Deep foundation pit dewatering device
By adopting a variable diameter pipe section and a multi-layer filtration structure in the deep foundation pit dewatering device, the problem of pipe blockage was solved, the stable operation of the water pump was achieved, and the smooth progress of deep foundation pit dewatering was ensured.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-28
- Publication Date
- 2026-04-03
AI Technical Summary
In existing technologies, deep foundation pit dewatering devices are prone to well blockage due to excessive sand content in well water in thick sandy and silty soil layers, which affects drainage projects.
Design a deep foundation pit dewatering device, including a well, a filling layer, a steel pipe and a pump. The steel pipe has a variable diameter section to block silt, the filter section adopts a multi-layer filter structure, the filling layer uses filter materials such as sand, gravel and clay, and the pump is located in the filter section. The trapezoidal and inverted trapezoidal openings reduce the rise of silt and reduce the probability of pump blockage.
This effectively reduces the probability of sediment entering the water pump, lowers the risk of the pump becoming clogged, and ensures the smooth progress of the drainage project.
Smart Images
Figure CN224078222U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of building construction technology, and in particular to a deep foundation pit dewatering device. Background Technology
[0002] For deep foundation pits, dewatering is an essential step. Dewatering refers to the process of clearing water into the pit during excavation when the groundwater level is higher than the bottom surface. This is done to ensure that the pit can be constructed under dry conditions, and to prevent slope instability, quicksand, pit bottom heave, piping, and a decrease in the bearing capacity of the foundation.
[0003] In existing technologies, the dewatering of pits using manholes results in a significant amount of sand production in thick sandy and silty soil layers. The excessive sand content in the well water can easily clog the filter pipes inside the manholes, causing damage to the water pumps and impacting drainage projects. Utility Model Content
[0004] To address the aforementioned problems, this utility model provides a deep foundation pit dewatering device, comprising a well, a filling layer, a steel pipe, a pump, and a pumping pipe; the well is located on one side of the foundation pit to be excavated; the filling layer is located between the foundation pit to be excavated and the well; the steel pipe includes a sedimentation pipe section, a filter pipe section, and a well pipe section connected sequentially from bottom to top; the pump is located inside the filter pipe section; one end of the pumping pipe is connected to the pump, and the other end is connected to a drainage ditch; wherein, the sedimentation pipe section contains a variable diameter pipe section, and the variable diameter pipe section has interconnected trapezoidal openings and inverted trapezoidal openings from bottom to top.
[0005] Furthermore, the filter pipe section includes a filter well pipe, a wire mesh layer, and a nylon cloth layer stacked sequentially from the outside to the inside.
[0006] Furthermore, the filter well pipe includes a pipe body, which is provided with multiple layers of filter holes, with adjacent layers of filter holes arranged alternately.
[0007] Furthermore, the filling layer includes, from bottom to top, a sand and gravel section, a gravel section, and a clay section.
[0008] Furthermore, the design depth of the filter pipe section is greater than the design depth of the excavation pit.
[0009] Furthermore, it also includes a placement rack connected to the filter pipe section, the placement rack being used to place the water pump.
[0010] Furthermore, it also includes a water collection pipe, and there are multiple pipe wells, each of which is equipped with a water pumping pipe. Multiple water pumping pipes are connected to the water collection pipe, and the outlet of the water collection pipe is connected to the drainage ditch.
[0011] Furthermore, a filter layer is provided at the bottom of the well.
[0012] Furthermore, the filter layer is a gravel layer.
[0013] Furthermore, the sedimentation pipe section and the filter pipe section are welded together, as are the filter pipe section and the well pipe section.
[0014] The beneficial effects of this utility model are as follows:
[0015] In this invention, after the well is excavated, a steel pipe is placed inside the well, and then a filler layer, which is a filter material, is placed between the well and the steel pipe. Then, a water pump is placed inside the steel pipe to pump out the water that seeps into the steel pipe from the foundation pit. During the period when the water pump is not working, the silt will enter the inverted trapezoidal opening under the action of gravity and settle at the bottom of the inverted trapezoidal opening. When the water pump is working, the silt at the bottom can be partially blocked by the inner wall of the inverted trapezoidal opening, thereby reducing the amount of silt moving upward and reducing the probability of the water pump being blocked. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments 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, wherein:
[0017] Figure 1 This is a schematic diagram of the deep foundation pit dewatering device provided in this embodiment of the utility model.
