Water collecting pit dewatering construction method and water stopping structure

Abstract

The invention relates to the technical field of building construction, in particular to a sump dewatering construction method and a water stop structure, and the sump dewatering construction method comprises the steps of firstly excavating a sump slot in a preset position of a deep foundation pit, placing a water pumping device, laying a filter layer and pumping water, forming a first concrete layer, placing a water stop slot, balancing weight, erecting a baffle and pouring concrete; taking out the counterweight after the concrete is solidified, arranging a waterproof layer, continuously pumping water before the concrete is solidified, taking out the water pumping device after the concrete is solidified, dismantling the baffle, and pouring the concrete. The water stop structure of the sump is prepared through the construction method and comprises a filter layer, a concrete layer, a water stop groove and the like. The technical effects that the water level of the sump is effectively reduced, the water stopping effect of the sump is improved, and the structural stability and the waterproof performance are enhanced are achieved.

Description

Technical Field

[0001] This application relates to the field of building construction technology, and in particular to a method for constructing a sump for dewatering and a water-stopping structure. Background Technology

[0002] In deep foundation pit construction, groundwater level control has always been a key challenge, especially in localized deep pits such as sump pits, which significantly impacts the stability and safety of the entire project. Effective groundwater level control technology can ensure a dry working environment for the foundation pit, reduce the impact of groundwater on the surrounding soil, and prevent safety accidents such as foundation pit collapse due to excessively high water levels, thereby improving project quality and construction efficiency.

[0003] In deep foundation pit construction, especially in the control of groundwater levels in locally deep pits such as sump pits, traditional dewatering techniques often employ methods such as multi-wellpoint intensive dewatering, chemical grouting for water sealing, or sheet pile retaining. Multi-wellpoint intensive dewatering involves arranging multiple dewatering wells around the sump pit to continuously lower the water level through pumping; chemical grouting for water sealing involves injecting grout into the strata to form a water-tight layer; and sheet pile retaining uses temporary sheet piles to isolate external water flow. These methods can control groundwater levels to some extent, but their effectiveness varies under different geological conditions.

[0004] These conventional methods in existing technologies have many drawbacks. In highly permeable strata such as gravel layers, groundwater recirculation is rapid. Multi-wellpoint intensive dewatering methods require long-term operation and are energy-intensive. Chemical grouting for sealing is costly and carries a high risk of pollution due to the high porosity of gravel layers, leading to uncontrollable grout diffusion. Sheet pile retaining structures require additional support structures, cannot be integrated with permanent waterproofing layers, and are prone to creating leakage channels after removal. These methods suffer from low dewatering efficiency, unstable water-sealing effects, complex construction procedures, and inability to coordinate with permanent waterproofing systems, making it particularly difficult to balance cost and effectiveness in gravel strata. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this application provides a method for constructing a sump for dewatering and a water-stopping structure. By completing the filtration, pumping device erection, and water-stopping structure pouring simultaneously with dewatering, efficient dewatering and permanent water-stopping structure construction are achieved, shortening the construction period. Through the design of the central concrete layer and baffle, the normal operation of the pumping device during the pouring period and its maintainability in the later stage are ensured, taking into account both construction efficiency and structural reliability.

[0006] This application is achieved through the following technical solution: A method for dewatering a sump pit includes the following steps: S1. Excavate a water collection pit at the predetermined location of the deep foundation pit; S2. Place a pumping device around the periphery of the water collection pit, lay a filter layer at the bottom of the water collection pit and cover the pumping device with the filter layer, and start the pumping device to lower the water level of the water collection pit to below the top surface of the filter layer. S3. A first concrete layer is formed above the filter layer and in the central area of ​​multiple pumping devices; S4. Place the water-stop groove on the first concrete layer; add counterweights inside the water-stop groove; erect baffles around the pumping device to form a disassembly and assembly channel for the pumping device between the baffles; pour concrete between the water-stop groove and the sump pit and outside the disassembly and assembly channel. S5. After the concrete has hardened, remove the counterweight inside the waterstop groove; install a waterproof layer inside the waterstop groove.

