Foundation pit dewatering well and water stop curtain collaborative anti-seepage structure and construction method

Abstract

This invention relates to the field of seepage prevention and dewatering technology for underground engineering and foundation pits, particularly to a seepage prevention structure and construction method for a combined dewatering well and a water-stop curtain. The structure includes a positioning top frame, a seepage-proof enclosure box, and dewatering well pipes. The positioning top frame and the seepage-proof enclosure box have internal installation grooves. A sliding groove is formed in the inner wall of the installation groove. A positioning column is installed inside the installation groove. A guide installation mechanism is provided on the outer side of the positioning column. The guide installation mechanism includes a sliding ring, a slider is fixedly connected to the outer side of the sliding ring, and a rubber fan-shaped clamping plate is fixedly connected to the bottom of the sliding ring. This invention can precisely constrain the vertical position of the column and dewatering well pipes, ensuring that all pipe components are arranged neatly and with the required verticality. Furthermore, the rubber components fill the gaps between the components to form a sealing buffer, preventing collision and wear of the pipe components during hoisting and sinking operations, significantly improving on-site assembly efficiency and seepage prevention sealing.

Description

Technical Field

[0001] This invention relates to the field of underground engineering and foundation engineering pit seepage prevention and dewatering technology, specifically to a seepage prevention structure and construction method that combines dewatering wells and water-stop curtains in foundation pits. Background Technology

[0002] As the scale of underground and foundation engineering construction such as urban rail transit, fully underground sewage treatment plants, and bridge foundations across rivers and lines continues to expand, projects such as subway station foundation pits, deep foundation pits of fully underground sewage treatment plants, bridge abutments and bridge foundation pits are gradually developing towards greater depth, larger area and higher groundwater risk. Related projects are often inevitably located in water-rich sand and gravel layers, silt layers, weak interlayers and areas with developed confined water.

[0003] These types of strata have high porosity, high permeability, and abundant groundwater recharge, making them highly susceptible to problems such as continuous seepage on the sidewalls, sudden gushing at the bottom of the pit, piping, quicksand, pit bottom heave, and settlement of the surrounding strata during excavation and foundation construction. This is especially true in the construction of subway stations, fully underground sewage treatment plants, and bridge foundations, where the surrounding area typically includes existing roads, underground pipelines, adjacent structures, or water bodies. These conditions place high demands on the magnitude of dewatering, the continuity of waterstopping, and the stability of the retaining structure. Improper coordination between the waterstop curtain and the dewatering system can easily lead to increased leakage, pit deformation, and disturbance to the surrounding environment.

[0004] Current mainstream construction methods often separate and independently construct the water-stop curtain and dewatering wells. This typically requires first constructing water-stop structures such as mixing piles, diaphragm walls, high-pressure jet grouting piles, or sheet piles in sections, and then separately drilling and installing dewatering wells. These two processes are independent, have long construction cycles, and are prone to creating overlapping cold joints, construction disturbance zones, or seepage channels between the water-stop structure and the dewatering wells. For long, narrow, or large-area deep foundation pits such as subway stations and fully underground sewage treatment plants, as well as deep abutments, water-bearing abutments, or foundation pits in complex strata within bridge foundations, traditional separate water-stop and dewatering construction is more prone to problems such as insufficient installation accuracy, difficulty in controlling the verticality of pipe fittings, and incomplete sealing in certain areas.

[0005] Existing split-type water-stopping and dewatering construction techniques lack integrated assembly carriers. When supporting columns, dewatering well pipes, and other components are buried on-site, there is a lack of unified limiting and guiding structures. Typically, the verticality and spacing of the pipes are controlled manually. During hoisting and lowering, well pipes and columns are prone to tilting, collisions, or localized deformation. Irregular assembly gaps exist between components and the retaining structure, requiring multiple grouting and sealing points later. This results in low assembly efficiency and numerous weak points in the seal. Simultaneously, the continuous water and soil pressure outside the foundation pit acts on the sidewalls of the water-stopping curtain, making it easy for the segmented cast-in-place or assembled retaining units to experience horizontal displacement. The joints, when squeezed open, form new seepage channels. Conventional reinforcement methods often involve single-sided, single-point support, making it difficult to simultaneously lock and limit multiple sets of retaining boxes at multiple points. The overall structural rigidity is insufficient, and the anti-seepage system is prone to deformation and instability during long-term construction or service, failing to meet the requirements for anti-seepage stability and construction efficiency for subway stations, fully underground sewage treatment plants, and bridge foundation pits.

