Construction method of basement foundation pit dewatering engineering

Abstract

The construction method comprises the following steps that when a foundation pit is excavated, temporary drainage ditches and water-collecting wells are arranged, the drainage ditches are arranged on the periphery of the bottom of the foundation pit, one water-collecting well is arranged at each corner of the drainage ditches, and drainage pumps are arranged in the water-collecting wells to pump and drain water; after excavation of the slope of the foundation pit is completed, an intercepting ditch and a top drainage well are arranged at the top of the foundation pit; the drainage ditches and the water collecting wells are staggered in the width direction; auxiliary drainage wells are excavated at the corners of the drainage ditches, auxiliary drainage pumps are arranged in the auxiliary drainage wells, and the auxiliary drainage wells are communicated with the parts, outside the distribution range of the water collecting wells, of the drainage ditches; continuously pumping water during the construction period of the inner side of the foundation pit until the dead weight of the building is greater than the buoyancy generated by underground water. The problem that existing foundation pit surface drainage precipitation is insufficient in drainage capacity when coping with working conditions such as heavy rainfall can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of foundation pit construction technology, in particular to a construction method of a basement foundation pit dewatering project. BACKGROUND

[0002] The basement refers to the height of the room ground below the outdoor ground level exceeding one half of the net height of the room. In order to carry out the basement construction, the foundation pit opening operation needs to be carried out. In the process of foundation pit excavation, and in the process of carrying out the basement construction in the foundation pit, the foundation pit dewatering operation needs to be carried out. The foundation pit dewatering refers to the dewatering work done to ensure that the foundation pit can be constructed under dry conditions to prevent slope instability, foundation quicksand, pit bottom uplift, pit bottom piping and foundation bearing capacity reduction when the underground water level is higher than the excavation bottom surface during the excavation of the foundation pit.

[0003] At present, the foundation pit dewatering methods mainly include: open ditch plus catchment well dewatering, light well point dewatering, jet well point dewatering, electro-osmotic well point dewatering, deep well point dewatering and the like. The open ditch plus catchment well dewatering, also known as open drainage dewatering, is a widely used foundation pit dewatering method at present. The foundation pit open drainage dewatering guides the water flow by excavating a ditch around the basement foundation pit. Compared with other foundation pit dewatering methods, it has the characteristics of simple construction and low cost. However, with the development of the basement engineering in the direction of deep and large, the existing foundation pit open drainage dewatering method has the problem of insufficient drainage capacity when dealing with strong rainfall and other working conditions. SUMMARY

[0004] In order to improve the problem of insufficient drainage capacity of the existing foundation pit open drainage dewatering when dealing with strong rainfall and other working conditions, the present application provides a construction method of a basement foundation pit dewatering project.

[0005] The construction method of the basement foundation pit dewatering project provided by the present application adopts the following technical scheme: The application discloses a construction method of a basement foundation pit dewatering project, which comprises the following steps: when the foundation pit is excavated, a temporary drainage ditch and a water collecting well are arranged, the drainage ditch is arranged around the bottom of the foundation pit, one water collecting well is arranged at each corner of the drainage ditch, a drainage pump is arranged in the water collecting well to drain water, the depth of the drainage ditch is more than 300mm lower than the elevation of the bottom of the foundation pit, and the depth of the water collecting well is more than 600mm lower than the elevation of the bottom of the foundation pit; the foundation pit earthwork is excavated gradually, during the excavation of the foundation pit, the drainage ditch and the water collecting well are deepened on one side while the foundation pit earthwork is excavated on the other side, and the drainage ditch and the water collecting well are deepened before the foundation pit is deepened; after the excavation of the foundation pit slope is completed, a water intercepting ditch and a top drainage well are arranged on the top of the foundation pit; after the foundation pit is excavated to the design elevation, the formal drainage ditch and the water collecting well are arranged on the basis of the temporary drainage ditch and the water collecting well, and the drainage ditch and the water collecting well are hardened; the drainage ditch is arranged in a staggered mode along the width direction of the drainage ditch and the water collecting well, the width dimension of the drainage ditch outside the distribution range of the water collecting well accounts for 5%-10% of the total width of the drainage ditch; an auxiliary drainage well is arranged at the corner of the drainage ditch, an auxiliary drainage pump is arranged in the auxiliary drainage well, and the auxiliary drainage well is communicated with the part of the drainage ditch outside the distribution range of the water collecting well; water is continuously pumped during the construction of the inner side of the foundation pit, and the pumping is stopped when the weight of the building is greater than the buoyancy of the underground water.

