A water collecting well strong gushing water guide and discharge steady flow pressure seal and re-plugging treatment method

Abstract

The present application relates to a kind of water collecting well strong gushing water's guide and discharge steady flow pressure seal and re-plugging processing method in underground engineering waterproofing technical field, to solve the technical problems of difficult grouting, pressure seal easy failure and low pumping efficiency under the condition of strong gushing water.The technical scheme is as follows: after pumping positioning, arrange the flow pressure seal steel plate with drain hole above the gushing point to realize steady flow guide and discharge, then set the frame structure with sandbag or block weight on the steel plate to resist scouring, finally implement wellhead closure, pressure grouting and micro-expansion concrete re-plugging.The present application is mainly used for strong gushing water treatment of water collecting well such as basement floor and foundation pit bottom.

Description

Technical Field

[0001] This invention relates to the field of underground engineering drainage and water-stopping treatment technology, and in particular to a method for guiding, stabilizing, pressing, sealing, and resealing strong water in sump pits at locations such as basement floor slabs and foundation pit bottoms. Background Technology

[0002] In projects such as basement floors and foundation pit bottoms, sump pits are a common drainage measure used to collect seepage water and pump it out to control the groundwater level. With the increasing scale of underground projects and the growing complexity of geological conditions, strong water inrushes may occur at the bottom of sump pits, often carrying debris such as mud, sand, and tree roots. These strong water inrush conditions typically manifest as: a rapid rise in water level after pumping; water flowing from the inrush point in a scattered or turbulent manner; high local water head and high flow velocity; significantly increasing the difficulty of construction and disposal.

[0003] Currently, conventional methods for dealing with water inrush problems in sump wells include grouting, filling with sealing materials, stacking sandbags, covering with a single steel plate, and chiseling out and redoing with concrete. However, under conditions of strong water inrush, these methods generally have the following defects and shortcomings: (1) General grouting is difficult to form: the grout is easily diluted, dispersed or carried away by the high-speed water flow, resulting in phenomena such as "cannot be injected, cannot be injected, serious grout return, and incomplete solidification", which leads to sealing failure or repeated rework. (2) Insufficient resistance to top support of the pressure sealing structure: When only steel plates are used for covering or sandbags are stacked, the steel plates are easily lifted by the water flow, the sandbags are scattered or the stacking becomes unstable, and long-term stable pressure sealing cannot be achieved. (3) Low pumping efficiency and easy to clog pumps: When the gushing water carries tree roots and other debris, it is easy to clog the pump inlet, causing a decrease in pumping capacity, pump stoppage or even backflow of water, which further aggravates the deterioration of the gushing water condition. (4) Lack of measures to stabilize the flow and reduce the water head makes it difficult to form a construction window: The strong water inrush is turbulent and dispersed, and the scouring and disturbance are strong, which makes it impossible to provide stable construction conditions for subsequent sealing, reinforcement or grouting operations.

[0004] Therefore, there is an urgent need for a systematic treatment method that can first guide and stabilize the flow to reduce the water head under strong water inrush conditions, then achieve reliable pressure sealing to resist scouring, and create conditions for subsequent resealing or compaction grouting reinforcement. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for guiding, stabilizing, sealing and resealing water in a water collection well with strong water inflow, so as to solve the construction difficulties caused by the difficulty of grouting, easy failure of sealing, low pumping efficiency and lack of stable flow conditions under strong water inflow conditions.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well, comprising the following steps: S1. Pumping and positioning: A water pump is installed in the water collection well to pump water, lowering the water level in the well, and confirming and marking the location, range, and water outflow pattern of the water inflow point; S2. Guiding and stabilizing flow: A guiding and sealing steel plate is arranged above the water inflow point, and a drainage hole is opened on the guiding and sealing steel plate to convert the water inflow from vertical dispersion into a directional transverse flow along the bottom of the well, and guide it to the direction of the water pump suction inlet; S3. Sealing the water inflow point: A counterweight limiting structure is added to the guiding and sealing steel plate to resist the upward pressure and scouring of the water flow, and to maintain the stable sealing of the guiding and sealing steel plate; S4. Wellhead sealing and structural reinforcement: After the water inflow is controlled, the wellhead and surrounding structure of the water collection well are sealed and reinforced; S5. Compacting grouting: Grouting pipes are laid around the water collection well or in the affected area to carry out compacting grouting, filling and reinforcing the seepage channels; S6. Final sealing and seepage prevention repair of holes: Micro-expansion concrete is used to reseal the holes and the sealed areas.