[0006] Therefore, in response to the above problems, a seepage prevention structure and construction method combining foundation pit dewatering wells and water-stop curtains are proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a seepage prevention structure and construction method for the combined use of foundation pit dewatering wells and water-stop curtains, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] The foundation pit dewatering well and water-stop curtain collaborative seepage prevention structure includes a positioning top frame, a seepage prevention enclosure box and a dewatering well pipe. The positioning top frame and the seepage prevention enclosure box are provided with an installation groove inside. The inner wall of the installation groove is provided with a sliding groove. The installation groove is provided with a positioning column pile inside. The positioning column pile is provided with a guide installation mechanism on the outside.

[0010] The guide installation mechanism includes a sliding ring, a slider fixedly connected to the outer side of the sliding ring, a rubber fan-shaped fastening plate fixedly connected to the bottom of the sliding ring, a connecting ring fixedly connected to the bottom of the rubber fan-shaped fastening plate, a connecting plate fixedly connected to the outer side of the connecting ring, a spring rod fixedly connected to the top of the connecting plate, a fastening ring fixedly connected to the top of the spring rod, and a rotating groove provided in the side wall of the slider, with a roller provided inside the rotating groove.

[0011] As a further optimization of the present invention, a stable support mechanism is provided between the seepage-proof enclosure boxes. The stable support mechanism includes a stable base plate, a fixed rod fixedly connected to the top of the stable base plate, a movable block slidably connected to the outside of the fixed rod, a push rod provided to the outside of the movable block, an abutment block hinged to the bottom of the push rod, a threaded seat fixedly connected to the outside of the movable block, a positioning screw threadedly connected to the inside of the threaded seat, a limit block fixedly connected to the bottom of the abutment block, a movable hole opened inside the limit block, a movable groove opened inside the stable base plate, a guide rail fixedly connected inside the movable groove, and a lifting handle fixedly connected to the top of the positioning top frame.

[0012] As a further optimization of the present invention, the interior of the seepage-proof enclosure is provided with a grouting mechanism, the grouting mechanism includes grouting holes, a mud trough is provided between the installation slots, and a cover plate is provided on the top of the grouting holes.

[0013] As a further optimization of the present invention, the seepage-proof enclosure box is fixed and symmetrically distributed at the bottom of the positioning top frame, the sliding groove is symmetrically distributed in the inner wall of the installation groove, and the sliding ring is evenly distributed on the outer side of the positioning column pile.

[0014] As a further optimization of the present invention, the slider is slidably connected inside the slide groove, the roller rolls tightly against the inner wall of the slide groove, and the mounting grooves are evenly distributed inside the positioning top frame and the waterproof enclosure.

[0015] As a further optimization of the present invention, the rubber fan-shaped fastening plates are symmetrically distributed at the bottom of the sliding ring, and the bottom of the rubber fan-shaped fastening plates is tightly attached to the outside of the positioning column pile. The connecting plates are evenly distributed on the outside of the connecting ring, and the fastening ring is located on the outside of the bottom of the rubber fan-shaped fastening plates.

[0016] As a further optimization of the present invention, the following features are provided: the stabilizing base plate is fixed and symmetrically distributed between the two seepage-proof enclosure boxes; the top of the fixing rod is fixedly connected to the bottom of the positioning top frame; the pushing rod is symmetrically distributed on the outside of the moving block; and the abutting block is located at the connection between the stabilizing base plate and the seepage-proof enclosure box.

[0017] As a further optimization of the present invention, the limiting block is slidably connected inside the moving groove, the guide rail is located in the moving hole inside the limiting block, and the abutment blocks are symmetrically distributed on the top of the stable base plate.

