Construction method of foundation pit intelligent controlled dewatering system

Abstract

This application relates to a construction method for an intelligent controlled dewatering system for foundation pits. The solution includes S00: arranging the dewatering wells in the foundation pit; S10: lowering the steel casing of the dewatering wells; S20: sealing the dewatering well pipes; S30: constructing the dewatering wells through the bottom slab; S40: remote intelligent dewatering control; S50: constructing the post-casting strip of the dewatering wells through the bottom slab; and S60: sealing the dewatering wells through the bottom slab. This application provides multiple convenient construction structures to accelerate construction efficiency.

Description

Technical Field

[0001] The present application relates to the field of construction engineering technology, and in particular to a construction method of an intelligent controlled dewatering system for a foundation pit. Background Art

[0002] Dewatering wells are an effective means of controlling water levels in foundation pits. Dewatering wells, through the structure of the wellbore and well wall, draw groundwater into the well and then drain it out through pipes within the well, thereby achieving the purpose of dewatering the foundation pit. However, dewatering wells present some practical challenges.

[0003] First, the dewatering operation of dewatering wells is very cumbersome. During foundation pit construction, dewatering wells often require frequent desilting, maintenance, and overhaul. Because dewatering wells are located deep within the foundation pit, operating space is limited and the environment is complex. Furthermore, the constantly fluctuating water level in the foundation pit requires constant adjustment of the dewatering volume, which increases the operational complexity.

[0004] Secondly, it is also very difficult to construct a dewatering well through the base plate. During foundation pit construction, a thick base plate is laid at the bottom of the pit to ensure the stability of the project. When crossing the base plate through the dewatering well, the base plate needs to be excavated and reinforced, which will affect the stability of the project. In addition, when the dewatering well passes through the base plate, the integrity of the wellbore and well wall must be ensured to avoid safety issues such as groundwater leakage and well collapse.

[0005] Therefore, there is an urgent need for a construction method of an intelligent controlled dewatering system for foundation pits, providing a set of intelligent dewatering systems for foundation pits and a variety of auxiliary structures for foundation pit crossing bottom plates to ensure the integrity of the dewatering well shaft wall and the foundation pit bottom plate during the construction of the foundation pit crossing bottom plate, while greatly reducing the difficulty of foundation pit dewatering operations and having good technical benefits.

[0006] Application Contents

[0007] The purpose of this application is to address the above-mentioned problems existing in the prior art and to provide a construction method for an intelligent controlled dewatering system for a foundation pit.

[0008] In order to achieve the above application objectives, this application adopts the following technical solutions: The construction method of the foundation pit intelligent controlled dewatering system includes the following steps:

[0009] S00. Layout of dewatering wells in foundation pits: Avoid setting up dewatering wells near subway areas and existing structures. Set up dewatering wells inside the foundation pit and outside the foundation pit away from structures. The wells at these dewatering wells will serve as both drainage wells and emergency wells outside the pit.

[0010] S10. Lowering the steel casing of the dewatering well: Drive the steel casing into the soil and install the steel pipe concentrically with the steel casing;

[0011] Cover the mouth of the steel pipe with the material distribution protection cone, make the outer edge of the feeding tube fit the steel casing, and fill the graded sand and gravel between the steel pipe and the steel casing through the empty slot between the internal support fixed frame;

[0012] After filling is completed, remove the feeding tube and pull out the steel casing;

[0013] S20, Seal the dewatering well pipe: Arrange a layer of wire mesh outside the steel pipe, and then fill it with graded sand and gravel;

[0014] The support rod is fixed by the groove so that the movable rod and the support rod form a corbel bracket;

[0015] Placing the closed ring plate on the corbel bracket to temporarily seal the filling area of the outer wall of the precipitation well;

[0016] S30, remote intelligent control of precipitation: monitor the water level in the precipitation well through the input liquid level sensor;

[0017] When the water level exceeds the liquid level sensor, the wireless transmitter module transmits a wireless signal, the wireless relay receives the wireless signal and controls the AC contactor switch, so that the submersible pump can pump water;

[0018] When the water level in the precipitation well drops below the liquid level sensor, the submersible pump is controlled to stop operating;

