Groundwater control structure for group foundation pit near subway

Abstract

The present application provides a kind of subway group foundation pit groundwater control structure close to, including water stop curtain structure, subway foundation pit, far subway foundation pit, observation well, precipitation well and recharge well;Subway foundation pit is close to a subway station or a subway interval tunnel setting;The inside of subway foundation pit and far subway foundation pit is respectively provided with water stop curtain structure;Observation well is set in subway foundation pit, far subway foundation pit and in subway foundation pit and far subway foundation pit outside;Precipitation well is set in subway foundation pit and far subway foundation pit;Recharge well is set in subway foundation pit and far subway foundation pit outside.The present application provides a kind of subway group foundation pit groundwater control structure close to, solves subway group foundation pit groundwater control structure close to and can suffer from the leakage of water stop curtain, protects subway station, protects subway interval tunnel safety, surrounding other building structures and municipal pipeline etc. structure impermeable, environmental deformation problem.

Description

Technical Field

[0001] This invention relates to the field of geotechnical foundation pit engineering technology in the building environment, and particularly to a groundwater control structure for foundation pits near subway lines. Background Technology

[0002] In the field of groundwater control for building foundation pits and basements, ensuring pit safety and protecting the surrounding environment is crucial. Traditional groundwater control methods, especially for mass foundation pits near subway lines, are ineffective, offering no guarantee of pit safety or protection against groundwater level drops near sensitive structures like subway stations. To address this, a new integrated pumping and irrigation system for groundwater control in mass foundation pits near subway lines has been developed. Summary of the Invention

[0003] To address the shortcomings of the existing technology, this invention provides a groundwater control structure for foundation pits near subway stations, which solves the problems of seepage from the water-stop curtain, protection of subway stations, protection of subway tunnel safety, and structural seepage resistance and environmental deformation of surrounding buildings and municipal pipelines.

[0004] To achieve the above objectives, the present invention provides a groundwater control structure for adjacent subway group foundation pits, comprising multiple water-stop curtain structures, several near-subway foundation pits, several far-subway foundation pits, multiple observation wells, multiple dewatering wells, and multiple recharge wells; the near-subway foundation pits are located adjacent to a subway station or a subway tunnel section; the far-subway foundation pits are located at a greater distance from the subway station or the subway tunnel section than the near-subway foundation pits; the water-stop curtain structures are respectively arranged on the inner sides of the near-subway foundation pits and the far-subway foundation pits; the observation wells are located inside the near-subway foundation pits, inside the far-subway foundation pits, and outside the near-subway foundation pits and the far-subway foundation pits; the dewatering wells are located inside the near-subway foundation pits and the far-subway foundation pits; and the recharge wells are located outside the near-subway foundation pits and the far-subway foundation pits.

[0005] Preferably, the water-stopping curtain structure includes TRD method piles, CSM method piles, triaxial mixing piles, or diaphragm wall retaining structures; the permeability coefficient of the water-stopping curtain structure is less than 1. cm / s.

[0006] Preferably, the near-subway foundation pit is divided into several small foundation pits on the side adjacent to the subway station or the subway tunnel, and a large foundation pit is formed on the side of the small foundation pits away from the subway station or the subway tunnel; the depth of the small foundation pits is less than the depth of the large foundation pit.

[0007] Preferably, the depth of the water-stop curtain structure near the subway foundation pit is greater than the depth of the water-stop curtain structure far from the subway foundation pit.

[0008] Preferably, the dewatering wells are arranged in a quincunx pattern within the near-subway foundation pit or the far-subway foundation pit, avoiding engineering piles, column piles, retaining walls, trestle bridges, and reinforced structures.

[0009] Preferably, the dewatering well includes a filter, a well pipe, a filter media layer, a water-stopping material layer, and a sedimentation pipe; the filter is located at the bottom of the well pipe, and the sedimentation pipe is located at the bottom of the filter; the water-stopping material layer is located around the well pipe and above the filter; the filter media layer is located around the filter and the sedimentation pipe and is partially higher than the filter; the positions of the filter media layer and the filter correspond to the positions of an aquifer; a water-stopping plate is provided inside the water-stopping material layer, and the position of the water-stopping plate corresponds to the position of the foundation pit bottom plate; a clay ball is provided on the upper part of the filter media layer; the clay ball is compacted and grouted between itself and the bottom of the foundation pit to stop water leakage; the depth of the dewatering well is 5-20m shallower than the depth of the corresponding water-stopping curtain structure.

