A drainage well system for a ground-mounted water-stop curtain and its construction method

Abstract

This invention relates to a drainage well system for a foundation pit suitable for a ground-mounted waterproof curtain. The system includes a drainage well body positioned within the backfill area of ​​the foundation pit, located between the main structural wall and the ground-mounted waterproof curtain. The drainage well bodies are arranged at predetermined intervals within the backfill area. The outer facade of the main structural wall is provided with a waterproof layer. Each drainage well body includes a non-porous solid pipe section and a perforated filter section located below the non-porous solid pipe section. The perforated filter section is externally covered with a filter layer, and the surrounding hollow spaces of the filter layer are filled with graded filter media. The lower end of the drainage well body is positioned below the bottom of the foundation pit and above the stable waterproof layer. A pumping system is installed within the drainage well body to promptly pump out seepage water from the foundation pit when the water level within the drainage well body rises to a preset level. The pumping system is connected to the municipal stormwater drainage network. This invention can serve as a long-term drainage facility and also enables water resource reuse.

Description

Technical Field

[0001] This invention relates to the field of foundation pit engineering technology, specifically to a drainage well system for a ground-mounted water-stop curtain and its construction method. Background Technology

[0002] In deep foundation pit engineering, ground-mounted water-stop curtains are often used as retaining and water-stopping structures, such as diaphragm walls, pile banks, and jet grouting piles. After the main structure (such as the main structural wall) is completed, a ring-shaped trench will be formed between it and the foundation pit retaining structure. This trench is usually backfilled with plain soil or lime-soil, but its seepage prevention performance and density are not as good as the original soil.

[0003] During the later stages of use, because the water-stop curtain is not completely impermeable, and due to the pressure of water and soil, groundwater will slowly seep into the trench through minor defects or bypass paths in the water-stop curtain. If this seepage water cannot be drained in time, it will soak the exterior walls of the main structure for a long time and exert seepage pressure on the backfill soil of the trench, which may lead to backfill soil loss, ground settlement, and even adverse effects on the main structure.

[0004] Traditional solutions involve setting up temporary dewatering wells at the bottom of the foundation pit. A few projects have also attempted to install drainage blind ditches within the pit, such as the underground structure drainage system integrating pipe well dewatering and pit seepage prevention and anti-buoyancy disclosed in Chinese patent CN214574064U. The underground structure drainage system is located on one side of the basement, and the basement has a base slab. The basement structure drainage system includes a pressure-reducing dewatering well, a drainage blind ditch, and a ring-shaped rainwater pipe network. The drainage blind ditch is located on one side of the basement, and the pressure-reducing dewatering well is installed inside the drainage blind ditch. The pressure-reducing dewatering well includes a steel pipe and a reinforcing cage. The steel pipe is fitted inside the reinforcing cage. The steel pipe consists of a filter pipe and a solid pipe. The filter pipe is located at the bottom, and the solid pipe is located above the filter pipe. The height of the reinforcing cage is greater than the height of the filter pipe. Filter material is filled between the reinforcing cage and the steel pipe. A water pump is installed inside the steel pipe, and the water pump is connected to the ring-shaped rainwater pipe network through a pipe equipped with a water stop valve.

[0005] However, the drainage wells in the aforementioned existing technologies will be gradually closed as the main structure is constructed, which cannot solve the long-term seepage problem in the trench after the structure is completed. Moreover, the blind drain is prone to failure due to soil settlement and is difficult to connect to the municipal pipe network system to realize resource utilization. Summary of the Invention

[0006] The present invention aims to provide a drainage well system and its construction method for a ground-mounted water-stop curtain system in a ferrule, in order to overcome the shortcomings of the prior art. The technical problem to be solved by the present invention is achieved through the following technical solution.

[0007] A drainage well system for a foundation pit suitable for a ground-mounted waterproof curtain includes a drainage well body located within a backfill area of ​​the foundation pit, between the main structural wall and the ground-mounted waterproof curtain. The drainage well bodies are arranged at predetermined intervals within the backfill area. The outer facade of the main structural wall is provided with a waterproof layer. The drainage well body includes a non-porous solid pipe section and a perforated filter section located below the non-porous solid pipe section. The perforated filter section is covered with a filter layer, and the surrounding grooves of the filter layer are filled with graded filter media. The lower end of the drainage well body is positioned below the bottom of the foundation pit and above the stable waterproof layer. A pumping system is installed within the drainage well body to promptly pump out seepage water from the foundation pit when the water level within the drainage well body rises to a preset level. The pumping system is connected to the municipal stormwater pipe network.

