Fixing method for anti-seepage transition section of irregular rock slope of pit landfill

Abstract

The invention discloses a method for fixing an anti-seepage transition section of an irregular rock slope of a mine pit landfill, which comprises the following steps of: wet-spraying anti-seepage gelling composite spraying filler on the irregular rock slope (1-2), and forming an anti-seepage gelling composite spraying filler layer (2) on the surface of the anti-seepage transition section; an anti-seepage geomembrane (3) is laid on a self-regular rock slope surface (1-1), then a rubber pad (7) and a thin steel plate (6) are laid on the anti-seepage geomembrane (3) from inside to outside, a hollow grouting anchor rod (4) is drilled from drill holes of the thin steel plate (6) and the rubber pad (7) in a self-drilling mode, and an anti-seepage plugging agent (8) is adopted for trimming. The method is applied to reinforcement of the irregular rock slope anti-seepage transition section of the mine pit landfill, the problem that the irregular rock slope anti-seepage transition section is prone to damage in the fixing process is solved, potential hazards are eliminated, the safety and reliability of an anti-seepage system are improved, good economic benefits are achieved, and safety and environmental protection benefits are remarkable.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine slope anti-seepage, and specifically relates to a reinforcement method for an irregular rock slope anti-seepage transition section of a mine landfill. The method can be widely used in mine slope anti-seepage, and is particularly suitable for slope anti-seepage of abandoned mines used as solid waste landfills. Background Art

[0002] The mine anti-seepage system consists of two parts: base anti-seepage and slope anti-seepage. The main function of the anti-seepage system is to isolate the infiltration of leachate and avoid secondary pollution. Its role in protecting the overall ecological environment of the mine and its surroundings cannot be ignored.

[0003] The anti-seepage system of mine pits mostly uses anti-seepage geomembrane as the anti-seepage lining, and sets protective layers on the upper and lower sides according to the undulation of the slope surface. The base anti-seepage can effectively solve the problem of base flatness through site finishing, ensuring the safety and reliability of the laying of anti-seepage geomembrane. However, due to the previous mining activities, the slopes are mostly irregular shapes with large undulations. The direct laying of anti-seepage geomembrane forms stress concentration areas due to the irregular slopes. The lateral pressure formed by the accumulation of solid waste during the operation of the landfill causes anti-seepage damage, which is highly concealed and has a high repair cost.

[0004] At present, a variety of new anti-seepage materials are used in mine slope anti-seepage, such as new cementitious materials, which are used in combination with anti-seepage geomembranes to solve the problem of difficulty and low reliability in anti-seepage of irregular rock slopes. A mine steep slope anti-seepage system based on polymer polymer mineral anti-seepage materials published in Chinese patent application 202411113707.3 adopts the method of filling the outer geocell with polymer polymer mineral anti-seepage materials, and the inner geocell is filled with graded pebbles; the Chinese patent with publication number CN112523264A uses the hanging net spraying technology to level and passivate the slope base before laying, which has problems such as high construction cost, great difficulty and great hidden dangers of the spraying layer; the Chinese patent with publication number CN217782093U needs to process the slope to improve the anti-skid stability of the protective structure and the anti-seepage membrane, which has problems such as complex construction technology, great excavation difficulty and slope disturbance instability.

[0005] The fixing method of the anti-seepage transition section is very important to the safety and reliability of the landfill anti-seepage system. So far, there is no unified standard for the fixing method of the transition section, and most of them adopt a single steel slope fixing method. This method can easily cause damage to the anti-seepage body of the transition section, and has great potential risks. Summary of the invention

[0006] The purpose of the present invention is to provide a method for fixing the anti-seepage transition section of an irregular rock slope in a mine landfill, which is convenient in construction, economical and effective, safe and reliable, in order to address the technical difficulties such as the high construction difficulty, high construction cost, easy damage to the anti-seepage body of the transition section, and potential hidden dangers and risks in the current anti-seepage transition section fixation.

[0007] To achieve the above-mentioned purpose of the present invention, the present invention provides a method for fixing an irregular rock slope anti-seepage transition section of a mine landfill, wherein the anti-seepage transition section is divided by an anti-seepage boundary line, one side of the anti-seepage boundary line is an irregular rock slope surface, and the other side of the anti-seepage boundary line is a regular rock slope surface, and the following steps are adopted for implementation:

[0008] S1 anti-seepage gelled composite spray filler preparation

[0009] The solidified cementitious material, building sand / tailings sand and water are mixed and configured to prepare an anti-seepage cementitious composite spray filler. When the total mass of the anti-seepage cementitious composite spray filler is 100%, the proportions of the components are: 19% to 26% of the solidified cementitious material, 53% to 62% of the building sand / tailings sand, and 16% to 21% of water;