[0018] Figure 2 yes Figure 2 Sectional view at point AA.
[0019] Figure 3 This is a schematic diagram of the structure of the filter tube section provided in an embodiment of this utility model.
[0020] In the diagram: 10. Excavation pit to be excavated; 20. Drainage ditch; 1. Manhole; 2. Filling layer; 3. Steel pipe; 4. Water pump; 5. Pumping pipe; 6. Placement frame; 7. Water collection pipe; 8. Rainwater collection pipe; 11. Filter layer; 21. Gravel section; 22. Gravel section; 23. Clay section; 31. Sedimentation pipe section; 32. Filter pipe section; 33. Well pipe section; 311. Variable diameter pipe section; 321. Filter well pipe; 322. Wire mesh layer; 323. Nylon cloth layer; 3111. Trapezoidal opening; 3112. Inverted trapezoidal opening; 3211. Pipe body; 3212. Filter hole. Detailed Implementation
[0021] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this utility model can be combined with each other. For ease of description, the words "upper," "lower," "left," and "right" appearing below only indicate that they are consistent with the upper, lower, left, and right directions of the drawings themselves, and do not limit the structure.
[0022] like Figure 1 , Figure 2 and Figure 3 As shown, this utility model proposes a deep foundation pit dewatering device, including a manhole 1, a filling layer 2, a steel pipe 3, a water pump 4, and a pumping pipe 5. The manhole 1 is located on one side of the foundation pit 10 to be excavated; the filling layer 2 is located between the foundation pit 10 to be excavated and the manhole 1; the steel pipe 3 includes a sedimentation pipe section 31, a filter pipe section 32, and a well pipe section 33 connected sequentially from bottom to top; the water pump 4 is located inside the filter pipe section 32; one end of the pumping pipe 5 is connected to the water pump 4, and the other end of the pumping pipe 5 is connected to the drainage ditch 20; wherein, the sedimentation pipe section 31 is provided with a reducing pipe section 311, and the reducing pipe section 311 has interconnected trapezoidal openings 3111 and inverted trapezoidal openings 3112 from bottom to top. Specifically, the manhole 1 is arranged outside the foundation pit 10 to be excavated and can be adjusted according to site conditions. The steel pipe 3 is buried before the foundation pit is excavated, and the burial elevation is the site elevation at the corresponding location. The dewatering period for the foundation pit begins from the excavation of the soil below the capping beam layer until the superstructure meets the anti-buoyancy requirements, and the dewatering level only needs to be reduced to 0.5 meters below the bottom of the foundation pit. Furthermore, the inner wall surface of the trapezoidal opening 3111 is preferably provided with a smooth surface to reduce the adsorption effect of silt on the inner wall surface. More specifically, the opening connecting the trapezoidal opening 3111 and the inverted trapezoidal opening 3112 can be designed to be as small as possible to improve the effect of blocking silt passage, and the slope of the inner wall surface on both sides of the trapezoidal opening 3111 can be designed to be as large as possible to facilitate the downward movement of silt. Specifically, the slope of the inner wall surface on both sides of the trapezoidal opening 3111 is preferably 70°.
[0023] Specifically, the implementation principle of this embodiment is as follows: After the well 1 is excavated, a steel pipe 3 is placed in the well 1, and then a filling layer 2 is filled between the well 1 and the steel pipe 3. The filling layer 2 is a filter material. Then, a water pump 4 is placed in the steel pipe 3. The water pump is used to pump out the water that seeps into the steel pipe 3 from the foundation pit. During the filtration process, it cannot be completely ensured that no mud or sand will enter the well. Therefore, a variable diameter pipe section 311 is set. During the time when the water pump is not working, the mud and sand will enter the inverted trapezoidal opening 3112 from the trapezoidal opening 3111 under the action of gravity and be deposited at the bottom of the inverted trapezoidal opening 3112. Then, when the water pump 4 is working, the mud and sand at the bottom can be partially blocked by the inner wall of the inverted trapezoidal opening 3112, thereby reducing the amount of mud and sand moving upward and reducing the probability of the water pump being blocked.