[0008] Preferably, the pumping system includes a submersible pump, a liquid level sensor, and a control unit. The submersible pump is located at the bottom of the drainage well body, the liquid level sensor is located at a predetermined position in the lower part of the drainage well body, and the control unit is connected to the liquid level sensor via a wireless data transmission module.

[0009] Preferably, the filter layer is a geotextile filter cloth.

[0010] Preferably, the graded filter media is clean quartz sand with a particle size of 2-5 mm.

[0011] Preferably, the spacing between the drainage well bodies is no greater than 1 / 4 to 1 / 3 of the side length of the adjacent foundation pit.

[0012] Preferably, the porosity of the perforated filter section is 15% to 20%.

[0013] The construction method for any of the aforementioned methods for a drainage well system within a trench suitable for a ground-mounted water-stop curtain includes the following steps: S1, Construction of main structural wall and ground-mounted water-stop curtain; After the deep foundation pit is excavated and supported, the main structural wall and ground-mounted water-stop curtain are constructed. A ring-shaped backfill area is reserved between the main structural wall and the ground-mounted water-stop curtain. A waterproof layer is laid on the outside of the main structural wall. S2, locate the installation point of the dewatering well body; arrange the installation points of the dewatering well body in the circumferential direction within the backfill area of ​​the fertilizer trench; S3, Install the drain well body; Place the well pipe into the well pit according to the location. The well pipe includes a non-porous solid pipe section and a perforated filter section located below the non-porous solid pipe section. Cover the outside of the perforated filter section with geotextile filter cloth and backfill the surrounding area with graded filter material. The lower end of the well pipe should penetrate below the bottom of the foundation pit and be located above the stable water-resistant layer. S4, Install the pumping system; Install a level sensor in the perforated filter section. The level sensor is connected to the control unit outside the well pipe via a wireless data transmission module. Place the submersible pump at the bottom of the perforated filter section. The submersible pump is connected to the drainage pipe. The cables of the drainage pipe and the submersible pump are led out through the reserved hole at the wellhead. The cable of the submersible pump is connected to the control unit. When the level sensor detects that the water level in the drainage well body exceeds the set threshold, the control unit controls the submersible pump to start and discharge the seepage water collected in the drainage well body in a timely manner. S5, connected to the municipal stormwater pipe network; after installing a check valve and anti-backflow device at the end of the drainage pipe, it is connected to the municipal stormwater pipe network; S6, backfill the backfill area of ​​the fertilizer trench in layers and seal the wellhead; S7, System Debugging and Handover: After completing the aforementioned installation steps, conduct water flow tests and linkage tests. Once the system is confirmed to be running stably, hand it over to the subsequent management unit.

[0014] Preferably, in S1, the waterproof layer is formed by laying waterproof membrane or by applying fluorine-coated waterproof coating.

[0015] Preferably, in S2, the spacing between the drainage well bodies is 1 / 4 to 1 / 3 of the side length of the adjacent foundation pit, and they are densely arranged in the corner area of ​​the foundation pit.

[0016] Preferably, in S6, the fertilizer trench is backfilled in layers using plain soil, lime soil, graded sand and gravel or fluidized solidified soil, with each layer not exceeding 300mm in thickness; when the backfill reaches 300mm below the ground, concrete supports are poured around the wellhead, and cast iron maintenance covers with sealing rings are installed, with the covers flush with the ground.

[0017] The present invention has the following beneficial effects: 1) The main body of the drainage well is set on the seepage path in the backfill area of ​​the fertilizer pit. The seepage water between the main structure and the water-stop curtain is extracted by the water pump to avoid water accumulation and erosion of the main structure, and to realize long-term monitoring of the water level at the bottom of the pit.

[0018] 2) The main body of the drainage well is installed after the main structure and the backfill area of ​​the fertilizer trench are completed. Compared with the temporary drainage well in the existing technology, it can be used as a permanent facility, which can continuously deal with the problems of groundwater leakage and buoyancy during the service life of the structure. It can also be used for municipal purposes such as irrigation in the later stage. It can serve as a long-term drainage facility and realize the reuse of water resources.

[0019] 3) The reserved interface of the main drainage pipe can be used as a maintenance and dewatering facility for underground pipe network after the completion of the project, such as road drainage and pipeline maintenance dewatering, thereby improving the overall benefits of the project.

