Temporary dewatering well plugging device and method for basement under pressure water condition

Abstract

The application discloses a kind of temporary dewatering well plugging device and plugging method under pressure water condition, and the device includes anti-filter sand mechanism, water stop sealing mechanism, controllable pressure relief mechanism and pressure into fixed mechanism.Anti-filter sand mechanism includes filter cartridge, filter layer assembly and conical flow collection part, filters pressure water and collects scattered water flow to the top center water outlet of filter cartridge;Water stop sealing mechanism includes water stop and lower water stop, forming double flexible waterproof barrier;Controllable pressure relief mechanism includes drain pipe and pressure relief valve, releases well high pressure head, offsets water pressure upward buoyancy;Pressure into fixed mechanism steps down device to design plugging elevation.The device creates dry working surface by pressure relief, anti-filter sand, step-down, flexible water stop, completes upper pressure plate and steel casing rigid welding;After valve leakage detection, the component can be disassembled and recycled, and double-layer rigid permanent waterproof is formed by pouring concrete in well and adding top sealing plate, to realize safe and efficient permanent plugging.

Description

Technical Field

[0001] This invention belongs to the field of dewatering well sealing technology, and more specifically, relates to a sealing device and method for temporary dewatering wells in basements under confined water conditions. Background Technology

[0002] Setting up temporary dewatering wells during the basement construction phase is a core supporting measure to lower the groundwater level and ensure the safety of foundation and raft slab construction. For projects with highly permeable foundations, low-lying areas, and high pressurized water heads, the subsequent sealing of dewatering wells directly affects the long-term safety and durability of the main building structure. In high pressurized water environments, the water pressure inside the wells is high, and the risk of water inrush carrying sand is prominent, which greatly increases the difficulty of sealing construction. If the sealing technology and equipment are not suitable, major engineering hazards such as piping, leakage, and foundation soil erosion are very likely to occur.

[0003] Currently, there are three main types of dewatering well sealing schemes in the industry: one is simple pumping and depressurization grouting sealing, which relies on continuous pumping to reduce the water head and then grouting to seal; the second is rubber airbag inflation sealing, which uses the expansion of the airbag to squeeze the well wall to achieve temporary water stop; and the third is conventional grouting sealing device, which directly injects grout into the well to complete the sealing. However, the above schemes all have the following defects: (1) The pumping and depressurization scheme lacks a controllable pressure relief structure. Under high water head, the sealing device is easy to float and drift, and the water pump is permanently left in the well and cannot be recovered; (2) The grouting scheme is difficult to control the grouting pressure. High pressure water can easily cause grout backflow, resulting in a high sealing failure rate; (3) Airbag sealing requires special high-pressure equipment. The wellhead deformation adaptability is poor. Under high water pressure, the airbag is easy to break. It can only achieve temporary water stop and cannot form a permanent rigid anti-seepage structure. The overall construction cost is high and the construction period is uncontrollable.

[0004] Therefore, there is an urgent need for a temporary dewatering well sealing device for basements under pressurized water conditions, which can achieve safe, efficient and permanent sealing of dewatering wells, reduce project costs and shorten the construction period. Summary of the Invention

[0005] To address the problems of existing dewatering well sealing technologies, such as the floating of sealing components under high-pressure water head, sand inrush and leakage, pressure instability, high construction costs, and non-reusability, this invention provides a temporary dewatering well sealing device for basements under confined water conditions. The device includes a reverse filtration and sand-prevention mechanism installed in the temporary dewatering well, comprising a filter cylinder, a filter layer assembly within the filter cylinder, and a conical confluence section. The filter layer assembly performs gradient filtration of the confined water. The conical confluence section collects the diffused filtered confined water from all sides towards the outlet at the center of the top of the filter cylinder. A water-stopping sealing mechanism is provided on the reverse filtration and sand-prevention mechanism, including an upper water-stopping component and a lower water-stopping component respectively located at the top and bottom of the filter cylinder. The upper water-stopping component includes an upper rubber pad and an upper pressure plate, and the lower water-stopping component includes a lower pressure plate and a concave rubber pad. By applying a pressure load to the upper pressure plate, the upper rubber pad and the concave rubber pad are pressed tightly together. The inner wall of the steel casing is tightly fitted to form a double flexible waterproof barrier; a controllable pressure relief mechanism includes a drain pipe and a pressure relief valve. The inlet end of the drain pipe is connected to the outlet at the center of the top of the filter cartridge. The pressure relief valve controls the water flow and continuously releases the high-pressure water head in the well to counteract the upward buoyancy of the water pressure; and a pressing and fixing mechanism applies a load to the top of the upper water stop and slowly presses it down step by step to counteract the upward buoyancy of the pressurized water; the device is pressed down to the designed sealing elevation by the pressing and fixing mechanism, and the outer edge of the upper pressure plate is fully welded to the inner wall of the steel casing to form the first rigid waterproof layer; after the leak test is qualified, the drain pipe and the pressing and fixing mechanism are disassembled, and underwater concrete is poured into the temporary dewatering well until it is below the raft surface layer; the exposed steel casing at the top of the raft is cut off, and a steel plate is welded to the concrete surface layer in the well to form the second rigid waterproof layer, completing the permanent sealing of the dewatering well.

[0006] Furthermore, the lower pressure plate is an annular steel plate with an outer diameter smaller than the inner diameter of the steel sleeve. A through hole coaxial with the bottom inlet of the filter cylinder is opened in the center, and its top is welded and fixed to the bottom end face of the filter cylinder. The concave rubber pad is a concave annular rubber component with an outer diameter that matches the inner diameter of the steel sleeve. The central opening is aligned with the through hole of the lower pressure plate and is fixed to the bottom surface of the lower pressure plate by self-tapping screws. The axial thickness of the concave rubber pad gradually increases from the central opening to the outer edge, forming an inward concave slope on the side facing the well, and a thick sealing lip is formed on the outer edge.

[0007] Furthermore, the upper water-stopping component includes an upper rubber pad and an upper pressure plate; the upper rubber pad is an annular rubber gasket, which is fitted onto the lower end of the drain pipe through a central opening, and its bottom fits against the top of the conical confluence part; the upper pressure plate is an annular steel plate, the outer diameter of which is adapted to the inner diameter of the steel sleeve, and the central opening is fitted onto the outer side of the lower end of the drain pipe and welded to the pipe body, and its plate body presses over the upper rubber pad.

[0008] Furthermore, the filter cartridge adopts a circular steel barrel structure with a barrel diameter smaller than the inner diameter of the steel sleeve. Coaxial water passage holes are opened at the center of the bottom and top. The bottom water passage hole is the pressurized water inlet, and the top water passage hole is the filtered water outlet. The filter layer assembly is filled in the internal cavity of the filter cartridge and includes, from bottom to top, a geotextile layer, a gravel layer, a coarse sand layer, a fine sand layer, and a filter screen layer at the top water outlet.

[0009] Furthermore, the conical confluence is located at the top of the inner cavity of the filter cylinder, above the fine sand layer. It is formed by cast-in-place concrete to create an inwardly sloping conical structure. The slope slopes from the inner wall of the filter cylinder toward the central outlet at the top, and an outlet hole coaxial with the top of the filter cylinder is opened at the center.

[0010] Furthermore, the drain pipe includes a vertical pipe, an elbow, and a horizontal pipe; the vertical pipe is arranged vertically, with its lower end sealed and welded to the top outlet of the filter cartridge, and the pipe body is welded and fixed to the center opening of the upper pressure plate; the elbow is a turning pipe fitting, with internal threaded interfaces at both ends, connecting the top of the vertical pipe and the end of the horizontal pipe respectively; the horizontal pipe is arranged horizontally, with one end connected to the elbow via a thread, and the other end serving as a drain outlet; multiple sets of pressure relief valves are provided, and these multiple sets of pressure relief valves are installed in series within the vertical pipe section.