[0018] As a further optimization of the present invention, the grouting holes are evenly distributed on the top of the positioning top frame, and the mud trough and the installation trough are in a connected state.

[0019] The construction method of the foundation pit dewatering well and the cutoff wall combined seepage prevention structure includes the following steps:

[0020] S1. Precast component fabrication and on-site layout:

[0021] The factory pre-fabricates the positioning top frame, seepage-proof enclosure box, positioning column pile, guide installation mechanism, stabilizing support mechanism and grouting mechanism components in batches. The excavation edge line of the foundation pit is laid out, the working base is leveled, the positioning lines of each seepage-proof enclosure box are marked, and the base debris is cleaned.

[0022] S2. The entire waterproofing unit is hoisted into place:

[0023] Using the hoisting handle, the positioning top frame and the integrated component of the seepage-proof enclosure box are hoisted and lowered to the foundation pit along the layout point. The stable support mechanism is assembled, and the positioning screw is rotated to drive the moving block and the pushing rod to make the contact block press against the side wall of the seepage-proof enclosure box. The limiting block slides along the guide rail and locks in place, thus completing the fixed support between multiple sets of seepage-proof enclosure boxes.

[0024] S3. Positioning and guiding assembly of column piles:

[0025] Insert the positioning column into the installation groove inside the positioning top frame and the seepage-proof enclosure box. The slider on the outside of the sliding ring of the guide installation mechanism slides down along the sliding groove. The roller reduces the sliding friction. When lowered, the rubber fan-shaped fastening plate automatically fits the positioning column body. The spring rod and fastening ring provide radial pre-tightening force to complete the vertical limit of the positioning column.

[0026] S4. Installation and grouting of dewatering well pipes:

[0027] Dewatering well pipes are interspersed in each installation slot. The verticality of the pipes is adjusted, the cover plate is lifted, and anti-seepage grout is injected into the connected mud tank through the grouting hole at the top of the positioning top frame. The grout fills the gap between the installation slot, the positioning column pile and the dewatering well pipe. After the grout solidifies, it forms a local water-stopping curtain, realizing the coordinated anti-seepage of water-stopping and dewatering wells.

[0028] S5. Precipitation Trial Operation and Seepage Prevention Verification:

[0029] After the grout reaches the designed strength, the dewatering well pipe pumping equipment is connected to carry out dewatering trial operation, monitor the seepage of the foundation pit sidewall, check whether there is any leakage at the joints of the seepage-proof enclosure box, the gap between the positioning column pile and the dewatering well pipe, and reinforce the seepage points by injecting seepage-proof grout through the grouting hole to complete the overall construction.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. In this invention, an integrated water-stop unit is formed by setting a positioning top frame and a seepage-proof enclosure box. With the internally connected grouting mechanism, seepage-proof grout can be directly injected into the installation trench. After the grout solidifies, it can form a continuous closed water-stop layer around the dewatering well pipe and the positioning column pile, integrating dewatering and curtain seepage prevention into one, eliminating the need to separately construct the water-stop wall and dewatering well. This greatly simplifies the seepage prevention construction process of water-rich foundation pits and effectively blocks the lateral seepage of external groundwater, reducing the risk of water inrush and seepage in the foundation pit from the source.

[0032] 2. In this invention, by adding a guiding installation mechanism, during assembly, the sliding ring slides smoothly down the slide groove by relying on the slider and roller. The rubber fan-shaped fastening plate adaptively hugs and positions the column pile under the action of the spring rod and fastening ring. This can not only accurately constrain the vertical position of the column pile and the dewatering well pipe, ensuring that the arrangement of various pipe fittings is neat and the verticality meets the standards, but also use the rubber parts to fill the gaps between the components to form a sealing buffer, avoiding collision and wear of the pipe fittings during hoisting and sinking operations, and significantly improving the on-site assembly efficiency and seepage prevention and sealing performance.