[0019] S40. Construction of dewatering well through the bottom plate: Excavate the foundation pit to the designed elevation, clean the foundation pit base, place the steel pipe fixing frame on the outside of the steel pipe to ensure the steel pipe is vertical, fill the lower part of the steel pipe with sand and gravel, and fill the outer part of the steel pipe and the lower part of the foundation pit base with the sand particles of the water filter pipe left when the steel casing was removed (so the steel pipe is in a closed state below the foundation pit base), weld and fix the steel plate on the outer wall of the steel pipe, and lay the foundation pit leveling layer;

[0020] Remove the steel pipe fixing frame, weld and fix the steel plate on the outer wall of the steel pipe, and lay the foundation pit leveling layer;

[0021] A waterproof layer is provided outside the fixed steel plate and the foundation pit leveling layer;

[0022] Apply water-stop putty between the fixed steel plate and the waterproof layer;

[0023] S50, Construction of post-cast strip through the bottom plate of the dewatering well: Install a steel plate on the top of the dewatering well to temporarily seal the dewatering well;

[0024] The steel mold is placed on a steel plate, and a dense mesh is set on the outside of the steel mold;

[0025] Pour the bottom slab concrete and remove the steel mold after the concrete strength reaches the required level;

[0026] S60, Seal the dewatering well through the bottom plate: Install a sealing steel plate at the dewatering well mouth, connect the steel strands and anchors to the bottom of the sealing steel plate, pass the steel strands through the prestressed anchor rods, and fill the cavity of the bottom plate post-cast zone with micro-expansion concrete;

[0027] Then, the weight plate is pressed on the slightly expansive concrete, and the weight block is placed on the weight plate;

[0028] After the micro-expansive concrete hardens and reaches the construction strength, remove the weight block, tension the prestressed steel strands, and lock them with anchors.

[0029] Furthermore, in step S10, the material distribution protection cone is a conical closed structure, the feeding tube is an inverted conical ring, the inner support fixing frame is horizontally welded to the lower edge of the conveying feeding and material distribution protection cone to form a fixed structure, and the lower outer edge of the steel casing is provided with a steel casing reinforcement rib.

[0030] Furthermore, in step S20, the movable rod is fixed by a fixed block and a fixed shaft welded on the outer side of the upper part of the steel pipe, so that the movable rod is hinged to the outer wall of the steel pipe, and the movable rod is hinged to the support rod through the fixed shaft. A groove is also provided on the conveying steel pipe to fix the support rod through the groove.

[0031] Furthermore, in step S30, the steel pipe fixing frame is composed of a fixing frame outer ring, a fixing frame inner ring, a fixing frame inner support rod and a fixing frame vertical rod. The fixing frame outer ring and the fixing frame inner ring are welded to form concentric rings through the fixing frame inner support rod, and the fixing frame vertical rod is vertically welded to the lower part of the fixing frame outer ring.

[0032] Furthermore, in step S40, the liquid level sensor is connected to the wireless transmitting module via a wired connection, the submersible pump is connected to the delivery AC contactor via a wired connection, and the wireless relay is connected via a wired connection and controls the AC contactor switch.

[0033] Furthermore, an independently provided power supply supplies power to the wireless transmitting module, the wireless relay and the AC contactor.

[0034] Furthermore, in step S50, the steel mold is composed of a side template and a bottom template to form a coverless box body, and a diagonal support fixing block is provided on the upper edge of the interior of the box body, and the notch of the diagonal support fixing block fixes the diagonal support rod inside the box body.

[0035] Compared with the prior art, this application has the following beneficial effects:

[0036] 1. The structure involved in this application can solve the construction problem of the intelligent control dewatering system of the foundation pit, and has good technical benefits; it adopts the optimization layout technology of dewatering of the foundation pit near the subway, solves the layout problem of the dewatering well near the subway and buildings, and optimizes the layout of the dewatering well; adopts the synchronous construction technology of dewatering pipe wells and aggregated sand and gravel vibration pipe sinking to improve the efficiency of the external filling material of the dewatering well steel pipe; uses the self-expanding steel pipe of the dewatering well pipe to reuse the pipe mouth technology, solves the problem of temporary closure of the dewatering well pipe well mouth, and improves the material utilization rate.

