A kind of underground tunnel underground water seepage treatment structure

Abstract

This invention provides a structure for treating underground seepage in a reservoir-adjacent tunnel, including an auxiliary chamber and interception and drainage facilities. The auxiliary chamber and facilities are located within the reservoir bank between the reservoir and the tunnel to be excavated, and are positioned closer to the tunnel. These facilities effectively block seepage through permeable faults and fissures between the reservoir and the tunnel. The auxiliary chamber is positioned above the highest normal water level of the reservoir during tunnel excavation. The interception and drainage facilities are located within the bedrock below the auxiliary chamber and include a first curtain grouting and drainage system arranged parallel to each other along the length of the auxiliary chamber. The first curtain grouting system is located closer to the reservoir, and the drainage system is located closer to the tunnel. This invention solves the problem of severe leakage in reservoir-adjacent tunnels during excavation due to reservoir water infiltration, fissure development, and permeable faults, effectively improving the safety and construction quality during tunnel excavation.

Description

Technical Field

[0001] This utility model relates to the field of underground tunnel engineering technology, specifically to an underground seepage treatment structure for a reservoir tunnel. Background Technology

[0002] Groundwater is a significant risk in tunnel construction, impacting both safety and progress, and increasing investment. This is particularly true for tailrace tunnels (or water diversion tunnels) of pumped-storage power stations utilizing existing reservoirs as lower (or upper) reservoirs. When the tunnel is located below the reservoir's water level, and the tunnel is close to the reservoir bank with well-developed rock seepage channels, the impact of groundwater during excavation becomes extremely pronounced, potentially even creating connections to the reservoir water. Current methods for addressing seepage during tunnel excavation primarily involve drainage combined with sealing, but this slows progress and carries significant construction risks. For tunnels connected to stable external reservoir water, conventional interception and drainage methods pose even greater potential risks. Utility Model Content

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a structure for treating underground seepage in near-reservoir tunnels. This invention can solve the problem of severe leakage in near-reservoir tunnels during excavation due to reservoir water infiltration, fissure development, and permeable faults, effectively improving the safety and construction quality during tunnel excavation.

[0004] This utility model provides a structure for treating underground seepage in a reservoir tunnel, including an auxiliary chamber and interception and drainage facilities. The auxiliary chamber and interception and drainage facilities are arranged inside the reservoir bank between the reservoir and the tunnel to be excavated, and are located on the side closer to the tunnel to be excavated. The auxiliary chamber and interception and drainage facilities can block seepage through permeable faults and fissures between the reservoir and the tunnel to be excavated. The auxiliary chamber is located above the highest normal water level of the reservoir during tunnel excavation. The interception and drainage facilities are located in the bedrock below the auxiliary chamber and include a first curtain grouting and drainage system arranged side by side along the length of the auxiliary chamber. The first curtain grouting is located on the side closer to the reservoir, and the drainage system is located on the side closer to the tunnel to be excavated.

[0005] As a preferred technical solution of this utility model: the interception and drainage facility also includes a second curtain grouting arranged in parallel with the first curtain grouting and drainage system, and the second curtain grouting is arranged on the back water side of the drainage system.

[0006] As a preferred technical solution of this utility model: the bottom elevation of the second curtain grouting is the same as the bottom slab elevation of the tunnel to be excavated, and the top elevation is the same as the arch elevation of the tunnel to be excavated.

[0007] As a preferred technical solution of this utility model: the bottom elevation of the first curtain grouting is lower than the bottom slab elevation of the tunnel to be excavated, and the top elevation is the same as the reservoir water level elevation or the bottom slab elevation of the auxiliary chamber.

[0008] As a preferred technical solution of this utility model: the drainage system includes a plurality of drainage holes arranged at intervals along the length of the auxiliary chamber, and a drainage pipe is installed in each of the plurality of drainage holes. The drainage pipe is connected to an external water pump device for pumping water.

[0009] As a preferred technical solution of this utility model: the bottom elevation of the drainage hole is not higher than the bottom elevation of the tunnel to be excavated.

[0010] As a preferred technical solution of this utility model: the first curtain grouting and the second curtain grouting are respectively arranged at an angle away from the drainage system, so as to reserve space for the arrangement of drainage holes between them.

[0011] As a preferred embodiment of this utility model: the annular gap between the drainage pipe and the drainage hole is filled sequentially from the bottom of the hole to the opening with a layer of crushed stone, a layer of fine sand, a layer of clay, and a layer of pre-shrinkable mortar.

[0012] As a preferred technical solution of this utility model: the bottom of the drainage pipe is set as a flower pipe section, and the height of the crushed stone layer after filling is higher than the height range of the flower pipe section.