[0007] To address the issue of insufficient coverage by the flow-guiding and sealing steel plate, which could lead to water overflowing from the edges and affecting the flow guidance and sealing effect, this application further specifies that in step S2, the size of the flow-guiding and sealing steel plate covers the water inflow point and extends outwards beyond the edge of the water inflow area by 50-150mm. By limiting the size of the steel plate extending beyond the edge of the water inflow area, complete coverage and effective sealing of the water inflow point are ensured, providing a reliable boundary for stable flow guidance.

[0008] To address the problem of debris carried by gushing water easily clogging drain holes or pump inlets, leading to drainage interruptions and deterioration of operating conditions, this application further specifies that in step S2, when gushing water carries debris, a filter screen or interception component is added to the drain hole, and / or a filter screen is installed at the pump inlet. By adding filtration measures, debris is effectively intercepted, ensuring continuous and stable operation of the drainage system and reducing maintenance risks and the probability of pump blockage.

[0009] To address the issue that counterweights placed directly on steel plates are easily dispersed or displaced by water flow, leading to sealing failure, this application further specifies that in step S3, the counterweight limiting structure includes a frame filled with sandbags or block counterweights. The frame structure constrains the counterweights, fixing their position and effectively transferring weight, thereby providing a stable and lasting downward clamping force.

[0010] To address the potential shortcomings in structural strength, reliability of connection with steel plates, and on-site adaptability when using general-purpose frames, this application further specifies that the frame is a reinforcing cage. Using a reinforcing cage as the specific frame form offers advantages such as structural robustness, ease of on-site fabrication, and reliable connection with steel plates, enhancing the overall integrity and applicability of the counterweight limiting structure.

[0011] To address the issue of insufficient or excessive application of fixed counterweights in a single application, which makes it difficult to accurately resist dynamic water head pressure, the above technical solution employs a graded stacking method when filling the block counterweights. The weights are gradually increased according to the water head and the lifting trend of the flow-guiding and pressure-sealing steel plate until the flow-guiding and pressure-sealing steel plate stabilizes. This graded stacking method dynamically adjusts the counterweights, enabling economical and precise stable pressure sealing, adapting to changes in inrush pressure, and improving construction controllability.

[0012] To address the issue of weak bonding between old and new concrete surfaces during wellhead sealing, which can easily become leakage channels, this application further specifies that step S4 specifically includes: roughening the surface of the existing concrete structure around the wellhead, followed by formwork erection, rebar installation, rebar tying, and pouring grout or high-strength repair material to form a sealed space. Through a series of processes including roughening, rebar installation, rebar tying, and pouring high-strength material, a strong bond between the old and new structures is ensured, forming a sealed cover plate with high integrity and good sealing performance.

[0013] To address the issue of limited structural load-bearing capacity in the wellhead sealing area, which could lead to deformation or failure under complex loads, this application further specifies that step S4 includes: installing additional structural beams around the water collection well to improve sealing and load-bearing performance. By adding structural beams, the overall stiffness and load-bearing capacity of the wellhead area are significantly enhanced, improving the long-term safety and durability of the sealing structure.

[0014] To address the problem of uncontrollable grout diffusion and poor reinforcement effect caused by improper selection of grouting materials or unscientific processes, this application further specifies that in step S5, the compaction grouting uses cement-based grout, quick-setting cement-based grout, or chemical grout, and employs a segmented and sequential grouting method to control the diffusion range. By limiting the appropriate grout type and the segmented and sequential grouting process, effective and controllable filling of the reinforced area is achieved, improving the reliability and quality of grouting reinforcement.