[0037] 2. This application adopts a precise adjustment and fixing bracket for the enclosed outer steel pipe through the bottom plate of the precipitation well, which solves the problem of vertical precision control of the outer steel pipe when the precipitation well passes through the bottom plate, and improves the accuracy of the outer steel pipe installation;

[0038] 3. This application adopts remote intelligent control dewatering technology to solve the problem of constantly changing water levels in dewatering wells and the tedious and difficult operation of artificial dewatering; adopts steel molds and fine mesh reserved post-casting strip technology to solve the problem of reserving post-casting strips of foundation pit bottom plate; adopts closed steel plate prestressed tensioning technology and micro-expansion concrete weight filling technology to solve the problem of closing the bottom plate after dewatering is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a construction diagram of the optimized layout technology for dewatering of the subway foundation pit;

[0040] Figure 2 This is a schematic diagram of the technical structure of the simultaneous construction of the dewatering pipe well and the sand and gravel collection and vibration sinking pipe;

[0041] Figure 3 It is a schematic diagram of the steel pipe and steel sleeve structure;

[0042] Figure 4 1. It is a top view of the material distribution device;

[0043] Figure 5 It is a schematic diagram of customized steel pipe structure;

[0044] Figure 6 yes Figure 5 A magnified view of middle A;

[0045] Figure 7 This is a schematic diagram of the technical structure of the self-expanding steel pipe reuse nozzle of the precipitation well;

[0046] Figure 8 This is a construction diagram of a precise adjustment and fixing bracket for a dewatering well with a closed outer jacket steel pipe passing through the bottom plate;

[0047] Figure 9 This is a schematic diagram of the structure of the precise adjustment and fixing bracket of the enclosed outer jacket steel pipe through the bottom plate of the dewatering well;

[0048] Figure 10This is a schematic diagram of the precise adjustment of the fixed bracket layout for the enclosed outer jacket steel pipe through the bottom plate of the dewatering well;

[0049] Figure 11 This is a schematic diagram of the dewatering well after construction through the bottom plate;

[0050] Figure 12 It is a schematic diagram of remote intelligent precipitation control technology;

[0051] Figure 13 This is a schematic diagram of the construction technology of steel molds and dense mesh to reserve post-casting strips;

[0052] Figure 14 It is a schematic diagram of the steel mold structure;

[0053] Figure 15 It is a cross-sectional view of the steel mold structure;

[0054] Figure 16 This is a construction diagram of the closed steel plate prestressed tensioning technology and the micro-expansion concrete weight filling technology;

[0055] Figure 17 This is a detailed diagram of the construction of closed steel plate prestressed tension technology and micro-expansion concrete weight filling technology;

[0056] Figure 18 This is the construction flow chart for this application.

[0057] In the figure, 1. Area near the subway; 2. Area of existing structures; 3. Location of dewatering wells inside the foundation pit; 4. Location of dewatering wells outside the foundation pit; 5. Steel pipe; 6. Steel casing; 7. Steel casing reinforcement ribs; 8. Feeding tube; 9. Material separation protection cone; 10. Internal support bracket; 11. Fixed block; 12. Fixed shaft; 13. Groove; 14. Movable rod; 15. Support rod; 16. Closed ring plate; 17. Wire mesh; 18. Graded sand and gravel; 19. Steel pipe bracket; 20. Outer ring of bracket; 21. Inner ring of bracket; 22. Inner support rod of bracket; 23. Vertical rod of bracket; 24. Waterproof layer; 25. Leveling layer of foundation pit; 2 6. Sand for filter well pipe; 27. Fine mesh; 28. Steel mold; 29. Side formwork; 30. Bottom formwork; 31. Diagonal brace; 32. Diagonal brace fixed block; 33. Enclosed steel plate; 34. Steel strand; 35. Anchor; 36. Micro-expansive concrete; 37. Ballast plate; 38. Ballast block; 39. Prestressed anchor; 40. Submersible liquid level sensor; 41. Submersible pump; 42. Wireless transmitter module; 43. Power supply; 44. Wireless relay; 45. AC contactor; 46. Bottom plate concrete; 47. Water-stop putty; 48. Fixed steel plate; 49. Steel plate; 50. Sand and gravel; 51. Foundation pit base surface. DETAILED DESCRIPTION

[0058] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0059] Those skilled in the art should understand that, in the disclosure of this application, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms cannot be understood as limiting this application.