[0011] Preferably, the pressing and fixing mechanism includes a pressing bracket, a pressing assembly, and a first pressure-bearing frame; the pressing bracket is located on top of the upper water stop; the pressing assembly includes a jack and a threaded telescopic rod, the jack is fixedly located at the center of the top of the pressing bracket, and the threaded telescopic rod is provided in four sets, which are respectively arranged in pairs on both sides of the jack; the first pressure-bearing frame is located on top of the pressing assembly, and its top abuts against the upper floor slab or the bottom of the beam, providing a fixed reaction force support point for the jack to lift.

[0012] Preferably, the pressing and fixing mechanism includes a pressing bracket, a top pressing assembly, and a second pressure-bearing frame; the second pressure-bearing frame includes a side bracket, a crossbeam, a circumferential baffle, and a clamp; the circumferential baffle is an annular steel plate, welded and fixed to a set elevation on the outer wall of the steel sleeve; the clamp is tightly fastened to the outer wall of the steel sleeve below the circumferential baffle; the side bracket is provided in two sets, symmetrically arranged on both sides of the steel sleeve, and its lower end is fixedly connected to the clamp.

[0013] Preferably, the pressing and fixing mechanism includes a pressing bracket, a third pressure-bearing frame, and a lever pressing assembly; the third pressure-bearing frame is fixed to the outer periphery of the steel sleeve and includes a fulcrum square tube, an auxiliary square tube, and a fixed crossbar; the lever pressing assembly includes a toothed rod, a locking crossbar, and a pressure rod; the toothed rod is a vertical rod with one-way teeth, which is vertically fixed at the top center of the pressing bracket; the two ends of the locking crossbar are fixed to the fulcrum square tube and the auxiliary square tube respectively by bolts, and an elastic clip is provided in the middle of the rod body, which is inserted into the tooth groove of the toothed rod to form a one-way locking structure; one end of the pressure rod is hinged to the upper part of the fulcrum square tube, and a clip is provided on its rod body, which is a one-way claw structure with an inclined surface. When the pressure rod is pressed down, the clip is inserted into the straight surface of the tooth groove of the toothed rod, transmitting the downward pressure and pushing the toothed rod to move downward synchronously.

[0014] According to another aspect of the present invention, a method for sealing temporary dewatering wells in basements under confined water conditions is also provided, comprising the following steps: S1: During the raft foundation pouring stage, steel casings are placed on top of temporary dewatering wells before the raft foundation is poured, until the project construction reaches the point where dewatering is stopped; S2: Remove the water pump inside the dewatering well, clean the debris, mud and slurry inside the dewatering well, and use a wire brush to clean the dirt attached to the well wall to ensure that there are no obstacles inside the well and the well wall is flat; S3: Lay waterproof protective cloth around the wellhead and compact it to fix it. Place the device coaxially at the wellhead of the steel casing to ensure that the center of the device is aligned with the center of the well. S4: Open the pressure relief valve. The pressurized water in the well is filtered through the sand and soil by the reverse filter and sand prevention mechanism and then continuously discharged outward along the drain pipe to counteract the upward buoyancy of the pressurized water on the device. S5: Apply vertical load to the sealing body by pressing in the fixing mechanism, press down the sealing device slowly in steps, maintain the pressure relief and drainage state throughout the process, gradually offset the buoyancy of the pressurized water, until the sealing device is accurately pressed to the design sealing elevation; during the pressing process, the double-layer rubber pad of the water-stop sealing mechanism is pressed tightly against the inner wall of the steel sleeve to form a circumferential flexible seal and maintain a dry working environment at the top of the device; S6: Relying on the dry working surface, the outer edge of the upper pressure plate is fully welded to the inner wall of the steel sleeve to form the first rigid waterproof layer, which together with the two internal flexible rubber seals constitutes a rigid-flexible composite seepage prevention system. S7: Close the pressure relief valve to cut off the drainage channel and let it stand for 24 hours to observe the leakage. If there is leakage at the weld, open the pressure relief valve to drain the water and then repair the weld. Continue until there is no leakage and the sealing performance meets the standard. S8: After the leak test is passed, all detachable drainage pipe fittings and pressing and fixing mechanisms are removed in sequence, and the pipes are recycled and transported to the next wellhead for reuse; then underwater concrete is poured into the temporary dewatering well until it is below the raft slab surface layer. S9: Cut off the exposed steel casing at the top of the raft, weld a steel plate onto the concrete surface inside the well to form a second rigid waterproof layer, and finally apply anti-corrosion treatment to the surface of the steel plate to complete the permanent sealing of the dewatering well.

[0015] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The temporary dewatering well sealing device of the present invention, through the gradient filter layer structure of the reverse filtration and sand prevention mechanism, can intercept sand particles in the well step by step during the depressurization process of pressurized water, achieving a filtration effect that allows water to pass through but not sand, effectively avoiding the hidden dangers of foundation soil loss, well wall piping and settlement caused by depressurization and drainage, and ensuring the long-term safety of the foundation and main structure; the water-stopping sealing mechanism, through the upper and lower flexible water-stopping components combined with the self-tightening sealing effect of pressurized water, combined with the rigid waterproof layer formed by welding the upper pressure plate and the steel sleeve, together constitutes a rigid-flexible composite seepage prevention system, which can resist the erosion of high pressurized water for a long time and significantly reduce the risk of leakage after the sealing is completed.

[0016] 2. The temporary dewatering well plugging device of the present invention can controllably release the high-pressure water head in the well through the pressure relief valve, fundamentally solving the defects of the plugging device floating and being difficult to enter and position in the well under high pressure head; in conjunction with the pressing and fixing mechanism, it can press down steadily in stages and accurately control the elevation, which can avoid the device from tilting and getting stuck; the dry working environment created by the pressure relief and flexible sealing ensures the welding quality of the upper pressure plate and the steel casing, and the weld leakage can be drained and repaired by opening the valve, and the valve leakage can be directly replaced without the need for overall rework, which greatly improves the efficiency of plugging construction and the first-time pass rate.

[0017] 3. The temporary dewatering well plugging device of the present invention uses threaded, bolted, or hinged assembly connections for its core components such as the pressing and fixing mechanism, drain pipe, and pressure relief valve. After the plugging operation is completed, all components can be disassembled and recycled and transferred to other dewatering wells for reuse. It does not need to be permanently buried in the well for disposal, which greatly reduces the one-time investment in steel materials. At the same time, the construction does not require the use of special high-pressure grouting equipment or airbag inflation equipment, which reduces equipment rental and maintenance costs. Compared with traditional grouting plugging and airbag plugging solutions, the overall cost of plugging a single well is significantly reduced.

[0018] 4. The temporary dewatering well sealing device of the present invention has a pressing and fixing mechanism that can be selected according to different pressure-bearing support forms based on site conditions. It can rely on the upper floor slab and beam to provide reaction force, or it can achieve construction without a roof slab through the lateral bearing structure of the outer wall of the steel sleeve. It can also adopt a manual lever structure to adapt to the operation scenario without hydraulic power, covering most basement dewatering well sealing conditions. In addition, multiple sets of pressure relief valves can be set in series according to the pressure head level to adapt to the construction needs of different water pressure levels. The overall structure can be adapted to various specifications of wellhead pipe diameters and is suitable for temporary dewatering well sealing projects in basements in various low-lying areas and highly permeable foundations. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the precipitation well base in an embodiment of the present invention; Figure 2 This is a schematic diagram of the reverse filtration and sand prevention mechanism and the water-stop sealing mechanism in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the temporary dewatering well sealing device for basements under confined water conditions in the first embodiment of the present invention; Figure 4 This is a schematic diagram of the pressing and fixing mechanism in the second embodiment of the present invention; Figure 5 This is a schematic diagram of the side bracket structure in the second embodiment of the present invention; Figure 6 This is a schematic diagram of the pressing and fixing mechanism in the third embodiment of the present invention; Figure 7 This is a top view of the third pressure-bearing frame in the third embodiment of the present invention; Figure 8 This is a schematic diagram of the rack structure in the third embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the pressure rod and the rack working together in the third embodiment of the present invention; Figure 10 This is a schematic diagram of the pressure bar structure in the third embodiment of the present invention.

