jet pump and high-pressure water mechanism, a large amount of seepage water is actively pumped out of the tunnel, significantly improving drainage efficiency and solving the problem of low standards in traditional drainage networks, which leads to urban underground tunnels becoming severely flooded areas during the rainy season.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: an underground tunnel drainage system suitable for the rainy season, comprising, from the inside out, a secondary lining, a waterproof layer, a drainage layer, and an initial support, and drainage ditches set on both sides of the tunnel road surface; the drainage layer is provided with a plurality of inner circumferential drainage blind pipes arranged along the tunnel axis, and the outer surface of the initial support is provided with a plurality of outer circumferential drainage blind pipes arranged along the tunnel axis; the bottom ends of the inner and outer circumferential drainage blind pipes are connected to the drainage ditches on both sides through connecting pipes; the drainage ditches include variable cross-section drainage ditches and side drainage ditches; the variable cross-section drainage ditches are connected to a plurality of jet pumps, the jet pumps are connected to a high-pressure water mechanism, and the variable cross-section drainage ditches and side drainage ditches are connected by horizontal pipes.

[0006] The above-mentioned underground tunnel drainage system suitable for the rainy season includes a variable cross-section drainage ditch comprising an inlet section at the top, a contraction section connected to the bottom of the inlet section, an acceleration section connected to the bottom of the contraction section, and a diffuser section connected to the bottom of the acceleration section. The inlet section is rectangular, the contraction section is V-shaped, the diffuser section is trapezoidal, and the acceleration section has an overflow hole in the middle that is connected to the suction pipe of a jet pump.

[0007] The above-mentioned underground tunnel drainage system suitable for the rainy season includes a high-pressure water mechanism comprising an urban rainwater storage tank, a water supply pipe connected to the outlet of the urban rainwater storage tank, and a multi-stage centrifugal pump installed on the water supply pipe. The other end of the water supply pipe is connected to the inlet pipe of the jet pump, and a water valve is installed on the outlet of the urban rainwater storage tank.

[0008] In the above-mentioned underground tunnel drainage system suitable for the rainy season, the height ratio of the contraction section, acceleration section and diffusion section is 2.5~3.2:1:4.2~4.7, the inclination angle α of the contraction section is 11°~13°, and the diffusion angle β of the diffusion section is 6°~9°.

[0009] The aforementioned underground tunnel drainage system suitable for the rainy season has a stainless steel lining on the inner wall of the acceleration section and is equipped with flow guiding ribs.

[0010] The aforementioned underground tunnel drainage system suitable for the rainy season has a stainless steel lining coated with a hydrophobic coating.

[0011] The aforementioned underground tunnel drainage system suitable for the rainy season includes a pressure sensor located in the middle of the acceleration section.

[0012] The aforementioned underground tunnel drainage system suitable for the rainy season includes a drainage pipe at the bottom of the diffuser section.

[0013] The above-mentioned underground tunnel drainage system suitable for the rainy season has a jet pump outlet pipe connected to a turbine generator.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. This invention sets up an inner circumferential drainage blind pipe and an outer circumferential drainage blind pipe, and connects the inner circumferential drainage blind pipe and the outer circumferential drainage blind pipe to a variable cross-section drainage ditch, so that the groundwater in the outer layer of the initial support and the seepage water inside the tunnel are discharged into the variable cross-section drainage ditch. Combined with the setting of a jet pump and a high-pressure water mechanism, the passive drainage is transformed into active pumping, and a large amount of seepage water is quickly pumped away from the tunnel.

[0016] 2. This invention incorporates the Venturi effect by designing a variable cross-section drainage ditch with a rectangular inlet section, a V-shaped contraction section, an acceleration section, and a trapezoidal diffuser section. This accelerates the seepage flow, and, in conjunction with a jet pump and a high-pressure water mechanism, effectively improves drainage efficiency and prevents water accumulation within the variable cross-section drainage ditch, especially during heavy rains, which can cause tunnel flooding and water mist within the tunnel, affecting driving safety. By controlling the height ratio of the contraction, acceleration, and diffuser sections, as well as the inclination angle of the contraction section and the diffusion angle of the diffuser section, the energy loss of the seepage flow in the contraction section is reduced, and water hammer effects are avoided in the diffuser section.

[0017] 3. This invention improves cavitation resistance by setting a stainless steel lining on the inner wall of the acceleration section; reduces turbulent dissipation by setting guide ribs to maintain laminar flow acceleration, thereby reducing the pressure at the suction port of the jet pump and improving drainage efficiency; at the same time, the use of jet pump for drainage can obtain high-speed water flow, and the water energy can be converted into electrical energy by connecting a turbine generator to power a multi-stage centrifugal pump.