[0007] By adopting the above technical solutions, the dewatering of the foundation pit is closely integrated with the construction of the main structure of the sump pit, solving the problem of constructing a sump pit under high groundwater conditions. Continuous pumping ensures a dry environment for concrete pouring and curing, preventing groundwater erosion and damage to the newly poured concrete, and guaranteeing the strength and density of the concrete. Using prefabricated "waterstop grooves" as inner molds eliminates the complex internal formwork and demolding procedures of traditional methods, simplifying on-site operations and shortening the construction period.

[0008] Optionally, after step S4, the method further includes: S4a: Before the concrete sets, the pumping device is continuously activated to lower the water level below the top surface of the filter layer; S4b: After the concrete has solidified, the pumping device is taken out through the disassembly and assembly channel, the baffle is removed, and concrete is poured into the disassembly and assembly channel.

[0009] By adopting the above technical solutions, the importance of continuous dewatering during concrete curing (setting) is clearly emphasized. This is a key guarantee to prevent groundwater pressure from damaging incompletely hardened concrete and to ensure the waterproof performance and strength of the final structure. Achieving equipment recovery and structural integrity (S4b): A feasible method for recovering expensive pumping equipment is provided, avoiding permanent burial of the equipment in concrete and reducing costs. Simultaneously, by backfilling the dismantling channels, the integrity and seamlessness of the concrete structure surrounding the sump are ensured, eliminating potential leakage points.

[0010] Optionally, in step S4, the step of counterweighting the waterstop groove includes: injecting water into the waterstop groove, wherein the weight provided by the water is greater than the buoyancy force on the waterstop groove when the concrete is poured.

[0011] By adopting the above technical solution, water is a readily available and inexpensive counterweight material on the construction site, which is convenient and easy to control. This effectively overcomes the enormous buoyancy generated during concrete pouring, preventing the hollow water-stop channel from floating or shifting, and ensuring the accuracy of its final position. This is a prerequisite for guaranteeing the function and structural quality of the sump pit.

[0012] Optionally, in step S4, the step of placing the water-stop groove onto the first concrete layer includes: transporting the water-stop groove to the deep foundation pit; and hoisting the water-stop groove onto the first concrete layer within the deep foundation pit.

[0013] By adopting the above technical solutions, hoisting is an efficient method for installing large prefabricated components in deep foundation pits, which is in line with the practice of building construction.

[0014] Optionally, step S3 includes: S31. Erect a casting template above the filter layer and in the central area of ​​multiple pumping devices; S32. Pour concrete into the casting template, and after the concrete solidifies, the first concrete layer is formed. S33. Remove the casting formwork.

[0015] By adopting the above technical solutions and through standardized formwork erection, pouring, and demolding, the flatness and strength of the first concrete layer can be ensured, providing a solid and reliable foundation for the precise installation of the subsequent waterstop groove.

[0016] Optionally, before step S1, step S1a is also included: prefabricating a water-stop groove off-site, and making horizontal and vertical keels on the outside of the water-stop groove body; arranging connecting bars on the horizontal and vertical keels so that the connecting bars are connected to the subsequently poured concrete.

[0017] By adopting the above technical solution, the connecting bars extend into the subsequently poured concrete, making the precast waterstop groove form a solid whole with the external concrete, greatly enhancing the connection strength and shear resistance between the two. The horizontal and vertical joists strengthen the structural rigidity and stability of the waterstop groove itself, making it less prone to deformation during transportation, hoisting, and bearing the lateral pressure of concrete. Off-site prefabrication can be carried out simultaneously with the foundation pit excavation, achieving parallel operations and saving overall construction time.

[0018] Optionally, in step S5, the step of setting a waterproof layer inside the waterstop groove includes: cleaning the inner wall of the waterstop groove and laying a waterproof membrane on the inner wall.