[0010] S2 anti-seepage gelled composite spray filler wet spray

[0011] The anti-seepage gelled composite sprayed filling material prepared in step S1 is wet sprayed on the irregular rock slope surface, and the wet spraying is extended to the regular rock slope surface on the other side of the anti-seepage boundary by a length of L1, so as to form an anti-seepage gelled composite sprayed filling material layer on the surface of the anti-seepage transition section; the surface of the anti-seepage gelled composite sprayed filling material layer sprayed on the irregular rock slope surface is uniform and straight, and the thickness of the anti-seepage gelled composite sprayed filling material layer sprayed in the length section of L1 smoothly transitions to 0;

[0012] S3 anti-seepage geomembrane laying

[0013] An anti-seepage geomembrane is laid from the regular rock slope surface, and is extended along the anti-seepage boundary line to the irregular rock slope surface for a length of L2. The anti-seepage gelled composite spraying filling material layer and the bidirectional extension section of the anti-seepage geomembrane form an overlap section;

[0014] S4 Rubber pad, thin steel plate laying, fixing

[0015] According to the designed aperture and spacing, holes are drilled in the rubber pad and thin steel plate respectively, and then the rubber pad and thin steel plate are laid on the anti-seepage geomembrane from the inside to the outside, and the drilling positions on the rubber pad and thin steel plate correspond to each other; the hollow grouting anchor rod is self-drilled through the drill holes of the thin steel plate and rubber pad, and penetrates into the rock in the anti-seepage gelled composite sprayed filling material layer, the rock penetration angle is α, and the rock penetration depth is La;

[0016] S5 anti-seepage plugging agent trimming

[0017] After the hollow grouting anchor rod is fixed, cut off the excess part of the extended laying section of the anti-seepage geomembrane, use the anti-seepage plugging agent to fill and bond the gaps between the thin steel plate, rubber pad, anti-seepage geomembrane and the anti-seepage cementitious composite spray filling material layer, and evenly apply the anti-seepage plugging agent along the periphery of the thin steel plate.

[0018] Generally, the solidified cementitious material used in step S1 is the solidified cementitious material for tailings filling. According to the "General Industrial Solid Waste Storage and Landfill Pollution Control Standard" (GB 18599-2020), an anti-seepage cementitious composite spraying material with specified anti-seepage effectiveness is prepared. The results of experimental research show that for the anti-seepage standards specified for Class I landfills, the best effect is achieved when the mass ratio of solidified cementitious material, construction sand / tailings sand, and water is 1:3:1.

[0019] Preferably, the solidified cementitious material used in step S1 is mixed with a stabilizer, a composite powder, water glass and cement, and the content of each component when the total mass is calculated as 100% is: 9% to 15% of the stabilizer, 9% to 15% of the composite powder, 28% to 45% of the water glass, and 28% to 47% of the cement; the mass percentage of the stabilizer is 50% to 60% of calcium chloride and 40% to 50% of sodium borate tetrahydrate; the composite powder is mixed with carbide slag powder, desulfurized gypsum, fly ash and blast furnace slag, and the mass percentage is 29% to 37% of carbide slag powder, 15% to 20% of desulfurized gypsum, 19% to 24% of fly ash, and 20% to 26% of blast furnace slag.

[0020] Preferably, the construction sand / tailings sand used in step S1 is medium sand, the mass of particles with a particle size greater than 0.25 mm exceeds 50% of the total weight, and the average particle size is 0.5 mm to 0.25 mm.

[0021] Preferably, in step S2, the thickness of the anti-seepage gelled composite spraying filling material layer formed by wet spraying on the irregular rock slope is δ=5cm-15cm, and the wet spraying length L1=1.0m-2.0m is extended on the regular rock slope.

[0022] Preferably, in step S3, in accordance with the anti-seepage effectiveness requirements of the "General Industrial Solid Waste Storage and Landfill Pollution Control Standard" (GB18599-2020), the laid anti-seepage geomembrane is a HDPE geomembrane with a specification of 1.5mm to 2.0mm, and the extended laying length L2 = 0.8m to 1.5m.

[0023] Preferably, in step S4, the hollow grouting anchor rod is a full-length corrugated thread, equipped with a fixing nut and a special quick grouting joint, the specification model of the hollow grouting anchor rod is R20~25, the drilling depth into the rock La=50cm~1.5m, the plane spacing of the borehole along the axial direction M=30cm~50cm, and the inclination angle of the hollow grouting anchor rod into the rock α=15°~25°; the nut is matched with the specification size of the hollow grouting anchor rod, and the nut specification model is M16~M20.