[0033] 3. In this invention, a stable support mechanism is provided between adjacent seepage-proof enclosure boxes. By adjusting the positioning screw, the moving block and the pushing rod can be driven to move the contact block to fit against the side wall of the box. The limiting block slides stably along the guide rail to achieve multi-point locking and fixing. Multiple sets of seepage-proof boxes can be spliced ​​and limited simultaneously, which improves the structural rigidity of the overall seepage-proof unit, prevents the box from shifting and deforming under the action of water and soil pressure in the foundation pit, and ensures the long-term stability and reliability of the overall seepage-proof system. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the positioning top frame and the outer side of the seepage-proof enclosure box of the present invention;

[0036] Figure 3 This is a cross-sectional view of the side structure of the positioning top frame and the seepage-proof enclosure box of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure on the outside of the positioning column pile of the present invention;

[0038] Figure 5 This is a schematic diagram of the outer structure of the guide installation mechanism of the present invention;

[0039] Figure 6 This is a schematic diagram of the structure of the guide installation mechanism of the present invention when it is deployed;

[0040] Figure 7 This is a schematic diagram of the outer structure of the stable support mechanism of the present invention;

[0041] Figure 8This is a schematic diagram of the structure between the connecting ring and the fastening ring of the present invention;

[0042] Figure 9 For the present invention Figure 3 Enlarged view of the structure at point A in the middle;

[0043] Figure 10 For the present invention Figure 6 Enlarged view of the structure at point B;

[0044] Figure 11 This is a physical image of the present invention.

[0045] In the diagram: 1. Positioning top frame; 11. Installation groove; 12. Sliding groove; 2. Anti-seepage enclosure box; 3. Lifting handle; 4. Dewatering well pipe; 5. Positioning column pile; 6. Grouting mechanism; 61. Grouting hole; 62. Mud trough; 63. Cover plate; 7. Guide installation mechanism; 71. Sliding ring; 72. Sliding block; 721. Rotating groove; 722. Roller; 73. Rubber fan-shaped fastening plate; 74. Connecting ring; 75. Connecting plate; 76. Spring rod; 77. Fastening ring; 8. Stable support mechanism; 81. Stable base plate; 82. Fixed rod; 83. Moving block; 84. Push rod; 85. Abutment block; 851. Limiting block; 852. Moving hole; 853. Moving groove; 854. Guide rail; 86. Threaded seat; 87. Positioning screw. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] Please see Figures 1-11 The present invention provides a technical solution:

[0049] The foundation pit dewatering well and the water-stop curtain work together to prevent seepage, including a positioning top frame 1, a seepage-proof enclosure box 2 and a dewatering well pipe 4. The positioning top frame 1 and the seepage-proof enclosure box 2 are provided with an installation groove 11. The inner wall of the installation groove 11 is provided with a sliding groove 12. The installation groove 11 is provided with a positioning column pile 5. The outer side of the positioning column pile 5 is provided with a guide installation mechanism 7.

[0050] The guide installation mechanism 7 includes a sliding ring 71, a slider 72 fixedly connected to the outer side of the sliding ring 71, a rubber fan-shaped fastening plate 73 fixedly connected to the bottom of the sliding ring 71, a connecting ring 74 fixedly connected to the bottom of the rubber fan-shaped fastening plate 73, a connecting plate 75 fixedly connected to the outer side of the connecting ring 74, a spring rod 76 fixedly connected to the top of the connecting plate 75, a fastening ring 77 fixedly connected to the top of the spring rod 76, and a rotating groove 721 is provided in the side wall of the slider 72, and a roller 722 is provided inside the rotating groove 721.

[0051] It should be noted that: the interior of the seepage-proof enclosure box 2 is equipped with a grouting mechanism 6, which includes grouting holes 61, a mud trough 62 between the installation grooves 11, and a cover plate 63 on the top of the grouting holes 61. The seepage-proof enclosure box 2 is fixed and symmetrically distributed at the bottom of the positioning top frame 1. The sliding grooves 12 are symmetrically distributed in the inner wall of the installation grooves 11. The sliding rings 71 are evenly distributed on the outer side of the positioning column piles 5. The sliders 72 are slidably connected to the inside of the sliding grooves 12. The rollers 722 roll tightly against the inner wall of the sliding grooves 12. The installation grooves 11 are evenly distributed inside the positioning top frame 1 and the seepage-proof enclosure box 2. The rubber fan-shaped fastening plates 73 are symmetrically distributed at the bottom of the sliding rings 71, and the bottom of the rubber fan-shaped fastening plates 73 is tightly against the outer side of the positioning column piles 5. The connecting plates 75 are evenly distributed on the outer side of the connecting rings 74. The fastening rings 77 are located on the outer side of the bottom of the rubber fan-shaped fastening plates 73.