[0010] Preferably, a water level sensor or a water pump is placed inside the observation well.

[0011] Preferably, the recharge well is located near the subway station or the subway tunnel section and avoids municipal pipelines, enclosures, roads and other buildings; the recharge well is close to a water source or is an integrated pumping and recharge system.

[0012] Preferably, the reinjection well includes a filter, a well pipe, a filter media layer, and a water-stopping material layer; the filter is located at the bottom of the well pipe, and the sedimentation pipe is located at the bottom of the filter; the water-stopping material layer is located around the well pipe and above the filter; the filter media layer is located around the filter and the sedimentation pipe and is partially higher than the filter; the positions of the filter media layer and the filter correspond to the position of a target aquifer for reinjection; clay balls are placed on the upper part of the filter media layer; the clay balls are compacted and grouted with grout or backfilled with micro-expansion concrete to stop the water ingress.

[0013] Because the present invention adopts the above technical solution, it has the following beneficial effects:

[0014] By coordinating a water-stop curtain structure, several near-subway foundation pits, several far-subway foundation pits, observation wells, dewatering wells, and recharge wells, the system addresses the leakage issues caused by the water-stop curtain on the groundwater control structure of nearby subway foundation pits, protects subway stations, subway tunnels, and other surrounding buildings and municipal pipelines, and mitigates environmental deformation problems. The near-subway foundation pits are divided into sections, with smaller pits less deep than larger ones, requiring no depressurization and typically constructed later, thus providing a buffer against deformation caused by subway construction. The depth of the water-stop curtain structure near the subway foundation pits is greater than that of the water-stop curtain structure in the far-subway foundation pits, forming a closed structure. The dewatering wells are 5-20m shallower than the water-stop curtain structure, fully utilizing its seepage bypass effect. The longer the bypass path, the greater the water-stopping effect, and the greater the water level difference between the inside and outside of the foundation pit, resulting in greater environmental protection. Observation wells are equipped with water level sensors to monitor the confined water level or, in emergencies, pumps to address issues related to the intelligent groundwater control platform and emergency response. Having a recharge well close to a water source or an integrated pumping and recharge system is advantageous for creating a recharge operation platform. Attached Figure Description

[0015] Figure 1 This is a top view schematic diagram of the groundwater control structure for adjacent subway group foundation pits according to an embodiment of the present invention;

[0016] Figure 2 This is a partial cross-sectional view of the groundwater control structure for the adjacent subway group foundation pit according to an embodiment of the present invention. Detailed Implementation

[0017] The following is based on the attached diagram. Figure 1 and Figure 2 The present invention provides preferred embodiments and describes them in detail to enable a better understanding of the functions and features of the present invention.

[0018] Please see Figure 1 and Figure 2This invention discloses a groundwater control structure for adjacent subway group foundation pits, comprising multiple water-stop curtain structures, several near-subway foundation pits 1, several far-subway foundation pits 2, multiple observation wells, multiple dewatering wells 3, and multiple recharge wells 4. The near-subway foundation pits 1 are located adjacent to a subway station 5 or a subway tunnel 6. The far-subway foundation pits 2 are located at a greater distance from the subway station 5 or the subway tunnel 6 than the near-subway foundation pits 1. Water-stop curtain structures are respectively installed on the inner sides of the near-subway foundation pits 1 and the far-subway foundation pits 2. Observation wells are located inside the near-subway foundation pits 1, inside the far-subway foundation pits 2, and outside the near-subway foundation pits 1 and the far-subway foundation pits 2. Dewatering wells 3 are located inside the near-subway foundation pits 1 and the far-subway foundation pits 2. Recharge wells 4 are located outside the near-subway foundation pits 1 and the far-subway foundation pits 2. This invention solves the problems of seepage from the water-stop curtains affecting the groundwater control structure for adjacent subway group foundation pits, protecting the subway station, protecting the subway tunnel 6, and preventing structural seepage and environmental deformation of surrounding buildings, municipal pipelines, etc.