[0060] like Figure 1 , the optimization layout technology of dewatering near the subway foundation pit, the location of the dewatering well is set to avoid the area 1 near the subway and the area 2 near the existing structure. At the same time, the dewatering well point 3 is set inside the foundation pit, and the dewatering well point 4 is set outside the foundation pit away from the structural area. The well at the dewatering well point 4 outside the foundation pit is used as a dewatering well and also as an emergency well outside the pit.

[0061] like Figure 2 — Figure 4 The synchronous construction technology of the dewatering pipe well and the sand and gravel vibration sinking pipe is adopted. The material distribution protection cone 9 is a conical closed structure, the feeding barrel is an inverted conical ring, and the internal support fixing frame 10 is horizontally welded to the feeding barrel 8 and the lower edge of the material distribution protection cone 9 to form a fixed structure. The lower outer edge of the steel casing 6 is provided with a steel casing reinforcement rib 7.

[0062] like Figure 5 — Figure 7 The self-expanding steel pipe of the precipitation well reuses the pipe mouth technology. A layer of wire mesh 17 is arranged outside the steel pipe 5, and then filled with graded sand and gravel 18. The movable rod 14 is fixed by the fixed block 11 and the fixed shaft 12 welded on the outer side of the upper part of the steel pipe 5, so that the movable rod 14 is hinged to the outer wall of the steel pipe 5. Similarly, the movable rod 14 and the support rod 15 are also hinged through the fixed shaft 12. A groove 13 is also provided on the steel pipe 5, and the support rod 15 is fixed by the groove 13, so that the movable rod 14 and the support rod 15 form a corbel bracket, and the closed ring plate 16 is placed on the corbel bracket to realize the temporary closure of the filling area of the outer wall of the precipitation well.

[0063] like Figure 8 — Figure 11The dewatering well passes through the bottom plate to close the outer jacket steel pipe and accurately adjust the fixing bracket. The steel pipe fixing frame 19 is composed of a fixing frame outer ring 20, a fixing frame inner ring 21, a fixing frame inner support rod 22 and a fixing frame vertical rod 23. The fixing frame outer ring 20 and the fixing frame inner ring 21 are concentric rings welded and fixed by the fixing frame inner support rod 22, and the fixing frame vertical rod 23 is vertically welded to the lower part of the fixing frame outer ring 20.

[0064] like Figure 12 , remote intelligent control precipitation technology, the immersion liquid level sensor 40 is wired to the wireless transmitting module 42, the submersible pump 41 is wired to the AC contactor 45, the wireless relay 44 is wired to control the switch of the AC contactor 45, and the independently set power supply 43 supplies power to the wireless transmitting module 42, the wireless relay 44 and the AC contactor 45.

[0065] like Figure 13 — Figure 15 The steel mold and the dense mesh reserve post-casting strip technology, the steel mold 28 is composed of a side template 29 and a bottom template 30 to form an uncovered box, the upper edge of the box is provided with a diagonal support fixed block 32, the diagonal support fixed block 32 notch fixes the diagonal support rod 31 inside the box.

[0066] like Figure 16 — Figure 17 The closed steel plate prestressing and micro-expansive concrete weight filling technology uses a closed steel plate 33 installed at the dewatering wellhead. A steel strand 34 and anchor 35 are connected to the lower portion of the closed steel plate 33. The steel strand 34 passes through a prestressed anchor rod 39, and the cavity in the base plate post-cast zone is filled with micro-expansive concrete 36. A weight plate 37 is then pressed against the micro-expansive concrete 36, and a weight block 38 is placed on the weight plate 37. After the micro-expansive concrete 36 hardens and reaches the construction strength, the steel strand 34 is prestressed and locked with an anchor 35. The weighting improves the setting efficiency of the micro-expansive concrete 36, while the prestressing ensures that the dewatering well construction area on the base plate is permanently sealed.