[0019] By adopting the above technical solution, the water-stop groove itself is impermeable, and a waterproof membrane is laid on its inner side, forming a "rigid and flexible" dual waterproof system, which greatly improves the reliability of the water collection pit in preventing leakage.

[0020] Optionally, steps following step S5 may also be included: S5a. Install a waterproof layer for the foundation slab on the solidified concrete surface.

[0021] By adopting the above technical solution, the independent waterproofing system of the sump pit is seamlessly connected with the waterproofing system of the entire building foundation slab, forming a complete and continuous underground waterproofing system, thus preventing the junction of the sump pit and the foundation slab from becoming a weak point for leakage.

[0022] A water-stopping structure for a sump pit, prepared based on any of the above-mentioned sump pit dewatering construction methods, includes a filter layer, a concrete layer, and a water-stopping groove arranged sequentially from bottom to top; the filter layer and the concrete layer fill the sump pit groove, the concrete layer wraps around the outer periphery of the water-stopping groove, and a waterproof layer is provided on the inner wall of the water-stopping groove.

[0023] By adopting the above technical solution, the water-stopping structure consists of a filter layer, a concrete layer, and a water-stopping groove, and is fabricated using a specific construction method. The filter layer prevents impurities from entering the pumping device, ensuring smooth pumping. The concrete layer encases the water-stopping groove, enhancing structural stability. The waterproof layer on the inner wall of the water-stopping groove effectively prevents water penetration, avoiding water outflow from the pit or infiltration from external water, extending the service life of the sump, ensuring the stable functioning of the sump, and meeting the requirements for water level control and waterproofing in engineering construction.

[0024] A water-stopping structure for a water collection pit, wherein the water-stopping groove is a funnel-shaped structure with the groove opening gradually increasing from bottom to top, and the outer periphery of the water-stopping groove is provided with transverse and longitudinal keels; connecting bars are arranged on the transverse and longitudinal keels, and the connecting bars are inserted into the concrete layer.

[0025] By adopting the above technical solution, the trumpet-shaped (larger at the top and smaller at the bottom) opening facilitates water flow collection, conforms to the principles of fluid dynamics, and improves water collection efficiency. The keel and connecting reinforcement are key design features that ensure a firm bond between the waterstop groove and the external concrete, allowing them to share the load, and are crucial guarantees for the stability and reliability of the structure.

[0026] In summary, this application includes at least one of the following beneficial technical effects: This application achieves permanent water isolation through a composite structure of a water-stop groove and concrete, significantly improving the efficiency of rainwater drainage. This application uses the inner wall of the waterstop groove as the waterproof base layer, which simplifies the construction process and shortens the construction period; This application significantly enhances the anti-buoyancy capability by mechanically anchoring the bent steel bars to the concrete, effectively resisting the buoyancy of groundwater. Attached Figure Description

[0027] Figure 1 This is a flowchart of a water collection pit dewatering construction method according to an embodiment of this application; Figure 2 This is a schematic diagram of the waterstop groove in a water collection pit dewatering construction method according to an embodiment of this application; Figure 3 This is a schematic diagram of the baffle structure described in Embodiment 1; Figure 4 This is a schematic diagram of the connecting rib described in Embodiment 1.

[0028] In the diagram: 1. Sump pit; 11. First concrete layer; 12. Baffle; 13. Disassembly and assembly passage; 14. Concrete; 15. Concrete layer; 2. Pumping device; 3. Filter layer; 4. Water-stop groove; 41. Horizontal keel; 411. Connecting bar; 42. Longitudinal keel; 5. Waterproof layer of foundation slab. Detailed Implementation

[0029] The following will be combined with the appendix Figure 1-4 The technical solutions of the various embodiments of this application have been clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Example

[0030] Reference Figures 1-3 This application discloses a method for dewatering a sump pit, comprising the following steps: S1. Excavate a water collection pit at the predetermined location of the deep foundation pit.