[0052] Furthermore, the grouting holes 61 are evenly distributed on the top of the positioning top frame 1, and the mud trough 62 is in communication with the installation groove 11.

[0053] Specifically: The positioning top frame 1 and the seepage-proof enclosure box 2 are combined to form the main load-bearing frame of the entire seepage-proof structure. The seepage-proof enclosure box 2 is symmetrically fixed to the bottom of the positioning top frame 1 to form an integrated water-stopping unit. Several installation grooves 11 are evenly opened inside the two. The inner wall of the installation groove 11 is symmetrically provided with sliding grooves 12, which can simultaneously accommodate the orderly arrangement of the dewatering well pipe 4 and the positioning column pile 5, and uniformly constrain the layout spacing of various pipe fittings. The sliding grooves 12 can also provide a vertical sliding track for the guide installation mechanism 7. The hoisting handle 3 set on the top of the positioning top frame 1 facilitates the hoisting, transportation, and lowering of the entire unit into place.

[0054] Meanwhile, the guide installation mechanism 7 is fitted on the outside of the positioning column pile 5. The sliding ring 71 on it is fixed to the outside of the slider 72. The roller 722 in the rotating groove 721 on the side wall of the slider 72 can roll and fit against the inner wall of the groove 12, converting sliding friction into rolling friction, reducing the resistance of the positioning column pile 5 in lowering, and ensuring the vertical and smooth installation of the pile body. The rubber fan-shaped tight-fitting plate 73 symmetrically arranged at the bottom of the sliding ring 71 forms an elastic clamping structure with the connecting ring 74, connecting plate 75, spring rod 76 and fastening ring 77. Relying on the spring force, the rubber fan-shaped tight-fitting plate 73 tightly fits the pile body, which not only restricts the horizontal sway of the positioning column pile 5 and maintains the verticality of the installation, but also uses the rubber material to fill the gaps of the components to form an annular water-proof sealing layer to block the seepage channel.

[0055] As a further implementation of this scheme, a stable support mechanism 8 is provided between the seepage-proof enclosure boxes 2. The stable support mechanism 8 includes a stable base plate 81, a fixed rod 82 is fixedly connected to the top of the stable base plate 81, a movable block 83 is slidably connected to the outside of the fixed rod 82, a push rod 84 is provided on the outside of the movable block 83, an abutment block 85 is hinged to the bottom of the push rod 84, a threaded seat 86 is fixedly connected to the outside of the movable block 83, a positioning screw 87 is threadedly connected inside the threaded seat 86, a limit block 851 is fixedly connected to the bottom of the abutment block 85, a movable hole 852 is opened inside the limit block 851, a movable groove 853 is opened inside the stable base plate 81, a guide rail 854 is fixedly connected inside the movable groove 853, and a lifting handle 3 is fixedly connected to the top of the positioning top frame 1.

[0056] It should be noted that: the stable base plate 81 is fixed and symmetrically distributed between the two seepage-proof enclosure boxes 2; the top of the fixing rod 82 is fixedly connected to the bottom of the positioning top frame 1; the pushing rod 84 is symmetrically distributed on the outside of the moving block 83; the abutting block 85 is located at the connection between the stable base plate 81 and the seepage-proof enclosure box 2; the limiting block 851 is slidably connected inside the moving groove 853; the guide rail 854 is located in the moving hole 852 inside the limiting block 851; and the abutting block 85 is symmetrically distributed on the top of the stable base plate 81.