[0018] 4. This invention uses a pressure sensor located in the middle of the acceleration section to detect the amount of water seepage in the tunnel. When the water volume is too high and the pressure in the acceleration section drops significantly, the high-pressure water mechanism is activated to quickly drain the water using a jet pump.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the underground tunnel drainage system of the present invention.

[0021] Figure 2 This is a schematic diagram of the variable cross-section drainage ditch of the present invention.

[0022] Figure 3 This is a schematic diagram of the jet pump of the present invention.

[0023] Figure 4 This is a schematic diagram of the high-pressure water mechanism of the present invention.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1—Secondary lining; 2—Waterproof layer; 3—Drainage layer; 31—Inner circumferential drainage blind pipe; 4—Initial support; 41—Outer circumferential drainage blind pipe; 5—Variable cross-section drainage ditch; 51—Inlet section; 52—Contraction section; 53—Acceleration section; 54—Diffuser section; 55—Drainage pipe; 6—Jet pump; 61—Suction pipe; 62—Inlet pipe; 63—Outlet pipe; 7—High-pressure water mechanism; 71—Urban rainwater storage tank; 72—Water delivery pipe; 73—Multi-stage centrifugal pump; 8—Connecting pipe; 9—Side drainage ditch; 10—Horizontal pipe. Detailed Implementation

[0026] Example 1

[0027] like Figure 1 As shown, the underground tunnel drainage system of this embodiment includes a secondary lining 1, a waterproof layer 2, a drainage layer 3, and an initial support 4 arranged sequentially from the inside to the outside, and drainage ditches set on both sides of the tunnel road surface; the drainage layer 3 is provided with a plurality of inner circumferential drainage blind pipes 31 arranged along the tunnel axis, and the outer surface of the initial support 4 is provided with a plurality of outer circumferential drainage blind pipes 41 arranged along the tunnel axis. The bottom ends of the inner circumferential drainage blind pipes 31 and the outer circumferential drainage blind pipes 41 are connected to the drainage ditches on both sides through connecting pipes 8 respectively; the drainage ditch includes a variable cross-section drainage ditch 5 and a side drainage ditch 9, the variable cross-section drainage ditch 5 is connected to a plurality of jet pumps 6, the jet pumps 6 are connected to a high-pressure water mechanism 7, and the variable cross-section drainage ditch 5 and the side drainage ditch 9 are connected by a horizontal pipe 10.

[0028] In practical use, in this embodiment, a waterproof layer 2 is set to prevent seepage water from entering the tunnel interior. A drainage layer 3 with several inner circumferential drainage blind pipes 31 arranged along the tunnel axis is set to drain as much water as possible from the initial support 4 that seeps into the drainage layer 3, preventing a large amount of water from entering the waterproof layer 2. An initial support 4 with several outer circumferential drainage blind pipes 41 arranged along the tunnel axis is set to reduce seepage water entering the tunnel structure. Variable cross-section drainage ditches 5 and side drainage ditches 9 are set on both sides of the tunnel road surface, and the inner circumferential drainage blind pipes 31 and outer circumferential drainage blind pipes 41 are connected to the variable cross-section drainage ditches 5 and side drainage ditches 9 respectively, to quickly drain seepage water. By connecting a jet pump 6 and a high-pressure water system 8 to the variable cross-section drainage ditch 5, passive drainage is changed to active pumping during periods of heavy seepage in the rainy season, improving the tunnel's drainage efficiency. A horizontal pipe 10 is set to allow a large amount of accumulated water in the side drainage ditch 9 to be drained into the variable cross-section drainage ditch 5 for rapid discharge. Preferably, in this embodiment, the waterproof layer 2 is made of concrete with a seepage resistance grade of P8 or higher to improve the seepage prevention effect, and the drainage layer 3 is made of permeable concrete to facilitate the absorption of seepage by the inner circumferential drainage blind pipe 31.

[0029] Furthermore, such as Figure 1 , Figure 2 and Figure 3 As shown, in this embodiment, the variable cross-section drainage ditch 5 includes an inlet section 51 at the top, a contraction section 52 connected to the bottom of the inlet section 51, an acceleration section 53 connected to the bottom of the contraction section 52, and a diffuser section 54 connected to the bottom of the acceleration section 53. The inlet section 51 is rectangular, the contraction section 52 is V-shaped, the diffuser section 54 is trapezoidal, and the acceleration section 53 has an overflow hole in the middle that is connected to the suction pipe 61 of the jet pump 6.

[0030] In practical use, in this embodiment, the variable cross-section drainage ditch 5 is configured from top to bottom as a rectangular inlet section 51, a V-shaped contraction section 52, an acceleration section 53, and a trapezoidal diffuser section 54. The Venturi effect is used to increase the flow velocity of the water in the acceleration section 53, and the jet pump 6 is used to draw the water out through the suction pipe 61. According to the test, the flow velocity of the water in the acceleration section 53 is increased by more than 70% compared with the flow velocity of the traditional straight ditch.