[0031] S2. Place a pumping device 2 around the periphery of the water collection pit 1, lay a filter layer 3 at the bottom of the water collection pit 1 and cover the pumping device 2 with the filter layer 3, and start the pumping device 2 to lower the water level of the water collection pit 1 to below the top surface of the filter layer 3.

[0032] S3. A first concrete layer 11 is formed above the filter layer 3 and in the central area of ​​the plurality of pumping devices 2.

[0033] S4. Place the water-stop groove 4 on the first concrete layer 11; add counterweights to the inside of the water-stop groove 4; erect baffles 12 around the pumping device 2 to form a disassembly and assembly channel 13 between the baffles 12; pour concrete 14 between the water-stop groove 4 and the water collection pit 1 and outside the disassembly and assembly channel 13.

[0034] S5. After the concrete 14 has solidified, remove the counterweight inside the waterstop groove 4; and install a waterproof layer inside the waterstop groove 4.

[0035] Specifically, in step S1, the first step is to determine the predetermined location of the sump pit based on the design requirements of the deep foundation pit. Surveying instruments, such as total stations and levels, can be used to accurately mark the location and dimensions of the sump pit. Then, excavation equipment such as excavators is used for excavation. The type of excavator can be selected based on the size and depth of the sump pit; for example, small excavators are suitable for shallower and smaller sump pits, while large excavators are suitable for deeper and larger sump pits. During excavation, care must be taken to control the depth and slope of the pit to avoid over-excavation or under-excavation. Alternative excavation equipment can also be loaders, which can complete the initial excavation of the sump pit under certain special site conditions.

[0036] In step S2, the pumping device 2 can be a submersible pump, which has advantages such as small size and easy installation. The submersible pumps are evenly distributed along the inner circumference of the sump pit 1 to ensure complete extraction of groundwater from the pit. A filter layer 3, made of gravel, is laid at the bottom of the pit. Gravel has large pores, allowing water to flow through quickly. The filter layer 3 should cover the pumping device 2 during installation. After starting the pumping device 2, groundwater will pass through the filter layer 3, lowering the water level in the sump pit 1 below the top surface of the filter layer 3. Alternatively, the pumping device 2 can be a centrifugal pump, etc. The filter layer 3 can also be made of other materials with filtration functions, such as a mixture of gravel and coarse sand. The gravel has large pores, allowing water to flow through quickly, while the coarse sand further filters impurities from the water.

[0037] In step S3, a casting template is erected above the filter layer 3 and in the central area of ​​the multiple pumping devices 2. The casting template is made of wood, which is low-cost and easy to process and install. Concrete 14 is poured into the casting template, and after the concrete 14 solidifies, the first concrete layer 11 is formed. C15 concrete 14 can be used, as it has good strength and durability. After the casting template is removed, the first concrete layer 11 is firmly formed within the sump pit 1. Other types of concrete 14, such as high-performance concrete 14, can be selected according to actual needs.

[0038] In step S4, the waterstop trough 4 must first be transported to the deep foundation pit. A crane can be used to lift the waterstop trough 4 into the deep foundation pit, and then a crane or similar equipment is used to lift the waterstop trough 4 onto the first concrete layer 11. A counterweight is added to the inside of the waterstop trough 4, and water is injected into it. The weight provided by the water is greater than the buoyancy force experienced by the waterstop trough 4 during concrete pouring 14, thus preventing the waterstop trough 4 from floating during the concrete pouring process. Baffles 12 are erected around the pumping device 2, and these baffles 12 can be made of wooden planks to form a disassembly and assembly channel 13 for the pumping device 2. Concrete 14 is poured between the waterstop trough 4 and the sump pit 1, and outside the disassembly and assembly channel 13. The concrete 14 must be poured evenly and densely to ensure a good structure. Other materials with sufficient strength, such as aluminum alloy plates, can be used for the baffles 12.

[0039] In step S5, a waterproof layer is installed inside the waterstop groove 4. The inner wall of the waterstop groove 4 is cleaned to remove excess water stains and impurities. Then, a waterproof membrane is laid on the inner wall. SBS waterproof membrane can be used, as it has good waterproof performance and weather resistance. Alternative waterproof membranes include APP waterproof membrane, etc.

