Foundation pit inner bottom plate dewatering structure and construction method

Abstract

The invention relates to the technical field of civil engineering, in particular to a foundation pit inner bottom plate dewatering structure and a construction method.The foundation pit inner bottom plate dewatering structure comprises a bottom plate, a steel pipe is installed in the bottom plate, a water collecting well is arranged at the bottom of the bottom plate, galvanized pipes are arranged in the water collecting well and the bottom plate, and the galvanized pipes penetrate through the bottom plate into the water collecting well; the top of the surface of the galvanized pipe is fixedly connected with a mantle fiber, and a steel plate water stop ring is fixedly arranged on the surface of the galvanized pipe. According to the cleaning device, a sliding plate is driven by a driven rod to move up and down in a reciprocating mode, when sundries are wound around a third rotating rod, a cutter can cut off the sundries, the situation that the sundries influence operation of the third rotating rod is avoided, when the water suction pump pumps sewage in a foundation pit, solid objects enter the water suction pump, and blocking is avoided; and the situation that the water suction pump is blocked due to the fact that the third rotating rod cannot rotate due to the fact that sundries are wound on the third rotating rod is avoided, and use of the water suction pump is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to a bottom plate dewatering structure in a foundation pit and a construction method thereof. Background Art

[0002] Civil engineering is a general term for the science and technology of building various types of engineering facilities. It refers to the materials and equipment used and the technical activities such as survey, design, construction, maintenance and repair carried out; it also refers to the object of engineering construction, that is, various engineering facilities built above or below the ground, on land or in water, which directly or indirectly serve human life, production, military affairs, and scientific research.

[0003] However, when working in the foundation pit, it is usually necessary to drain the groundwater in the pit to facilitate the excavator and manual work in the foundation pit. Most of the existing construction methods directly use water pumps to pump water in the foundation pit. This construction method requires a large number of water pumps, which increases the construction cost. In addition, when the existing water pumps are pumping out the sewage in the foundation pit, solid objects may enter the water pumps and cause blockage. It takes time to clear the water pumps, which reduces the pumping efficiency of the foundation pit. Summary of the invention

[0004] To this end, the present invention provides a foundation pit bottom plate dewatering structure and a construction method to solve the above-mentioned problems.

[0005] The present invention provides the following technical solutions: a bottom plate dewatering structure in a foundation pit, comprising a bottom plate, a steel pipe is installed inside the bottom plate, a water collection well is arranged at the bottom of the bottom plate, a galvanized pipe is arranged inside the water collection well and the bottom plate, the galvanized pipe penetrates the bottom plate to the water collection well, a thread is fixedly connected to the top of the surface of the galvanized pipe, a steel plate water stop ring is fixedly arranged on the surface of the galvanized pipe, a nylon net is arranged on the surface of the galvanized pipe, a water pump is arranged in the pit of the bottom plate, and a fine crushed stone filter layer is filled in the gap formed between the water collection well and the outside of the nylon net; The water pump includes a pump machine, the bottom of the pump machine is fixedly connected to the bottom of the bottom plate pit, the output end of the pump machine is fixedly connected to a first water pumping pipe, the front end of the first water pumping pipe is fixedly connected to a switching pipe, the bottom of the switching pipe is fixedly connected to a second water pumping pipe, and the bottom of the second water pumping pipe is fixedly connected to a first support plate.

[0006] As a preferred solution of the present invention, a trapezoidal box is fixedly connected to the bottom of the first support plate, a sealing plate is fixedly connected to the inclined surface of the trapezoidal box, a first rotating rod is rotatably connected to the inner wall of the trapezoidal box, an impeller is fixedly connected to the surface of the first rotating rod, a second rotating rod is fixedly connected to the right end of the first rotating rod, and a floating plate is fixedly installed on the surface of the trapezoidal box.

[0007] As a preferred solution of the present invention, a first connecting groove is formed through the top of the floating plate, a second connecting groove is formed through the top of the floating plate, the right end of the second rotating rod is fixedly connected to the first bevel gear, the inner wall of the first connecting groove is rotatably connected to the third rotating rod, the surface of the third rotating rod is fixedly connected to the second bevel gear, the first bevel gear and the second bevel gear are meshed, the bottom of the trapezoidal box is fixedly connected to the second support plate, the rear side of the second support plate is fixedly connected to the filter plate, the top of the third rotating rod is fixedly connected to the cam, the surface of the cam is provided with a transmission groove, the top of the floating plate is fixedly connected to the limiting frame, the limiting frame and the inner wall of the second connecting groove are slidably connected to a slide plate, and the bottom of the slide plate is fixedly connected to a tool.

