Quick plugging system and construction method for leakage of water-stop curtain in deep foundation pit of water-rich silty sand layer

Abstract

The present invention relates to a rapid plugging system and construction method for the leakage of the water-stop curtain in deep foundation pits with water-rich silty sand layers. Through the technology of isolating water diversion and pressure relief by filling the foundation pit, first, plugs are made with fillers such as cotton wadding, and then a diversion device is used for water diversion, pressure relief and diversion. The diversion device is convenient to manufacture and the construction steps are simple, realizing the rapid plugging of leakage points and improving the construction efficiency; through the technology of rapid backpressure with a flexible cable net water injection bladder bag supported by a steel section support, when water seepage occurs around the foundation pit, water is injected into the flexible cable net water injection bladder bag through a water injection device, and the bladder bag expands to generate a reverse pressure, pressing against the foundation pit wall to quickly block the leakage channel and prevent water seepage, ensuring construction safety. At the same time, the water injection volume and pressure can be flexibly controlled through the water injection system, which can meet the needs of different foundation pit environments; through the technology of backpressure after a blind ditch with a perforated drain pipe filled with gravel is built inside, the groundwater level in the foundation pit can be effectively controlled, reducing the phenomenon of foundation pit leakage.

Description

Technical Field

[0001] The present invention belongs to the field of foundation pit leakage plugging, and particularly relates to a rapid plugging system and construction method for water stop curtain leakage in deep foundation pits in water-rich silty sand layers. Background Technique

[0002] With the continuous advancement of the urbanization process, deep foundation pit projects have been widely applied in the fields of underground construction, subways, tunnels, etc. However, during the construction of deep foundation pits, due to the high groundwater level and complex geological conditions, especially in areas with poor hydrogeological conditions such as water-rich silty sand layers, the problem of water stop in foundation pits has always been a difficult point in construction. Traditional water stop methods such as concrete cut-off walls and steel sheet pile water stops can prevent water leakage to a certain extent, but in areas with soft soil and strong water permeability such as water-rich silty sand layers, the waterproof effect is often not satisfactory. Especially during the excavation of the foundation pit, due to soil layer deformation or improper construction, it is easy to cause the failure of the water stop curtain and lead to leakage.

[0003] Existing water stop technologies usually rely on the continuity and stability of waterproof materials. However, during the construction of deep foundation pits, once leakage occurs, it is difficult to handle and the construction period is tight. Therefore, there is an urgent need for a new plugging system that can quickly solve leakage, is easy to construct, and has a good water stop effect. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a rapid plugging system and construction method for water stop curtain leakage in deep foundation pits in water-rich silty sand layers.

[0005] The construction method of this rapid plugging system for water stop curtain leakage in deep foundation pits in water-rich silty sand layers includes the following specific steps:

[0006] Step 1: The leakage orifice of the foundation pit is plugged with cotton wool filler, and a diversion device is installed to divert the seepage water to the steel pipe well, and the steel pipe well uses a submersible pump to divert the water to the external drainage ditch;

[0007] Step 2: Grout and plug the outside of the water stop curtain of the foundation pit;

[0008] Step 3: Install a water injection bladder bag on the inner side of the foundation pit support structure; the water injection bladder bag is filled with water to seal the seepage channel;

[0009] Step 4: Set a horizontal drainage pipe and a water collecting tank at the internal support to drain the seepage water at the bottom of the foundation pit to the water collecting ditch and water collecting tank outside the foundation pit;

[0010] Step 5: Layout drainage blind ditches inside the foundation pit, and connect the drainage blind ditches inside the foundation pit and the steel pipe wells outside the foundation pit through drainage pipes.

[0011] Preferably, in step one, after the foundation pit leaks, the hole opening is cleaned, plugged with cotton wool filler, and the operation is carried out in the way of combining an excavator with manual work. A diversion device is installed at the leakage hole of the foundation pit. The diversion device includes a galvanized pipe, a lower adapter, and a stop valve. The upper part of the galvanized pipe is wound with hemp yarn to make it easy to insert into the hole. The diversion device diverts the seepage water to the steel pipe well area. A submersible pump is arranged at the upper part of the steel pipe well to divert the water to the external drainage ditch area. Before installing the diversion device, the lower adapter and the stop valve are removed first, and a wooden board is placed on the galvanized pipe.