[0040] Furthermore, refer to Figure 2 and Figure 4 Before step S1, the waterstop groove 4 needs to be prefabricated off-site. Horizontal joists 41 and longitudinal joists 42 are fabricated on the outer side of the waterstop groove 4. The horizontal joists 41 and longitudinal joists 42 can be made of channel steel or angle steel, which have good strength and stability. Connecting bars 411 are arranged on the horizontal joists 41 and longitudinal joists 42. The connecting bars 411 can be bent steel bars to connect with the subsequently poured concrete 14, enhancing the bond between the waterstop groove 4 and the concrete layer 15. Alternative joist materials can also be I-beams, and the connecting bars 411 can also be made of other metal materials with a certain strength.

[0041] Reference Figure 2 and Figure 3 Before the concrete 14 solidifies, the pumping device 2 is continuously activated to lower the water level below the top surface of the filter layer 3, ensuring that the concrete 14 solidifies in a dry environment, thereby improving the strength and waterproof performance of the concrete 14. After the concrete 14 solidifies, the pumping device 2 is removed through the disassembly channel 13, the baffle 12 is removed, and concrete 14 is poured into the disassembly channel 13 to make the structure of the entire sump pit more complete and stable.

[0042] Preferably, after step S5, a foundation slab waterproof layer 5 can be applied to the solidified concrete 14 to further improve the waterproof performance of the sump. The foundation slab waterproof layer 5 is a waterproof underlayment with good flexibility and waterproof performance. An alternative waterproof coating can be an acrylic waterproof coating, etc.

[0043] The implementation principle of this embodiment is as follows: by arranging a pumping device 2 in a ring around the pit and laying a filter layer 3, groundwater can be continuously and efficiently pumped out. The filter layer 3 ensures smooth water flow and prevents silt from clogging the pump. This step is carried out before the main structure construction, creating a relatively dry working environment free from groundwater intrusion for the subsequent pouring of concrete 14, which is a fundamental prerequisite for ensuring project quality. Step 1: First, a "first concrete layer 11" is poured in the central area of ​​the pit. This small-scale foundation provides a stable and flat base for the subsequent installation of the core component "waterstop groove 4". Step 2: After the prefabricated "waterstop groove 4" is hoisted into place, the method of water injection counterweight is cleverly used to resist the huge buoyancy generated during the pouring of concrete 14, ensuring that the waterstop groove 4 is accurately positioned and does not shift. This is an economical and efficient on-site anti-buoyancy measure. Step 3: A large volume of concrete 14 is poured between the water-stop groove 4 and the pit wall, firmly connecting it to the keel and connecting bars 411 on the outside of the precast water-stop groove 4, forming a composite integral load-bearing and waterproof structure. During the pouring of the main concrete 14, a baffle 12 is erected around the pumping device 2, forming a temporary "disassembly and assembly channel 13". The ingenuity of this design lies in that it allows the pumping device 2 to operate continuously throughout the pouring and solidification of the concrete 14, ensuring the continuity of the rainwater runoff effect. After the concrete 14 solidifies, the expensive pumping equipment can be easily removed from the channel for recycling, reducing costs. Finally, a second pour of concrete 14 is performed on the channel, ensuring the integrity and density of the concrete 14 structure around the entire sump pit, eliminating potential leakage hazards caused by the equipment's presence. Its principle is to achieve efficient, high-quality and economical construction of water collection pits under high groundwater levels through a series of interconnected processes, including "creating conditions through active precipitation, combining prefabrication and cast-in-place construction, and reserving channels to ensure recycling," integrating the precipitation process with the construction process of permanent waterproof structures.

[0044] This application also discloses a water-stopping structure for a sump pit, which is made using a sump pit dewatering construction method.