[0031] Preferably, in this embodiment, the angle between the suction pipe 61 and the axial direction of the acceleration section 53 is less than 90° to prevent a large amount of mud and sand from entering the jet pump 6.

[0032] Furthermore, such as Figure 1 , Figure 3 and Figure 4 As shown, in this embodiment, the high-pressure water mechanism 7 includes an urban rainwater storage tank 71, a water supply pipe 72 connected to the outlet of the urban rainwater storage tank 71, and a multi-stage centrifugal pump 73 installed on the water supply pipe 72. The other end of the water supply pipe 72 is connected to the inlet pipe 62 of the jet pump 6. A water valve is installed on the outlet of the urban rainwater storage tank 71.

[0033] In practical use, in this embodiment, a city rainwater storage tank 71 is connected to a water supply pipe 72, and a multi-stage centrifugal pump 73 is installed on the water supply pipe 72. Water from the city rainwater storage tank 71 is accelerated by the multi-stage centrifugal pump 73 through the water supply pipe 72 and injected into the inlet pipe 62 of the jet pump 6. This water is then ejected at high speed from the nozzle of the jet pump 6 as the working fluid. A vacuum is created at the throat inlet of the jet pump 6 because the surrounding air is drawn away by the working fluid. The suction pipe 61 immediately draws in the water flow from the acceleration section 53. Then, the working fluid and the water flow from the acceleration section 53 are ejected together from the outlet pipe 63 of the jet pump 6. A water valve is installed at the outlet of the city rainwater storage tank 71 to control the supply of working fluid to the jet pump 6 during the rainy season. In this embodiment, the multi-stage centrifugal pump 73 is a CDL stainless steel vertical multi-stage centrifugal pump.

[0034] Furthermore, such as Figure 2 As shown, in this embodiment, the height ratio of the contraction section 52, the acceleration section 53 and the diffusion section 54 is 2.5~3.2:1:4.2~4.7, the inclination angle α of the contraction section 52 is 11°~13°, and the diffusion angle β of the diffusion section 54 is 6°~9°.

[0035] In practical use, in this embodiment, by setting the height ratio of the contraction section 52, acceleration section 53, and diffusion section 54 to 2.5~3.2:1:4.2~4.7, and controlling the inclination angle α of the contraction section 52 to 10°~13°, the water flow can be smoothly accelerated in the contraction section 52, avoiding boundary layer separation caused by large-angle sudden changes, generating energy-consuming eddies, and slowing down the water flow velocity in the acceleration section 53; by controlling the diffusion angle β of the diffusion section 54 to 6°~9°, the water flow pressure recovery speed can be slowed down, converting kinetic energy into pressure energy while avoiding water hammer effect.

[0036] Furthermore, such as Figure 2 As shown, in this embodiment, the inner wall of the acceleration section 53 is provided with a stainless steel lining and guide ribs.

[0037] In practical use, in this embodiment, a stainless steel lining is provided on the inner wall of the acceleration section 53 to improve the cavitation resistance performance, and a flow guide rib is provided to reduce turbulent dissipation and maintain laminar flow to the downstream of the acceleration section 53. Preferably, in this embodiment, the angle between the flow guide rib and the mainstream direction of the water flow is 30°~35°, which is used to guide the water flow to generate lateral momentum and delay boundary layer separation.

[0038] Furthermore, such as Figure 2 As shown, in this embodiment, the stainless steel liner is coated with a hydrophobic coating.

[0039] In practical use, in this embodiment, by coating the stainless steel liner with a hydrophobic coating, the kinetic energy loss of the water flow can be reduced; preferably, in this embodiment, the hydrophobic coating is a nano-silica composite layer with a hydrophobic angle greater than 130°, which can effectively reduce kinetic energy loss, increase flow velocity, and further reduce the pressure of the acceleration section 53.

[0040] Furthermore, such as Figure 2 As shown in the figure, in this embodiment, a pressure sensor is provided in the middle of the acceleration section 53.

[0041] In actual use, in this embodiment, a pressure sensor is installed at the overflow hole in the middle of the acceleration section 53 and connected to the jet pump 6. When the pressure is detected to be lower than 0.1MPa, the water valve at the outlet of the urban rainwater storage tank 71 is opened, and the water is drained through the jet pump 6.

[0042] Furthermore, such as Figure 2 As shown, in this embodiment, a drain pipe 55 is provided at the bottom of the diffuser section 54.

[0043] In actual use, in this embodiment, a drainage pipe 55 is provided at the bottom of the diffuser section 54 to allow water from the diffuser section 54 to be discharged from the tunnel structure.