[0024] Preferably, in step S4, the thin steel plate is a steel plate with a thickness of less than 3 mm, a specification size of 2 mm to 3 mm, a width B = 30 cm to 50 cm, an axis length L3 = 1 to 2 m, a surface pre-drilled, the hole diameter matches the specification of the hollow grouting anchor, the hole spacing M2 = 30 cm to 50 cm, and a rubber pad is lined; the rubber pad is a high-pressure resistant rubber pad with a thickness of 3 mm to 5 mm.

[0025] Preferably, in step S5, the anti-seepage and leak-proofing agent is an inorganic waterproof leak-proofing material, code-named FDⅡGB23440-2009.

[0026] After adopting the above technical solution, the fixing method of the anti-seepage transition section of the irregular rock slope of a mine landfill of the present invention specifically shows the following positive effects:

[0027] (1) The present invention forms an overlap section by bidirectionally extending a new type of anti-seepage gelling anti-seepage geomembrane, thereby improving the stability of the transition section fixed structure, and has the advantages of strong operability and reliable construction.

[0028] (2) The present invention utilizes the anchoring stability of the hollow grouting anchor rod and the cushioning effect of the high-pressure resistant rubber pad to form a fixed structure with good air tightness, thereby improving the safety and stability of the anti-seepage transition section.

[0029] (3) The anti-seepage gelled composite spray filler developed by the present invention makes full use of the chemical properties of fine-grained minerals in tailings sand. Under the action of external compounds, it forms a water-impermeable polymer colloid through physical and chemical reactions. The polymer does not react chemically with acids, alkalis and other salts, and has good workability. The permeability is extremely low, only 1 / 3000 of that of high-quality clay, and the permeability coefficient can reach k = 0.3×10 -9 .

[0030] (4) The anti-seepage gelled composite spray filler developed by the present invention has good acid and alkali resistance, strong stability, high consolidation strength, is easy to construct and lay, has high spraying efficiency, and does not require rolling.

[0031] (5) The anti-seepage gelled composite spray filler developed by the present invention can give the slurry good coagulation characteristics and mechanical properties, and the 28-day strength is greater than 20MPa.

[0032] (6) The solidified cementitious material developed by the present invention and the tailings sand used are all industrial solid wastes and do not require secondary calcination. The production process is simple, environmentally friendly, and requires little investment, thereby reducing the carbon emissions and energy consumption of the calcination of traditional cementitious material clinkers.

[0033] (7) The present invention is applied to the reinforcement of the anti-seepage transition section of the irregular rock slope in a mine landfill, which overcomes the problem that the anti-seepage transition section of the irregular rock slope is easily damaged during the fixing process. It not only has good economic benefits, but also has significant safety and environmental protection benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a plane view of a method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill according to the present invention;

[0035] Figure 2 A cross-sectional view of a method for fixing an irregular rock slope anti-seepage transition section of a mine landfill in the present invention.

[0036] Figure numerals: 1-1—regular rock slope; 1-2—irregular rock slope; 2—anti-seepage cementitious composite spray filling material layer; 3—anti-seepage geomembrane; 4—hollow grouting anchor rod; 5—nut; 6—thin steel plate; 7—rubber pad; 8—anti-seepage plugging agent; 9—anti-seepage boundary line. DETAILED DESCRIPTION

[0037] To better describe the present invention, a method for fixing an anti-seepage transition section on an irregular rock slope of a mine landfill according to the present invention is further described in detail below in conjunction with the accompanying drawings.

[0038] In the embodiment, after a certain abandoned mine solid waste landfill was filled to a relative elevation of 15m, the irregular rock slope area accounted for about 20%. A new type of anti-seepage cementitious material and HDPE geomembrane were used for joint anti-seepage. The transition section of the two anti-seepage materials was fixed with a single steel bar slope. During operation, the anti-seepage membrane in the transition section was damaged, and effective engineering measures were urgently needed to handle or manage it.

[0039] Depend on Figure 2 The cross-sectional view of the fixing method of the irregular rock slope anti-seepage transition section of the mine landfill of the present invention is shown in combination with Figure 1 It can be seen that the anti-seepage transition section is divided by the anti-seepage boundary line 9, one side of the anti-seepage boundary line 9 is the irregular rock slope 1-2, and the other side of the anti-seepage boundary line 9 is the regular rock slope 1-1. In the embodiment, the fixing method of the anti-seepage transition section of the irregular rock slope of a mine landfill of the present invention is implemented by the following steps:

[0040] S1 anti-seepage gelled composite spray filler preparation

[0041] According to the "General Industrial Solid Waste Storage and Landfill Pollution Control Standard" (GB 18599-2020), the tailings filling gelling agent, medium sand and water are mixed to prepare an anti-seepage gelled composite spray filling material. When the total mass of the anti-seepage gelled composite spray filling material is 100%, the ratio of each component is: 20% tailings filling gelling agent, 60% sand, and 20% water, that is, 1:3:1.