[0012] Preferably, during the construction of the foundation pit, a steel support is installed on the inner side of the foundation pit support structure, and a flexible cable net and a water injection bladder bag are arranged on the inner side of the steel support. In step three, the surface catchment ditch is connected to the water injection bladder bag through a water injection pipe, and water is injected into the water injection bladder bag through a valve. When the water injection bladder bag is filled with water, the generated expansion pressure acts reversely on the foundation pit wall to seal the seepage channel, so as to achieve the purpose of water stop.

[0013] Preferably, in step three, the steel support is a support structure, and is fixed to the flexible cable net and the water injection bladder bag through a connector. The connector is used to firmly fix the flexible cable net and the water injection bladder bag on the steel support.

[0014] Preferably, in step four, a steel drainage vertical pipe of the foundation pit is arranged on the foundation pit retaining pile, a horizontal drainage pipe is arranged at the inner support of the foundation pit, and a water collecting tank is arranged on the side of the inner support of the foundation pit far away from the foundation pit retaining pile. The horizontal drainage pipe uses a submersible pump to drain the seepage water at the bottom of the foundation pit to the catchment ditch and the water collecting tank outside the foundation pit. Two steel water collecting tank hanging ears are welded on both sides of the water collecting tank, and the water collecting tank is placed on the inner support of the foundation pit through the water collecting tank hanging ears.

[0015] Preferably, in step two, according to the leakage position of the waterproof curtain, the positions of the grouting holes are set, and the grouting holes are arranged in a plum blossom shape. Vertical grouting pipes are used for grouting. During the drilling process of the grouting holes, a drill with a sensor is used to adjust the drilling verticality in real time. A grouting pump, an oil pressure pump, and a mixer are arranged outside the foundation pit for grouting operation, and cement sealing is carried out after grouting.

[0016] Preferably, in step five, a foundation pit trench is excavated at the design position of the drainage blind ditch, medium sand is laid at the bottom and both sides of the trench to form a medium sand filter layer, a permeable geotextile layer is laid on the medium sand filter layer, and graded gravel is arranged on the permeable geotextile layer as a drainage layer. A drain pipe is laid on the permeable geotextile layer. The drain pipe connects the drainage blind ditch in the foundation pit and the steel pipe well outside the foundation pit, and a back pressure valve is arranged on the drain pipe.

[0017] Preferably, there is also a step six after step five. In step six, several steel pipe support piles are driven around the foundation pit. A layer of waterproof and sealing material is sprayed on the inner wall of the steel pipe support piles; a concrete layer reinforced with a steel mesh is wrapped around the outer wall of the steel pipe support piles; a water stop plate is installed at the top of the steel pipe support piles; by setting up drainage pipes to connect multiple steel pipe support piles, a complete drainage system is formed to guide the water flow inside and outside the foundation pit to the external drainage system; the drainage pipes include longitudinal drainage pipes and transverse drainage pipes. The longitudinal drainage pipes are arranged along the depth direction of the foundation pit, and the transverse drainage pipes connect multiple longitudinal drainage pipes.

[0018] The rapid plugging system for the leakage of the water stop curtain in the deep foundation pit with rich water and silty sand layer is constructed by the method described in any one of the above.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1) Through the isolation of the foundation pit filling and the water diversion and pressure relief plugging technology, the present invention first plugs with fillers such as cotton wool, and then uses the diversion device for water diversion and pressure relief and diversion. The diversion device is easy to manufacture and the construction steps are simple, realizing the rapid plugging of the leakage point and improving the construction efficiency.