[0013] The beneficial effects provided by this utility model are as follows:

[0014] This invention can solve the problem of serious leakage caused by reservoir water infiltration, fissure development and permeable faults during the excavation of tunnels near reservoirs, effectively improving the safety and construction quality during tunnel excavation.

[0015] This invention effectively intercepts and drains water seepage from permeable faults by setting up auxiliary chambers and interception facilities between the tunnel to be excavated and the existing reservoir. This significantly reduces the risk of reservoir water entering the tunnel through faults and fissures, and avoids the threat of seepage and water inrush to the excavation operation, thereby improving the safety level and construction efficiency during the tunnel excavation process.

[0016] This invention forms a triple anti-seepage structure of "interception-guidance-re-blocking" by setting up a first curtain grouting, a drainage system, and a second curtain grouting. This structure can effectively control the seepage path within the fault, achieve comprehensive sealing and drainage from point to surface, and significantly improve the reliability of the entire tunnel seepage treatment system.

[0017] The drainage holes are filled with multiple layers of gravel, fine sand, clay and pre-shrink mortar to effectively seal the gaps in the drilled holes and drainage pipes. Combined with the vacuum pump to create negative pressure, the drainage efficiency of the drainage holes can be significantly improved. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A plan view of the underground seepage treatment structure of the Linku Tunnel provided in this embodiment of the utility model;

[0020] Figure 2 A typical cross-sectional view of the underground seepage treatment structure of the Linku Tunnel provided in this embodiment of the utility model on a non-permeable fault.

[0021] Figure 3 A typical cross-sectional view of the underground seepage treatment structure of the Linku Tunnel provided in this embodiment of the utility model on a permeable fault.

[0022] Figure 4 A schematic diagram of the drainage system provided in an embodiment of this utility model.

[0023] Attached reference numerals: 1. Existing reservoir; 2. Reservoir bank; 3. Tunnel to be excavated; 4. Auxiliary chamber; 5. Permeable fault (single line schematic); 6. First curtain grouting; 7. Drainage hole; 8. Second curtain grouting; 11. Drainage pipe; 12. Main drainage pipe; 13. Crushed stone layer; 14. Fine sand layer; 15. Clay layer; 16. Pre-shrink mortar layer. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of this utility model, the preferred embodiments of this utility model are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present utility model. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present utility model.

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0026] For pumped storage power station projects that use existing reservoir 1 as the lower (or upper) reservoir, the tailrace tunnel (or water diversion tunnel) is usually located below the reservoir water level. When the tunnel is close to the reservoir bank and seepage channels are well developed in the rock mass, the impact of groundwater during tunnel excavation will be particularly significant, and may even form seepage channels that are directly connected to the reservoir water.

[0027] The tunnel 3 to be excavated is located below the reservoir water level and close to the reservoir. During construction, there is a risk of reservoir water backflow or seepage, especially when a permeable fault 5 exists connecting the reservoir and the tunnel, further exacerbating this risk. This invention provides a structure for treating underground seepage in tunnels near reservoirs, effectively solving the above problems. Figures 1 to 4 As shown, the system specifically includes an auxiliary cavern 4 and interception and drainage facilities. The auxiliary cavern 4 and interception and drainage facilities are located inside the reservoir bank 2 between the existing reservoir 1 and the tunnel to be excavated 3, and are positioned closer to the tunnel to be excavated 3. The auxiliary cavern 4 and interception and drainage facilities can block seepage through the permeable fault 5 and fissures that connect the existing reservoir 1 and the tunnel to be excavated 3. The auxiliary cavern 4 is located above the highest normal water level of the reservoir during tunnel excavation and is a portal-shaped structure with dimensions of 3m × 4m. The interception and drainage facilities are located in the bedrock below the auxiliary cavern 4 and include a first curtain grouting 6 and a drainage system arranged side-by-side along the length of the auxiliary cavern 4. The first curtain grouting 6 is located closer to the reservoir, and the drainage system is located closer to the tunnel to be excavated 3.

[0028] The interception and drainage facility also includes a second curtain grouting 8 arranged side by side with the first curtain grouting 6 and the drainage system, and the second curtain grouting 8 is arranged on the back side of the drainage system.

[0029] The bottom elevation of the second curtain grouting 8 is the same as the bottom slab elevation of the tunnel 3 to be excavated, and the top elevation is the same as the arch elevation of the tunnel 3 to be excavated.

[0030] The bottom elevation of the first curtain grouting 6 is lower than the bottom slab elevation of the tunnel 3 to be excavated, with the difference controlled within 2m, and the top elevation is the same as the reservoir water level elevation or the bottom slab elevation of the auxiliary chamber 4.