[0020] 4) The drainage well structure relies on the water-stop curtain, the waterproof layer of the bottom slab, and the waterproof layer of the external wall of the structure to form a closed "basin-shaped" waterproof system. The water pump only pumps out the excess seepage water in the basin, avoiding the waste of water resources caused by continuously pumping groundwater over a larger area, and also avoiding the impact on the groundwater level around the project. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] The reference numerals in the attached drawings are as follows: 1. Main structural wall; 2. Waterproof layer; 3. Floor-standing water-stop curtain; 4. Drainage well body; 41. Solid pipe section without holes; 42. Perforated filter section; 43. Filter layer; 44. Filter media; 51. Submersible pump; 52. Liquid level sensor; 53. Control unit; 61. Anti-backflow device; 62. Municipal rainwater pipe network; 7. Stabilized waterproof layer. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] Example 1: Reference Figure 1 As shown, an improvement of the drainage well system in a sump suitable for a floor-mounted waterproof curtain is that it includes a drainage well body 4, which is located within the backfill area of ​​the sump, between the main structural wall 1 and the floor-mounted waterproof curtain 3. The drainage well bodies 4 are arranged at predetermined intervals within the backfill area, and the outer facade of the main structural wall 1 is provided with a waterproof layer 2. The drainage well body 4 includes a non-porous solid pipe section 41 and a drainage well located below the non-porous solid pipe section 41. The perforated filter section 42 is covered with a filter layer 43. The periphery of the filter layer 43 is filled with graded filter media 44. The lower end of the drainage well body 4 is placed below the bottom of the foundation pit and above the stable waterproof layer 7. The drainage well body 4 is equipped with a pumping system. The pumping system is used to promptly pump out the seepage water in the foundation pit from the drainage well body 4 when the water level in the drainage well body 4 rises to a preset water level. The pumping system is connected to the municipal rainwater pipe network 62.

[0025] In this embodiment, the main structural wall 1 is the basement exterior wall, and a waterproof layer 2 is laid on the outer surface of the wall. The waterproof layer 2 is made of waterproof membrane or waterproof coating. The ground-mounted water-stop curtain 3 is the water-stop structure outside the foundation pit, which penetrates the stable waterproof layer 7 below the bottom of the foundation pit. A backfill area of ​​a certain width is formed between the basement exterior wall and the ground-mounted water-stop curtain 3. The drainage well body 4 includes an upper non-porous solid pipe section 41 and a lower perforated filter section 42. The perforated filter section 42 is wrapped with geotextile filter cloth and filled with graded filter material to collect seepage water in the backfill area. The drainage well body 4 is vertically installed in the trench. The lower end of the perforated filter section 42 penetrates below the bottom of the foundation pit and is located on the stable waterproof layer 7, ensuring that only seepage water from the ground-mounted water-stop curtain 3, the foundation pit, or after rainfall enters the backfill area. The diameter of the main body 4 of the drainage well is usually 200~300mm, and the perforated filter section 42 has a pipe wall opening rate of 15%~20%, arranged in a plum blossom pattern.

[0026] Furthermore, the pumping system includes a submersible pump 51, a liquid level sensor 52, and a control unit 53. The submersible pump 51 is located at the bottom of the drainage well body 4, the liquid level sensor 52 is located at a predetermined position in the lower part of the drainage well body 4, and the control unit 53 is connected to the liquid level sensor 52 via a wireless data transmission module.

[0027] In this embodiment, the liquid level sensor 52 is used to monitor the water level in real time and send the signal to the control unit 53 outside the well. When the water level in the drainage well body 4 rises above the set water level, the control unit 53 controls the submersible pump 51 to start automatically and discharge the seepage water in time. When the water level drops below the set water level, the control unit 53 controls the submersible pump 51 to stop working. The submersible pump 51 is connected to the municipal rainwater pipe network 62 through a drainage pipe and an anti-backflow device 61 to realize the resource utilization of collected water.

[0028] Furthermore, the filter layer 43 is a geotextile filter cloth.

[0029] Furthermore, the graded filter media 44 is clean quartz sand with a particle size of 2~5mm.

[0030] Furthermore, the spacing between the drainage well bodies 4 is no greater than 1 / 4 to 1 / 3 of the side length of the adjacent foundation pit.

[0031] Furthermore, the perforated filter section 42 has an opening rate of 15% to 20%.