[0008] As a preferred solution of the present invention, a cleaning ring is fixedly connected to the bottom of the third rotating rod, cleaning brushes are fixedly connected to the four sides of the surface of the cleaning ring, and the brush head of the cleaning brush is in contact with the bottom of the filter plate.

[0009] As a preferred solution of the present invention, the distance between the cutter head of the cutter and the third rotating rod is 5 mm.

[0010] As a preferred solution of the present invention, a driven rod is fixedly connected to the left side of the slide plate, and the left end of the driven rod is in contact with the groove wall of the transmission groove.

[0011] As a preferred solution of the present invention, the material of the tool is stainless steel, and the tool is sharpened at one end close to the third rotating rod.

[0012] A construction method for dewatering the bottom plate in a foundation pit, using any of the above-mentioned dewatering structures for the bottom plate in a foundation pit, comprises the following steps: S1, set up a 300×400mm drainage ditch around the outer perimeter of the continuous wall at the top of the foundation pit with a slope of 1%, and set up a 1000×1500×1000mm sedimentation filter well before discharging into the municipal sewage pipeline. After three sedimentations, it is filtered through a mud separator and discharged into the municipal sewage pipeline; S2, during the earthwork excavation stage, a 300×200mm drainage ditch is set around the bottom of the foundation pit. The water collection well originally designed in the drawings is used as a temporary drainage water collection well to divert rainwater and underground seepage into the water collection well. Each water collection well is equipped with a mobile submersible pump to drain water to the drainage ditch on the top of the foundation pit. The water is pumped to the drainage ditch on the ground and enters the sedimentation tank for sedimentation. The drainage ditch is built with lime sand bricks and cement mortar; S3, when the foundation is excavated, a shallow pit with a diameter of 300 cm and a depth of about 20 cm is set at the corner of the foundation as the pumping position for removing water from the foundation in the later stage; S4. The construction site should be equipped with sufficient drainage equipment. A self-priming pump should be installed at the water collection well to pump out the accumulated water in the foundation pit to the intercepting ditch on the top of the foundation pit slope at any time. All sewage discharge should be filtered in the sedimentation tank before being discharged into the municipal pipeline. During the construction process, drainage facilities such as drainage ditches and water collection wells should be checked frequently, and dust and sludge at the bottom of the well should be cleaned in time to ensure the smooth flow of drainage ditches. During the excavation of bored piles, a temporary water collection pit can be dug in the pile hole. After the water is pumped out by a submersible pump, excavation can be started immediately after the power is turned off; S5, a precipitation well is set every 30 to 40 meters along the drainage ditch at the bottom of the foundation pit, with a total of 18 wells. Considering the potential leakage risk after the precipitation well is blocked in the later stage, the precipitation well is set in the original water collection well of the basement floor; S6. After the excavation of the bottom plate water collection well, the cushion layer is poured. A hole is drilled or manually excavated in the lower soil layer in the middle part of the water collection well with a water drill. The hole diameter is 200mm. A galvanized pipe is installed inside. The well depth is 800-1000cm below the bottom of the water collection well foundation pit. The top of the galvanized pipe extends 200mm from the bottom of the water collection well. A thread is reserved on the top of the pipe for later pipe opening plugging. A steel plate water stop ring is set 200mm below the bottom of the water collection well. The bottom of the galvanized pipe extends into the soil layer. A hole with a diameter of 20mm is opened on the pipe wall. A layer of nylon mesh is wrapped on the outside of the pipe for filtration. A 5mm fine crushed stone filter layer is backfilled on the outside of the pipe. The filter material is evenly lowered along the four sides of the well pipe. S7, pre-buried steel pipes at a height of 150 to 250 mm from the bottom plate surface to connect all the water collection wells in the negative third floor bottom plate, and adjacent water collection wells share a water pump.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, the methods proposed in S1-S7 can reinforce the soil at the bottom of the foundation pit, improve the strength of the soil at the bottom of the pit, reduce the uplift of the bottom of the pit and the deformation of the maintenance structure, prevent excessive settlement of the surface outside the pit, drain the groundwater in the pit, and facilitate the construction work of excavators and manual labor in the foundation pit.