[0021] 2) Through the rapid backpressure technology of the flexible cable net water injection bladder bag with a steel section support, when water seeps around the foundation pit, water is injected into the flexible cable net water injection bladder bag through the water injection device. The bladder bag expands to generate a reverse pressure, compressing the foundation pit wall, quickly blocking the leakage channel to prevent water seepage and ensuring the construction safety. At the same time, the water injection volume and pressure can be flexibly controlled through the water injection system, meeting the needs of different foundation pit environments.

[0022] 3) Through the backpressure technology after arranging the blind ditch with a gravel-filled perforated drain pipe inside, a gravel-filled perforated drain pipe blind ditch is arranged inside the foundation pit. The water inside the foundation pit is drained to the outside of the foundation pit through the drain pipe in the blind ditch. At the same time, a backpressure valve is set on the drain pipe to prevent the water outside the foundation pit from entering the inside of the foundation pit, effectively controlling the groundwater level inside the foundation pit and reducing the foundation pit leakage phenomenon.

[0023] 4) Through the stable reinforcement technology of the drainage steel pipe support pile, several steel pipe support piles are installed around the foundation pit, and a waterproof and sealing material is sprayed inside the steel pipe, and the external reinforcement protective layer can effectively prevent water leakage and enhance the stability of the pile body. The structure inside and outside the steel pipe support pile realizes the waterproof, drainage and reinforcement functions of the foundation pit. The design of the drainage pipe system can effectively guide the water flow to the external drainage system, maintaining the balance of the water levels inside and outside the foundation pit and avoiding the foundation pit leakage caused by too high water levels. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of plugging and diverting the fillers for the foundation pit leakage;

[0025] Figure 2 It is a schematic diagram of the diversion device;

[0026] Figure 3 It is the grouting plugging diagram of the water stop curtain outside the pit;

[0027] Figure 4 It is the schematic diagram of the rapid backpressure of the flexible cable net water injection bag of the steel support;

[0028] Figure 5 It is the schematic diagram of the rapid drainage of the hanging steel plate drainage groove of the internal support of the retaining pile;

[0029] Figure 6 It is the schematic diagram of the backpressure after the blind ditch of the perforated drain pipe with built-in gravel;

[0030] Figure 7 It is the schematic diagram of the reinforcement and stabilization of the drainage steel pipe support pile.

[0031] Description of the reference numerals: 1 - shear wall; 2 - structural side wall; 3 - leakage area; 4 - cotton wool plugging; 5 - steel pipe well; 6 - graded gravel; 7 - submersible pump; 8 - floor slab; 9 - diversion device; 10 - diversion pipe; 11 - stop valve; 12 - installation handle; 13 - adaptability; 14 - galvanized pipe; 15 - Rongmei pile; 16 - bored cast-in-place pile; 17 - water stop curtain; 18 - cement seal; 19 - grouting pipe; 20 - grouting pump; 21 - oil pump; 22 - mixer; 23 - connector; 24 - water injection bag; 25 - control valve; 26 - catch basin; 27 - flexible cable net; 28 - steel support; 29 - cement mixing pile; 30 - steel drainage riser; 31 - retaining pile; 32 - internal support of the foundation pit; 33 - horizontal drainage pipe; 34 - water collection tank; 35 - medium sand filter layer; 36 - concrete cover plate; 37 - permeable geotextile layer; 38 - drainage blind ditch; 39 - drain pipe; 40 - backpressure valve; 41 - steel pipe support pile; 42 - rubber water stop plate; 43 - reinforced concrete coating; 44 - waterproof coating; 45 - longitudinal drainage pipe; 46 - transverse drainage pipe. Detailed implementation manners

[0032] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0033] Embodiment 1

[0034] As an embodiment, as Figures 1 to 7 shown, the construction method of this rapid plugging system for the leakage of the water stop curtain in the deep foundation pit with water-rich silty sand layer includes the following steps:

[0035] Step 1: Plug the leakage orifice of the foundation pit with cotton wool filler 4, install a diversion device 9 to divert the seepage water to the steel pipe well 5, and the steel pipe well 5 uses a submersible pump 7 to divert the water to the external drainage ditch;