[0067] like Figure 18 As shown, the construction method of the foundation pit intelligent controlled dewatering system includes S00, arrangement of foundation pit dewatering well points: avoid setting dewatering well points in the area 1 adjacent to the subway and the area 2 adjacent to the existing structure, set up a dewatering well point 3 inside the foundation pit, set up a dewatering well point 4 outside the foundation pit away from the structure, and the well at the dewatering well point 4 outside the foundation pit serves as a dewatering well and also as an emergency well outside the pit;

[0068] S10, lowering the steel casing 6 of the dewatering well: driving the steel casing 6 into the soil, and driving the steel pipe 5 and the steel casing 6 concentrically;

[0069] Cover the mouth of the steel pipe 5 with the material distribution protection cone 9, make the outer edge of the feeding tube 8 fit the steel casing 6, and fill the graded sand and gravel 18 between the steel pipe 5 and the steel casing 6 through the empty slot between the inner support bracket 10;

[0070] After filling is completed, remove the feeding tube 8 and pull out the steel casing 6;

[0071] In this embodiment, the material distribution protection cone 9 is a conical closed structure, the feeding tube 8 is an inverted conical ring, the internal support fixing frame 10 is horizontally welded to the lower edge of the conveying feeding and material distribution protection cone 9 to form a fixed structure, and the lower outer edge of the steel casing 6 is provided with a steel casing reinforcement rib 7.

[0072] S20, closing the dewatering well pipe: arranging a layer of wire mesh 17 outside the steel pipe 5, and then filling it with graded sand and gravel 18;

[0073] The support rod 15 is fixed by the groove 13 so that the movable rod 14 and the support rod 15 form a corbel bracket;

[0074] Place the closed ring plate 16 on the corbel bracket to achieve temporary closure of the filling area of the outer wall of the precipitation well;

[0075] In this embodiment, the movable rod 14 is fixed by a fixed block 11 and a fixed shaft 12 welded on the outer side of the upper part of the steel pipe 5, so that the movable rod 14 is hinged to the outer wall of the steel pipe 5, and the movable rod 14 is hinged to the support rod 15 through the fixed shaft 12. A groove 13 is also provided on the conveying steel pipe 5 to fix the support rod 15 through the groove 13.

[0076] S30, remote intelligent control of precipitation: monitoring the water level in the precipitation well through the immersion liquid level sensor 40;

[0077] When the water level exceeds the liquid level sensor, the wireless transmitter module 42 transmits a wireless signal, the wireless relay 44 receives the wireless signal and controls the AC contactor 45 to switch, so that the submersible pump 41 operates to pump water;

[0078] When the water level in the precipitation well drops below the liquid level sensor, the submersible pump 41 is controlled to stop operating;

[0079] In this embodiment, the liquid level sensor is connected to the wireless transmitting module 42 by wire, the submersible pump 41 is connected to the delivery AC contactor 45 by wire, the wireless relay 44 is connected by wire and controls the switch of the AC contactor 45, and an independently set power supply 43 supplies power to the wireless transmitting module 42, the wireless relay 44 and the AC contactor 45.

[0080] S40, construction of the dewatering well through the bottom plate: the foundation pit is excavated to the designed elevation, the foundation pit base surface 51 is cleaned, the steel pipe fixing frame 19 is placed outside the steel pipe 5 to ensure that the steel pipe 5 is vertical, the lower part of the steel pipe 5 is filled with sand and gravel 50, and the outer part of the steel pipe 5 and the lower part of the foundation pit base surface 51 are filled with the water filter pipe sand 26 left when the steel casing 6 was removed (so that the steel pipe 5 is in a closed state below the foundation pit base surface 51), the steel plate 48 is welded and fixed to the outer wall of the steel pipe 5, and the foundation pit leveling layer 25 is laid;

[0081] Remove the steel pipe fixing frame 19, weld and fix the steel plate 48 on the outer wall of the steel pipe 5, and lay the foundation pit leveling layer 25;

[0082] A waterproof layer 24 is provided outside the fixed steel plate 48 and the foundation pit leveling layer 25;

[0083] Apply water-stop putty 47 between the fixed steel plate 48 and the waterproof layer 24;

[0084] In this embodiment, the steel pipe fixing frame 19 is composed of a fixing frame outer ring 20, a fixing frame inner ring 21, a fixing frame inner support rod 22 and a fixing frame vertical rod 23. The fixing frame outer ring 20 and the fixing frame inner ring 21 are welded to form concentric rings through the fixing frame inner support rod 22, and the fixing frame vertical rod 23 is vertically welded to the lower part of the fixing frame outer ring 20.