[0014] 2. In the present invention, water drives the impeller to rotate, so that the impeller drives the first rotating rod to rotate, so that the first rotating rod drives the second rotating rod to rotate, so that the first bevel gear rotates, thereby driving the second bevel gear to rotate, so that the third rotating rod at the bottom rotates, thereby driving the filter plate and the cleaning brush to rotate, and the solid matter adsorbed on the filter plate is swept off, and the slide plate is driven up and down by the driven rod to reciprocate. When debris is entangled on the third rotating rod, the cutter can cut off the debris to avoid the debris from affecting the operation of the third rotating rod. When the water pump extracts sewage in the foundation pit, solid objects will not enter the water pump to cause blockage. When the cleaning brush is in use, debris is not easy to be entangled on the third rotating rod, causing the third rotating rod to be unable to rotate, thereby causing blockage in the water pump, which is convenient for the use of the water pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the bottom plate dewatering construction method in the foundation pit of the present invention; Figure 2 It is a schematic diagram of the bottom plate dewatering structure in the foundation pit of the present invention; Figure 3 It is a schematic diagram of the structure of the sedimentation tank in the present invention; Figure 4 It is a schematic diagram of the lower drainage ditch structure in the present invention; Figure 5 It is a schematic diagram of the upper drainage ditch structure in the present invention; Figure 6 It is a schematic diagram of the support structure in the present invention; Figure 7 It is a schematic diagram of the structure of the water pump in the present invention; Figure 8 For the present invention Figure 7 Schematic diagram of the local structure of the water pump; Fig. 9 For the present invention Figure 8 Schematic diagram of the local structure of the water pump; Fig.10 For the present invention Fig. 9 Schematic diagram of the local structure of the water pump; Fig.11 It is a schematic diagram of the impeller structure in the present invention; Fig.12 For the present invention Fig. 9 A magnified view of the structure at A; Fig.13 For the present invention Fig.10 Enlarged view of the structure at B in the figure.

