Water stopping curtain reconstruction water plugging method and device for pit bottom inrush

Abstract

The invention belongs to the technical field of buildings and water conservancy projects, and particularly relates to a waterproof curtain rebuilding water plugging method and device for pit bottom inrush. Comprising the steps that a precipitation well is dug, and a submersible pump is installed in the precipitation well and used for reducing the underground water level outside a foundation pit; a steel pipe with the diameter larger than 1 m is manufactured; an anti-seepage groove is cut in the original waterproof curtain; double-layer plastic waterproof plates are installed on the two sides of the anti-seepage groove; and the mixed slurry is poured into the anti-seepage groove to form the reconstructed anti-seepage wall. The underground water level is balanced through the dewatering well outside the pit and the steel pipe in the pit, water inrush is stopped, underground water is changed into still water from dynamic water, slurry loss in the grouting process is prevented, and the success rate of water plugging is increased. And the double-layer plastic waterproof plate and the grouting body are combined to form three waterproof layers, so that the sealing effect is improved. The anti-seepage groove is cut on the original waterproof curtain, namely, the structure of the original waterproof curtain is used as a retaining wall of the anti-seepage groove, and the trouble of retaining the wall by mud can be saved.

Description

Technical Field

[0001] The invention belongs to the technical field of construction and water conservancy engineering, and particularly relates to a method and device for recreating water blocking of a sudden gushing water-stopping curtain at the bottom of a pit. Background Art

[0002] In engineering construction, deep foundation pits are often excavated for underground structure construction. Water-stop curtains are commonly used water interception facilities in urban buildings and complex underground pipeline sites. However, water-stop curtains such as mixing piles, rotary jet piles, and underground continuous walls are more likely to cause water gushing due to incomplete construction quality or joint treatment. Even if the quality of the water-stop curtain is fine, it is possible that water will bypass the bottom of the water-stop curtain and then surge at the bottom of the foundation pit. When the groundwater is abundant or connected to surface water, the amount of water that surges is large, posing a major risk to the safety of the foundation pit itself and the surrounding environment. Therefore, rapid water blocking of sudden surges is crucial to ensure the safety of the project and the surrounding environment.

[0003] However, the existing method of blocking the sudden surge at the bottom of the pit by bypassing the bottom of the water-stop curtain is to use mixing piles, rotary jet piles, underground continuous walls, etc. to rebuild the water-stop curtain, but the construction period is long and the cost is high. Grouting the original water-stop curtain is easy to cause slurry loss during the construction and grouting of the water-stop curtain in a dynamic water environment, and the quality of the new water-stop curtain cannot be guaranteed. Therefore, it is necessary to design a method and device for reconstructing and blocking water from sudden surges at the bottom of the pit to solve the above problems. Summary of the invention

[0004] In view of the above problems, the present invention provides a method and device for recreating water blocking with a water-stopping curtain for sudden surge at the bottom of a pit, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for reconstructing water blocking of a sudden surge at the bottom of a pit with a water-stopping curtain, comprising the following steps:

[0006] Step S1 includes: digging a dewatering well outside the original water-stopping curtain closest to the sudden surge point, and installing a submersible pump in the dewatering well to lower the groundwater level outside the foundation pit to a height h1;

[0007] Step S2 includes making a steel pipe with a diameter greater than 1m, wherein the length of the steel pipe is l≥l0+l1+l2, where l0 is the surplus length of the steel pipe, l1 is the height of the steel pipe from the water level to the bottom of the foundation pit, and l2 is the depth of the steel pipe inserted into the soil at the bottom of the pit;

[0008] Step S3 includes driving the steel pipe into the bottom soil layer of the foundation pit with the surge point as the center, and the driving depth ensures that groundwater does not surge out from the outside of the steel pipe;

[0009] Step S4 includes cutting an anti-seepage groove on the original water-stop curtain;

[0010] Step S5 includes installing double-layer plastic waterproof panels on both sides of the anti-seepage groove;

[0011] Step S6 includes, when h1=l1, pouring the mixed slurry into the anti-seepage groove to form a reconstructed anti-seepage wall;

[0012] Step S7 includes, when the consolidation strength of the grouting body reaches above 0.5 MPa, removing the steel pipe in the foundation pit and performing foundation reinforcement treatment in a range of 3 to 6 times the diameter of the steel pipe.