[0006] By adopting the technical scheme, during the excavation of the foundation pit, the water intercepting ditch is used to intercept the surface water outside the foundation pit, the drainage ditch is used to collect the shallow underground water to the water collecting well, and the drainage pump in the water collecting well is used to pump and drain the water. When heavy rain occurs during the construction, the drainage pump in the auxiliary drainage well is simultaneously used to pump and drain the water, so that the efficiency of the water drainage is improved. The size of the communication between the drainage ditch and the water collecting well is greater than the size of the communication between the drainage ditch and the auxiliary drainage well, the drainage pump in the water collecting well is used to meet the water drainage demand under normal conditions, the drainage pump in the water collecting well is used as the main working equipment, and when the drainage pump in the water collecting well cannot meet the water drainage demand, the water pump in the auxiliary drainage well is used to pump and drain the excess water, so that the water drainage efficiency is considered and the water drainage power under normal conditions is reduced.

[0007] Optionally, the bottom of the drainage ditch is gradually inclined downward along the width direction of the drainage ditch and toward the center of the foundation pit, the auxiliary drainage well is close to the center of the foundation pit relative to the water collecting well, and the auxiliary drainage pump in the auxiliary drainage well is a sludge pump.

[0008] By adopting the technical scheme, the bottom of the drainage ditch is inclined in the direction of approaching the center of the foundation pit along the width direction of the bottom, so that more silt in the drainage ditch flows into the auxiliary drainage well, the silt entering the collecting well is reduced, and the working efficiency of the drainage pump in the collecting well is facilitated to be ensured; the silt entering the drainage ditch is discharged by the sludge pump, so that the silt is conveniently concentrated for treatment; the sludge pump is not prone to jam during use, but the use cost is relatively high at the same time, and the high-concentration sludge water is concentrated for discharge, which is beneficial to balance the foundation pit dewatering efficiency and the dewatering cost.

[0009] Optionally, a sludge collecting groove is arranged at the position of the bottom of the drainage ditch close to the auxiliary drainage well, the sludge collecting groove is in communication with the auxiliary drainage well, and is located outside the distribution range of the collecting well.

[0010] By adopting the technical scheme, the sludge collecting groove can converge more silt in the drainage ditch into the auxiliary drainage well.

[0011] Optionally, the drainage ditch is provided with a flow resistance plate, the flow resistance plate partially covers the sludge collecting groove from top to bottom, the end of the sludge collecting groove is exposed outside the flow resistance plate, and the thickness of the flow resistance plate is greater than the height difference of the bottom surface of the drainage ditch along the width direction.

[0012] By adopting the technical scheme, the thickness of the flow resistance plate is greater than the height difference of the bottom of the drainage ditch along the width direction, so that the water in the drainage ditch can flow into the collecting well preferentially.

[0013] Optionally, a slurry pool is arranged at the top of the foundation pit, and a flow guide groove body is arranged at the top of the foundation pit, the flow guide groove body is gradually inclined downward in the direction away from the foundation pit, and the flow guide groove body is used for guiding the sludge water discharged by the sludge pump to the slurry pool.