[0016] In the figure: 1, water pump; 2, steel pipe; 3, bottom plate; 4, galvanized pipe; 5, thread; 6, steel plate water stop ring; 7, water collection well; 8, nylon net; 9, fine crushed stone filter layer; 101, pump; 102, first water pumping pipe; 103, transfer pipe; 104, second water pumping pipe; 105, first support plate; 106, trapezoidal box; 107, floating plate; 108, second support plate; 109, filter plate; 110 , cleaning brush; 111, sealing plate; 112, impeller; 113, first rotating rod; 114, second rotating rod; 115, first bevel gear; 116, third rotating rod; 117, second bevel gear; 118, limit frame; 119, slide plate; 120, driven rod; 121, cam; 122, transmission groove; 123, first connecting groove; 124, tool; 125, second connecting groove; 126, cleaning ring. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-13 The technical solution provided by the present invention specifically includes the following embodiments: Embodiment 1: A bottom plate dewatering structure in a foundation pit, comprising a bottom plate 3, a steel pipe 2 is installed inside the bottom plate 3, a water collection well 7 is provided at the bottom of the bottom plate 3, a galvanized pipe 4 is provided inside the water collection well 7 and the bottom plate 3, the galvanized pipe 4 penetrates the bottom plate 3 to the water collection well 7, a sleeve thread 5 is fixedly connected to the top of the surface of the galvanized pipe 4, a steel plate water stop ring 6 is fixedly provided on the surface of the galvanized pipe 4, a nylon mesh 8 is provided on the surface of the galvanized pipe 4, a water pump 1 is provided in the pit of the bottom plate 3, and a fine crushed stone filter layer 9 is filled in the gap formed between the water collection well 7 and the outside of the nylon mesh 8; The water pump 1 includes a pump 101, the bottom of the pump 101 is fixedly connected to the bottom of the pit in the bottom plate 3, the output end of the pump 101 is fixedly connected to a first water pumping pipe 102, the front end of the first water pumping pipe 102 is fixedly connected to a transfer pipe 103, the bottom of the transfer pipe 103 is fixedly connected to a second water pumping pipe 104, and the bottom of the second water pumping pipe 104 is fixedly connected to a first support plate 105; the bottom of the first support plate 105 is fixedly connected to a trapezoidal box 106, and the inclined surface of the trapezoidal box 106 is fixed The inner wall of the trapezoidal box 106 is rotatably connected with a first rotating rod 113, the surface of the first rotating rod 113 is fixedly connected with an impeller 112, the right end of the first rotating rod 113 is fixedly connected with a second rotating rod 114, and the surface of the trapezoidal box 106 is fixedly installed with a floating plate 107; the top of the floating plate 107 is penetrated with a first connecting groove 123, the top of the floating plate 107 is penetrated with a second connecting groove 125, the right end of the second rotating rod 114 is fixedly connected with a first bevel gear 115, and the second connecting groove 126 is fixedly connected with a first bevel gear 115. The inner wall of a connecting groove 123 is rotatably connected to a third rotating rod 116, the surface of the third rotating rod 116 is fixedly connected to a second bevel gear 117, the first bevel gear 115 and the second bevel gear 117 are meshed, the bottom of the trapezoidal box 106 is fixedly connected to a second support plate 108, the rear side of the second support plate 108 is fixedly connected to a filter plate 109, the top of the third rotating rod 116 is fixedly connected to a cam 121, the surface of the cam 121 is provided with a transmission groove 122, the top of the floating plate 107 is fixedly connected to The limiting frame 118 is slidably connected with a slide plate 119 on the inner wall of the limiting frame 118 and the second connecting groove 125, and a cutter 124 is fixedly connected to the bottom of the slide plate 119; a cleaning ring 126 is fixedly connected to the bottom of the third rotating rod 116, and a cleaning brush 110 is fixedly connected to the surface of the cleaning ring 126 all around, and the brush head of the cleaning brush 110 contacts the bottom of the filter plate 109; a driven rod 120 is fixedly connected to the left side of the slide plate 119, and the left end of the driven rod 120 contacts the groove wall of the transmission groove 122; Water is pumped by the pump 101, and the water is first filtered from the filter plate 109 and enters the trapezoidal box 106. At this time, the water drives the impeller 112 to rotate, so that the impeller 112 drives the first rotating rod 113 to rotate, so that the first rotating rod 113 drives the second rotating rod 114 to rotate, so that the first bevel gear 115 rotates, thereby driving the second bevel gear 117 to rotate, so that the third rotating rod 116 at the bottom rotates, thereby driving the filter plate 109 and the cleaning brush 110 to rotate, and the solid matter adsorbed on the filter plate 109 is swept off. When the third rotating rod 116 rotates, the transmission groove 122 rotates synchronously , so that the cam 121 drives the driven rod 120 to move, and then through the limit of the set limit frame 118, the driven rod 120 drives the slide plate 119 to reciprocate up and down. When there are debris wrapped around the third rotating rod 116, the cutter 124 can cut off the debris to prevent the debris from affecting the operation of the third rotating rod 116. When the water pump 1 is pumping out sewage in the foundation pit, no solid objects will enter the water pump 1 to cause blockage. When the cleaning brush 110 is in use, the debris is not easy to be wrapped around the third rotating rod 116, causing the third rotating rod 116 to be unable to rotate, thereby causing the water pump 1 to be blocked, which is convenient for the use of the water pump 1; The cam 121 can be defined as a component with a curved surface or a curved groove. By swinging or rotating the cam 121, another component, the follower, can provide a predetermined movement. The path of the follower is mostly confined within a slide groove to obtain reciprocating motion.

[0019] The distance between the cutter head of the cutter 124 and the third rotating rod 116 is 5 mm. The cutter 124 is made of stainless steel, and one end of the cutter 124 close to the third rotating rod 116 is sharpened.