[0020] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-The base of the dewatering well, including: 11-Temporary dewatering well, 12-Raft foundation, 13-Steel casing 2-Reverse filtration and sand control mechanism, including: 21-Filter cartridge, 22-Filter layer assembly, 221-Geotextile layer, 222-Gravel layer, 223-Coarse sand layer, 224-Fine sand layer, 225-Filter mesh layer, 23-Conical confluence section; 3-Water-stop sealing mechanism, including: 31-lower water-stop component, 311-lower pressure plate, 312-concave rubber pad, 32-upper water-stop component, 321-upper pressure plate, 322-upper rubber pad; 4-Controllable pressure relief mechanism, including: 41-Drain pipe, 411-Vertical pipe, 412-Elbow, 413-Horizontal pipe, 42-Pressure relief valve; 5- Press-in fixing mechanism, including: 51- Press-in bracket, 511- First leg, 512- First pad, 52- Top pressure assembly, 521- Jack, 522- Threaded telescopic rod, 523- Pad block, 53- First pressure-bearing frame, 531- Second pad, 532- Second leg, 533- Third pad, 54- Second pressure-bearing frame, 541- Side bracket, 5411- Third leg, 5412- Connecting rod, 542- Crossbeam, 543- Circumferential stop. Plate, 544-Clamping hoop, 55-Third bearing frame, 551-Wing ring, 552-Fixing square frame, 553-Support square tube, 554-Auxiliary square tube, 555-Fixing crossbar, 56-Lever pressing assembly, 561-Toothed rod, 562-Securing crossbar, 5621-Elastic fastener, 563-Pressure rod, 5631-Front end rod, 5632-Rear end rod, 5633-Telescopic positioning component, 5634-Sliding groove, 5635-Fasting fastener, 564-Diagonal brace. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] This invention provides a sealing device for a temporary dewatering well in a basement under confined water conditions, comprising a reverse filtration and sand prevention mechanism 2, a water-stopping and sealing mechanism 3, a controllable pressure relief mechanism 4, and a pressing and fixing mechanism 5. The reverse filtration and sand prevention mechanism 2 includes a filter cylinder 21 disposed in the temporary dewatering well 11, a filter layer assembly 22 disposed in the filter cylinder 21, and a conical confluence part 23. The conical confluence part 23 collects the diffused pressurized water from all sides towards the outlet at the center of the top of the filter cylinder 21. The water-stopping and sealing mechanism 3 includes an upper water-stopping component 32 and a lower water-stopping component 31 respectively disposed at the top and bottom of the filter cylinder 21. The upper water-stopping component 32 includes an upper rubber pad 322 and an upper pressure plate 321, and the lower water-stopping component... 31 includes a lower pressure plate 311 and a concave rubber pad 312. By applying a pressing load to the upper pressure plate 321, the upper rubber pad 322 and the concave rubber pad 312 are pressed tightly and closely adhered to the inner wall of the steel sleeve 13, forming a double flexible waterproof barrier. The controllable pressure relief mechanism 4 includes a drain pipe 41 and a pressure relief valve 42. The input end of the drain pipe 41 is connected to the outlet at the center of the top of the filter cylinder 21. The pressure relief valve 42 controls the water output and continuously releases the high-pressure water head in the well to counteract the upward buoyancy of the water pressure. The pressing and fixing mechanism 5 applies a load to the top of the upper water stop 32, slowly pressing it down step by step to counteract the upward buoyancy of the pressurized water and pressing the device down to the designed sealing elevation. The dewatering well sealing device of the present invention relies on the dewatering well base 1. During construction, the pressure relief valve 42 continuously releases pressure to counteract the buoyancy of the water pressure. The reverse filter and sand prevention mechanism 2 prevents sand and soil loss. The device is pressed into place step by step by the pressing and fixing mechanism 5. The double flexible waterproof barrier of the water-stop sealing mechanism 3 provides a temporary dry working surface to complete the rigid welding of the upper pressure plate 321 and the steel sleeve 13. After the valve is closed and leak is checked, all detachable components can be disassembled and recycled. Concrete is poured into the well and a top sealing plate is added to form a double-layer rigid permanent waterproof. It effectively solves the industry problems of easy floating, sand leakage, high construction risk, and large one-time investment in consumables when sealing dewatering wells with high pressure head. It achieves safe, efficient, recyclable, and durable permanent sealing of dewatering wells.

[0023] like Figure 1 As shown, the dewatering well base 1 is the supporting foundation of the entire sealing device of the present invention, including a temporary dewatering well 11, a raft slab 12, and a steel sleeve 13. The temporary dewatering well 11 is a vertical water collection well hole pre-drilled and formed during the foundation pit construction stage; the raft slab 12 is the main reinforced concrete foundation slab of the basement, which is the permanent load-bearing structure of the building; the steel sleeve 13 is a vertical seamless steel cylinder pre-embedded in the raft slab 12, concentrically fitted above the wellhead of the temporary dewatering well 11.

[0024] like Figure 2As shown, the reverse filtration and sand control mechanism 2 is entirely located inside the temporary dewatering well 11 of the dewatering well base 1. It can be lowered to the design elevation as a whole during the pressurization operation. During the controlled depressurization process, it progressively intercepts sand and soil in the well to prevent soil erosion and piping damage. At the same time, it centrally transports the filtered pressurized water to the controlled depressurization mechanism 4 to ensure the continuous unobstructed depressurization channel. The reverse filtration and sand control mechanism 2 includes a filter cylinder 21, a filter layer assembly 22, and a conical confluence section 23.

[0025] The filter cylinder 21 adopts a circular steel barrel structure, with a barrel diameter slightly smaller than the inner diameter of the steel sleeve 13, allowing it to move vertically up and down in the well without getting stuck. The filter cylinder 21 has coaxial water passage holes at the bottom and top center, with the bottom water passage hole serving as the pressurized water inlet and the top water passage hole serving as the filtered water outlet. The inside of the barrel forms a closed receiving cavity for filling the filter layer assembly 22.

[0026] The filter layer assembly 22 is installed inside the filter cylinder 21, and includes, from bottom to top, a geotextile layer 221, a gravel layer 222, a coarse sand layer 223, a fine sand layer 224, and a filter screen layer 225 at the top outlet, forming a five-stage gradient filtration system. The geotextile layer 221 is filled into the bottom inlet hole of the filter cylinder 21, serving as the first filtration barrier. It is used to initially intercept large particles of soil, gravel, and debris in the well, preventing large-diameter particles from entering the filter layer and clogging the gaps between the filter media. At the same time, it supports and limits the gravel layer 222 above, preventing the filter media from scattering and being lost from the bottom inlet. The crushed stone layer 222 fills the bottom layer of the filter cylinder 21, above the geotextile layer 221, and is formed by uniformly filling crushed stone. This crushed stone layer 222 has the largest pore size and serves as the second-stage filtration layer, primarily trapping larger sand particles while also forming the main permeable framework to ensure high-flow-rate water passage and prevent rapid clogging and failure of the filter layer under high-pressure water. The coarse sand layer 223 fills the top of the crushed stone layer 222, formed by uniformly laying coarse-graded sand, with smaller pore sizes than the crushed stone layer 222, and serves as the third-stage filtration layer. Its function is to further trap medium-sized sand particles, progressively refining the filtration accuracy, sharing the filtration load of the upper fine filter media, and extending the effective working time of the entire reverse filtration structure. The fine sand layer 224, filled above the coarse sand layer 223, is formed by fine-graded sand and serves as the final particle filter layer. This fine sand layer 224 can trap fine silt and soil particles in the water, ensuring that the depressurized water is free of silt and sand. This fundamentally prevents the soil around the temporary dewatering well 11 from being carried out during the depressurization process, thus preventing the risks of foundation erosion, settlement, and piping. The filter mesh layer 225 is fixedly installed at the center outlet at the top of the filter cylinder 21. It is made of wire mesh and covers the entire drainage section. On the one hand, it prevents the filter material of the fine sand layer 224 from being washed into the drainage pipe 41 by the high-pressure water flow, avoiding pipe blockage and depressurization failure. On the other hand, it provides final protective filtration for the water flow, maintaining the structural stability of the internal filter layer and preventing interlayer mixing of the filter material under water pressure.