[0024] In one embodiment, the filter pipe section 32 includes a filter well pipe 321, a wire mesh layer 322, and a nylon cloth layer 323 stacked sequentially from the outside to the inside. This three-layer filtration ensures effective filtration.
[0025] In one embodiment, the filter well pipe 321 includes a pipe body 3211, which has multiple layers of filter holes 3212, with adjacent layers of filter holes arranged alternately. Specifically, the pipe body 3211 can be made of steel pipe, the hole spacing of the filter holes 3212 is preferably 60 mm, the hole diameter is preferably 30 mm, the adjacent layers of filter holes are arranged alternately in a quincunx pattern, and the porosity of the pipe body 3211 is not less than 30% (i.e., the proportion of the surface area of the pipe body occupied by the filter holes).
[0026] In one embodiment, the filling layer 2 includes a gravel section 21, a pebble section 22, and a clay section 23 arranged sequentially from bottom to top. Specifically, the pebble section 22 is made of hard sand and gravel with good roundness and uniform particle size, preferably with a particle size of 5 mm and a thickness of 75 mm.
[0027] In one embodiment, the design depth of the filter pipe section 32 is greater than the design depth of the excavation pit 10.
[0028] In one embodiment, a placement rack 6 is also included, which is connected to the filter pipe section 32 and is used to place the water pump. The placement rack is used to support the water pump to ensure the stable operation of the water pump, and has holes or gaps for water supply.
[0029] In one embodiment, the system also includes a water collection pipe 7. Multiple manholes 1 are included, each manhole 1 containing a pumping pipe 5. Multiple pumping pipes 5 are connected to the water collection pipe 7, and the outlet of the water collection pipe 7 is connected to the drainage ditch 20. Furthermore, a rainwater collection pipe 8 is included. The rainwater collection pipe 8 connects to each water collection pipe 7. Water collection pipes 7 should be laid along the perimeter of the foundation pit to collect groundwater drained from each manhole 1 and discharge it into municipal pipelines or divert it to other safe areas outside the site (such as the drainage ditch 20). The rainwater collection pipe 8 can be a PVC pipe with a diameter of 250mm, ensuring its flow rate meets the requirements of the total inflow of water into the foundation pit. The cable connecting the pump 4 inside the manhole 1 can be laid along the direction of the water collection pipe 7 and connected to a distribution box. The distribution box should be equipped with a three-phase five-wire residual current circuit breaker, which should automatically disconnect power within 0.1 seconds, with a residual current operating current not exceeding 30mA, to ensure circuit safety.
[0030] In one embodiment, a filter layer 11 is provided at the bottom of the well 1. Specifically, the filter layer 11 is used to filter water that seeps into the well from the bottom of the well 1.
[0031] In one embodiment, the top surface of the steel pipe 3 is preferably higher than the ground.
[0032] In one embodiment, the filter layer 11 is a gravel layer. The gravel layer has a good filtration effect and can filter out mud and sand.
[0033] In one embodiment, the sedimentation pipe section 31 and the filter pipe section 32, and the filter pipe section 32 and the well pipe section 33 are welded together. Specifically, the sedimentation pipe section 31 and the filter pipe section 32, and the filter pipe section 32 and the well pipe section 33 are butt welded together, and at least three 14mm reinforcing ribs are welded to the joint to ensure the connection strength of the joint.
[0034] Specifically, the construction steps for well dewatering are as follows: well measurement and positioning → drilling rig positioning → drilling → backfilling well filter layer 11 → hoisting steel pipe 3 → backfilling the filling layer between steel pipe 3 and well wall 1 → well washing → installing water pump 4 inside steel pipe 3 and installing water pumping control circuit → test pumping → dewatering well working normally → steel pipe 3 pulled out after dewatering is completed → well sealing.