[0013] Furthermore, the step S4 also includes using a channel box cutting machine to cut the anti-seepage groove in the middle of the original water-stop curtain. When the remaining parts on both sides of the original water-stop curtain form a whole, clean water cutting is used; when the remaining parts on both sides of the original water-stop curtain cannot form a whole, mud wall protection is used, and the mud specific gravity is 1.1-1.3.

[0014] Furthermore, the step S4 also includes that the width of the anti-seepage groove is 1 / 3 of the diameter or thickness of the original water-stop curtain, the depth of the anti-seepage groove is h2, and the depth of the anti-seepage groove passing through the sudden water bypassing the seepage point and entering the impermeable layer is not less than 1.0m.

[0015] Furthermore, the step S5 also includes that the double-layer plastic waterproof board is connected by welding or overlapping and gluing, and is fixed to the skeleton steel bars by wire binding, the spacing between the double-layer plastic waterproof boards is 1 / 3-1 / 2 of the width of the anti-seepage groove, and when the double-layer plastic waterproof board is overlapped and glued, the overlap seams are staggered by not less than 2.0m.

[0016] Furthermore, the step S6 also includes: the water-cement ratio of the cement slurry is 0.50-0.70, the water-cement ratio of the bentonite slurry is 0.60-0.90, the amount of the accelerating agent added is 1%-2% of the sum of the weight of cement and bentonite, the cement slurry and the bentonite slurry are mixed with the accelerating agent at the outlet of the grouting pipe to obtain the mixed slurry, and the mixed slurry is poured into the impermeable groove through the grouting pipe using a grouting pump.

[0017] The present invention also provides a device for reconstructing and plugging water with a water-stopping curtain for sudden gushing at the bottom of a pit, which is applied to the method for reconstructing and plugging water with a water-stopping curtain for sudden gushing at the bottom of a pit as described in any one of the above items, comprising a steel pipe, a top permeable mesh circular steel plate, a bottom permeable mesh circular steel plate, and a straw woven blanket;

[0018] The steel pipe is opened at both ends, and the top water-permeable mesh circular steel plate and the bottom water-permeable mesh circular steel plate are installed in the steel pipe to divide the steel pipe into three chambers, and at least three layers of the straw woven blanket are placed vertically and crosswise in the middle chamber.

[0019] Furthermore, the water-stopping curtain reconstructing and blocking water device for sudden surges at the bottom of a pit also includes a filter screen, a drain pipe and a drain valve. A hole is opened on the side wall of the steel pipe, and the hole is located above the middle chamber. The drain pipe is connected to the opening, and the filter screen is installed at the opening.

[0020] Furthermore, the water-stopping curtain reconstructing and blocking water device for sudden surges at the bottom of a pit also includes an arc L-shaped connecting piece, the diameters of the top water-permeable mesh circular steel plate and the bottom water-permeable mesh circular steel plate are equal to the inner diameter of the steel pipe, and the top water-permeable mesh circular steel plate and the bottom water-permeable mesh circular steel plate are both connected and fixed to the side wall of the steel pipe via the arc L-shaped connecting piece.

[0021] Technical effects and advantages of the present invention:

[0022] 1. Use the submersible pump installed in the precipitation well and the steel pipe inserted into the foundation pit to surround the sudden gushing point to adjust the water level inside and outside the foundation pit to the same height, so that the sudden gushing water stops and the groundwater changes from dynamic water to static water, preventing the loss of mixed slurry during the grouting process, which is conducive to improving the success rate of water blocking.

[0023] 2. Using double-layer plastic waterproof board and grouting body to form three layers of waterproofing is beneficial to improve the sealing effect.