[0057] Furthermore: The stable support mechanism 8 is assembled between adjacent seepage-proof enclosure boxes 2, the stable base plate 81 is laid on the foundation pit base, the upper end of the fixed rod 82 is connected to the bottom of the positioning top frame 1 to form a vertical support frame, the rotating positioning screw 87 can drive the threaded seat 86 and the moving block 83 to rise and fall along the fixed rod 82, the symmetrical push rods 84 on both sides of the moving block 83 are opened synchronously, driving the bottom hinged abutment block 85 to press tightly against the box joint, the limiting block 851 at the bottom of the abutment block 85 is sleeved on the guide rail 854 through the moving hole 852 and slides smoothly along the moving groove 853 to achieve multi-point synchronous tightening and limiting, resisting the side pressure of water and soil in the foundation pit, preventing the seepage-proof enclosure box 2 from shifting, the splicing gap from opening and leaking, and improving the overall structural rigidity and stability.

[0058] Specifically: The grouting mechanism 6 is integrated inside the seepage-proof enclosure box 2. Grouting holes 61 are evenly arranged on the top of the positioning top frame 1. The grouting holes 61 are equipped with openable and closable cover plates 63. Mud slurry tanks 62 are opened between the installation slots 11. After opening the cover plate 63, seepage-proof grout can be injected into the mud slurry tank 62 through the grouting holes 61. The grout can flow and fill all the gaps between the dewatering well pipe 4, the positioning column pile 5 and the box components in the installation slot 11. After the grout solidifies, it will form a continuous and sealed seepage-proof curtain, sealing all component assembly gaps and blocking the infiltration of external groundwater into the foundation pit from the side.

[0059] Meanwhile, the dewatering well pipe 4 is arranged inside the installation trench 11, and works in conjunction with the seepage-proof enclosure box 2, the grouting mechanism 6, and the guiding installation mechanism 7 to form a collaborative seepage-proof system. The grouting-formed closed curtain isolates the external groundwater supply, and the dewatering well pipe 4 continuously pumps out the water accumulated inside the foundation pit. The two work together to achieve the dual water control effect of "intercepting water from the outside and draining water from the inside". With the support mechanism 8 and the guiding installation mechanism 7, the overall structure and pipe fittings are limited and reinforced. The whole structure has the advantages of convenient assembly, strong sealing and structural stability. It is suitable for integrated seepage-proof dewatering construction of deep foundation pits in water-rich strata such as subway stations, fully underground sewage treatment plants, and bridge foundations.

[0060] Work process: During construction, the positioning top frame 1 and the seepage-proof enclosure box 2 are hoisted together to the predetermined position in the foundation pit by the hoisting handle 3 on the top of the positioning top frame 1. A stable support mechanism 8 is assembled between multiple sets of seepage-proof enclosure boxes 2. The stable base plate 81 of the stable support mechanism 8 is laid on the foundation pit base. The top of the fixed rod 82 is fixedly connected to the bottom of the positioning top frame 1. Rotating the positioning screw 87 can drive the threaded seat 86 to move the moving block 83 vertically along the fixed rod 82. The push rod 84 on the outside of the moving block 83 is simultaneously opened and drives the bottom hinged abutment block 85 to press against the side wall connection of the seepage-proof enclosure box 2. The limiting block 851 at the bottom of the abutment block 85 slides horizontally on the guide rail 854 in the moving groove 853 of the stable base plate 81 through its own moving hole 852, so as to realize the multi-point synchronous pressing and limiting of the seepage-proof enclosure box 2 and prevent the box from shifting due to water and soil pressure.