[0019] Water-stop curtains are used to seal or partially seal the confined aquifer beneath the foundation slab of an excavation pit; water-stop curtain structures include TRD method piles, CSM method piles, triaxial mixing piles, or diaphragm wall retaining structures; the permeability coefficient of the water-stop curtain structure is less than 1. cm / s. The key is the quality of the cutoff wall itself, as well as the addition of high-pressure jet grouting piles between the bored piles and the vertical cutoff wall. Alternatively, overlapping and precise double-row high-pressure jet grouting piles, interlocking piles, Larssen sheet piles, grouting, RJP, MJS, or N-JET can be used. Multiple production pumping tests and verification tests should be conducted before excavation to verify the groundwater control capacity and effectiveness of the foundation pit, ensuring the water-stopping effect and quality of the vertical cutoff wall on the confined aquifer, forming an integrated cutoff structure.

[0020] The substation foundation pit 1 section is divided into several small foundation pits on one side near the subway station 5 or the subway tunnel 6, and a large foundation pit is formed on the side away from the subway station 5 or the subway tunnel 6. The depth of the small foundation pits is less than the depth of the large foundation pit. No pressure reduction is required. Construction is generally carried out later. This provides a buffer and protection against deformation caused by the construction of the subway and other structures in the foundation pit.

[0021] The depth of the water-stop curtain structure near the subway pit 1 is greater than the depth of the water-stop curtain structure far from the subway pit 2, forming a closed structure. The water-stop curtain is constructed first.

[0022] The dewatering wells 3 are densely arranged in a plum blossom pattern in the area near or far from the subway foundation pit 1, avoiding engineering piles, column piles, retaining walls, trestle bridges and reinforced bodies. Being close to the support is conducive to making an operating platform.

[0023] The dewatering well 3 includes a filter 7, a well pipe 8, a filter media layer 9, a water-stopping material layer 10, and a sedimentation pipe 11. The filter 7 is installed at the bottom of the well pipe 8, and the sedimentation pipe 11 is installed at the bottom of the filter 7. The water-stopping material layer 10 is located around the well pipe 8 and above the filter 7. The filter media layer 9 is located around the filter 7 and the sedimentation pipe 11 and is partially higher than the filter 7. The positions of the filter media layer 9 and the filter 7 correspond to the positions of an aquifer. A water-stopping plate is installed inside the water-stopping material layer 10, and the position of the water-stopping plate corresponds to the position of the foundation pit bottom plate. A clay ball 12 is installed on the top of the filter media layer 9. The clay ball 12 is compacted and grouted between itself and the bottom of the foundation pit to stop the water. The depth of the dewatering well 3 is 5-20m shallower than the depth of the corresponding water-stopping curtain structure, so as to give full play to the seepage and bypass effect of the water-stopping curtain. The longer the bypass path, the greater the water-stopping effect, the greater the water level difference inside and outside the foundation pit, and the greater the environmental protection effect.

[0024] The observation well is equipped with a water level sensor to monitor the confined water level or, in an emergency, a water pump to draw water, addressing issues related to the intelligent groundwater control platform and emergency response. It also guides the integrated automatic operation and maintenance of pumping and irrigation systems, resolving problems related to the intelligent groundwater control platform and emergency response.

[0025] The recharge well 4 is located outside the pit, near the subway station 5 or the subway tunnel 6, and avoids municipal pipelines, enclosures, roads and other buildings; the recharge well 4 is close to a water source, which is conducive to the construction of a recharge operation platform or pumping and recharge integration.

[0026] The reinjection well 4 includes a filter 7, a well pipe 8, a filter media layer 9, and a water-stopping material layer 10; the filter 7 is installed at the bottom of the well pipe 8, and a sedimentation pipe 11 is installed at the bottom of the filter 7; the water-stopping material layer 10 is installed around the well pipe 8 and above the filter 7; the filter media layer 9 is installed around the filter 7 and the sedimentation pipe 11 and is partially higher than the filter 7; the positions of the filter media layer 9 and the filter 7 correspond to the position of a target aquifer for reinjection; a clay ball 12 is installed on the top of the filter media layer 9; the clay ball 12 is compacted and grouted with grout or backfilled with micro-expansion concrete to stop the water ingress.