[0032] Example 2: The construction method of any one of the drainage well systems in the trench for ground-mounted water-stop curtains as described in claims 1-6 is characterized by comprising the following steps: S1, Construction of main structural wall 1 and ground-mounted water-stop curtain 3; After the deep foundation pit is excavated and supported, the main structural wall 1 and ground-mounted water-stop curtain 3 are constructed. A ring-shaped backfilling area is reserved between the main structural wall 1 and the ground-mounted water-stop curtain 3. The width of the backfilling area is not less than 600mm. A waterproof layer 2 is laid on the outside of the main structural wall 1. S2, locate the installation point of the dewatering well body 4; arrange the installation points of the dewatering well body 4 in the circumferential direction within the backfill area of ​​the fertilizer trench; S3, Install the drainage well body 4; Place the well pipe into the well pit according to the location. The well pipe includes a non-porous solid pipe section 41 and a perforated filter section 42 located below the non-porous solid pipe section 41. Cover the outside of the perforated filter section 42 with geotextile filter cloth and backfill the surrounding area with graded filter material, which is clean quartz sand with a particle size of 2~5mm; The non-porous solid pipe section 41 and the perforated filter section 42 are sealed with sealing rings or connected by welding to ensure air tightness; The lower end of the well pipe should penetrate below the bottom of the foundation pit and be located above the stable aquitard 7 to ensure that only seepage water in the backfill area of ​​the foundation pit is collected, and to avoid direct pumping of groundwater; S4, Install the pumping system; Install a level sensor 52 inside the perforated filter section 42. The level sensor 52 is connected to the control unit 53 outside the well pipe via a wireless data transmission module. Place the submersible pump 51 at the bottom of the perforated filter section 42. The submersible pump 51 is connected to the drainage pipe. The cables of the drainage pipe and the submersible pump 51 are led out through the reserved hole at the wellhead. The cable of the submersible pump 51 is connected to the control unit 53. When the level sensor 52 detects that the water level in the drainage well body 4 exceeds the set threshold, the control unit 53 controls the submersible pump 51 to start and discharge the seepage water collected in the drainage well body 4 in a timely manner. S5, connected to the municipal stormwater pipe network 62; after installing a check valve and an anti-backflow device 61 at the end of the drainage pipe, it is connected to the municipal stormwater pipe network 62; S6, backfill the backfill area of ​​the fertilizer trench in layers and seal the wellhead; S7, System Debugging and Handover; After completing the aforementioned installation steps, conduct water flow tests and linkage tests to simulate water accumulation triggering the liquid level sensor 52, verifying the automatic start and stop of the submersible pump 51, wireless data upload, and smooth drainage; After confirming that the system is running stably, it is incorporated into the project's smart operation and maintenance platform and handed over to the post-management unit as a permanent municipal infrastructure.

[0033] Furthermore, in S1, the waterproof layer 2 is formed by laying waterproof membrane or by applying fluorine-coated waterproof coating.

[0034] Furthermore, in S2, the spacing of the drainage well body 4 is 1 / 4 to 1 / 3 of the side length of the adjacent foundation pit, and is densely arranged at the corners of the foundation pit, the ground-mounted water-stop curtain 3, and the weak stratum.

[0035] Furthermore, in S6, the fertilizer trench is backfilled in layers using plain soil, lime soil, graded sand and gravel or fluidized solidified soil, with each layer not exceeding 300mm in thickness and a compaction coefficient not less than 0.94; when backfilling to 300mm below ground level, concrete supports are poured around the wellhead, and cast iron maintenance covers with sealing rings are installed, with the covers flush with the ground.

[0036] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments described in this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0039] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0040] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0041] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A drainage well system for a ground-mounted water-stop curtain system within a trench, characterized in that: The system includes a drainage well body (4), which is located within a backfill area of ​​a fertilizer trench. The backfill area is situated between the main structural wall (1) and a floor-mounted water-stop curtain (3). The drainage well bodies (4) are arranged at predetermined intervals within the backfill area. The exterior of the main structural wall (1) is provided with a waterproof layer (2). The drainage well body (4) includes a non-porous solid pipe section (41) and a perforated filter section (42) located below the non-porous solid pipe section (41). The exterior of section (42) is covered with a filter layer (43), and the surrounding grooves of the filter layer (43) are filled with graded filter material (44). The lower end of the drainage well body (4) is placed below the bottom of the foundation pit and above the stable waterproof layer (7). The drainage well body (4) is equipped with a pumping system. The pumping system is used to promptly pump out the seepage water in the foundation pit from the drainage well body (4) when the water level in the drainage well body (4) rises to the preset water level. The pumping system is connected to the municipal rainwater pipe network (62).