[0014] By adopting the technical scheme, the slurry pool is used for collecting the sludge water discharged by the sludge pump, so as to facilitate the sedimentation of solids in the sludge water; in the case of arranging the flow guide groove body, the slurry pool can be arranged at a position farther away from the foundation pit, so as to reduce the adverse effect of the slurry pool on the slope structure of the foundation pit; in addition, in the case of arranging the flow guide groove body, the pumping distance of the sludge pump can be reduced, so as to reduce the working load of the sludge pump.

[0015] Optionally, a geotextile is arranged on the slope of the foundation pit during excavation of the foundation pit, and the geotextile is positioned by positioning anchor rods.

[0016] By adopting the technical scheme, the geotextile has a protective effect on the slope of the foundation pit, so as to reduce water and soil loss of the slope of the foundation pit, thereby reducing the silt entering the drainage ditch.

[0017] Optionally, the inner wall of the water intercepting trench is hardened, and a water permeable pipe is inserted on the side of the water intercepting trench away from the foundation pit, one end of the water permeable pipe in the water intercepting trench is provided with a plastic film pipe, one end of the plastic film pipe is sleeved on the end of the water permeable pipe and is tightly fixed.

[0018] By adopting the above technical scheme, the side of the water intercepting trench away from the foundation pit is the water-facing side, the water permeable pipe is arranged on the side of the water intercepting trench away from the foundation pit, so that the surface water of the soil outside the foundation pit can seep into the water intercepting trench through the water permeable pipe, and the water intercepting trench can intercept more surface water. The plastic film pipe is arranged at one end of the water permeable pipe in the water intercepting trench, which can guide the water in the water permeable pipe into the water intercepting trench and prevent the water in the water intercepting trench from flowing back to the outside of the water intercepting trench.

[0019] Optionally, a top drainage well is arranged in the water intercepting trench, a top drainage pump is arranged in the top drainage well, the drainage pipe of the top drainage pump is a hose, and a tee joint is connected in series to the top drainage pump. Two ports of the tee joint are connected in series to the drainage pipes of the top drainage pump, and the other port is used for connecting the drainage pipe of the drainage pump.

[0020] By adopting the above technical scheme, when the drainage pump in the water collecting pit drains water through the drainage pipe, the tee joint can be used to drain water into the drainage pipe of the top drainage pump, which is convenient for centralized drainage operation.

[0021] Optionally, the port of the tee joint connected to the drainage pump is a bypass port, and the bypass port of the tee joint is inclined towards the top drainage pump.

[0022] By adopting the above technical scheme, in the installed state of the tee joint, the bypass port is inclined towards the foundation pit, so that the included angle between the directions of the two water flows injected into the tee joint is acute, which is beneficial to reducing the mutual hindering effect between the two water flows injected into the tee joint.

[0023] Optionally, a positioning member is arranged on the top of the foundation pit, the positioning member is provided with a positioning port for placing the tee joint, the positioning port is arranged upward, and the positioning port can keep the bypass port of the tee joint in an upward state.

[0024] By adopting the above technical scheme, when the tee joint is placed in the positioning port of the positioning member, the bypass port is upward, so that the water flow injected into the tee joint by the top drainage pump is not easy to enter the bypass port.

[0025] In summary, the present application has at least one of the following beneficial technical effects: When heavy rain occurs during construction, the drainage pump in the auxiliary drainage well is started to drain water to improve the efficiency of water drainage. The drainage pump in the water collecting well is the main working equipment. When the drainage pump in the water collecting well cannot meet the drainage demand, the excess water is pumped out through the water pump in the auxiliary drainage well, which is beneficial to reduce the power consumption of water drainage under normal conditions while ensuring the efficiency of water drainage; The bottom of the drainage ditch is inclined in the direction of the center of the foundation pit along the width direction of the drainage ditch, so that more sediment in the drainage ditch flows into the auxiliary drainage well, which can reduce the sediment entering the water collecting well and is beneficial to ensure the working efficiency of the drainage pump in the water collecting well. The sediment entering the drainage ditch is discharged by the sludge pump, which is convenient for centralized treatment of the sediment. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a top view of the foundation pit of the embodiment.