[0015] To address the potential leakage risks arising from surface shrinkage or micro-cracks after the concrete body has been sealed, this application further specifies that in step S6, after resealing with micro-expansion concrete, an anti-seepage repair material is also used to reinforce the surface impermeability. This surface impermeability reinforcement treatment constructs multiple waterproofing lines, further reducing the risk of future leakage and improving the reliability and durability of the overall waterproofing system.

[0016] The beneficial effects of this invention are: 1. By combining steel plate sealing with counterweight limiting structure, it can continuously resist the upward force and scouring effect of water inrush, significantly overcoming the problems of easy lifting of steel plates, easy scattering of sandbags and easy instability of stacking in traditional methods. The sealing structure is stable and reliable.

[0017] 2. By directing the flow of water, the ineffective disturbance of the water flow to the construction area is reduced, and the pumping efficiency is improved. At the same time, combined with filtration measures, it effectively prevents debris from clogging the water pump, reduces the risk of pump stoppage due to blockage, and ensures continuous drainage.

[0018] 3. This method can be combined with wellhead sealing, compaction grouting and micro-expansion concrete resealing processes to achieve full filling and reinforcement of seepage channels and cavities, thereby significantly improving the integrity and durability of the sealing body and effectively reducing the risk of rework due to subsequent leakage.

[0019] 4. The diversion and sealing steel plates, steel cages, sandbags, filter screens and grouting pipes used are all common materials on the construction site, which are easy to obtain and assemble. They are highly adaptable and can be widely used in water collection wells with various geological conditions and water inrush conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of the present invention. Figure 3 ; Figure 4 This is a schematic diagram of the structure of the present invention. Figure 4 ; Figure 5 This is a schematic diagram of the structure of the present invention. Figure 5 ; Figure 6 This is a schematic diagram of the structure of the present invention. Figure 6 ; Figure 7 This is a schematic diagram of the structure of the present invention. Figure 7 ; Figure 8 This is a schematic diagram of the structure of the flow-guiding pressure sealing steel plate; Figure 9 This is a structural diagram of the framework; Figure 10 This is a schematic diagram of the grouting pipe structure.

[0022] The labels in the diagram are as follows: 1. Sump well; 2. Pump; 3. Water inrush point; 4. Diversion and sealing steel plate; 41. Drainage hole; 5. Grouting pipe; 51. Grouting hole; 52. Enclosed section; 53. Tip; 6. Frame; 7. Sandbag; 8. New structural beam; 9. Micro-expansion concrete; 10. Basement floor slab; 11. Formwork; 12. Drilled rebar; 13. Rebar mesh. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The core of this invention lies in transforming the approach to treating strong water inrush from direct sealing or grouting to a systematic process of first controlling and stabilizing the water flow, then pressure sealing, and finally sealing / reinforcing. This process first reduces the water head and guides the water flow by diverting and stabilizing the flow, then uses counterweights to pressure seal against scouring and backlash, and finally implements structural reinforcement and permanent sealing under stable conditions, thereby systematically overcoming the shortcomings of existing technologies.

[0025] Example 1: This example provides a method for guiding, stabilizing, and sealing strong water inflow in a water collection well, followed by resealing. The specific steps are as follows: S1. Sampling and Positioning: See Figure 1 First, in the collection well 1 where a strong water inflow occurs, select an appropriate pump type, flow rate, and head parameters based on the water inflow volume, water head height, and space inside the well. Place one or more high-flow-rate pumps 2 to forcefully pump out the water, quickly lowering the water level in the collection well 1 and creating working conditions. After the water level drops and the water inflow point 3 is exposed, construction personnel enter the collection well 1 to carefully observe and mark the specific location, affected area, and water outflow pattern of the water inflow point 3 (such as whether it contains sand, whether it is jet-like, or whether it carries a large amount of mud, sand, tree roots, or other debris), providing a basis for subsequent drainage and sealing operations.