[0020] Embodiment 2: A construction method for dewatering the bottom plate in a foundation pit, using any dewatering structure for the bottom plate in a foundation pit, comprising the following steps: S1, set up a 300×400mm drainage ditch around the outer perimeter of the continuous wall at the top of the foundation pit with a slope of 1%, and set up a 1000×1500×1000mm sedimentation filter well before discharging into the municipal sewage pipeline. After three sedimentations, it is filtered through a mud separator and discharged into the municipal sewage pipeline; S2, during the earthwork excavation stage, a 300×200mm drainage ditch is set around the bottom of the foundation pit. The water collection well originally designed in the drawings is used as a temporary drainage water collection well to divert rainwater and underground seepage into the water collection well. Each water collection well is equipped with a mobile submersible pump to drain water to the drainage ditch on the top of the foundation pit. The water is pumped to the drainage ditch on the ground and enters the sedimentation tank for sedimentation. The drainage ditch is built with lime sand bricks and cement mortar; S3, when the foundation is excavated, a shallow pit with a diameter of 300 cm and a depth of about 20 cm is set at the corner of the foundation as the pumping position for removing water from the foundation in the later stage; S4. The construction site should be equipped with sufficient drainage equipment. A self-priming pump should be installed at the water collection well to pump out the accumulated water in the foundation pit to the intercepting ditch on the top of the foundation pit slope at any time. All sewage discharge should be filtered in the sedimentation tank before being discharged into the municipal pipeline. During the construction process, drainage facilities such as drainage ditches and water collection wells 7 should be checked frequently, and dust and sludge at the bottom of the well should be cleaned in time to ensure the smooth flow of drainage ditches. During the excavation of bored piles, a temporary water collection pit can be dug in the pile hole. After the water is pumped out by a submersible pump, excavation can be started immediately after the power is turned off; S5, a precipitation well is set every 30 to 40 meters along the drainage ditch at the bottom of the foundation pit, with a total of 18 wells. Considering the potential leakage risk after the precipitation well is blocked in the later stage, the precipitation well is set in the original water collection well of the basement floor; S6, after the excavation of the bottom plate water collection well, the cushion layer is poured, and a hole is drilled or manually excavated in the lower soil layer in the middle part of the water collection well 7 with a water drill, the hole diameter is 200mm, and a galvanized pipe 4 is installed inside. The well depth is 800-1000cm below the bottom of the foundation pit of the water collection well 7. The top of the galvanized pipe 4 extends 200mm from the bottom of the water collection well 7. A thread 5 is reserved on the top of the pipe for later pipe opening plugging. A steel plate water stop ring 6 is set 200mm below the bottom of the water collection well 7. A hole with a diameter of 20mm is opened on the wall of the part of the pipe where the bottom of the galvanized pipe 4 extends into the soil layer. A layer of nylon mesh 8 is wrapped on the outside of the pipe for filtration. A fine crushed stone filter layer 9 with a particle size of 5mm is backfilled on the outside of the pipe, and the filter material is evenly lowered along the four sides of the well pipe; S7, pre-buried steel pipe 2 at a height of 150-250mm from the floor surface, connecting all the water collection wells in the negative third floor floor 3, and adjacent water collection wells share a water pump 1; Use deep well submersible pumps, which are configured according to the number of actual drainage wells. The pump head is 30m. Before installation, a comprehensive inspection of the pump and control system must be carried out to prevent power outages. A 200-kilowatt generator is planned to ensure 24-hour uninterrupted pumping and drainage. During the construction of this project, the groundwater level should be artificially lowered to no higher than 0.5m below the lowest point of the foundation pit; the basement foundation pit dewatering of this project should be carried out until the 15th floor is poured and the basement top slab backfilling is completed, the garage ground cushion is completed and the bottom slab post-casting belt is poured to reach the design strength, and the basement bottom slab is completely closed, then the basement construction dewatering can be stopped; During the precipitation period, the groundwater level changes and the settlement and displacement of surrounding buildings, underground pipelines and other municipal facilities should be detected. When excavating the foundation pit, attention should be paid to the stability of the slope. If any abnormal phenomenon is found, it should be reported in time; Regularly inspect the operation of the drainage system, promptly discover and deal with system operation failures and hidden dangers, promptly repair water pumps, and check the sand content of the discharged water and whether the drainage connection pipes are unobstructed; Observe the water level and observation frequency as required. After pumping begins, before the water level reaches the designed precipitation depth, observe the water level and water volume three times a day. When the water level reaches the designed water level and tends to be stable, observe once a day. In the rainy season, observe 2 to 3 times a day. After the precipitation stops, reliable sealing measures should be taken for the precipitation pipe wells. The sealing time for this project is when the tower is built to the 15th floor and the outdoor covering is completed, and the construction of the first floor of the pure basement is completed and the outdoor covering is completed; When the conditions for stopping precipitation are met and the conditions for sealing the well are met, the water pump will pump out the accumulated water in the collection well, the deep water pump will pump out the accumulated water in the precipitation well, clean up the garbage and debris in the precipitation well, and fill it densely with expansive concrete that is one grade higher than the base slab concrete.