[0027] Figure 2 is Figure 1 is an enlarged view of A in

[0028] Figure 3 is a cross-sectional view of the foundation pit in the embodiment.

[0029] Figure 4 is a schematic view of the position of the water interception ditch of the embodiment.

[0030] BRIEF DESCRIPTION OF DRAWINGS: 10, foundation pit; 1, drainage ditch; 11, sludge collecting tank; 12, flow resistance plate; 2, water collecting well; 21, drainage pump; 3, water interception ditch; 31, permeable pipe; 32, plastic film pipe; 4, top drainage well; 41, top drainage pump; 42, three-way pipe joint; 421, bypass opening; 5, auxiliary drainage well; 51, sludge pump; 6, slurry pool; 7, flow guide groove body; 8, positioning member; 81, bottom plate; 82, side plate; 83, positioning opening. DETAILED DESCRIPTION

[0031] The following will be described in detail in combination with the accompanying Figures 1-4 The application is further described in detail.

[0032] The embodiment of the application discloses a construction method of a basement foundation pit water drainage engineering. Referring to Figure 1 and Figure 2 , the construction method of the basement foundation pit water drainage engineering comprises the following steps: Step 1, when the foundation pit 10 is excavated, a temporary drainage ditch 1 and a water collecting well 2 are arranged, the drainage ditch 1 is arranged at the bottom of the foundation pit 10, one water collecting well 2 is arranged at each corner of the drainage ditch 1, a water collecting well 2 can be additionally arranged between two corners of the drainage ditch 1 according to the need, a drainage pump 21 is arranged in the water collecting well 2 to pump and drain the water, the depth of the drainage ditch 1 is more than 300mm lower than the elevation of the bottom of the foundation pit 10, the depth of the water collecting well 2 is more than 600mm lower than the elevation of the bottom of the foundation pit 10; the excavation of the foundation pit 10 is deepened gradually, during the excavation process of the foundation pit 10, the soil of the foundation pit 10 is excavated on one side, and the drainage ditch 1 and the water collecting well 2 are deepened on the other side, the drainage ditch 1 and the water collecting well 2 are deepened before the foundation pit 10 is deepened; During the excavation process of the foundation pit 10, the geotextile is laid on the side slope of the foundation pit 10 with the soil excavation of the foundation pit 10, the geotextile is used to reduce water and soil loss during the excavation process of the foundation pit 10, and the geotextile is positioned by the positioning anchor rod; Step 2, after the side slope of the foundation pit 10 is excavated, a water intercepting ditch 3 and a top drainage well 4 are arranged on the top of the foundation pit 10; the inner wall of the water intercepting ditch 3 is hardened; a top drainage pump 41 is arranged in the top drainage well 4 to drain water; Step 3, after the foundation pit 10 is excavated to the design elevation, on the basis of the temporary drainage ditch 1 and the water collecting well 2, the formal drainage ditch 1 and the water collecting well 2 are arranged, and the drainage ditch 1 and the water collecting well 2 are hardened; the wall of the drainage ditch 1 and the wall of the water collecting well 2 are realized by using the water permeable brick, or the water permeable brick is used to realize the water permeable after being hardened by using the cement material, and the water discharge hole is arranged to realize the water permeable; The drainage ditch 1 is arranged in the width direction of the drainage ditch 1 and the water collecting well 2, the width size of the drainage ditch 1 outside the distribution range of the water collecting well 2 accounts for 5%-10% of the total width of the drainage ditch 1; the auxiliary drainage well 5 is arranged at the corner part of the drainage ditch 1, two auxiliary drainage wells 5 are arranged in the embodiment, the auxiliary drainage pump 21 is arranged in the auxiliary drainage well 5, and the auxiliary drainage well 5 is communicated with the part of the drainage ditch 1 outside the distribution range of the water collecting well 2; Step 4, the water is continuously pumped during the construction period inside the foundation pit 10, and the pumping is stopped when the self weight of the building is greater than the buoyancy generated by the groundwater.