[0024] 3. Cut an anti-seepage groove on the original waterproof curtain, that is, use the structure of the original waterproof curtain as the protective wall of the anti-seepage groove, which can save the trouble of mud wall protection.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram showing groundwater flowing around and surging through the bottom of a water-stop curtain according to an embodiment of the present invention is shown;

[0028] Figure 2 A schematic diagram showing a dewatering well outside a foundation pit according to an embodiment of the present invention is shown;

[0029] Figure 3 A schematic diagram showing the location of a precipitation well according to an embodiment of the present invention;

[0030] Figure 4 A schematic structural diagram of a steel pipe according to an embodiment of the present invention is shown;

[0031] Figure 5 A schematic diagram showing that the water level outside the foundation pit and the water level of the steel pipe are kept balanced according to an embodiment of the present invention;

[0032] Figure 6 A cross-sectional view of an original water-stop curtain according to an embodiment of the present invention is shown;

[0033] Figure 7 A schematic structural diagram of an anti-seepage groove according to an embodiment of the present invention is shown;

[0034] Figure 8 A schematic diagram showing a double-layer plastic waterproof board installed in an anti-seepage groove according to an embodiment of the present invention;

[0035] Fig. 9 A cross-sectional view showing the installation of a double-layer plastic waterproof board and the injection of mixed slurry in an anti-seepage groove according to an embodiment of the present invention Figure 1 ;

[0036] Fig.10 A cross-sectional view showing the installation of a double-layer plastic waterproof board and the injection of mixed slurry in an anti-seepage groove according to an embodiment of the present invention Figure 2 ;

[0037] Fig.11 A schematic diagram showing a plastic waterproof sheet tied to a skeleton steel bar according to an embodiment of the present invention;

[0038] Fig.12 A cross-sectional view of an arc L-shaped connector according to an embodiment of the present invention is shown;

[0039] Fig.13 A schematic diagram of the three-dimensional structure of an arc L-shaped connector according to an embodiment of the present invention is shown.

[0040] Figure numerals: 1. Support structure; 101. Original water-stop curtain; 102. Reconstructed anti-seepage trough water-stop curtain; 103. Anti-seepage trough; 104. Plastic waterproof board; 105. Skeleton steel bar; 106. Mixed slurry; 2. Surge point; 201. Surge channel; 3. Dewatering well; 301. Motor; 302. Submersible pump; 303. Drain pipe; 4. Steel pipe; 401. Top permeable mesh round steel plate; 402. Bottom permeable mesh round steel plate; 403. Permeable mesh; 404. Screw; 405. Arc L-shaped connector; 406. Straw woven blanket; 407. Drain pipe; 408. Drain valve. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] like Figures 1 to 3 , Figures 5 to 10 As shown, a method for reconstructing water blocking with a water-stopping curtain for sudden water inrush at the bottom of a pit according to an embodiment of the present invention comprises the following steps:

[0043] Step S1 includes, outside the original water-stop curtain 101 closest to the sudden surge point 2, digging a dewatering well 3, installing a submersible pump 302 in the dewatering well 3, for lowering the groundwater level outside the foundation pit to a height h1;

[0044] Step S2 includes making a steel pipe 4 with a diameter greater than 1m, wherein the length of the steel pipe 4 is l≥l0+l1+l2, where l0 is the surplus length of the steel pipe 4, l1 is the height from the water level of the steel pipe 4 to the bottom of the foundation pit, and l2 is the depth of the steel pipe 4 inserted into the soil at the bottom of the pit;

[0045] Step S3 includes driving the steel pipe 4 into the bottom soil layer of the foundation pit with the surge point 2 as the center, and the driving depth ensures that groundwater does not surge out from the outside of the steel pipe 4;

[0046] Step S4 includes cutting an anti-seepage groove 103 on the original waterproof curtain 101;

[0047] Step S5 includes installing a double-layer plastic waterproof board 104 in the anti-seepage groove 103;

[0048] Step S6 includes, when h1=l1, pouring the mixed slurry 106 into the anti-seepage groove 103 to form a reconstructed anti-seepage wall;

[0049] Step S7 includes, when the consolidation strength of the grouting body reaches above 0.5 MPa, removing the steel pipe 4 in the foundation pit, and performing foundation reinforcement treatment on a range of 3 to 6 times the diameter of the steel pipe 4 .