[0044] Furthermore, such as Figure 3As shown, in this embodiment, the outlet pipe 63 of the jet pump 6 is connected to a turbine generator.

[0045] In practical use, in this embodiment, by connecting a turbine generator to the outlet pipe 63 of the jet pump 6, the high-speed water jet ejected by the jet pump 6 can be converted into electrical energy for use. Since the water flow speed in the acceleration section 53 is fast, the flow rate of the high-speed water jet ejected by the jet pump 6 can be increased, further improving the power output. In this embodiment, the turbine generator is an industrial-grade turbine generator and is electrically connected to the multi-stage centrifugal pump 73, which can supply power to the multi-stage centrifugal pump 73.

[0046] The drainage method of the present invention is as follows: the seepage water in the surrounding rock is absorbed by the outer circumferential drainage blind pipe 41 set on the outer surface of the initial support 4 and sent into the drainage ditch through the connecting pipe 8; some of the seepage water in the surrounding rock seeps into the drainage layer 3, is absorbed by the inner circumferential drainage blind pipe 31, and sent into the drainage ditch through the connecting pipe 8; the seepage water entering the side drainage ditch 9 enters the variable cross-section drainage ditch 5 through the horizontal pipe 10, and then the seepage water entering the variable cross-section drainage ditch 5 is continuously accelerated through the contraction section 52 and the acceleration section 53, so that the static pressure of the acceleration section 53 is greatly reduced, forming a significant low-pressure area. At the same time, the working fluid accelerated by the multi-stage centrifugal pump 73 is injected into the inlet pipe 62 of the jet pump 6, so that the suction pipe 61 of the jet pump 6 further applies negative pressure to the low-pressure area, enhances the suction effect, and quickly discharges the seepage water of the variable cross-section drainage ditch 5; the water not discharged by the jet pump 6 can be discharged through the drainage pipe 55 of the diffuser section 54.

[0047] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A drainage system for underground tunnels suitable for the rainy season, characterized in that, The structure includes a secondary lining (1), a waterproof layer (2), a drainage layer (3), and an initial support (4) arranged sequentially from the inside to the outside, and drainage ditches set on both sides of the tunnel road surface; the drainage layer (3) is provided with several inner circumferential drainage blind pipes (31) arranged along the tunnel axis, and the initial support (4) is provided with several outer circumferential drainage blind pipes (41) arranged along the tunnel axis. The bottom ends of the inner circumferential drainage blind pipes (31) and the outer circumferential drainage blind pipes (41) are connected to the drainage ditches on both sides through connecting pipes (8); the drainage ditch includes a variable cross-section drainage ditch (5) and a side drainage ditch (9). The variable cross-section drainage ditch (5) is connected to several jet pumps (6), and the jet pumps (6) are connected to a high-pressure water mechanism (7). The variable cross-section drainage ditch (5) and the side drainage ditch (9) are connected through a horizontal pipe (10); The variable cross-section drainage ditch (5) includes an inlet section (51) at the top, a contraction section (52) connected to the bottom of the inlet section (51), an acceleration section (53) connected to the bottom of the contraction section (52), and a diffuser section (54) connected to the bottom of the acceleration section (53). The inlet section (51) is rectangular, the contraction section (52) is V-shaped, and the diffuser section (54) is trapezoidal. An overflow hole and a suction pipe (61) of a jet pump (6) are provided in the middle of the acceleration section (53). The height ratio of the contraction section (52), acceleration section (53) and diffusion section (54) is 2.5~3.2:1:4.2~4.7, the inclination angle α of the contraction section (52) is 11°~13°, and the diffusion angle β of the diffusion section (54) is 6°~9°; a pressure sensor is provided in the middle of the acceleration section (53), a stainless steel liner is provided on the inner wall of the acceleration section (53), and a flow guide rib is provided, and a hydrophobic coating is applied to the stainless steel liner.

2. The underground tunnel drainage system suitable for the rainy season according to claim 1, characterized in that, The high-pressure water mechanism (7) includes an urban rainwater storage tank (71), a water supply pipe (72) connected to the outlet of the urban rainwater storage tank (71), and a multi-stage centrifugal pump (73) installed on the water supply pipe (72). The other end of the water supply pipe (72) is connected to the inlet pipe (62) of the jet pump (6). A water valve is installed on the outlet of the urban rainwater storage tank (71).

3. The underground tunnel drainage system suitable for the rainy season according to claim 1, characterized in that, The bottom of the diffuser section (54) is provided with a drain pipe (55).

4. A drainage system for underground tunnels suitable for the rainy season according to claim 1, characterized in that, The outlet pipe (63) of the jet pump (6) is connected to a turbine generator.

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