[0045] Specifically, refer to Figures 2-3 It includes a filter layer 3, a concrete layer 15, and a water-stop groove 4 arranged sequentially from bottom to top; the filter layer 3 and the concrete layer 15 fill the water collection pit 1, the concrete layer 15 wraps around the outer periphery of the water-stop groove 4, and the inner wall of the water-stop groove 4 is provided with a waterproof layer.

[0046] Preferably, the filter layer 3 is filled with gravel, which allows water to flow through quickly. The laying of the filter layer 3 can prevent impurities from entering the pumping device 2, ensuring the normal operation of the pumping device 2, and at the same time, it can also perform preliminary filtration of groundwater, reducing suspended solids in the water.

[0047] The concrete layer 15 surrounds the water-stop groove 4, providing support and protection and enhancing its stability. Simultaneously, the concrete layer 15 also acts as a water barrier, preventing groundwater from seeping into the sump from the sides. Alternatively, the concrete layer 14 can be high-performance concrete, etc.

[0048] Reference Figures 3-4 The water-stop groove 4 has a trumpet-shaped structure with the opening gradually increasing from bottom to top. This structural design increases the contact area between the water-stop groove 4 and the concrete layer 15, improving the bonding strength between the two. The outer periphery of the water-stop groove 4 is provided with horizontal and vertical ribs 41 and 42, which can be made of channel steel or angle steel, providing good strength and stability. Connecting ribs 411, which can be hooked steel bars, are arranged on the horizontal and vertical ribs 41 and 42. These connecting ribs 411 are inserted into the concrete layer 15, further strengthening the connection between the water-stop groove 4 and the concrete layer 15, making the entire water-stop structure more stable.

[0049] The waterproof layer effectively prevents groundwater from seeping into the sump from the inner wall of the waterstop 4, ensuring a dry environment for the sump. Simultaneously, the waterproof layer design also creates a dry inner wall for the waterstop 4, allowing subsequent construction to proceed in a dry environment.

[0050] The implementation principle of this embodiment is as follows: the waterstop trough 4 is not an isolated container, but is deeply anchored in the concrete layer 15 surrounding it through prefabricated longitudinal and transverse keels 41 and connecting bars 411 on its outer side. This design makes the steel waterstop trough 4 and the outer concrete 14 form a tightly integrated whole structure, which can jointly resist external soil pressure and water pressure, greatly enhancing the stability and deformation resistance of the structure. The waterstop trough 4 is designed in a "trumpet shape" that is wider at the top and narrower at the bottom. This shape is conducive to collecting water flow in the pit over a larger area, conforms to fluid dynamics, and improves water collection efficiency. Two core waterproof barriers are set up: the first layer (rigid waterproofing): the C15 concrete layer 15 surrounding the waterstop trough 4 itself has a certain impermeability, forming the first solid rigid waterproof layer. The second layer (flexible waterproofing): the SBS waterproof membrane laid on the inner wall of the waterstop trough 4, as a flexible waterproof layer, can adapt to minor structural deformations without cracking, compensating for any small pores or cracks that may exist in the concrete 14. The "rigid and flexible" dual waterproofing system greatly improves the seepage prevention reliability of the entire water collection pit. The bottommost filter layer 3 plays a crucial role in foundation treatment. It provides a clear infiltration path for groundwater, allowing it to smoothly enter the pumping area (construction phase), while effectively filtering out impurities such as silt and sand, preventing blockages in the drainage system and ensuring the long-term stability of the entire sump foundation. Its principle is based on a design concept of "composite structure enhancing stability, double waterproofing ensuring seepage prevention, and optimized form improving efficiency," constructing a permanent underground structure that integrates structural load-bearing, efficient water collection, and reliable waterproofing. It not only solves the problems encountered during the construction phase but also guarantees long-term usability and safety after completion.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of this application.