[0035] Furthermore, when laying out the construction of well 1, it should be checked against the foundation pit support design drawings before construction can proceed. Well 1 should avoid the locations of ground beams, walls, and columns. Depending on the geological conditions, impact drilling, auger drilling, or rotary drilling can be used for drilling well 1. The hole diameter is 400mm, and the drilling depth should be 0.3–0.4m greater than the design depth. The deviation between the well depth of well 1 and the design depth should not be less than 50mm. After drilling, the mud should be flushed with a large pump to reduce sedimentation. Clean water should be injected to dilute the mud to a specific gravity close to 1.1 before inserting steel pipe 3 and adding filter material. Forcibly inserting steel pipe 3 into the collapsed area is strictly prohibited. Bottom collapse; Due to the concentrated distribution and continuous drilling of well 1, well washing should be carried out in a timely manner and should not be left unattended for too long, or well washing should be carried out in a concentrated manner after drilling is completed; Well washing method: Use piston machinery or air compressor to wash the well, and acid washing should be carried out if necessary; Well washing requirements: Wash until the sand is clear and the water is clean, and the water flow in the hole is smooth; After the well washing is completed, a single well test pumping should be carried out; The well body of well 1 should be vertical, and the lowered steel pipe 3 should be vertically erected in the center of the well, and its inclination (i.e., the angle between the axis of well 1 and the axis of steel pipe 3) should not be greater than 1 degree; When lowering steel pipe 3, it should be erected in the center of the well, and its inclination should not be greater than 1 degree.
[0036] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.
Claims
1. A deep foundation pit dewatering device, characterized in that, The utility model relates to a kind of water pumping system, including: Pipe well, is located in the side of the foundation pit to be dug; Filler layer, is located between the foundation pit to be dug and the pipe well; Steel pipe, the steel pipe includes sand pipe section, filter pipe section and well pipe section connected in order from bottom to top; Water pumping pump, is located in the filter pipe section; Water pumping pipe, one end of the water pumping pipe is connected to the water pumping pump, the other end of the water pumping pipe is connected to drain ditch; Wherein, the sand pipe section is equipped with variable-diameter pipe section, the variable-diameter pipe section is equipped with trapezoidal opening and inverted trapezoidal opening connected with each other from bottom to top.
2. The deep foundation pit dewatering device according to claim 1, characterized in that: The filter pipe section includes filter well pipe, steel wire mesh layer and nylon cloth layer arranged in order from outside to inside.
3. The deep foundation pit dewatering device according to claim 2, characterized in that: The filter well pipe includes pipe body, the pipe body is equipped with multiple layers of filter holes, adjacent two layers of filter holes are staggered.
4. The deep foundation pit dewatering device according to claim 1, characterized in that: The filler layer includes gravel section, gravel section and clay section arranged in order from bottom to top.
5. The device for dewatering deep foundation pit according to claim 1, characterized in that: The design depth of the filter pipe section is greater than the design depth of the foundation pit to be dug.
6. The deep foundation pit dewatering device according to claim 1, characterized in that: It also includes a rack, the rack is connected to the filter pipe section, and the rack is used to place the water pumping pump.
7. The deep foundation pit dewatering device according to claim 1, characterized in that: It also includes a water collecting pipe, the pipe well has multiple, each of the pipe well is equipped with water pumping pipe, multiple water pumping pipes are connected to water collecting pipe, and the water outlet of the water collecting pipe is connected to the drain ditch.
8. The deep foundation pit dewatering device according to claim 1, characterized in that: The bottom of the pipe well is equipped with filter layer.
9. The deep foundation pit dewatering device according to claim 8, characterized in that, The filter layer is gravel layer.
10. The deep foundation pit dewatering device according to claim 1, characterized in that, The sand pipe section and the filter pipe section, the filter pipe section and the well pipe section are welded and connected.