[0031] The drainage system includes multiple drainage holes 7 arranged at intervals along the length of the auxiliary chamber 4. Each drainage hole 7 is equipped with a drainage pipe 11, which is connected to an external water pump device for pumping water, so as to achieve centralized discharge of seepage water.

[0032] The bottom elevation of the drainage hole 7 is not higher than the bottom elevation of the tunnel 3 to be excavated.

[0033] The first curtain grouting 6 and the second curtain grouting 8 are respectively arranged at an angle away from the drainage system, so as to reserve space for the arrangement of drainage holes 7 between them.

[0034] The annular gap between the drainage pipe 11 and the drainage hole 7 is filled with a layer of crushed stone 13, a layer of fine sand 14, a layer of clay 15 and a layer of pre-shrinkable mortar 16 in sequence from the bottom of the hole to the opening.

[0035] In this embodiment, the drain pipe 11 is made of PVC, PE or PP and has a diameter of 3 to 5 cm. The bottom of the drain pipe 11 is set as a perforated pipe section with a length of not less than 2 m. The drain pipe 11 is inserted into the drain hole 7 and its bottom is 10 cm away from the bottom of the hole.

[0036] Furthermore, the height of the crushed stone layer 13 after filling is 50cm higher than the section of the flower pipe, the filling thickness of the fine sand layer 14 and the clay layer 15 is not less than 50cm, and the filling thickness of the pre-shrinkable mortar layer 16 is not less than 2m.

[0037] Based on the description and drawings of this utility model, those skilled in the art can easily manufacture or use the underground seepage treatment structure for the Linku Tunnel of this utility model, and can produce the positive effects described in this utility model.

[0038] Unless otherwise specified, in this utility model, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this utility model are for illustrative purposes only and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0039] Unless otherwise expressly specified and limited, the terms "set up," "connected," and "linked" in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A structure for treating underground seepage in a reservoir tunnel, characterized in that: The system includes an auxiliary cavern and interception and drainage facilities, which are located inside the reservoir bank between the reservoir and the tunnel to be excavated, and are positioned closer to the tunnel. The auxiliary cavern and interception and drainage facilities are designed to block seepage through permeable faults and fissures between the reservoir and the tunnel. The auxiliary cavern is positioned above the highest normal water level of the reservoir during tunnel excavation. The interception and drainage facilities are located in the bedrock below the auxiliary cavern and include a first curtain grouting and drainage system arranged side by side along the length of the auxiliary cavern. The first curtain grouting system is located closer to the reservoir, and the drainage system is located closer to the tunnel.

2. The underground seepage treatment structure for the Linku Tunnel according to claim 1, characterized in that: The interception and drainage facility also includes a second curtain grouting system arranged alongside the first curtain grouting system and the drainage system, with the second curtain grouting system located on the back side of the drainage system.

3. The in-reservoir tunnel groundwater treatment structure according to claim 2, characterized by: The bottom elevation of the second curtain grouting is the same as the bottom slab elevation of the tunnel to be excavated, and the top elevation is the same as the arch elevation of the tunnel to be excavated.

4. The in-reservoir tunnel groundwater treatment structure according to claim 1, characterized by: The bottom elevation of the first curtain grouting is lower than the bottom slab elevation of the tunnel to be excavated, while the top elevation is the same as the reservoir water level or the bottom slab elevation of the auxiliary chamber.

5. The in-reservoir tunnel groundwater treatment structure according to claim 1, characterized by: The drainage system includes multiple drainage holes spaced apart along the length of the auxiliary chamber, each drainage hole containing a drainage pipe connected to an external water pump device for pumping water.

6. The reservoir tunnel groundwater treatment structure of claim 5, wherein: The bottom elevation of the drainage hole shall not be higher than the bottom elevation of the tunnel to be excavated.

7. The in-reservoir tunnel groundwater treatment structure according to claim 2, characterized by: The first and second curtain grouting are respectively arranged at an angle away from the drainage system, so as to reserve space for the arrangement of drainage holes between them.

8. The in-reservoir tunnel groundwater treatment structure according to claim 5, characterized by: The annular gap between the drainage pipe and the drainage hole is filled with a layer of crushed stone, a layer of fine sand, a layer of clay, and a layer of pre-shrinkable mortar from the bottom of the hole to the opening.

9. The reservoir tunnel groundwater treatment structure of claim 8, wherein: The bottom of the drainage pipe is set as a perforated section, and the height of the crushed stone layer after filling is higher than the height range of the perforated section.

Images