[0027] The conical confluence 23 is located at the top of the inner cavity of the filter cylinder 21, above the fine sand layer 224. It is formed by cast-in-place concrete, creating an inwardly sloping conical structure. The slope slopes from the inner wall of the filter cylinder towards the central outlet at the top, with a water outlet hole coaxial with the top of the filter cylinder at the center. This conical confluence 23 supports the pressurized load transmitted by the water-stop sealing mechanism 3 above, enhancing the structural strength of the top of the filter cylinder. After being filtered by the filter layer assembly 22, the pressurized water disperses upwards from various points on the top surface of the filter layer. The slope of the conical confluence 23 guides all the dispersed pressurized water to the central outlet, concentrating the water flow into the drain pipe 41 of the controllable pressure relief mechanism 4. Simultaneously, this structure prevents water from stagnating at the top of the filter cylinder, ensuring smooth pressure relief and drainage, and evenly distributing the water flow velocity throughout the filter layer, thus improving the overall utilization efficiency of the filter layer.

[0028] The water-stop sealing mechanism 3, in conjunction with the inner wall of the steel sleeve 13, forms a double circumferential water-stop barrier, preventing pressurized water from flowing upwards through the circumferential gap between the device and the steel sleeve 13, thus creating a dry working surface for the rigid welding of the upper pressure plate 321 and the steel sleeve 13. The water-stop sealing mechanism 3 includes a lower water-stop component 31 and an upper water-stop component 32.

[0029] The lower water-stopping component 31 is located at the bottom of the reverse filter sand-prevention mechanism 2, forming the first bottom flexible water-stopping barrier. It includes a lower pressure plate 311 and a concave rubber pad 312. The lower pressure plate 311 is an annular steel plate with an outer diameter slightly smaller than the inner diameter of the steel sleeve 13. A through hole coaxial with the bottom inlet of the filter cylinder 21 is opened in the center. Its top is welded and fixed to the bottom end face of the filter cylinder 21, serving as the mounting base for the concave rubber pad 312 and transmitting the vertical pressing load to ensure uniform stress on the bottom structure of the filter cylinder. The concave rubber pad 312 is a concave annular rubber component with an outer diameter adapted to the inner diameter of the steel sleeve 13. The central opening is aligned with the through hole of the lower pressure plate 311 and is fixed to the bottom surface of the lower pressure plate 311 by self-tapping screws. The axial thickness of the concave rubber pad 312 gradually increases from the central opening to the outer edge, forming an inward concave slope on the side facing the well. The outer edge forms a thick sealing lip. Due to the large outer edge, the elastic deformation margin is more sufficient after being compressed, allowing it to tightly fit the inner wall of the steel casing 13, filling the small unevenness and weld defects of the well wall, and forming a continuous closed circumferential waterstop. At the same time, the inward concave slope of the concave rubber pad 312 faces the water inlet side. When pressurized water rushes upward, the water pressure directly acts on the inward concave slope. The outer edge of the rubber pad is pushed radially outward and pressed axially upward, so that the fit between the rubber pad and the inner wall of the steel sleeve 13 and the bottom surface of the lower pressure plate 311 increases synchronously with the increase of water head pressure, forming a water pressure self-tightening sealing effect. The thinner central section of the concave rubber pad 312 deforms less under pressure, and will not excessively compress the geotextile layer 221 at the inlet, preventing the geotextile from being compacted and blocked, maintaining the water permeability of the filter layer, and ensuring the continuous drainage capacity of the controllable pressure relief mechanism 4. The structure of the concave rubber pad 312, which is thick at the outer edge and thin at the center, forms a convex guide lip at the bottom of the device. When the entire device is pressed down, the thick outer edge contacts the inner wall of the steel sleeve 13 first, automatically centering and correcting the deviation, avoiding the device from being eccentric, tilting, or stuck in the well wall. Meanwhile, the thick outer edge serves as the main friction contact surface, providing stronger resistance to wear and scratches. It can withstand scratches from well wall burrs, welding slag, and concrete laitance, ensuring the sealing surface remains intact and effective throughout the entire step-by-step pressing process, preventing leakage due to friction damage.

[0030] The upper water-stopping component 32 is located at the top of the reverse filter sand-prevention mechanism 2, above the conical confluence 23, forming a second top flexible water-stopping barrier. It includes an upper rubber pad 322 and an upper pressure plate 321. The upper rubber pad 322 is an annular rubber gasket, which is fitted onto the outside of the vertical pipe 411 of the drain pipe 41 through a central opening, with its bottom fitting against the top of the conical confluence 23. The upper rubber pad 322 has good elasticity and pressure-bearing deformation capacity, and can expand and extend radially after being pressed, tightly fitting against the inner wall of the steel sleeve 13. The upper pressure plate 321 is an annular steel plate with an outer diameter that matches the inner diameter of the steel sleeve 13. It is fitted onto the outside of the vertical pipe 411 through a central opening and welded to the pipe body. The plate covers the upper rubber pad 322, and its top surface is the direct pressure surface for the pressing and fixing mechanism 5, while its outer edge is the working edge for later welding to the steel sleeve 13.

[0031] When the water-stop sealing mechanism 3 performs the sealing operation, the downward pressure of the pressing and fixing mechanism 5 acts directly on the upper pressure plate 321, pushing the entire device down while vertically squeezing the upper rubber pad 322, causing it to compress and expand circumferentially, tightly fitting against the inner wall of the steel sleeve 13 to form a top circumferential water-stop strip; together with the bottom concave rubber pad 312, it forms a double seal, completely blocking the water leakage channel in the circumferential gap. After the device is pressed into place, the outer edge of the upper pressure plate 321 is fully welded to the steel sleeve 13 to form a rigid waterproof layer, which, together with the two internal flexible rubber seals, constitutes a rigid-flexible composite seepage prevention system, greatly improving the long-term seepage resistance of the sealing structure and reducing the risk of later leakage.

[0032] The controllable pressure relief mechanism 4 actively releases the high-pressure water head in the well to counteract the upward buoyancy of the pressurized water on the sealing device, solving the problem of the device floating and being difficult to press into place under high pressure conditions. At the same time, it works with the water-stop sealing mechanism 3 to maintain a dry working environment at the top of the device, providing working conditions for rigid welding and leakage repair. The controllable pressure relief mechanism 4 includes a drain pipe 41 and a pressure relief valve 42.