[0033] The implementation principle of a construction method for a basement foundation pit dewatering project according to an embodiment of this application is as follows: During the excavation of the foundation pit 10, the intercepting ditch 3 intercepts surface water outside the foundation pit 10, and the drainage ditch 1 collects shallow groundwater into the sump well 2, which is then pumped out by the drainage pump 21. When heavy rainfall occurs during construction, the drainage pump 21 in the auxiliary drainage well 5 is simultaneously activated to pump out the dewatering water, thereby improving the dewatering efficiency. The dimension connecting the drainage ditch 1 and the sump well 2 is larger than the dimension connecting the drainage ditch 1 and the auxiliary drainage well 5. Under normal circumstances, the drainage pump 21 in the sump well 2 is sufficient to meet the drainage needs, making it the main working equipment. When the drainage pump 21 in the sump well 2 cannot meet the drainage needs, the excess water is pumped out by the pump in the auxiliary drainage well 5, which helps to reduce the electricity consumption for dewatering under normal conditions while ensuring drainage efficiency.

[0034] Reference Figure 2 and Figure 3 In this embodiment, the bottom of the drainage ditch 1 gradually slopes downwards towards the center of the foundation pit 10 along its own width direction. The slope angle of the bottom of the drainage ditch 1 is in the range of 3°-8°. The auxiliary drainage well 5 is closer to the center of the foundation pit 10 than the water collection well 2. The auxiliary drainage pump 21 in the auxiliary drainage well 5 is a sludge pump 51.

[0035] When drainage ditch 1 drains water into collection well 2 and auxiliary drainage well 5, the silt in drainage ditch 1 will flow along the width of drainage ditch 1 towards the side closer to the center of foundation pit 10, so that most of the silt in drainage ditch 1 enters auxiliary drainage well 5 and is then discharged through drainage pump 21 in auxiliary drainage well 5.

[0036] Reference Figure 1 To centrally treat the sludge discharged by sludge pump 51, a sludge tank 6 is provided at the top of the foundation pit 10. A guide channel 7 is also provided at the top of the foundation pit 10, gradually sloping downwards away from the foundation pit 10. The guide channel 7 is used to divert the sludge discharged by sludge pump 51 to the sludge tank 6. Sludge pump 51 pumps the high-concentration sludge into the sludge tank 6 for sedimentation to facilitate the separation of sludge and sand.

[0037] Reference Figure 1 and Figure 4A sludge collection trough 11 is installed at the bottom of the drainage ditch 1 near the auxiliary drainage well 5. The sludge collection trough 11 is installed in a one-to-one correspondence with the auxiliary drainage well 5. The sludge collection trough 11 is designed with an L-shaped structure to adapt to the corner of the drainage ditch 1. The sludge collection trough 11 is connected to the auxiliary drainage well 5 and is located outside the distribution range of the collection well 2. The drainage ditch 1 is equipped with a flow-blocking plate 12, which is installed in a one-to-one correspondence with the auxiliary drainage well 5. The shape of the flow-blocking plate 12 is designed with an L-shaped structure to adapt to the sludge collection trough 11. The length of the flow-blocking plate 12 is less than the length of the sludge collection trough 11, and the width of the flow-blocking plate 12 is greater than the width of the sludge collection trough 11. The flow-blocking plate 12 partially covers the sludge collection trough 11 from top to bottom, and the two ends of the sludge collection trough 11 are exposed outside the flow-blocking plate 12. The thickness of the flow-blocking plate 12 is greater than the height difference of the bottom surface of the drainage ditch 1 along the width direction.

[0038] During the drainage process of drainage ditch 1, silt and sand enter the auxiliary drainage well 5 through sludge collection trough 11. The thickness of the flow baffle 12 is greater than the height difference along the width of the bottom edge of drainage ditch 1, which allows the water in drainage ditch 1 to flow preferentially into the collection well 2.