[0026] S2. Conductor current stabilization: See Figure 2 and Figure 8According to the marked water inrush area, cut or select a suitable-sized flow-guiding and sealing steel plate 4. This flow-guiding and sealing steel plate 4 can be a single piece or an assembled plate, made of Q235 steel, with a preferred thickness of 10-30mm (e.g., 20mm). The size of the flow-guiding and sealing steel plate 4 is determined based on the range of water inrush influence; its planar dimensions should completely cover the water inrush point 3 and extend 50-150mm (e.g., 100mm) beyond the edge of the water inrush area on all sides. One or more drainage holes 41 are pre-drilled in the center of the flow-guiding and sealing steel plate 4 or at the location corresponding to the water inrush point 3.

[0027] The prepared diversion and sealing steel plate 4 is hoisted to directly above the water inrush point 3 and placed smoothly. After the diversion and sealing steel plate 4 is in place, the originally upward-gushing vertical flow or turbulent flow is restricted below the diversion and sealing steel plate 4 and directed out through the drain hole 41, transforming into a smoother lateral flow along the basement floor slab 10, thereby significantly reducing the local water head at the water inrush point 3. By adjusting the placement angle of the diversion and sealing steel plate 4 or adding a simple diversion channel, this directional water flow can be effectively guided to the vicinity of the suction inlet of the pump 2, improving the collection and drainage efficiency of the pumping system.

[0028] If the gushing water contains debris, to reduce the risk of pump blockage, a layer of wire mesh can be tied to the drain hole 41 as a filter or interception component, and / or a filter basket can be installed at the suction inlet of the water pump 2.

[0029] S3. Water inrush point sealing: See Figure 3 and Figure 9 Under strong water inrush, the weight of the guiding and sealing steel plate 4 alone may not be enough to resist the upward force of the water flow. Therefore, a counterweight limiting structure needs to be added above the guiding and sealing steel plate 4. That is, under strong water inrush, if the guiding and sealing steel plate 4 is lifted, floated, or unstable in sealing, a counterweight limiting structure needs to be added above it to resist the upward force and scouring of the water flow, thus solving the problem of the steel plate not being able to hold its position.

[0030] In this embodiment, a reinforcing cage is used as the frame 6. First, a rectangular reinforcing cage (i.e., frame 6) made of steel bars with a diameter of 16 mm to 20 mm is welded or tied onto the flow-guiding and sealing steel plate 4. This reinforcing cage is used to limit the counterweight and prevent it from being washed away, displaced, or rolled into the pump suction port by the water flow. Subsequently, sandbags 7 are filled into the reinforcing cage as counterweight. The sandbags 7 are filled in a tiered stacking manner: the counterweight is gradually increased according to the water head and the lifting trend of the flow-guiding and sealing steel plate 4. First, a layer of sandbags 7 is filled in, and it is observed whether the flow-guiding and sealing steel plate 4 is stable and whether the water flow turns into a controllable directional flow. If the flow-guiding and sealing steel plate 4 still has a lifting trend, subsequent sandbags 7 are added until the flow-guiding and sealing steel plate 4 is completely and stably attached to the bottom of the well, with no lifting phenomenon, and all the water flow is discharged orderly from the drain hole 41. The presence of the reinforcing cage effectively prevents the sandbags 7 from being washed away or displaced by the water flow, ensuring that the counterweight can continuously and stably press the flow-guiding and sealing steel plate 4 to the bottom of the well. In other words, the combination of the steel cage and the sandbag 7 provides a continuous downward compressive force, and the sandbag 7 itself also forms a certain filtering effect, reducing the probability of debris entering the pump body of the water pump 2.