[0050] Specifically, Figure 3 As shown, there are at least three precipitation wells 3, the middle precipitation well 3 is located on the vertical line between the sudden surge point 2 and the original water-stop curtain 101, the angle α between the precipitation wells 3 on both sides and the sudden surge point 2 and the precipitation wells 3 on both sides is 30°-60°, and the distance between two adjacent precipitation wells 3 is 10m-20m. Figure 1 , Figure 2 as well as Figure 5As shown, the surge channel 201 is located at the bottom of the foundation pit, and the upper end is the surge point 2. Secondly, a support structure 1 is set in the foundation pit, and the double-layer plastic waterproof board 104 and the grouting body in the anti-seepage groove 103 constitute the reconstructed anti-seepage groove water-stop curtain 102. In addition, a motor 301 and a drain pipe 303 are also provided. The motor 301 is connected to the submersible pump 302 through the drain pipe 303, and the submersible pump 302 is driven to discharge water by starting the motor 301. In addition, as Figure 1 , Figure 2 , Figure 5 , Figure 6 as well as Fig.10 In the figure, H is the height from the excavation surface of the foundation pit to the ground.

[0051] In this embodiment, the water level outside the foundation pit is adjusted by using the opened dewatering well 3 and the submersible pump 302 installed in the dewatering well 3, and the steel pipe 4 inserted into the foundation pit is used to surround the sudden surge point 2. The water level of the sudden surge water in the steel pipe 4, that is, the water level in the foundation pit, is until h1=l1, indicating that the water levels inside and outside the foundation pit are equal, so that the sudden surge water stops. At this time, the groundwater is transformed from dynamic water to static water, which prevents the loss of the mixed slurry 106 during the grouting process, which is beneficial to improving the success rate of water plugging.

[0052] Secondly, on the one hand, by installing a double-layer plastic waterproof board 104 in the anti-seepage groove 103, on the other hand, pouring a mixed slurry 106 into the anti-seepage groove 103 to form a grouting body, the double-layer plastic waterproof board 104 and the mixed slurry form a reconstructed anti-seepage wall to block the gushing water, and the double-layer plastic waterproof board 104 and the grouting body form three layers of waterproofing, which is beneficial to improve the sealing effect.

[0053] In addition, an anti-seepage groove 103 is cut out on the original waterproof curtain 101, that is, the structure of the original waterproof curtain 101 is used as the protective wall of the anti-seepage groove 103, which can save the trouble of mud protective wall.

[0054] Optionally, the step S4 also includes using a channel box cutting machine to cut the anti-seepage groove 103 in the middle of the original water-stopping curtain 101. When the remaining parts on both sides of the original water-stopping curtain 101 form a whole, clean water cutting is used; when the remaining parts on both sides of the original water-stopping curtain 101 do not form a whole, mud wall protection is used, and the mud specific gravity is 1.1-1.3.

[0055] In this embodiment, a channel box cutting machine is used to cut the anti-seepage groove 103 in the middle of the original water-stopping curtain 101, and depending on whether the remaining part of the original water-stopping curtain 101 forms a whole, clean water cutting or mud wall protection is used respectively. This can ensure the structural stability of the anti-seepage groove 103 and facilitate the subsequent installation of the double-layer plastic waterproof board 104 and the injection of the mixed slurry 106 in the anti-seepage groove 103.