[0036] Step 2: Conduct external grouting plugging of the foundation pit for the waterproof curtain; according to the leakage position of the waterproof curtain, set the positions of the grouting holes, and the grouting holes are arranged in a plum blossom shape. Use the vertical grouting pipe 1 for grouting, and a drill with a sensor is used to adjust the drilling verticality in real time during the drilling process of the grouting holes. A grouting pump 20, an oil pressure pump 21, and a mixer 22 are arranged outside the foundation pit for grouting operations. After grouting, a cement seal 18 is carried out to effectively seal the leakage points of the foundation pit;

[0037] Step 3: Install a water injection bladder 24 inside the foundation pit support structure; the water injection bladder 24 is filled with water to block the seepage channel;

[0038] Step 4: Set a horizontal drainage pipe 33 and a water collection tank 34 at the internal support 32 to divert the seepage water at the bottom of the foundation pit to the catchment ditch 26 and the water collection tank 34 outside the foundation pit;

[0039] Step 5: Lay a drainage blind ditch 38 inside the foundation pit, and connect the drainage blind ditch 38 inside the foundation pit and the steel pipe well 5 outside the foundation pit through a drain pipe 39.

[0040] Embodiment 2

[0041] As another embodiment, this Embodiment 2 is proposed on the basis of Embodiment 1, and a construction method for a rapid plugging system for leakage of the waterproof curtain of a deep foundation pit in a water-rich silty sand layer is more specific:

[0042] As Figure 4 shown, during the construction of the foundation pit, install a steel section support 28 inside the foundation pit support structure, and arrange a flexible cable net 27 water injection bladder 24 inside the support. The steel section support 28 is a support structure and is fixed to the flexible cable net 27 water injection bladder 24 through a connecting piece 23; the connecting piece 23 is used to firmly fix the flexible cable net water injection bladder on the steel section support to ensure its stable displacement during the application of back pressure. The flexible cable net 27 water injection bladder 24 is made of water-resistant materials, has flexibility and elasticity, and is installed inside the foundation pit support structure.

[0043] In Step 1, it involves the technology of isolating, diverting water, and relieving pressure with fillers for the foundation pit: As Figure 1 and Figure 2As shown in the figure, after the foundation pit leaks, clean the hole, block it with cotton wool filler 4, and tamp the hole filler such as cotton wool with mechanical equipment. Use the method of excavator assisting manual work, install a diversion device at the leaking hole of the foundation pit, and wind jute on the upper part of the galvanized pipe 14 to make it easy to insert into the hole. The diversion device diverts the seepage water to the area of the steel pipe well 5. A submersible pump 7 is arranged on the upper part of the steel pipe well 5 to divert the water to the external drainage ditch area. The diversion device is selected with a model of DN600 and a material of high-strength PVC pipe. Before installing the diversion device, first remove the lower adapter 13 and the globe valve 11, and pad a 50-cm-thick wooden board on the galvanized pipe 14 to prevent damage during the installation process.

[0044] In step three, as Figure 4 shown in the figure, connect the surface catch basin 26 with the water injection bladder through the water injection pipe, and inject water into the bladder 24 through the valve 25 when needed. When the bladder 24 is filled with water, the generated expansion pressure will quickly act in the reverse direction on the foundation pit wall to seal the seepage channel, thereby achieving the purpose of water stop.

[0045] It should be noted that the same or similar parts in this embodiment and Embodiment 1 can be referred to each other and will not be elaborated in this application.