[0031] S4. Wellhead Sealing and Structural Reinforcement: See Figure 4 After the pumping and drainage stabilize and the water inflow is completely controlled, creating a dry or minimally waterlogged working environment within the sump well 1, the sealing and reinforcement of the wellhead and surrounding structure will begin to form a stable construction window. First, the surface of the existing concrete basement slab 10 (i.e., the existing structure) around the wellhead of sump well 1 will be roughened to expose a solid, rough surface. Then, formwork 11 will be erected at the wellhead of sump well 1, and reinforcing bars 12 will be drilled and installed in the roughened area according to the design, followed by binding of the sealing steel mesh 13. Finally, high-strength grout or high-strength polymer repair material will be poured to form a new, highly integrated sealed cover, improving the overall structural integrity.

[0032] S5. Compaction Grouting: See Figure 6 and Figure 10This step involves a compaction grouting process implemented through grouting pipes. To fill and reinforce seepage channels, cavities, or loose backfill areas beneath the basement floor slab 10, reducing the connectivity of seepage channels and improving the durability of resealing, grouting pipes 5 are installed around the sump 1 or in the affected area. The grouting pipes 5 are 32 mm diameter steel pipes with a pointed end 53 for easy penetration into the soil. The pipe body is divided into an area with grouting holes 51 and a closed section 52 without holes. Within the required grouting depth, a series of grouting holes 51 are evenly distributed along the height of the grouting pipe 5, while the closed section 52 controls the diffusion range of the grout. The grouting material can be cement-based grout, quick-setting cement-based grout, and / or chemical grout. In this embodiment, cement grout prepared with 42.5 grade ordinary Portland cement is used. During grouting, a segmented and sequential grouting process is adopted to control the diffusion range: grouting is first carried out through the grouting pipe 5 furthest from the water collection well 1, and then through the grouting pipe 5 closer to the water collection well 1; for each grouting hole, the grout is injected in segments from deep to shallow through the grouting pipe 5. The grout diffuses evenly outward through the grouting holes 51 on the pipe body, and by controlling the grouting pressure and rate, the grout effectively fills the soil.

[0033] S6. Final sealing of voids and seepage prevention repair: See Figure 7 After grouting is completed and meets the requirements, final sealing is carried out. First, micro-expansion concrete 9 is poured into the drained sump 1 through pre-embedded pipes or by removing part of the temporary structure, ensuring that the space below the guide sealing steel plate 4 is completely filled. The micro-expansion concrete 9 undergoes micro-expansion during hardening, tightly filling all gaps. After the concrete has cured, a layer of cement-based penetrating crystalline anti-seepage repair material is applied to its surface for enhanced surface waterproofing, forming multiple waterproof barriers to minimize the risk of later leakage.

[0034] At this point, the temporary drainage and sealing devices, including the water pump 2, the flow guiding and sealing steel plate 4, and the counterweight limiting structure (reinforcing cage 6, sandbag 7), have been permanently embedded in the concrete, and the treatment is complete.

[0035] Example 2 differs from Example 1 primarily in that, in step S3, the frame 6 of the counterweight limiting structure is a truss frame welded from channel steel. The internal counterweight is a precast concrete block (a block counterweight). During sealing, a graded stacking method is also used, gradually increasing the counterweight blocks according to the water head and the lifting trend of the steel plate until the flow-guiding sealing steel plate 4 remains stable under the impact of water flow. First, a layer of concrete blocks is placed, and the stability of the flow-guiding sealing steel plate 4 is observed. If it does not meet the requirements, a second layer is hoisted and stacked until the flow-guiding sealing steel plate 4 remains stable under the impact of water flow.

[0036] Example 3, the main difference between this example and Example 1 is: see Figure 5In step S4, to further enhance the sealing and load-bearing performance, in this embodiment, a new structural beam 8 (for example, with a cross-sectional dimension of 300 mm × 300 mm) can be added to the original basement floor slab 10 around the sump 1 according to the design drawings. The reinforcing bars of the new structural beam 8 are firmly connected to the reinforcing bars of the original basement floor slab 10 and are poured together with the aforementioned sealing cover plate, thereby greatly improving the load-bearing and sealing performance of the wellhead area.