[0033] The drain pipe 41 serves as a channel for guiding and discharging pressurized water, comprising a vertical pipe 411, an elbow 412, and a horizontal pipe 413. The vertical pipe 411 is installed vertically, with its lower end sealed and welded to the top outlet of the filter cartridge 21. The pipe body is welded and fixed to the center opening of the upper pressure plate 321. This vertical pipe 411 receives filtered, clean pressurized water and directs the water flow vertically upwards. The elbow 412 is a 90° turning fitting with internal threaded interfaces at both ends, connecting the top of the vertical pipe 411 to the end of the horizontal pipe 413. Its function is to redirect the vertically upward water flow in the vertical pipe 411 to a horizontal output, preventing high-pressure water from splashing upwards and contaminating the construction site, thus protecting the safety of workers. It also guides the water flow orderly to the drainage system around the wellhead. The horizontal pipe 413 is installed horizontally, with one end connected to the elbow 412 via a thread, and the other end serving as a drain outlet. An external drainage hose can be connected to guide the pressurized water to a designated collection point, preventing water accumulation and overflow around the wellhead. This pipe section is a completely detachable component with no permanent fixed connection. It can be removed and recycled first after passing the leak test.

[0034] The pressure relief valve 42 is a pressure-bearing shut-off valve. It is equipped with multiple sets according to the water pressure conditions. Multiple sets of pressure relief valves 42 are installed in series in the pipe section of the vertical pipe 411 to reduce pressure in stages and improve the control accuracy.

[0035] When the controllable pressure relief mechanism 4 performs drainage and pressure relief operations, after the sealing device is placed into the wellhead, the pressure relief valve 42 is kept fully open throughout the process. The pressurized water in the well is filtered by the reverse filter and sand prevention mechanism 2 and then continuously discharged outward along the vertical pipe 411, elbow 412 and horizontal pipe 413. This stage involves actively releasing the high-pressure water head inside the well through high-flow-rate water discharge, significantly offsetting the upward buoyancy of the pressurized water on the device, fundamentally solving the problem of the sealing device floating and failing to sink into place under high water head, and creating the force conditions for the step-by-step pressing operation of the pressing and fixing mechanism 5; after the device is pressed into the design elevation, the opening of the pressure relief valve 42 is adjusted to maintain stable water discharge, and with the upper and lower flexible seals of the water-stop sealing mechanism 3, all pressurized water is discharged from the central water discharge pipeline, completely blocking water leakage through the circumferential gap, ensuring that there is no water accumulation or gushing water on the top surface of the upper pressure plate 321, providing a dry construction environment for the full welding operation of the upper pressure plate 321 and the steel casing 13, avoiding weld defects and leakage risks caused by welding with water; after the welding is completed and the weld has cooled, the pressure relief valve 42 is completely closed, cutting off the entire water discharge channel, and the device is left to stand for 24 hours for leakage detection. If leakage occurs at the weld of the upper pressure plate 321, the pressure relief valve 42 can be reopened to drain the accumulated water. After drying, repair welding can be performed. If leakage occurs in the valve body, the pressure relief valve 42 can be directly disassembled and replaced until there is no leakage and the sealing performance meets the standards. After the leak test is qualified, the horizontal pipe 413, elbow 412, pressure relief valve 42 and the upper vertical pipe section are removed in sequence. All pipe fittings can be transferred to the next dewatering well for reuse, without the need to be buried in the well for permanent disposal, which greatly reduces the cost of engineering materials.

[0036] like Figure 3 As shown, in the first embodiment of the present invention, the pressing and fixing mechanism 5 is used to provide stable and controllable downward pressure, counteract the upward buoyancy generated by the high-pressure water in stages, and accurately press the main body of the device, which consists of the reverse sand filter mechanism 2, the water-stop sealing mechanism 3, and the controllable pressure relief mechanism 4, into the temporary dewatering well 11 at the designed elevation; it includes a pressing bracket 51, a top pressure component 52, and a first pressure-bearing frame 53.

[0037] The pressing bracket 51 is a lower force transmission base, which is placed directly on the top of the upper pressure plate 321 to evenly transmit the top pressure to the sealing body. It includes a first support leg 511 and a first pad 512. The first pad 512 is a steel pad, which provides a flat pressure base for the downward pressure load. The first support leg 511 is a steel support leg, which has four legs, which are vertically welded to the bottom of the first pad 512 respectively. The bottom of the four first support legs 511 contacts the upper pressure plate 321 and is evenly spaced around the top of the upper pressure plate 321 in the circumferential direction to ensure that the downward pressure is centered and without eccentricity, and to prevent the device from tilting and getting stuck in the well.

[0038] The top-pressing assembly 52 includes a jack 521 and a threaded telescopic rod 522. The jack 521 is fixedly installed at the top center of the first pad 512. It pushes the sealing body downward through the lifting stroke, and the pressing speed and pressure can be precisely controlled. The threaded telescopic rod 522 is provided in four sets, which are respectively paired on both sides of the jack 521. Its bottom is fixedly connected to the first pad 512, and its top is in contact with the bottom of the first pressure frame 53. When the jack 521 has exhausted its single lifting stroke and needs to return oil and add pad blocks, the threaded telescopic rod 522 extends and supports between the pressing bracket 51 and the first pressure frame 53, temporarily bearing all the vertical load and preventing the sealing body from rebounding and floating under water pressure.

[0039] The first bearing frame 53 is an upper reaction force bearing structure, with its top abutting against the upper floor slab or beam bottom, providing a fixed reaction force support point for the lifting of the jack 521. It includes a second pad 531, a second support leg 532, and a third pad 533. The second pad 531 is located on top of the jack 521, with its bottom being the force-bearing surface for the lifting of the jack 521. It is parallel and aligned with the first pad 512 below, ensuring that the force axis of the jack coincides with the center of the sealing device. The second support leg 532 has four legs, with both ends vertically fixed to the bottom surface of the third pad 533 and the second pad 531, forming a rigid force transmission frame to ensure vertical transmission of the reaction force. The third pad 533 is fixedly installed on the second support leg 532, with its top flat against the upper structural floor slab or beam bottom, distributing the reaction force evenly to the structural surface and preventing local stress from damaging the concrete structure.

[0040] During the jacking operation, first complete the assembly of the pressing and fixing mechanism 5, so that the third pad 533 is pressed against the upper structure to form a fixed reaction end. The jack 521 is placed in the center between the first pad 512 and the second pad 531. Start the jack 521 to lift, and the vertical load is evenly transferred to the sealing body through the pressing bracket 51, overcoming the buoyancy of the pressurized water and pushing the device to sink smoothly. After the single lifting stroke is exhausted, the threaded telescopic rod 522 is extended for support; the jack 521 is depressurized and the oil is returned, and a pad is added to its bottom to raise the lifting benchmark; after removing the threaded telescopic rod 522, the jack is lifted again, and the cycle is repeated until the sealing device is pressed into the design elevation.

[0041] like Figure 4-5 As shown, in the second embodiment of the present invention, the pressing and fixing mechanism 5 includes a pressing bracket 51, a top pressing component 52, and a second pressure-bearing frame 54. This pressing and fixing mechanism 5 solves the construction problem of having no upper floor slab or beam bottom as a support point, and is suitable for working conditions where there is no structure above the well opening and insufficient clearance.

[0042] The press-in bracket 51 and the top pressing component 52 are completely identical to those in the first embodiment.