[0021] The present scheme provides a bottom plate dewatering structure and construction method in a foundation pit. Through the methods proposed in S1-S7, the soil at the bottom of the foundation pit can be reinforced, the strength of the soil at the bottom of the pit can be improved, the bulge of the bottom of the pit and the deformation of the maintenance structure can be reduced, excessive surface settlement outside the pit can be prevented, the groundwater in the pit can be drained, and construction work by excavators and manual labor in the foundation pit can be facilitated. When the water pump 1 is in use, water is pumped through the pump 101, and the water is first filtered from the filter plate 109 and enters the trapezoidal box 106. At this time, the water will drive the impeller 112 to rotate, so that the impeller 112 drives the first rotating rod 113 to rotate, and the first rotating rod 113 drives the second rotating rod 114 to rotate, so that the first bevel gear 115 rotates, thereby driving the second bevel gear 117 to rotate, and the third rotating rod 116 at the bottom rotates, thereby driving the filter plate 109 and The cleaning brush 110 rotates to sweep off the solid matter adsorbed on the filter plate 109. When the third rotating rod 116 rotates, the transmission groove 122 rotates synchronously, so that the cam 121 drives the driven rod 120 to move, and then through the limit of the set limit frame 118, the driven rod 120 drives the slide plate 119 to reciprocate up and down. When there are debris wrapped around the third rotating rod 116, the tool 124 can cut off the debris to prevent the debris from affecting the operation of the third rotating rod 116. When the water pump 1 is pumping out sewage in the foundation pit, solid objects will not enter the water pump 1 to cause blockage. When the cleaning brush 110 is in use, debris is not easy to be wrapped around the third rotating rod 116, causing the third rotating rod 116 to be unable to rotate, thereby causing blockage of the water pump 1, which is convenient for the use of the water pump 1.

[0022] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A bottom plate dewatering structure in a foundation pit, characterized in that: It comprises a bottom plate (3), a steel pipe (2) is installed inside the bottom plate (3), a water collection well (7) is provided at the bottom of the bottom plate (3), a galvanized pipe (4) is provided inside the water collection well (7) and the bottom plate (3), the galvanized pipe (4) passes through the bottom plate (3) to the water collection well (7), a thread (5) is fixedly connected to the top of the surface of the galvanized pipe (4), a steel plate water stop ring (6) is fixedly provided on the surface of the galvanized pipe (4), a nylon mesh (8) is provided on the surface of the galvanized pipe (4), a water pump (1) is provided in the pit of the bottom plate (3), and a fine crushed stone filter layer (9) is filled in the gap formed by the inside of the water collection well (7) and the outside of the nylon mesh (8); The water pump (1) comprises a pump (101), the bottom of the pump (101) being fixedly connected to the bottom of a pit in a bottom plate (3), the output end of the pump (101) being fixedly connected to a first water pumping pipe (102), the front end of the first water pumping pipe (102) being fixedly connected to a transfer pipe (103), the bottom of the transfer pipe (103) being fixedly connected to a second water pumping pipe (104), and the bottom of the second water pumping pipe (104) being fixedly connected to a first support plate (105).

2. A foundation pit floor dewatering structure according to claim 1, characterized in that: The bottom of the first support plate (105) is fixedly connected to a trapezoidal box (106), the inclined surface of the trapezoidal box (106) is fixedly connected to a sealing plate (111), the inner wall of the trapezoidal box (106) is rotatably connected to a first rotating rod (113), the surface of the first rotating rod (113) is fixedly connected to an impeller (112), the right end of the first rotating rod (113) is fixedly connected to a second rotating rod (114), and a floating plate (107) is fixedly mounted on the surface of the trapezoidal box (106).

3. A foundation pit floor dewatering structure according to claim 2, characterized in that: A first connecting groove (123) is formed through the top of the floating plate (107), a second connecting groove (125) is formed through the top of the floating plate (107), a first bevel gear (115) is fixedly connected to the right end of the second rotating rod (114), a third rotating rod (116) is rotatably connected to the inner wall of the first connecting groove (123), a second bevel gear (117) is fixedly connected to the surface of the third rotating rod (116), the first bevel gear (115) and the second bevel gear (117) are meshed, and the trapezoidal box (106) is A second support plate (108) is fixedly connected to the bottom, a filter plate (109) is fixedly connected to the rear side of the second support plate (108), a cam (121) is fixedly connected to the top of the third rotating rod (116), a transmission groove (122) is provided on the surface of the cam (121), a limit frame (118) is fixedly connected to the top of the floating plate (107), a slide plate (119) is slidably connected between the limit frame (118) and the inner wall of the second connection groove (125), and a cutter (124) is fixedly connected to the bottom of the slide plate (119).