[0039] Reference Figure 4 A permeable pipe 31 is inserted into the side of the intercepting ditch 3 away from the foundation pit 10. A plastic film pipe 32 is provided at one end of the permeable pipe 31 located in the intercepting ditch 3. One end of the plastic film pipe 32 is sleeved on the end of the permeable pipe 31 and is secured by cable ties, steel wires or hose clamps.

[0040] The side of the intercepting ditch 3 away from the foundation pit 10 is the water-facing side. By installing a permeable pipe 31 on the side of the intercepting ditch 3 away from the foundation pit 10, surface water extending into the soil from the periphery of the foundation pit 10 can seep into the intercepting ditch 3 through the permeable pipe 31, allowing the intercepting ditch 3 to intercept more surface water. A plastic film pipe 32 is installed at one end of the permeable pipe 31 inside the intercepting ditch 3, which can guide the water in the permeable pipe 31 into the intercepting ditch 3, while preventing the water in the intercepting ditch 3 from flowing back out of the intercepting ditch 3.

[0041] Reference Figure 4 The drain pipe of the top drainage pump 41 is a flexible hose. The top drainage pump 41 is connected in series with a three-way pipe section 42. Two ports of the three-way pipe section 42 are aligned with each other, and the other port is set as a bypass port 421. The two aligned ports of the three-way pipe section 42 are respectively connected in series to the drain pipe of the top drainage pump 41. The bypass port of the three-way pipe section 42 is used to connect to the drain pipe of the drainage pump 21. The bypass port of the three-way pipe section 42 is inclined towards the top drainage pump 41, that is, inclined towards the direction of the foundation pit 10.

[0042] When the drainage pump 21 in the sump drains water through the drainage pipe, it can also drain the water into the drainage pipe of the top drainage pump 41 through the T-joint 42, which facilitates centralized drainage operations.

[0043] ReferenceFigure 4 The top of the foundation pit 10 is provided with a positioning component 8, which is a sheet metal structure. The positioning component 8 includes a bottom plate 81 and two side plates 82. The bottom plate 81 and the two side plates 82 together form a positioning opening 83. The positioning opening 83 is set upward and is used to place the tee pipe section 42. The positioning opening 83 and the two aligned port parts of the tee pipe section 42 form a clearance fit. The positioning opening 83 can keep the bypass port of the tee pipe section 42 in an upward state.

[0044] When the three-way pipe section 42 is placed in the positioning port 83 of the positioning member 8, the bypass port faces upward, making it difficult for the water flow injected into the three-way pipe section 42 by the top drainage pump 41 to enter the bypass port. In order to further reduce the water in the top drainage pump 41 entering the bypass port, a one-way valve can be installed at the bypass port to allow the drainage pipe of the drainage pump 21 to inject water in one direction through the bypass port.

[0045] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A construction method for a basement foundation pit dewatering project, characterized in that, Includes the following steps: When the foundation pit (10) is excavated, a temporary drainage ditch (1) and a sump (2) are set up. The drainage ditch (1) is set up around the bottom of the foundation pit (10). A sump (2) is set up at each corner of the drainage ditch (1). A drainage pump (21) is set up in the sump (2) to pump out the dewatering. The depth of the drainage ditch (1) is more than 300mm lower than the bottom elevation of the foundation pit (10). The depth of the sump (2) is more than 600mm lower than the bottom elevation of the foundation pit (10). The excavation of the foundation pit (10) is gradually deepened. During the excavation of the foundation pit (10), the drainage ditch (1) and the sump (2) are deepened at the same time as the excavation of the foundation pit (10). The deepening of the drainage ditch (1) and the sump (2) is carried out before the excavation of the foundation pit (10). After the slope of the foundation pit (10) is excavated, a water interception ditch (3) and a top drainage well (4) are set at the top of the foundation pit (10). After the foundation pit (10) is excavated to the design elevation, a formal drainage ditch (1) and a collection well (2) are set up on the basis of the temporary drainage ditch (1) and the collection well (2). The drainage ditch (1) and the collection well (2) are hardened. The drainage ditch (1) is set up in a staggered manner with the collection well (2) along its own width direction. The width of the drainage ditch (1) outside the distribution range of the collection well (2) accounts for 5%-10% of the total width of the drainage ditch (1). An auxiliary drainage well (5) is excavated at the corner of the drainage ditch (1). An auxiliary drainage pump (21) is set up in the auxiliary drainage well (5). The auxiliary drainage well (5) is connected to the part of the drainage ditch (1) outside the distribution range of the collection well (2). During the construction inside the foundation pit (10), water was continuously pumped out until the building's own weight exceeded the buoyancy generated by the groundwater.