[0061] The positioning top frame 1 and the seepage-proof enclosure 2 are evenly provided with installation grooves 11. The inner wall of the installation groove 11 is symmetrically provided with sliding grooves 12. After the positioning column 5 is inserted into the installation groove 11, the guide installation mechanism 7 on the outside of the positioning column 5 is lowered simultaneously. The slider 72 fixed on the outside of the sliding ring 71 of the guide installation mechanism 7 is embedded in the sliding groove 12. The slider 72 rotates and the roller 722 inside the groove 721 rolls and contacts the inner wall of the sliding groove 12, reducing the lowering friction to ensure that the positioning column 5 falls vertically and smoothly. The rubber fan-shaped fastening plate 73 connected to the bottom of the sliding ring 71 provides continuous inward pressure through the connecting plate 75 on the outside of the bottom connecting ring 74, the spring rod 76 and the fastening ring 77. The elastic pre-tightening force makes the rubber fan-shaped tight-fitting plate 73 tightly wrap around the outer wall of the positioning column pile 5, which not only restrains the horizontal displacement of the pile body, but also fills the assembly gap to form a water-proof seal. After the positioning column pile 5 and the dewatering well pipe 4 are all in place, the cover plate 63 on the top of the grouting hole 61 of the grouting mechanism 6 is opened, and the anti-seepage grout is injected into the mud tank 62 that is connected to the installation trench 11 through the grouting hole 61. The grout fills all the gaps between the dewatering well pipe 4, the positioning column pile 5 and the box in the installation trench 11. After the grout solidifies, it forms a continuous closed water-stop curtain around the dewatering well. In conjunction with the dewatering well pipe 4, groundwater is pumped out at the same time, and finally the dewatering well and the water-stop curtain work together to prevent seepage in the foundation pit.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A seepage prevention structure combining a foundation pit dewatering well and a water-stop curtain, comprising a positioning top frame (1), a seepage prevention enclosure box (2), and a dewatering well pipe (4), characterized in that: The positioning top frame (1) and the seepage-proof enclosure box (2) are provided with an installation groove (11), and a sliding groove (12) is provided in the inner wall of the installation groove (11). The installation groove (11) is provided with a positioning column (5), and a guide installation mechanism (7) is provided on the outside of the positioning column (5). The guide installation mechanism (7) includes a sliding ring (71), a slider (72) is fixedly connected to the outer side of the sliding ring (71), a rubber fan-shaped fastening plate (73) is fixedly connected to the bottom of the sliding ring (71), a connecting ring (74) is fixedly connected to the bottom of the rubber fan-shaped fastening plate (73), a connecting plate (75) is fixedly connected to the outer side of the connecting ring (74), a spring rod (76) is fixedly connected to the top of the connecting plate (75), a fastening ring (77) is fixedly connected to the top of the spring rod (76), a rotating groove (721) is provided in the side wall of the slider (72), and a roller (722) is provided inside the rotating groove (721).

2. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 1, characterized in that: A stable support mechanism (8) is provided between the seepage-proof enclosure boxes (2). The stable support mechanism (8) includes a stable base plate (81). A fixed rod (82) is fixedly connected to the top of the stable base plate (81). A moving block (83) is slidably connected to the outside of the fixed rod (82). A push rod (84) is provided on the outside of the moving block (83). An abutment block (85) is hinged to the bottom of the push rod (84). A threaded seat (86) is fixedly connected to the outside of the moving block (83). A positioning screw (87) is threadedly connected inside the threaded seat (86). A limit block (851) is fixedly connected to the bottom of the abutment block (85). A moving hole (852) is opened inside the limit block (851). A moving groove (853) is opened inside the stable base plate (81). A guide rail (854) is fixedly connected inside the moving groove (853). A hoisting handle (3) is fixedly connected to the top of the positioning top frame (1).

3. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 1, characterized in that: The interior of the seepage-proof enclosure box (2) is provided with a grouting mechanism (6), the grouting mechanism (6) includes a grouting hole (61), a mud trough (62) is provided between the installation grooves (11), and a cover plate (63) is provided on the top of the grouting hole (61).

4. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 1, characterized in that: The seepage-proof enclosure box (2) is fixed and symmetrically distributed at the bottom of the positioning top frame (1), the sliding groove (12) is symmetrically distributed in the inner wall of the installation groove (11), and the sliding ring (71) is evenly distributed on the outside of the positioning column pile (5).

5. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 1, characterized in that: The slider (72) is slidably connected inside the groove (12), the roller (722) rolls tightly against the inner wall of the groove (12), and the mounting groove (11) is evenly distributed inside the positioning top frame (1) and the seepage-proof enclosure box (2).

6. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 1, characterized in that: The rubber fan-shaped fastening plate (73) is symmetrically distributed at the bottom of the sliding ring (71), and the bottom of the rubber fan-shaped fastening plate (73) is tightly attached to the outside of the positioning column pile (5). The connecting plate (75) is evenly distributed on the outside of the connecting ring (74), and the fastening ring (77) is located on the outside of the bottom of the rubber fan-shaped fastening plate (73).

7. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 2, characterized in that: The stable base plate (81) is fixed and symmetrically distributed between the two seepage-proof enclosure boxes (2). The top of the fixed rod (82) is fixedly connected to the bottom of the positioning top frame (1). The push rod (84) is symmetrically distributed on the outside of the moving block (83). The abutting block (85) is located at the connection between the stable base plate (81) and the seepage-proof enclosure box (2).

8. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 2, characterized in that: The limiting block (851) is slidably connected inside the moving groove (853), the guide rail (854) is located in the moving hole (852) inside the limiting block (851), and the abutting blocks (85) are symmetrically distributed on the top of the stable base plate (81).

9. The seepage prevention structure combining foundation pit dewatering wells and water-stop curtains as described in claim 3, characterized in that: The grouting holes (61) are evenly distributed on the top of the positioning top frame (1), and the mud trough (62) and the installation trough (11) are in a connected state.

10. A construction method employing a combined seepage prevention structure of a foundation pit dewatering well and a water-stop curtain as described in any one of claims 1 to 9, characterized in that: Includes the following steps: S1. Precast component fabrication and on-site layout: Factory batch pre-determines the positioning top frame (1), seepage-proof enclosure box (2), positioning column pile (5), guide installation mechanism (7), stabilizing support mechanism (8) and grouting mechanism (6) supporting components. After the excavation of the foundation pit is completed, the working base is leveled, the positioning lines of each seepage-proof enclosure box (2) are marked, and the base debris is cleaned. S2. The entire waterproofing unit is hoisted into place: Using the hoisting handle (3), the positioning top frame (1) and the seepage-proof enclosure box (2) are hoisted together and lowered to the foundation pit along the layout point. The stable support mechanism (8) is assembled, and the positioning screw (87) is rotated to drive the moving block (83) and the pushing rod (84) so ​​that the contact block (85) presses against the side wall of the seepage-proof enclosure box (2). The limiting block (851) slides and locks along the guide rail (854) to complete the fixed support between multiple sets of seepage-proof enclosure boxes (2). S3. Positioning and guiding assembly of column piles: Insert the positioning column (5) into the installation groove (11) inside the positioning top frame (1) and the seepage-proof enclosure box (2). The slider (72) on the outside of the sliding ring (71) of the guide installation mechanism (7) slides down along the sliding groove (12). The roller (722) reduces the sliding friction. When it is lowered, the rubber fan-shaped fastening plate (73) automatically fits the positioning column (5) body. The spring rod (76) and the fastening ring (77) provide radial pre-tightening force to complete the vertical positioning of the positioning column (5). S4. Installation and grouting of dewatering well pipes: Dewatering well pipes (4) are interspersed in each installation slot (11). The verticality of the pipe is adjusted, the cover plate (63) is lifted, and anti-seepage grout is injected into the connected mud tank (62) through the grouting hole (61) at the top of the positioning top frame (1). The grout fills the gap between the installation slot (11), the positioning column pile (5) and the dewatering well pipe (4). After the grout solidifies, it forms a local water-stopping curtain, realizing the coordinated anti-seepage of water-stopping and dewatering well. S5. Precipitation Trial Operation and Seepage Prevention Verification: After the grout reaches the designed strength, the dewatering well pipe (4) is connected to the pumping equipment to carry out dewatering trial operation, monitor the seepage of the foundation pit sidewall, check whether there is leakage in the joint of the seepage-proof enclosure box (2), the gap between the positioning column pile (5) and the dewatering well pipe (4), and reinforce the seepage points by injecting seepage-proof grout through the grouting hole (61) to complete the overall construction.

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