2. The drainage well system for a ground-mounted water-stop curtain as described in claim 1, characterized in that: The pumping system includes a submersible pump (51), a liquid level sensor (52), and a control unit (53). The submersible pump (51) is located at the bottom of the drainage well body (4), and the liquid level sensor (52) is located at a set position in the lower part of the drainage well body (4). The control unit (53) is connected to the liquid level sensor (52) via a wireless data transmission module.

3. The drainage well system for a ground-mounted water-stop curtain as described in claim 1, characterized in that: The filter layer (43) is a geotextile filter cloth.

4. The drainage well system for a ground-mounted water-stop curtain as described in claim 1, characterized in that: The graded filter media (44) is clean quartz sand with a particle size of 2~5mm.

5. A drainage well system for a ground-mounted water-stop curtain system in a sump, as described in claim 1, is characterized in that: The spacing between the main bodies (4) of the drainage wells is no greater than 1 / 4 to 1 / 3 of the side length of the adjacent foundation pit.

6. A drainage well system for a ground-mounted water-stop curtain as described in claim 1, characterized in that: The perforated filter section (42) has an opening rate of 15% to 20%.

7. The construction method of any one of the drainage well systems in the trench suitable for ground-mounted water-stop curtains as described in claims 1-6, characterized in that: Includes the following steps: S1, Construction of main structural wall (1) and ground-mounted water-stop curtain (3); After the deep foundation pit is excavated and supported, the main structural wall (1) and ground-mounted water-stop curtain (3) are constructed. A ring-shaped backfill area is reserved between the main structural wall (1) and the ground-mounted water-stop curtain (3). A waterproof layer (2) is laid on the outside of the main structural wall (1). S2, locate the installation point of the drainage well body (4); arrange the installation points of the drainage well body (4) in the circumferential direction within the backfill area of ​​the fertilizer tank; S3, install the drain well body (4); place the well pipe into the well pit according to the location. The well pipe includes a non-porous solid pipe section (41) and a perforated filter section (42) located below the non-porous solid pipe section (41). Cover the outside of the perforated filter section (42) with geotextile filter cloth and backfill the surrounding area with graded filter material. The lower end of the well pipe should penetrate below the bottom of the foundation pit and be located above the stable water-resistant layer (7). S4, Install the pumping system; Install a level sensor (52) in the perforated filter section (42), the level sensor (52) is connected to the control unit (53) outside the well pipe through a wireless data transmission module, place the submersible pump (51) at the bottom of the perforated filter section (42), the submersible pump (51) is connected to the drainage pipe, the cables of the drainage pipe and the submersible pump (51) are led out through the reserved hole at the wellhead, and the cable of the submersible pump (51) is connected to the control unit (53); when the level sensor (52) detects that the water level in the drain well body (4) exceeds the set threshold, the control unit (53) controls the submersible pump (51) to start, and discharge the seepage water collected in the drain well body (4) in time; S5, connect to the municipal stormwater pipe network (62); after installing a check valve and an anti-backflow device (61) at the end of the drainage pipe, connect it to the municipal stormwater pipe network (62); S6, backfill the backfill area of ​​the fertilizer trench in layers and seal the wellhead; S7, System Debugging and Handover: After completing the aforementioned installation steps, conduct water flow tests and linkage tests. Once the system is confirmed to be running stably, hand it over to the subsequent management unit.

8. The construction method of a drainage well system in a trench suitable for a ground-mounted water-stop curtain according to claim 7, characterized in that: In S1, the waterproof layer (2) is made of waterproof membrane or waterproof coating with fluorine.

9. A construction method for a drainage well system within a trench suitable for a floor-mounted water-stop curtain, as described in claim 7, characterized in that: In S2, the spacing between the main bodies (4) of the drainage wells is 1 / 4 to 1 / 3 of the side length of the adjacent foundation pit, and they are densely arranged in the corner area of ​​the foundation pit.

10. The construction method of a drainage well system in a trench suitable for a ground-mounted water-stop curtain according to claim 7, characterized in that: In S6, the fertilizer trench is backfilled in layers using plain soil, lime soil, graded sand and gravel or fluidized solidified soil, with each layer not exceeding 300mm in thickness. When the backfill reaches 300mm below the ground, concrete supports are poured around the wellhead, and cast iron maintenance covers with sealing rings are installed, with the covers flush with the ground.

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