2. The construction method for a basement foundation pit dewatering project according to claim 1, characterized in that: The bottom of the drainage ditch (1) gradually slopes downwards towards the center of the foundation pit (10) along its width direction, and the auxiliary drainage well (5) is closer to the center of the foundation pit (10) than the water collection well (2); the auxiliary drainage pump (21) in the auxiliary drainage well (5) is a sludge pump (51).

3. The construction method for a basement foundation pit dewatering project according to claim 2, characterized in that: A sludge collection trough (11) is provided at the bottom of the drainage ditch (1) near the auxiliary drainage well (5). The sludge collection trough (11) is connected to the auxiliary drainage well (5) and is located outside the distribution range of the water collection well (2).

4. The construction method for a basement foundation pit dewatering project according to claim 3, characterized in that: The drainage ditch (1) is provided with a flow-blocking plate (12), which partially covers the sludge collection tank (11) from top to bottom. The end of the sludge collection tank (11) is exposed outside the flow-blocking plate (12), and the thickness of the flow-blocking plate (12) is greater than the height difference of the bottom surface of the drainage ditch (1) along the width direction.

5. The construction method for a basement foundation pit dewatering project according to claim 3, characterized in that: A mud pit (6) is provided at the top of the foundation pit (10), and a diversion channel (7) is provided at the top of the foundation pit (10). The diversion channel (7) gradually slopes downward in the direction away from the foundation pit (10). The diversion channel (7) is used to divert the mud and water discharged by the sludge pump (51) to the mud pit (6).

6. The construction method for a basement foundation pit dewatering project according to claim 1, characterized in that: During the excavation of the foundation pit (10), geotextile was laid on the slope of the foundation pit (10), and the geotextile was positioned using positioning anchor rods.

7. The construction method for a basement foundation pit dewatering project according to claim 1, characterized in that: The inner wall of the intercepting ditch (3) is hardened. A permeable pipe (31) is inserted into the side of the intercepting ditch (3) away from the foundation pit (10). A plastic film pipe (32) is provided at one end of the permeable pipe (31) inside the intercepting ditch (3). One end of the plastic film pipe (32) is sleeved on the end of the permeable pipe (31) and tied tightly.

8. The construction method for a basement foundation pit dewatering project according to claim 7, characterized in that: A top drainage pump (41) is installed in the top drainage well (4). The drainage pipe of the top drainage pump (41) is a flexible hose. A three-way pipe section (42) is connected in series to the top drainage pump (41). Two ports of the three-way pipe section (42) are connected in series to the drainage pipe of the top drainage pump (41), and the other port is used to connect to the drainage pipe of the drainage pump (21).

9. A construction method for a basement foundation pit dewatering project according to claim 8, characterized in that: The port of the three-way pipe section (42) connected to the drainage pump (21) is a bypass port, and the bypass port of the three-way pipe section (42) is inclined toward the top drainage pump (41).

10. A construction method for a basement foundation pit dewatering project according to claim 9, characterized in that: The top of the pit (10) is provided with a positioning component (8), which has a positioning port (83) for placing a three-way pipe section (42). The positioning port (83) is set upward, and the positioning port (83) can keep the bypass port of the three-way pipe section (42) in an upward state.

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