[0043] The second pressure-bearing frame 54 serves as an external reaction force bearing structure, including a side support 541, a crossbeam 542, a circumferential baffle 543, and a clamp 544. The circumferential baffle 543 is a ring-shaped steel plate, welded and fixed to a predetermined elevation on the outer wall of the steel sleeve 13. It acts as a vertical shoulder for the clamp 544, bearing the downward reaction force and transmitting it to the steel sleeve wall, preventing the clamp from sliding under pressure. The clamp 544 is a split steel clamp, encircling and fastening the outer wall of the steel sleeve 13 below the circumferential baffle 543, and is fixed by tightening end bolts. The clamp extends outwards on both sides and is fixedly connected to the side support 541. Two sets of side supports 541 are symmetrically arranged on both sides of the steel sleeve 13. Each set of side supports 541 includes a third leg 5411 and a connecting rod 5412. The third leg 5411 is a square tube with two parallel vertically arranged legs. The bottom of the two third legs 5411 is fixedly connected to the clamp 544, and the top is connected as a whole by the horizontally arranged connecting rod 5412. The two ends of the crossbeam 542 are fixedly connected to the two sets of connecting rods 5412 respectively. Its bottom is in contact with the top of the jack 521. Its bottom serves as the lifting reaction surface of the jack 521, transmitting the jacking force to the clamp 544 and the steel sleeve 13 through the two side supports 541.

[0044] In the second embodiment of the present invention, when the pressing and fixing mechanism 5 performs the pressing operation, a circumferential baffle 543 is first welded to the outer wall of the steel sleeve 13. Two sets of clamps 544 are fastened to the bottom of the baffle and the bolts are tightened for fixation. Simultaneously, the side brackets 541 and the crossbeam 542 are assembled on both sides. The lower end of the side bracket 541 is welded to the outside of the clamp 544 to form a pressure-bearing frame with the steel sleeve 13 pipe wall as the reaction force basis. The pressing bracket 51 and the jack 521 are placed on the top of the upper water stop 32, and the top of the jack 521 is pressed against the bottom surface of the crossbeam 542. The jack is started to lift, and the reaction force is provided by the blocking action of the circumferential baffle to push the sealing device downward. Similarly, by adding a pad 523 and cooperating with the threaded telescopic rod 522, the operation is repeated until the device reaches the design elevation.

[0045] like Figure 5-10 As shown, in the third embodiment of the present invention, the pressing and fixing mechanism 5 includes a pressing bracket 51, a third pressure-bearing frame 55, and a lever pressing assembly 56. This pressing and fixing mechanism 5 does not require hydraulic power equipment, but achieves precise pressing by relying on the lever principle. At the same time, it solves the problem of pressing rebound through a one-way toothed structure, and is suitable for working conditions with no power equipment, variable wellhead diameters, and high pressing accuracy requirements.

[0046] The third pressure-bearing frame 55 is fixed to the outer periphery of the steel sleeve 13 and includes a wing ring 551, a fixed square frame 552, a fulcrum square tube 553, an auxiliary square tube 554, and a fixed crossbar 555. The wing ring 551 is an annular steel wing plate welded to the outer wall of the steel casing 13, serving as a vertical limiting stop for the fixed frame 552 and bearing the downward pressure reaction force. The fixed frame 552 includes multiple square tubes, which are bolted together to form an annular frame that surrounds and is fixed to the outer wall of the steel casing below the wing ring 551. It is detachable and transportable, and adaptable to wellheads of different pipe diameters. The fulcrum square tube 553 is set vertically and fixedly connected to one side of the fixed frame 552. The auxiliary square tube 554 is symmetrically arranged with the fulcrum square tube 553, and its lower end is fixedly connected to the other side of the fixed frame 552. The fixed crossbar 555 is arranged horizontally, and its two ends are fixedly connected to the upper end of the fulcrum square tube 553 and the auxiliary square tube 554 respectively by bolts, enhancing the overall lateral stability of the frame and preventing the supports on both sides from expanding and deforming under pressure.

[0047] The lever pressing assembly 56 includes a toothed rod 561, a locking crossbar 562, a pressure rod 563, and a diagonal brace 564. The toothed rod 561 is a vertical rod with one-way teeth, vertically fixed to the center of the first pad 512. Its rod body is segmented with tongue and groove joints and can be lengthened according to the pressing depth. The locking crossbar 562 is bolted to the fulcrum square tube 553 and the auxiliary square tube 554 respectively. An elastic locking element 5621 is provided in the middle of the rod body. This elastic locking element 5621 engages with the tooth groove of the toothed rod 561, forming a one-way locking structure, allowing the toothed rod 561 to move downwards and preventing it from moving downwards. 1. Upward rebound; The pressure rod 563 is a telescopic lever component, hinged to the upper part of the fulcrum square tube 553. Through the lever amplification principle, it converts manual downward pressure into a vertical downward thrust of the toothed rod 561. Simultaneously, it relies on a telescopic structure to achieve adjustable lever arm and a one-way locking structure to achieve step-by-step downward pressure anti-rebound. It includes a front rod 5631, a rear rod 5632, a telescopic positioning component 5633, a sliding groove 5634, and a locking component 5635; the front rod 5631 and the fulcrum square tube... The upper part of rod 553 is hinged to form a lever fulcrum. Its rear end has an inner cavity with a spring fixed to its end face. The front end of the rear end rod 5632 is an insertion section that slides within the inner cavity of the front end rod 5631 and is fixedly connected to the other end of the spring, allowing relative sliding along the axial direction of the rod. The sliding groove 5634 is an elongated through groove along the axial direction of the rod, corresponding to the side walls of the front end rod 5631 and the rear end rod 5632. The telescopic positioning element... 5633 is a screw-type positioning component that passes through the sliding groove 5634 and is locked by a locking nut to fix the current telescopic length and lock the total lever arm of the pressure rod, adapting to different downward pressure resistance conditions. The clamping fastener 5635 is located at the bottom of the rear rod 5632 and engages with the one-way tooth groove of the toothed rod 561. The clamping fastener 5635 is a one-way claw structure with a bevel. When the pressure rod is pressed down, the claw engages with the straight surface of the tooth groove, transmitting the downward pressure and pushing the toothed rod to move downward synchronously. There are two sets of diagonal braces 564. One set of diagonal braces 564 connects the fulcrum square tube 553 and the locking crossbar 562 respectively, and the other set of diagonal braces 564 connects the auxiliary square tube 554 and the locking crossbar 562 respectively, enhancing the vertical load-bearing capacity of the locking crossbar 562 and preventing the crossbar from deforming and failing when the clamping component is under force.

[0048] In the third embodiment of the present invention, when the pressing and fixing mechanism 5 performs the pressing operation, the third pressure-bearing frame 55 is fixed to the outer wall of the steel sleeve 13 by the wing ring 551, the toothed rod 561 is vertically aligned with the center of the sealing device, and the bottom is attached to the upper pressure plate 321 by the pressing bracket 51. Pressing down on the free end of the pressing rod 563 amplifies the downward pressure through the lever, pushing the toothed rod 561 downward and causing the sealing body to sink; after a single pressing stroke, the elastic clip 5621 engages with the corresponding tooth groove of the toothed rod, locking the position of the toothed rod 561 to prevent rebound. After lifting the pressing rod 563 to reset, it is pressed down again, and the cycle is repeated to gradually press the device to the design elevation; if the pressing depth is insufficient, the toothed rod 561 can be lengthened by tongue and groove connection to meet the requirement of deep pressing.

[0049] The temporary dewatering well sealing device of the present invention, through the gradient filter layer structure of the reverse filtration and sand prevention mechanism, can intercept sand particles in the well step by step during the depressurization process of pressurized water, achieving a filtration effect that allows water to pass through but not sand, effectively avoiding the hidden dangers of foundation soil loss, well wall piping and settlement caused by depressurization and drainage, and ensuring the long-term safety of the foundation and main structure; the water-stopping sealing mechanism, through the upper and lower flexible water-stopping components combined with the self-tightening sealing effect of pressurized water, combined with the rigid waterproof layer formed by welding the upper pressure plate and the steel sleeve, together constitute a rigid-flexible composite seepage prevention system, which can resist the erosion of high pressurized water for a long time and significantly reduce the risk of leakage after the sealing is completed.