[0085] S50, construction of post-cast strip through bottom plate of dewatering well: a steel plate 49 is set on the upper part of dewatering well to temporarily seal the dewatering well;

[0086] The steel mold 28 is placed on the steel plate 49, and a dense mesh 27 is set outside the steel mold 28;

[0087] Pour the bottom slab concrete 46, and remove the steel mold 28 after the concrete strength reaches the required level;

[0088] S60, the dewatering well is closed through the bottom plate: a closing steel plate 33 is installed at the dewatering well mouth, a steel strand 34 and an anchor 35 are connected to the lower part of the closing steel plate 33, the steel strand 34 passes through the prestressed anchor rod 39, and the cavity of the bottom plate post-cast zone is filled with micro-expansion concrete 36;

[0089] Then, the weight plate 37 is pressed on the slightly expansive concrete 36, and the weight block 38 is placed on the weight plate 37;

[0090] After the slightly expansive concrete 36 hardens and reaches the construction strength, the weight block 38 is removed, the steel strand 34 is prestressed, and locked with the anchor 35;

[0091] In this embodiment, the steel mold 28 is composed of a side template 29 and a bottom template 30 to form an uncovered box body, and a diagonal support fixing block 32 is provided on the upper edge of the interior of the box body. The notch of the diagonal support fixing block 32 fixes the diagonal support rod 31 inside the box body.

[0092] The parts not described in detail in this application are prior art, so this application does not describe them in detail.

[0093] It is understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0094] Although this document uses a lot of professional terms, it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of this application; interpreting them as any additional restrictions is contrary to the spirit of this application.

[0095] This application is not limited to the above-mentioned optimal implementation method. Anyone can derive various other forms of products based on the inspiration of this application. However, no matter what changes are made in their shape or structure, any technical solution that is the same or similar to that of this application falls within the scope of protection of this application.