4. A foundation pit floor dewatering structure according to claim 3, characterized in that: A cleaning ring (126) is fixedly connected to the bottom of the third rotating rod (116), and cleaning brushes (110) are fixedly connected to the four sides of the surface of the cleaning ring (126), and the brush head of the cleaning brush (110) is in contact with the bottom of the filter plate (109).

5. The bottom plate dewatering structure in a foundation pit according to claim 3, characterized in that: The distance between the cutter head of the cutter (124) and the third rotating rod (116) is 5 mm.

6. A foundation pit floor dewatering structure according to claim 3, characterized in that: A driven rod (120) is fixedly connected to the left side of the slide plate (119), and the left end of the driven rod (120) is in contact with the groove wall of the transmission groove (122).

7. The bottom plate dewatering structure in a foundation pit according to claim 3, characterized in that: The knife (124) is made of stainless steel, and one end of the knife (124) close to the third rotating rod (116) is sharpened.

8. A construction method for dewatering the bottom plate in a foundation pit, using the dewatering structure for the bottom plate in a foundation pit according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, set up a 300×400mm drainage ditch around the outer perimeter of the continuous wall at the top of the foundation pit with a slope of 1%, and set up a 1000×1500×1000mm sedimentation filter well before discharging into the municipal sewage pipeline. After three sedimentations, it is filtered through a mud separator and discharged into the municipal sewage pipeline; S2, during the earthwork excavation stage, a 300×200mm drainage ditch is set around the bottom of the foundation pit. The water collection well originally designed in the drawings is used as a temporary drainage water collection well to divert rainwater and underground seepage into the water collection well. Each water collection well is equipped with a mobile submersible pump to drain water to the drainage ditch on the top of the foundation pit. The water is pumped to the drainage ditch on the ground and enters the sedimentation tank for sedimentation. The drainage ditch is built with lime sand bricks and cement mortar; S3, when the foundation is excavated, a shallow pit with a diameter of 300 cm and a depth of about 20 cm is set at the corner of the foundation as the pumping position for removing water from the foundation in the later stage; S4. Sufficient drainage equipment should be provided at the construction site. A self-priming pump should be installed at the water collection well to pump out the accumulated water in the foundation pit to the intercepting ditch on the top of the foundation pit slope at any time. All sewage discharge should be filtered in the sedimentation tank before being discharged into the municipal pipeline. During the construction process, drainage ditches and water collection wells (7) and other drainage facilities should be checked frequently, and dust and sludge at the bottom of the well should be cleaned in time to ensure the smooth flow of drainage ditches. During the excavation of bored piles, a temporary water collection pit can be dug in the pile hole. After the water is pumped out by a submersible pump, excavation can be started immediately after the power is turned off. S5, a precipitation well is set every 30 to 40 meters along the drainage ditch at the bottom of the foundation pit, with a total of 18 wells. Considering the potential leakage risk after the precipitation well is blocked in the later stage, the precipitation well is set in the original water collection well of the basement floor; S6, after the excavation of the bottom plate water collection well, the cushion layer is poured, and a hole is drilled or manually excavated in the lower soil layer in the middle part of the water collection well (7) with a water drill, and the hole diameter is 200mm. A galvanized pipe (4) is installed inside. The well depth is 800-1000cm below the bottom of the foundation pit of the water collection well (7). The top of the galvanized pipe (4) extends 200mm from the bottom of the water collection well (7). A thread (5) is reserved on the top of the pipe for later pipe opening plugging. A steel plate water stop ring (6) is set 200mm below the bottom of the water collection well (7). A hole with a diameter of 20mm is opened in the wall of the part of the galvanized pipe (4) extending into the soil layer. A layer of nylon mesh (8) is wrapped on the outside of the pipe for filtering. A fine crushed stone filter layer (9) with a particle size of 5mm is backfilled on the outside of the pipe. The filter material is evenly lowered along the four sides of the well pipe; S7, pre-buried steel pipes (2) at a height of 150 to 250 mm from the floor surface, connecting all the water collection wells in the negative third floor floor (3), and adjacent water collection wells share a water pump (1).

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