[0050] The temporary dewatering well plugging device of this invention can controllably release the high-pressure water head in the well through a pressure relief valve, fundamentally solving the defects of the plugging device floating and being difficult to insert into the well under high pressure head. With the step-by-step and stable pressing and precise control of the elevation of the pressing and fixing mechanism, the device can avoid tilting and jamming. The dry working environment created by the pressure relief and flexible sealing ensures the welding quality of the upper pressure plate and the steel casing. Moreover, the leakage of the weld can be drained and repaired by opening the valve, and the leakage of the valve can be directly replaced without the need for overall rework, which greatly improves the efficiency of the plugging construction and the first-time pass rate.

[0051] The temporary dewatering well plugging device of the present invention uses threaded, bolted, or hinged assembly connections for its core components such as the pressing and fixing mechanism, drain pipe, and pressure relief valve. After the plugging operation is completed, it can be completely dismantled and recycled, and transferred to other dewatering wells for reuse. It does not need to be permanently buried in the well for disposal, which greatly reduces the one-time investment in steel materials. At the same time, the construction does not require the use of special high-pressure grouting equipment or airbag inflation equipment, which reduces equipment rental and maintenance costs. Compared with traditional grouting plugging and airbag plugging solutions, the overall cost of plugging a single well is significantly reduced.

[0052] The temporary dewatering well sealing device of the present invention has a pressing and fixing mechanism that can be selected according to different pressure-bearing support forms based on site conditions. It can rely on the upper floor slab and beam to provide reaction force, or it can achieve construction without a roof slab through the lateral bearing structure of the outer wall of the steel sleeve. It can also adopt a manual lever structure to adapt to operation scenarios without hydraulic power, covering most basement dewatering well sealing conditions. In addition, multiple sets of pressure relief valves can be connected in series according to the pressure head level to adapt to the construction needs of different water level pressures. The overall structure can be adapted to various specifications of wellhead pipe diameters, and is suitable for temporary dewatering well sealing projects in basements in various low-lying areas and highly permeable foundations.

[0053] Another embodiment of the present invention provides a method for sealing temporary dewatering wells in basements under confined water conditions, comprising the following steps: S1: During the raft foundation pouring stage, after placing the steel casing 13 on the top of the temporary dewatering well 11, the raft foundation 12 is poured until the project construction reaches the point where dewatering is stopped. S2: Remove the water pump inside the dewatering well, clean the debris, mud and slurry inside the dewatering well, and use a wire brush to clean the dirt attached to the well wall to ensure that there are no obstacles inside the well and the well wall is flat; S3: Lay waterproof protective cloth around the wellhead and compact it to fix it. Place the device coaxially at the wellhead of steel casing 13 to ensure that the center of the device is aligned with the center of the well. S4: Open the pressure relief valve 42. After the pressurized water in the well is filtered through the sand and soil by the reverse filter sand prevention mechanism 2, it is continuously discharged outward along the drain pipe 41 to counteract the upward buoyancy of the pressurized water on the device. S5: Apply vertical load to the sealing body by pressing in the fixing mechanism 5, and slowly press down the sealing device step by step, maintaining a depressurization and drainage state throughout the process, gradually offsetting the buoyancy of the pressurized water, until the sealing device is precisely pressed to the design sealing elevation; during the pressing process, the double-layer rubber pad of the water-stop sealing mechanism 3 is pressed tightly against the inner wall of the steel sleeve to form a circumferential flexible seal, maintaining a dry working environment at the top of the device; S6: Relying on the dry working surface, the outer edge of the upper pressure plate 321 is fully welded to the inner wall of the steel sleeve 13 to form the first rigid waterproof layer, which together with the two internal flexible rubber seals constitutes a rigid-flexible composite seepage prevention system. S7: Close the pressure relief valve 42 to cut off the drainage channel, and let it stand for 24 hours to observe the leakage. If there is leakage at the weld, open the pressure relief valve to drain the water and then repair the weld. Continue until there is no leakage and the sealing performance meets the standard. S8: After the leak test is passed, all detachable drainage pipe fittings and pressing-in fixing mechanism 5 are removed in sequence, and recycled and transported to the next wellhead for reuse; then underwater concrete is poured into the temporary dewatering well 11 until it is below the raft slab surface layer. S9: Cut off the exposed steel casing 13 above the top of the raft 12, weld a steel plate to the concrete surface inside the well to form a second rigid waterproof layer, and finally perform anti-corrosion treatment on the surface of the steel plate to complete the permanent sealing of the dewatering well.

[0054] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for sealing temporary dewatering wells in basements under confined water conditions, characterized in that, include: The reverse filtration and sand control mechanism (2) installed in the temporary dewatering well (11) includes a filter cylinder (21), a filter layer assembly (21) installed in the filter cylinder (21) and a conical confluence part (23). The filter layer assembly (21) performs gradient filtration on the pressurized water; the conical confluence part (23) collects the filtered pressurized water that is scattered around to the outlet at the center of the top of the filter cylinder (21). The water-stop sealing mechanism (3) provided on the reverse filter sand prevention mechanism (2) includes an upper water-stop component (32) and a lower water-stop component (31) respectively provided on the top and bottom of the filter cylinder (21). The upper water-stop component (32) includes an upper rubber pad (322) and an upper pressure plate (321). The lower water-stop component (31) includes a lower pressure plate (311) and a concave rubber pad (312). By applying a pressing load to the upper pressure plate (321), the upper rubber pad (322) and the concave rubber pad (312) are pressed tightly and closely attached to the inner wall of the steel sleeve (13) to form a double flexible waterproof barrier. The controllable pressure relief mechanism (4) includes a drain pipe (41) and a pressure relief valve (42). The input end of the drain pipe (41) is connected to the outlet at the center of the top of the filter cylinder (21). The water output is controlled by the pressure relief valve (42) to continuously release the high pressure head in the well and counteract the upward buoyancy of the water pressure. And the pressing and fixing mechanism (5) applies a load to the top of the upper water stop (32) and slowly presses down in stages to counteract the upward buoyancy of the pressurized water; The device is pressed down to the designed sealing elevation by pressing in the fixing mechanism (5), and the outer edge of the upper pressure plate (321) is fully welded to the inner wall of the steel sleeve (13) to form the first rigid waterproof layer. After the leak test is qualified, the drain pipe and the pressing in the fixing mechanism (5) are disassembled, and underwater concrete is poured into the temporary dewatering well (11) until it is below the raft surface layer. The exposed steel sleeve (13) on the top of the raft (12) is cut off, and a steel plate is welded on the concrete surface layer in the well to form the second rigid waterproof layer, thus completing the permanent sealing of the dewatering well.

2. The device for sealing temporary dewatering wells in basements under confined water conditions according to claim 1, characterized in that, The lower pressure plate (311) is an annular steel plate with an outer diameter smaller than the inner diameter of the steel sleeve (13). A through hole coaxial with the bottom inlet of the filter cylinder (21) is opened in the center, and its top is welded and fixed to the bottom end face of the filter cylinder (21). The concave rubber pad (312) is a concave annular rubber component with an outer diameter that matches the inner diameter of the steel sleeve (13). The central opening is aligned with the through hole of the lower pressure plate (311) and is fixed to the bottom surface of the lower pressure plate (311) by self-tapping screws. The axial thickness of the concave rubber pad (312) gradually increases from the central opening to the outer edge, forming an inward concave slope on the side facing the well, and a thick sealing lip is formed on the outer edge.