[0037] This invention also relates to a flow-guiding and pressure-sealing device for implementing the above-described method. The device mainly includes a flow-guiding and pressure-sealing steel plate 4 and a counterweight limiting structure. The flow-guiding and pressure-sealing steel plate 4 covers the water inrush point 3 and has a drainage hole 41. The counterweight limiting structure is positioned above the flow-guiding and pressure-sealing steel plate 4 to provide downward clamping force and prevent counterweight displacement; the counterweight limiting structure includes a frame 6 made of a reinforcing cage or structural steel, and multiple sandbags 7 or block counterweights filled within the frame 6. This device constrains the counterweights through the frame 6, continuously and stably transferring their weight to the flow-guiding and pressure-sealing steel plate 4, thereby achieving effective pressure sealing and flow guidance in a strong water inrush environment.

[0038] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well, characterized in that, Includes the following steps: S1. Pumping and positioning: A pump (2) is installed in the water collection well (1) to pump and lower the water level in the water collection well (1), and the location, range and water outlet form of the water inflow point (3) are confirmed and marked. S2. Flow stabilization: A flow guiding and sealing steel plate (4) is arranged above the water inrush point (3). A drain hole (41) is opened on the flow guiding and sealing steel plate (4) to transform the water inrush from vertical dispersion to directional transverse flow along the bottom of the well and guide it to the suction port of the water pump (2). S3. Water inrush point (3) pressure sealing: A counterweight limiting structure is added to the flow guiding pressure sealing steel plate (4) to resist the top support and scouring of the water flow and keep the flow guiding pressure sealing steel plate (4) stable pressure sealing; S4. Wellhead sealing and structural reinforcement: After the water inflow is controlled, the wellhead and surrounding structure of the water collection well (1) are sealed and reinforced. S5. Compacting grouting: Grouting pipes (5) are laid around the water collection well (1) or in the affected area to carry out compacting grouting and fill and reinforce the seepage channels; S6. Final sealing and seepage prevention of the holes: Micro-expansion concrete (9) is used to reseal the holes and the sealed areas.

2. The method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well according to claim 1, characterized in that, In step S2, the size of the flow-guiding and sealing steel plate (4) covers the water inrush point (3) and extends outward 50-150mm beyond the edge of the water inrush area.

3. A method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well according to claim 1 or 2, characterized in that, In step S2, when the gushing water carries debris, a filter screen or interception component is added at the drain hole (41), and / or a filter screen is installed at the suction port of the water pump (2).

4. The method for guiding, stabilizing, and sealing strong water inflow in a water collection well and resealing it according to claim 1, characterized in that, In step S3, the counterweight limiting structure includes a frame (6) and is filled with sandbags (7) or block counterweights.

5. The method for guiding, stabilizing, and sealing strong water inflow in a water collection well and re-sealing it according to claim 4, characterized in that, The frame (6) is a steel cage.

6. The method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well according to claim 4, characterized in that, When filling the block counterweight, a graded stacking method is adopted, and the weight is gradually increased according to the lifting trend of the water head and the flow guiding pressure sealing steel plate (4) until the flow guiding pressure sealing steel plate (4) is stable.

7. The method for guiding, stabilizing, and sealing strong water inflow in a water collection well and re-sealing it according to claim 1, characterized in that, Step S4 specifically includes: roughening the surface of the existing concrete structure around the wellhead of the water collection well (1), and then setting up formwork, planting rebar, tying rebar, and pouring grout or high-strength repair material to form a closed space.

8. The method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well according to claim 7, characterized in that, Step S4 also includes: adding new structural beams (8) around the water collection well (1) to improve the sealing and load-bearing performance.

9. The method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well according to claim 1, characterized in that, In step S5, the compaction grouting uses cement-based grout, quick-setting cement-based grout, or chemical grout, and the diffusion range is controlled by segmented and sequential grouting.

10. The method for guiding, stabilizing, sealing, and resealing strong water inflow in a water collection well according to claim 1, characterized in that, In step S6, after resealing with micro-expansion concrete, surface impermeability is reinforced by using anti-seepage repair materials.

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