[0056] Alternatively, if Figure 1 , Figure 2 , Figure 5 , Figure 6 as well as Fig.10 As shown, the step S4 also includes that the width of the anti-seepage groove 103 is 1 / 3 of the diameter or width of the original water-stop curtain 101, the depth of the anti-seepage groove 103 is h2, and the depth of the anti-seepage groove 103 passing through the sudden water seepage point into the impermeable layer is not less than 1.0m.

[0057] Specifically, Figure 6 and Fig.10 l3 is the height from the excavation surface of the foundation pit to the water level at the bottom of the pit after water blocking is completed.

[0058] In this embodiment, by setting the width of the anti-seepage groove 103 to 1 / 3 of the diameter of the original water-stop curtain 101, and the depth of the anti-seepage groove 103 to pass through the sudden water seepage point and enter the impermeable layer to be no less than 1.0 m, there can be enough space inside the anti-seepage groove 103 to facilitate the installation of the double-layer plastic waterproof board 104 and the injection of the mixed slurry 106.

[0059] Alternatively, if Fig.10 As shown, the step S5 also includes that the double-layer plastic waterproof board 104 is connected by welding or overlapping and gluing, and is fixed to the skeleton steel bar 105 by wire binding, the spacing of the double-layer plastic waterproof board 104 is 1 / 3-1 / 2 of the width of the anti-seepage groove 103, and when the double-layer plastic waterproof board 104 is overlapped and glued, the overlap seam is staggered by not less than 2.0m.

[0060] In this embodiment, by placing two plastic waterproof boards 104 on both sides of the anti-seepage groove 103, and by setting the spacing between the double-layer plastic waterproof boards 104 to 1 / 3-1 / 2 of the width of the anti-seepage groove 103, there is enough space to pour the mixed slurry 106. Secondly, when the double-layer plastic waterproof boards 104 are overlapped and glued, the overlap seams are staggered by no less than 2.0m, which also facilitates that there is enough space between the double-layer plastic waterproof boards 104 to pour the mixed slurry 106. In addition, the double-layer plastic waterproof boards 104 and the skeleton steel bars 105 are tied and fixed with iron wire, which can facilitate ensuring the structural stability of the double-layer plastic waterproof boards 104.

[0061] Optionally, the step S6 also includes: the water-cement ratio of the cement slurry is 0.50-0.70, the water-cement ratio of the bentonite slurry is 0.60-0.90, the amount of the accelerating agent added is 1%-2% of the sum of the weight of cement and bentonite, the cement slurry and the bentonite slurry are mixed with the accelerating agent at the outlet of the grouting pipe to obtain the mixed slurry 106, and the mixed slurry 106 is poured into the impermeable groove 103 through the grouting pipe using a grouting pump.

[0062] In this embodiment, cement slurry and bentonite slurry are mixed separately in a ground mixing tank, wherein the water-cement ratio of the cement slurry is 0.50-0.70, the water-cement ratio of the bentonite slurry is 0.60-0.90, and the amount of the accelerating agent added is 1%-2% of the sum of the weight of cement and bentonite, and the obtained mixed slurry 106 has the best effect. The mixed slurry 106 is poured into the anti-seepage groove 103 through the grouting pipe using a grouting pump, which facilitates the mixing of the mixed slurry 106 into the anti-seepage groove 103.

[0063] like Figure 4 , Fig.12 as well as Fig.13 As shown, another embodiment of the present invention is a water-blocking device for reconstructing water from a pit bottom sudden surge, which is applied to the water-blocking method for reconstructing water from a pit bottom sudden surge as described in any of the above items, comprising a steel pipe 4, a top permeable mesh circular steel plate 401, a bottom permeable mesh circular steel plate 402 and a straw woven blanket 406;

[0064] The steel pipe 4 is opened at both ends, and the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 are installed in the steel pipe 4 to divide the steel pipe 4 into three chambers, and at least three layers of the straw woven blanket 406 are placed vertically and crosswise in the middle chamber.