Claims

1. The construction method of the foundation pit intelligent controlled dewatering system is characterized by: The following steps are involved: S00. Layout of dewatering wells in foundation pits: avoid setting dewatering wells in areas adjacent to subways (1) and existing structures (2). Set dewatering wells in the foundation pit (3). Set dewatering wells outside the foundation pit (4) away from structures. The wells at the dewatering wells outside the foundation pit (4) serve as drainage wells and also as emergency wells outside the pit. S10, lowering the steel casing (6) of the dewatering well: driving the steel casing (6) into the soil, and driving the steel pipe (5) and the steel casing (6) concentrically; Cover the mouth of the steel pipe (5) with the material distribution protection cone (9), make the outer edge of the feeding tube (8) fit the steel casing (6), and fill the graded sand and gravel (18) between the steel pipe (5) and the steel casing (6) through the empty slot between the inner support fixing frame (10); After the filling is completed, remove the feeding tube (8) and pull out the steel casing (6); The inner support fixing frame (10) is horizontally welded to the feeding barrel (8) and the lower edge of the material distribution protection cone (9) to form a fixed structure; S20, closing the dewatering well pipe: arranging a layer of wire mesh (17) outside the steel pipe (5), and then filling it with graded sand and gravel (18); The support rod (15) is fixed by the groove (13), so that the movable rod (14) and the support rod (15) form a bracket; Placing the closed ring plate (16) on the corbel bracket to achieve temporary closure of the filling area of the outer wall of the precipitation well; The movable rod (14) is fixed by a fixed block (11) and a fixed shaft (12) welded on the outer side of the upper portion of the steel pipe (5), so that the movable rod (14) is hinged to the outer wall of the steel pipe (5), and the movable rod (14) is hinged to the support rod (15) through the fixed shaft (12). A groove (13) is further provided on the steel pipe (5), and the support rod (15) is fixed through the groove (13); S30, remote intelligent control of precipitation: monitoring the water level in the precipitation well through the input liquid level sensor (40); When the water level exceeds the liquid level sensor, a wireless signal is transmitted through the wireless transmitting module (42), and the wireless relay (44) receives the wireless signal and controls the AC contactor (45) to switch, so that the submersible pump (41) operates to pump water; When the water level in the dewatering well drops below the liquid level sensor, the submersible pump (41) is controlled to stop operating; S40, construction of the dewatering well through the bottom plate: the foundation pit is excavated to the design elevation, the foundation pit base surface (51) is cleaned, the steel pipe fixing frame (19) is placed outside the steel pipe (5) to ensure that the steel pipe (5) is vertical, the lower part of the steel pipe (5) is filled with sand and gravel (50), the outer part of the steel pipe (5) and the lower part of the foundation pit base surface (51) are filled with the filter well pipe sand (26) left when the steel casing (6) is removed, the steel plate (48) is welded and fixed on the outer wall of the steel pipe (5), and the foundation pit leveling layer (25) is laid; A waterproof layer (24) is provided outside the fixed steel plate (48) and the foundation pit leveling layer (25); Apply water-stop putty (47) between the fixed steel plate (48) and the waterproof layer (24); S50, construction of post-cast strip through the bottom plate of the dewatering well: a steel plate (49) is set on the upper part of the dewatering well to temporarily seal the dewatering well; Placing a steel mold (28) on a steel plate (49), and providing a dense mesh (27) on the outside of the steel mold (28); pouring the bottom slab concrete (46), and removing the steel mold (28) after the concrete strength reaches the required level; S60, the dewatering well is closed through the bottom plate: a closing steel plate (33) is set at the dewatering well mouth, the lower part of the closing steel plate (33) is connected to the steel strand (34) and the anchor (35), the steel strand (34) passes through the prestressed anchor rod (39), and the cavity of the bottom plate post-cast zone is filled with micro-expansion concrete (36); Then, a weight plate (37) is pressed onto the micro-expansion concrete (36), and a weight block (38) is placed onto the weight plate (37); After the micro-expansion concrete (36) hardens and reaches the construction strength, the weight block (38) is removed, the prestressed steel strand (34) is tensioned, and the anchor (35) is used to lock it.

2. The construction method of the foundation pit intelligent controlled dewatering system according to claim 1, characterized in that: In step S10, the material distribution protection cone (9) is a conical closed structure, the feeding cylinder (8) is an inverted conical ring, and the lower outer edge of the steel casing (6) is provided with a steel casing reinforcement rib (7).

3. The construction method of the foundation pit intelligent controlled dewatering system according to claim 1, characterized in that: In step S40, the steel pipe fixing frame (19) is composed of a fixing frame outer ring (20), a fixing frame inner ring (21), a fixing frame inner support rod (22) and a fixing frame vertical rod (23), the fixing frame outer ring (20) and the fixing frame inner ring (21) are welded to form concentric rings through the fixing frame inner support rod (22), and the fixing frame vertical rod (23) is vertically welded to the lower part of the fixing frame outer ring (20).

4. The construction method of the foundation pit intelligent controlled dewatering system according to claim 1, characterized in that: In step S30, the liquid level sensor is connected to the wireless transmitting module (42) by wire, the submersible pump (41) is connected to the delivery AC contactor (45) by wire, and the wireless relay (44) is connected by wire and controls the switch of the AC contactor (45).

5. The construction method of the foundation pit intelligent controlled dewatering system according to claim 4 is characterized in that: An independently provided power supply (43) supplies power to the wireless transmitting module (42), the wireless relay (44) and the AC contactor (45).

6. The construction method of the foundation pit intelligent controlled dewatering system according to any one of claims 1 to 5, characterized in that: In step S50, the steel mold (28) is composed of a side template (29) and a bottom template (30) to form a coverless box body, and a diagonal support fixing block (32) is provided on the upper edge of the interior of the box body, and the notch of the diagonal support fixing block (32) fixes the diagonal support rod (31) inside the box body.

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