[0027] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A groundwater control structure for foundation pits near subway complexes, characterized in that, It includes multiple water-stop curtain structures, several near-subway foundation pits (1), several far-subway foundation pits (2), multiple observation wells, multiple dewatering wells (3), and multiple recharge wells (4); The near-subway pit (1) is located adjacent to a subway station (5) or a subway tunnel (6); the far-subway pit (2) is located at a greater distance from the subway station (5) or the subway tunnel (6) than the near-subway pit (1); The water-stop curtain structure is respectively provided on the inner side of the near subway pit (1) and the far subway pit (2); The observation well is located inside the near-subway foundation pit (1), inside the far-subway foundation pit (2), and outside the near-subway foundation pit (1) and outside the far-subway foundation pit (2); The dewatering well (3) is located in the near subway pit (1) and the far subway pit (2); The recharge well (4) is located outside the near subway pit (1) and the far subway pit (2); The near-metro foundation pit (1) is divided into sections, forming several small foundation pits on one side adjacent to the metro station (5) or the metro tunnel (6), and forming a large foundation pit on the side away from the metro station (5) or the metro tunnel (6); the depth of the small foundation pits is less than the depth of the large foundation pit; wherein the small foundation pits are constructed after the large foundation pit, which has a buffering and protective effect on the deformation caused by the construction of the metro in the foundation pit; The depth of the water-stop curtain structure of the near subway pit (1) is greater than the depth of the water-stop curtain structure of the far subway pit (2). The depth of the dewatering well (3) is shallower than the depth of the corresponding water-stopping curtain structure; The dewatering wells (3) are arranged in a plum blossom pattern in the near subway pit (1) or the far subway pit (2) and avoid engineering piles, column piles, retaining walls, trestle bridges and reinforced bodies. A water level sensor or water pump is placed inside the observation well; The recharge well (4) is located near the subway station (5) or the subway tunnel (6) and avoids municipal pipelines, enclosures, roads and other buildings; the recharge well (4) is close to a water source or a pumping and recharge integrated system.

2. The groundwater control structure for adjacent subway group foundation pits according to claim 1, characterized in that, The water-stopping curtain structure includes TRD method piles, CSM method piles, triaxial mixing piles, or underground continuous wall retaining structures; the permeability coefficient of the water-stopping curtain structure is less than 1e-7 cm / s.

3. The groundwater control structure for adjacent subway group foundation pits according to claim 1, characterized in that, The dewatering well (3) includes a filter (7), a well pipe (8), a filter media layer (9), a water-stopping material layer (10), and a sedimentation pipe (11); the filter (7) is disposed at the bottom of the well pipe (8), and the sedimentation pipe (11) is disposed at the bottom of the filter (7); the water-stopping material layer (10) is disposed around the well pipe (8) and above the filter (7); the filter media layer (9) is disposed between the filter (7) and the sedimentation pipe (11). 1) The outer periphery is partially higher than the filter (7); the positions of the filter material layer (9) and the filter (7) correspond to the positions of a water-bearing layer; a water-stopping plate is provided in the water-stopping material layer (10), and the position of the water-stopping plate corresponds to the position of the foundation pit bottom plate; a clay ball (12) is provided on the upper part of the filter material layer (9); the clay ball (12) is compacted and grouted between the bottom of the foundation pit to stop water; the depth of the dewatering well (3) is 5 to 20 m shallower than the depth of the corresponding water-stopping curtain structure.

4. The groundwater control structure for adjacent subway group foundation pits according to claim 1, characterized in that, The reinjection well (4) includes a filter (7), a well pipe (8), a filter media layer (9), and a water-stopping material layer (10); the filter (7) is provided at the bottom of the well pipe (8), and the sedimentation pipe (11) is provided at the bottom of the filter (7); the water-stopping material layer (10) is provided on the periphery of the well pipe (8) and above the filter (7); the filter media layer (9) is provided on the periphery of the filter (7) and the sedimentation pipe (11) and is partially higher than the filter (7); the positions of the filter media layer (9) and the filter (7) correspond to the position of a reinjection target aquifer; a clay ball (12) is provided on the upper part of the filter media layer (9); the clay ball (12) is compacted and grouted with grout or backfilled with micro-expansion concrete to stop water leakage between it and the ground.

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