[0065] Specifically, a soil cutting blade is provided at the bottom end of the steel pipe 4. The thickness of the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 are not less than 3mm, the aperture is 3mm-5mm, and the hole spacing is 5mm-10mm. Secondly, the straw woven blanket 406 is woven with dry straw after removing the residual leaves and then woven with thin ropes. The thickness of each layer is 30mm-50mm. The diameter of the straw woven blanket 406 is equal to the inner diameter of the steel pipe 4. In the chamber composed of the upper and lower mesh circular steel plates, no less than 3 layers of straw woven blankets 406 are placed in a vertical cross manner. In addition, if Fig.12 As shown, water-permeable mesh holes 403 are provided on the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 .

[0066] In this embodiment, a sediment isolation chamber, i.e., an intermediate chamber, is formed by a top permeable mesh circular steel plate 401 and a bottom permeable mesh circular steel plate 402, and no less than three layers of straw woven blankets 406 are placed in the sediment isolation chamber, which can be used to filter the sediment brought out by sudden water surges.

[0067] Alternatively, if Figure 4 As shown, the water-stopping curtain reconstructing and blocking water device for sudden surges at the bottom of a pit also includes a filter screen, a drain pipe 407 and a drain valve 408. A hole is opened on the side wall of the steel pipe 4, and the opening is located above the middle chamber. The drain pipe 407 is connected to the opening, and the filter screen is installed at the opening.

[0068] In this embodiment, when the water level difference between the inside and outside of the foundation pit is large, the drain valve 408 can be opened, and the water level in the steel pipe 4 can be adjusted by using the drain pipe 407. Secondly, fine sand may be leaked out after the sudden water is filtered through the straw blanket 406, and the fine sand can be filtered through the filter screen set at the opening.

[0069] Alternatively, if Fig.12 and Fig.13 As shown, the water-stopping curtain reconstructing and plugging device for sudden surge at the bottom of a pit also includes an arc L-shaped connecting piece 405, the diameters of the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 are equal to the inner diameter of the steel pipe 4, and the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 are both connected and fixed to the side wall of the steel pipe 4 via the arc L-shaped connecting piece 405.

[0070] In this embodiment, by providing the arc L-shaped connector 405, it is convenient to assemble the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 to the side wall of the steel pipe 4. Secondly, in order to facilitate installation, bolt holes are drilled in the side wall of the steel pipe 4, and the arc L-shaped connector 405 can be installed on the steel pipe 4 through the bolt holes using screws 404, and a horizontal groove is opened on the arc L-shaped connector 405, and the top water-permeable mesh circular steel plate 401 and the bottom water-permeable mesh circular steel plate 402 are installed in the horizontal groove and fixed using screws 404.

[0071] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reconstructing water blocking with a water-stopping curtain for sudden surge at the bottom of a pit, characterized in that: The following steps are involved: Step S1 includes, outside the original water-stop curtain (101) closest to the sudden surge point (2), digging a dewatering well (3), installing a submersible pump (302) in the dewatering well (3) to lower the groundwater level outside the foundation pit to a height h1; Step S2 comprises: manufacturing a steel pipe (4) with a diameter greater than 1 m, wherein the length of the steel pipe (4) is l≥l0+l1+l2, where l0 is the surplus length of the steel pipe (4), l1 is the height from the water level of the steel pipe (4) to the bottom of the foundation pit, and l2 is the depth of the steel pipe (4) inserted into the soil at the bottom of the pit; Step S3 comprises driving the steel pipe (4) into the bottom soil layer of the foundation pit with the surge point (2) as the center, and the driving depth ensures that groundwater does not surge out from the outside of the steel pipe (4); Step S4 includes cutting an anti-seepage groove (103) on the original waterproof curtain (101); Step S5 includes installing a double-layer plastic waterproof board (104) in the anti-seepage groove (103); Step S6 includes, when h1=l1, pouring the mixed slurry (106) into the anti-seepage groove (103) to form a reconstructed anti-seepage wall; Step S7 includes, when the consolidation strength of the grouting body reaches above 0.5 MPa, removing the steel pipe (4) in the foundation pit, and performing foundation reinforcement treatment on a range of 3 to 6 times the diameter of the steel pipe (4).