[0046] Embodiment 3

[0047] As another embodiment, this Embodiment 3 is proposed on the basis of Embodiment 2, and a more specific construction method for a rapid plugging system for leakage of the water-stop curtain in a deep foundation pit with water-rich silty sand layer:

[0048] Step four involves the rapid drainage technology of the hanging steel plate drainage groove for the internal support of the retaining pile: As Figure 5 shown in the figure, set the steel drainage vertical pipe 30 of the foundation pit on the foundation pit retaining pile 31, set the horizontal drainage pipe 33 at the second and third internal supports 32 of the foundation pit, and set a water collection tank 34 on the side of the internal support away from the retaining pile. Two steel water collection tank hanging ears are welded on both sides of the water collection tank 34, and the water collection tank 34 is placed on the internal support beam through the water collection tank hanging ears. Use the submersible pump 7 to drain the seepage water at the bottom of the foundation pit to the external drainage ditch and the internal support water collection tank 34, quickly reduce the seepage water in the foundation pit, and have a good water-stop effect;

[0049] Step five involves the backpressure technology of the blind ditch with the built-in gravel perforated drainage pipe: As Figure 6 shown in the figure, arrange a drainage blind ditch 38 inside the foundation pit. Excavate the foundation pit trench, lay medium sand at the bottom and both sides of the trench to form a medium sand filter layer 35, lay a permeable geotextile layer 37 on the medium sand filter layer 35, and then lay graded gravel 6 on the geotextile layer 37 as the drainage layer. Lay a drain pipe 3 on the geotextile layer, and the pipe material usually adopts high-strength PVC pipe. The pipe connects the internal drainage blind ditch 38 in the foundation pit with the external catch basin 26 of the foundation pit, and a backpressure valve 40 is set on the drain pipe 38 to effectively reduce the groundwater level inside the foundation pit and reduce the foundation pit leakage phenomenon;

[0050] Step six involves the technology of stabilizing and reinforcing the drainage steel pipe support piles: As Figure 7 shown, several steel pipe support piles 41 are driven around the foundation pit. A layer of waterproof and sealing material is sprayed on the inner wall of the steel pipe support piles 41. The waterproof and sealing material is a high-performance polyurethane waterproof coating, which has high adhesion and water resistance. The coating thickness of the waterproof and sealing material is 1 mm to 3 mm, which can effectively resist water seepage and water pressure. The outer wall of the steel pipe support piles is wrapped with a concrete layer 43 reinforced with a steel mesh, which plays a role in strengthening the pile body and enhancing the waterproof performance. A water stop plate 42 is installed at the top of the steel pipe support piles to prevent water from seeping in through the pile top; by setting up a water flow diversion pipeline, multiple steel pipe support piles 41 are connected. The diversion pipeline includes a longitudinal drainage pipe 45 and a transverse drainage pipe 46. The longitudinal drainage pipe 45 is arranged along the depth direction of the foundation pit, and the transverse drainage pipe 46 connects multiple longitudinal drainage pipes to ensure that the water flow inside and outside the foundation pit can be quickly and effectively discharged.

[0051] It should be noted that the same or similar parts in this embodiment and Embodiment II can be referred to each other and will not be elaborated in this application.

[0052] Embodiment IV

[0053] As another embodiment, this Embodiment IV is proposed on the basis of Embodiment III, such a rapid plugging system for the leakage of the water-stop curtain in the deep foundation pit with water-rich silty sand layer:

[0054] As Figure 1 、 Figure 2 shown, when a foundation pit leakage occurs near the foundation pit shear wall, the leakage point of the foundation pit is filled with fillers 4 such as cotton wadding. An external diversion device 9 is connected outside the foundation pit. The diversion device 9 uses a DN600 high-strength pipe as the diversion pipe 10 and is connected to the leakage point through a galvanized pipe 14. The area near the diversion device 9 is filled with graded gravel 6. The seepage water of the foundation pit is diverted to the steel pipe well 5 area through the diversion device 9. A submersible pump 7 is arranged on the upper part of the foundation pit bottom plate. The seepage water in the steel pipe well 5 is discharged to the outside area of the foundation pit through the submersible pump 7, and the leakage point of the foundation pit is quickly plugged with good drainage effect.

[0055] As Figure 3 shown, when the water-stop curtain of the foundation pit leaks, grouting outside the pit is used for plugging. The grouting hole positions are determined near the water-stop curtain of the foundation pit and are arranged in a plum blossom shape. The verticality is strictly controlled when the grouting holes of the foundation pit are drilled. The grouting of the foundation pit is carried out by using a grouting pump 20, an oil pressure pump 21 and a mixer 22. After the grouting is completed, a cement seal 18 is used for plugging to ensure airtightness.