Claims

1. A method for constructing a sump dewatering system, characterized in that, Includes the following steps: S1. Excavate a water collection pit at the preset location of the deep foundation pit (1). S2. Place a pumping device (2) around the inside of the water collection pit (1), lay a filter layer (3) at the bottom of the water collection pit (1) and cover the pumping device (2) with the filter layer (3), and start the pumping device (2) to lower the water level of the water collection pit (1) below the top surface of the filter layer (3). S3. A first concrete layer (11) is formed above the filter layer (3) and in the central area of ​​the multiple pumping devices (2). S4. Place the water-stop groove (4) on the first concrete layer (11); add counterweights inside the water-stop groove (4); erect baffles (12) around the pumping device (2) to form a disassembly and assembly channel (13) for the pumping device (2) between the baffles (12); pour concrete (14) between the water-stop groove (4) and the sump pit (1) and outside the disassembly and assembly channel (13). S5. After the concrete (14) has solidified, remove the counterweight inside the waterstop groove (4); and install a waterproof layer inside the waterstop groove (4).

2. The method for constructing a sump dewatering system according to claim 1, characterized in that, After step S4, the method further includes: S4a: Before the concrete (14) solidifies, the pumping device (2) is continuously started to lower the water level below the top surface of the filter layer (3); S4b: After the concrete (14) has solidified, the pumping device (2) is taken out through the disassembly channel (13), the baffle (12) is removed, and concrete (14) is poured into the disassembly channel (13).

3. The method for constructing a sump dewatering system according to claim 1, characterized in that, In step S4, the step of counterweighting the waterstop groove (4) includes: injecting water into the waterstop groove (4), wherein the gravity provided by the water is greater than the buoyancy of the waterstop groove (4) when the concrete (14) is poured.

4. The method for constructing a sump dewatering system according to claim 1, characterized in that, In step S4, the step of placing the water-stop groove (4) onto the first concrete layer (11) includes: transporting the water-stop groove (4) to the deep foundation pit; and hoisting the water-stop groove (4) onto the first concrete layer (11) within the deep foundation pit.

5. The method for constructing a sump dewatering system according to claim 1, characterized in that, Step S3 includes: S31. A casting template is erected above the filter layer (3) and in the central area of ​​multiple pumping devices (2); S32. Pour concrete (14) into the casting template, and after the concrete (14) solidifies, a first concrete layer (11) is formed. S33. Remove the casting formwork.

6. The method for constructing a sump dewatering system according to claim 1, characterized in that, Before step S1, S1a is also included: prefabricating a water-stop groove (4) off-site, making a horizontal keel (41) and a longitudinal keel (42) on the outside of the water-stop groove (4); arranging connecting bars (411) on the horizontal keel (41) and the longitudinal keel (42) so that the connecting bars (411) are connected to the subsequently poured concrete (14).

7. The method for constructing a sump dewatering system according to claim 5, characterized in that, In step S5, the step of setting a waterproof layer inside the waterstop groove (4) includes: cleaning the inner wall of the waterstop groove (4) and laying a waterproof membrane on the inner wall.

8. The method for constructing a sump dewatering system according to claim 1, characterized in that, It also includes steps following step S5: S5a. A waterproof layer (5) is installed on the upper surface of the solidified concrete (14).

9. A water-stopping structure for a water collection pit, characterized in that, It is prepared by the water collection pit dewatering construction method as described in any one of claims 1-8, including a filter layer (3), a concrete layer (15) and a water-stop groove (4) arranged sequentially from bottom to top; the filter layer (3) and the concrete layer (15) fill the water collection pit groove (1), the concrete layer (15) wraps around the outer periphery of the water-stop groove (4), and the inner wall of the water-stop groove (4) is provided with a waterproof layer.

10. The water-stopping structure of a water collection pit according to claim 9, characterized in that, The water-stop groove (4) is a trumpet-shaped structure with the groove opening gradually increasing from bottom to top. The water-stop groove (4) is provided with horizontal keel (41) and vertical keel (42) distributed in both directions. Connecting bars (411) are arranged on the horizontal keel (41) and the vertical keel (42), and the connecting bars (411) are inserted into the concrete layer (15).

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