3. The device for sealing temporary dewatering wells in basements under confined water conditions according to claim 2, characterized in that, The upper water stop component (32) includes an upper rubber pad (322) and an upper pressure plate (321); the upper rubber pad (322) is an annular rubber pad, which is fitted onto the lower end of the drain pipe (41) through a central opening, and its bottom is in contact with the top of the conical confluence part (23); the upper pressure plate (321) is an annular steel plate, the outer diameter of which is adapted to the inner diameter of the steel sleeve (13), the central opening is fitted onto the outer side of the lower end of the drain pipe (41) and welded and fixed to the pipe body, and its plate body is pressed over the upper rubber pad (322).

4. A sealing device for temporary dewatering wells in basements under confined water conditions according to any one of claims 1-3, characterized in that, The filter cylinder (21) adopts a circular steel barrel structure with a barrel diameter smaller than the inner diameter of the steel sleeve (13). Coaxial water passage holes are opened at the center of the bottom and top. The bottom water passage hole is the pressurized water inlet, and the top water passage hole is the filtered water outlet. The filter layer assembly (22) is filled in the internal cavity of the filter cylinder (21) and includes a geotextile layer (221), a gravel layer (222), a coarse sand layer (223), a fine sand layer (224), and a filter screen layer (225) at the top water outlet, arranged sequentially from bottom to top.

5. A sealing device for temporary dewatering wells in basements under confined water conditions according to claim 4, characterized in that, The conical confluence part (23) is located at the top of the inner cavity of the filter cylinder (21), above the fine sand layer (224). It is formed by cast-in-place concrete to form an inwardly sloping conical structure. The slope surface slopes from the inner wall of the filter cylinder towards the central outlet at the top, and an outlet hole coaxial with the top of the filter cylinder is opened at the center.

6. A sealing device for temporary dewatering wells in basements under confined water conditions according to any one of claims 1-3, characterized in that, The drain pipe (41) includes a vertical pipe (411), an elbow (412), and a horizontal pipe (413). The vertical pipe (411) is set in a vertical direction, and its lower end is sealed and welded to the top outlet of the filter cylinder (21). The pipe body is welded and fixed to the center opening of the upper pressure plate (321). The elbow (412) is a turning pipe fitting, and both ends are provided with internal thread interfaces, which are respectively connected to the top end of the vertical pipe (411) and the end of the horizontal pipe (413). The horizontal pipe (413) is set in a horizontal direction, and one end is connected to the elbow (412) by a thread, and the other end is a drain outlet. The pressure relief valve (42) is provided in multiple sets, and multiple sets of pressure relief valves (42) are installed in series in the pipe section of the vertical pipe (411).

7. A sealing device for temporary dewatering wells in basements under confined water conditions according to any one of claims 1-3, characterized in that, The pressing and fixing mechanism (5) includes a pressing bracket (51), a top pressing assembly (52), and a first pressure-bearing frame (53); the pressing bracket (51) is located on the top of the upper water stop (32); the top pressing assembly (52) includes a jack (521) and a threaded telescopic rod (522), the jack (521) is fixedly located at the center of the top of the pressing bracket (51), and the threaded telescopic rod (522) is provided in four sets, which are respectively paired on both sides of the jack (521); the first pressure-bearing frame (53) is located on the top of the top pressing assembly (52), and its top abuts against the upper floor slab or the bottom of the beam, providing a fixed reaction force support point for the jack (521) to lift.

8. A sealing device for temporary dewatering wells in basements under confined water conditions according to any one of claims 1-3, characterized in that, The pressing and fixing mechanism (5) includes a pressing bracket (51), a top pressing component (52), and a second pressure-bearing frame (54); the second pressure-bearing frame (54) includes a side bracket (541), a crossbeam (542), a circumferential baffle (543), and a clamp (544); the circumferential baffle (543) is an annular steel plate, which is welded and fixed to a set elevation on the outer wall of the steel sleeve (13); the clamp (544) is clamped on the outer wall of the steel sleeve (13) below the circumferential baffle (543); the side bracket (541) is provided in two sets, which are symmetrically arranged on both sides of the steel sleeve (13), and its lower end is fixedly connected to the clamp (544).

9. A sealing device for temporary dewatering wells in basements under confined water conditions according to any one of claims 1-3, characterized in that, The pressing and fixing mechanism (5) includes a pressing bracket (51), a third pressure-bearing frame (55), and a lever pressing assembly (56); the third pressure-bearing frame (55) is fixed to the outer periphery of the steel sleeve (13) and includes a fulcrum square tube (553), an auxiliary square tube (554), and a fixing crossbar (555); the lever pressing assembly (56) includes a toothed bar (561), a locking crossbar (562), and a pressure bar (563); the toothed bar (561) is a vertical rod with unidirectional teeth, which is vertically fixed at the center of the top of the pressing bracket (51); the locking crossbar (562) has two ends connected to the center of the steel sleeve (13), and the lever pressing assembly (563) includes a toothed bar (561), a locking crossbar (562), and a locking crossbar (563). The rod is fixed to the fulcrum square tube (553) and the auxiliary square tube (554) respectively by bolts. The middle part of the rod body is provided with an elastic clip (5621). The elastic clip (5621) is inserted into the tooth groove of the toothed rod (561) to form a one-way locking structure. One end of the pressure rod (563) is hinged to the upper part of the fulcrum square tube (553). The rod body is provided with a fastener (5635). The fastener (5635) is a one-way claw structure with a bevel. When the pressure rod is pressed down, the fastener (5635) is inserted into the straight surface of the tooth groove of the toothed rod (561) to transmit the downward pressure and push the toothed rod (561) to move downward synchronously.

10. A method for sealing temporary dewatering wells in basements under confined water conditions, characterized in that, Includes the following steps: S1: During the raft slab pouring stage, a steel casing (13) is placed on top of the temporary dewatering well (11) before the raft slab (12) is poured, until the project construction reaches the point where dewatering is stopped; S2: Remove the water pump inside the dewatering well, clean the debris, mud and slurry inside the dewatering well, and use a wire brush to clean the dirt attached to the well wall to ensure that there are no obstacles inside the well and the well wall is flat; S3: Lay waterproof protective cloth around the wellhead and compact it. Place the device coaxially at the wellhead of the steel casing (13) to ensure that the center of the device is aligned with the center of the well. S4: Open the pressure relief valve (42). After the pressurized water in the well is filtered through the sand and soil by the reverse filter sand prevention mechanism (2) step by step, it is continuously discharged outward along the drain pipe (41) to counteract the upward buoyancy of the pressurized water on the device. S5: Apply vertical load to the sealing body by pressing in the fixing mechanism (5), press down the sealing device slowly in steps, maintain the pressure relief and drainage state throughout the process, gradually offset the buoyancy of the pressurized water, until the sealing device is accurately pressed to the design sealing elevation; during the pressing process, the double-layer rubber pad of the water-stop sealing mechanism (3) is pressed tightly against the inner wall of the steel sleeve to form a circumferential flexible seal and maintain a dry working environment at the top of the device; S6: Relying on the dry working surface, the outer edge of the upper pressure plate (321) is fully welded to the inner wall of the steel sleeve (13) to form the first rigid waterproof layer, which together with the two internal flexible rubber seals constitutes a rigid-flexible composite seepage prevention system. S7: Close the pressure relief valve (42) to cut off the drainage channel, and let it stand for 24 hours to observe the leakage. If there is leakage at the weld, open the pressure relief valve to drain the water and then repair the weld. Continue until there is no leakage and the sealing performance meets the standard. S8: After the leak test is qualified, all detachable drainage pipe fittings and pressing and fixing mechanisms (5) are removed in sequence and recycled and transported to the next wellhead for reuse; then underwater concrete is poured into the temporary dewatering well (11) until it is below the raft surface layer. S9: Cut off the exposed steel casing (13) at the top of the raft (12), weld a steel plate on the concrete surface inside the well to form a second rigid waterproof layer, and finally perform anti-corrosion treatment on the surface of the steel plate to complete the permanent sealing of the dewatering well.

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