[0056] As Figure 4As shown in the figure, a steel support 28 is arranged near the cement mixing piles of the foundation pit. A flexible cable net 27 is arranged inside the steel support 28. Water injection bladder bags 24 are installed on the flexible cable net 27. The water injection bladder bags 24 are arranged in a separated manner and fixed to the flexible cable net 27 through connectors 23. The water injection bladder bags 24 are connected to water injection pipes, and the water injection pipes are connected to the external catch drain 26. The water injection is controlled by a control valve 25. When the foundation pit leaks, the water injection valve 25 is opened, and the water injection bladder bags 24 quickly expand to press against the foundation pit wall, sealing the water seepage pipe.

[0057] As Figure 5 shown in the figure, a steel drainage riser 30 is arranged near the retaining piles of the foundation pit. The steel drainage riser 30 extends deep into the bottom of the foundation pit. Drainage pipes 33 are added on the internal support of the foundation pit. A water collection tank 34 is arranged on one side of the internal support of the foundation pit away from the retaining pile. When there is leakage at the bottom of the foundation pit, the submersible pump 7 on the ground is started to drain the seepage water at the bottom of the foundation pit to the external catch drain 26 and the water collection tank of the internal support, reducing the damage caused by the leakage of the foundation pit.

[0058] As Figure 6 shown in the figure, a drainage blind ditch 38 is arranged inside the foundation pit. The outside of the drainage blind ditch 38 is a medium sand filter layer 35, and the inside is a permeable geotextile layer 37 and a graded gravel 6 water collection layer. A concrete cover plate 36 is added on the upper part of the drainage blind ditch 38 to ensure that the blind ditch will not float. A drain pipe 39 is arranged in the graded gravel 6 water collection layer. The pipe is connected to the external catch well 26. An anti-pressure valve 40 is arranged on the drain pipe 39 to ensure that the water flow can only flow from the inside to the external catch well, controlling the groundwater level inside the foundation pit and preventing the water level from being too high to form leakage of the foundation pit.

[0059] As Figure 7 shown in the figure, the foundation pit is supported by steel pipe support piles 41. The outside of the steel pipe support piles 41 is wrapped with a reinforced concrete coating with wire mesh 43 to reinforce the support piles. A waterproof coating 44 is used inside, and a rubber water stop plate 42 is arranged at the top. Each support pile is connected through a longitudinal drainage pipe 45 and a transverse drainage pipe 46. The seepage water at the bottom is drained to the external catch drain 26 through the submersible pump 7, reducing the damage caused by the leakage of the foundation pit.

[0060] It should be noted that the parts that are the same or similar to those in Embodiment 3 in this embodiment can be referred to each other and will not be elaborated in this application.