2. A method for reconstructing and plugging water with a water-stopping curtain for sudden water inrush at the bottom of a pit according to claim 1, characterized in that: The step S4 also includes using a channel box cutting machine to cut the anti-seepage groove (103) in the middle of the original water-stopping curtain (101). When the remaining parts on both sides of the original water-stopping curtain (101) form a whole, clean water cutting is used; when the remaining parts on both sides of the original water-stopping curtain (101) do not form a whole, mud wall protection is used, and the mud specific gravity is 1.1-1.

3.

3. A method for reconstructing and plugging water with a water-stopping curtain for sudden water inrush at the bottom of a pit according to claim 1, characterized in that: The step S4 also includes that the width of the anti-seepage groove (103) is 1 / 3 of the diameter of the original waterproof curtain (101), the depth of the anti-seepage groove (103) is h2, and the depth of the anti-seepage groove (103) is not less than 1.0 m from the sudden water seepage point into the impermeable layer.

4. A method for reconstructing and plugging water with a water-stopping curtain for sudden water inrush at the bottom of a pit according to claim 3, characterized in that: The step S5 also includes the double-layer plastic waterproof board (104) being connected by welding or overlapping and gluing, and being fixed to the skeleton steel bar (105) by wire binding, the spacing of the double-layer plastic waterproof board (104) being 1 / 3-1 / 2 of the width of the anti-seepage groove (103), and the overlap seam of the double-layer plastic waterproof board (104) being staggered by no less than 2.0m when the double-layer plastic waterproof board (104) is overlapped and gluing.

5. A method for reconstructing and plugging water with a water-stopping curtain for sudden water inrush at the bottom of a pit according to claim 4, characterized in that: The step S6 also includes the water-cement ratio of the cement slurry being 0.50-0.70, the water-cement ratio of the bentonite slurry being 0.60-0.90, the amount of the accelerating setting agent added being 1%-2% of the sum of the weight of the cement and the bentonite, the cement slurry and the bentonite slurry being mixed with the accelerating setting agent at the outlet of the grouting pipe to obtain the mixed slurry (106), and the mixed slurry (106) being poured into the impermeable groove (103) through the grouting pipe using a grouting pump.

6. A water-blocking device for regenerating water from a sudden surge at the bottom of a pit, characterized in that: A method for reconstructing and plugging water with a water-stopping curtain for a sudden outburst at the bottom of a pit as claimed in any one of claims 1 to 5, comprising a steel pipe (4), a top permeable mesh circular steel plate (401), a bottom permeable mesh circular steel plate (402) and a straw woven blanket (406); The steel pipe (4) is open at both ends, and the top water-permeable mesh circular steel plate (401) and the bottom water-permeable mesh circular steel plate (402) are installed in the steel pipe (4) to divide the steel pipe (4) into three chambers, and at least three layers of the straw woven blanket (406) are placed vertically and crosswise in the middle chamber.

7. A water-blocking device for reconstructing water from a water-stopping curtain for sudden surges at the bottom of a pit according to claim 6, characterized in that: It also includes a filter screen, a drain pipe (407) and a drain valve (408). A hole is opened on the side wall of the steel pipe (4), and the hole is located above the middle chamber. The drain pipe (407) is connected to the hole, and the filter screen is installed at the hole.

8. A water-blocking device for reconstructing water from a water-stopping curtain for sudden surges at the bottom of a pit according to claim 7, characterized in that: It also includes an arc L-shaped connecting piece (405), the diameters of the top water-permeable mesh circular steel plate (401) and the bottom water-permeable mesh circular steel plate (402) are equal to the inner diameter of the steel pipe (4), and the top water-permeable mesh circular steel plate (401) and the bottom water-permeable mesh circular steel plate (402) are both connected and fixed to the side wall of the steel pipe (4) through the arc L-shaped connecting piece (405).

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