[0061] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

Claims

1. Construction method of a rapid plugging system for leakage of a water-stop curtain in a deep foundation pit with water-rich silty sand layer, characterized in that, It includes the following specific steps: Step 1: Seal the leakage orifice of the foundation pit with cotton wool filler, install a diversion device to divert the seepage water to the steel pipe well, and the steel pipe well uses a submersible pump to divert the water to the external drainage ditch; After the foundation pit leaks, clean the orifice, seal it with cotton wool filler, and use an excavator to assist manual work. Install a diversion device at the leakage orifice of the foundation pit. The diversion device includes a galvanized pipe, a lower adapter, and a stop valve. Wrap the upper part of the galvanized pipe with hemp rope to make it easy to insert into the hole; the diversion device diverts the seepage water to the area of the steel pipe well. A submersible pump is arranged at the upper part of the steel pipe well to divert the water to the external drainage ditch area; before installing the diversion device, first remove the lower adapter and the stop valve, and pad a wooden board on the galvanized pipe; Step 2: Inject grout outside the foundation pit to seal the water-stop curtain; Step 3: Install a water injection bladder bag inside the foundation pit support structure; fill the water injection bladder bag with water to seal the seepage channel; During the construction of the foundation pit, install a steel support inside the foundation pit support structure, and arrange a flexible cable net and a water injection bladder bag inside the steel support; in Step 3, connect the surface catchment ditch and the water injection bladder bag through a water injection pipe, and inject water into the water injection bladder bag through a valve; When the water injection bladder bag is filled with water, the generated expansion pressure acts on the foundation pit wall in the reverse direction to seal the seepage channel, so as to achieve the purpose of water stop; Step 4: Set a horizontal drainage pipe and a water collection tank at the internal support to drain the seepage water at the bottom of the foundation pit to the catchment ditch and water collection tank outside the foundation pit; Step 5: Lay a drainage blind ditch inside the foundation pit, and connect the drainage blind ditch inside the foundation pit and the steel pipe well outside the foundation pit through a drain pipe; Excavate a foundation pit trench at the designed position of the drainage blind ditch, lay medium sand at the bottom and both sides of the trench to form a medium sand filter layer, lay a permeable geotextile layer on the medium sand filter layer, and then lay graded gravel on the permeable geotextile layer as a drainage layer; lay a drain pipe on the permeable geotextile layer, and the drain pipe connects the drainage blind ditch inside the foundation pit and the steel pipe well outside the foundation pit. A backpressure valve is arranged on the drain pipe.

2. The construction method of a rapid plugging system for leakage of a water-rich silty sand layer deep foundation pit water-stop curtain according to claim 1, characterized in that, In Step 3, the steel support is a support structure, and is fixed to the flexible cable net and the water injection bladder bag through a connecting piece; the connecting piece is used to firmly fix the flexible cable net and the water injection bladder bag on the steel support.

3. The construction method of a rapid plugging system for leakage of a water-rich silty sand layer deep foundation pit water stop curtain according to claim 1, characterized in that, In Step 4, set a steel drainage vertical pipe for the foundation pit on the foundation pit retaining pile, set a horizontal drainage pipe at the internal support of the foundation pit, and set a water collection tank on the side of the internal support of the foundation pit far from the foundation pit retaining pile. The horizontal drainage pipe uses a submersible pump to drain the seepage water at the bottom of the foundation pit to the catchment ditch and water collection tank outside the foundation pit; two steel water collection tank hanging ears are welded on both sides of the water collection tank, and the water collection tank is placed on the internal support of the foundation pit through the water collection tank hanging ears.

4. The construction method of a rapid plugging system for leakage of the water-stop curtain in a deep foundation pit with water-rich silty sand layer according to claim 1, characterized in that, In Step 2, according to the leakage position of the water-stop curtain, set the position of the grouting holes, and the grouting holes are arranged in a plum blossom shape; use a vertical grouting pipe for grouting, and use a drill with a sensor to adjust the drilling verticality in real time during the drilling process of the grouting holes; arrange a grouting pump, an oil pressure pump and a mixer outside the foundation pit for grouting operation, and perform cement sealing after grouting.

5. The construction method of a rapid plugging system for leakage of a water-rich silty sand layer deep foundation pit water-stop curtain according to claim 1, characterized in that There is still Step Six after Step Five. In Step Six, several steel pipe support piles are driven around the foundation pit. A waterproof sealing material is sprayed on the inner wall of the steel pipe support piles; a concrete layer reinforced with a steel mesh is wrapped around the outer wall of the steel pipe support piles; a water stop plate is installed at the top of the steel pipe support piles; by setting up drainage pipes to connect multiple steel pipe support piles, a complete drainage system is formed to guide the water flow inside and outside the foundation pit to the external drainage system; the drainage pipes include longitudinal drainage pipes and transverse drainage pipes. The longitudinal drainage pipes are arranged along the depth direction of the foundation pit, and the transverse drainage pipes connect multiple longitudinal drainage pipes.

6. A rapid plugging system for the leakage of the waterproof curtain in a deep foundation pit with water-rich silty sand layer, which is constructed by the method described in any one of Claims 1-5.

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