[0042] S2 anti-seepage gelled composite spray filler wet spray

[0043] The anti-seepage gelled composite sprayed filling material prepared in step S1 is wet sprayed on the irregular rock slope surface, and is extended to the regular rock slope surface 1-1 on the other side of the anti-seepage boundary 9 by a wet spraying length of L1=1.5m, thereby forming an anti-seepage gelled composite sprayed filling material layer 2 on the surface of the anti-seepage transition section; the surface of the anti-seepage gelled composite sprayed filling material layer 2 sprayed on the irregular rock slope surface 1-2 is uniform and straight, evenly covered and has an average thickness of δ=5cm, and the thickness of the anti-seepage gelled composite sprayed filling material layer 2 sprayed in the length section L1 has a uniform transition from 5cm to 0.

[0044] S3 anti-seepage geomembrane laying

[0045] According to the "General Industrial Solid Waste Storage and Landfill Pollution Control Standard" (GB 18599-2020), a 1.5mm HDPE anti-seepage geomembrane 3 with a specified anti-seepage effect is laid from the regular rock slope 1-1, and extended along the anti-seepage boundary line 9 to the irregular rock slope 1-2 with a length of L2=1.0m. The anti-seepage cementitious composite spray filling material layer 2 and the anti-seepage geomembrane 3 extend in both directions to form an overlap section.

[0046] S4 Rubber pad, thin steel plate laying, fixing

[0047] The surface of the thin steel plate 6 is pre-drilled according to the diameter of the hollow grouting anchor rod 4. The thin steel plate 6 is a steel plate with a thickness of 2mm to 3mm and a width of B = 30cm. The axis length L3 = 1.5m, and the pre-drilled holes are arranged at equal intervals along the axis, with a spacing of M2 = 30cm; the rubber pad 7 is a high-pressure resistant rubber pad with a thickness of 3mm, and the width, axis length, and hole diameter are arranged in the same manner as the thin steel plate 6. The rubber pad 7 and the thin steel plate 6 are laid on the anti-seepage geomembrane 3 from the inside to the outside, and the drilling positions on the rubber pad 7 and the thin steel plate 6 correspond; the specification of the hollow grouting anchor rod 4 is R20, and the hollow grouting anchor rod 4 is self-drilled from the drilling holes of the thin steel plate 6 and the rubber pad 7, and penetrates into the rock in the anti-seepage gelled composite spray filling material layer 2, the rock entry inclination angle is α=20°, the rock entry depth is La=50cm, the plane spacing M=30cm, which is the same as the aperture spacing M, and grouting is injected from the bottom after entering the rock, and the grouting can be returned to the hole mouth, and it is fixed with an M16 nut 5.

[0048] S5 anti-seepage plugging agent trimming

[0049] After the hollow grouting anchor rod 4 is fixed, the excess part of the extended laying section of the anti-seepage geomembrane 3 is cut off, leaving 30cm, and the gaps between the thin steel plate 6, rubber pad 7, anti-seepage geomembrane 3 and the anti-seepage gel composite spraying filling material layer 2 are filled and bonded with the anti-seepage plugging agent 8, and the anti-seepage plugging agent 8 is evenly applied along the periphery of the thin steel plate 6 to further improve the sealing performance. The anti-seepage plugging agent 8 is selected as a quick-setting type according to the setting time, code FDⅡGB 23440-2009.

[0050] Example 2

[0051] In Example 2, the curing gelling material, tailings sand and water are mixed in a mass ratio of 1:3:1 to prepare an anti-seepage gelling composite spraying filler. The tailings sand is the medium sand after tailings classification, the mass of particles with a particle size greater than 0.25mm exceeds 50% of the total weight, and the average particle size is 0.3mm. Among them, the curing gelling material is mixed with a stabilizer, a composite powder, water glass and cement, and the content of each component when the total mass is calculated as 100% is: stabilizer 15%, composite powder 15%, water glass 36%, cement 34%; the mass percentage of the stabilizer is 60% calcium chloride and 40 sodium borate tetrahydrate; the composite powder is mixed with carbide slag powder, desulfurized gypsum, fly ash and blast furnace slag, and the mass percentage is 32% carbide slag powder, 18% desulfurized gypsum, 24% fly ash and 26% blast furnace slag. The rest is the same as Example 1. The test results after implementation show that the anti-seepage effect is improved by 25% compared with Example 1, and the cost of the anti-seepage gelled composite spray filler is reduced by 41%.

Claims

1. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill, wherein the anti-seepage transition section is divided by an anti-seepage boundary line (9), one side of the anti-seepage boundary line (9) is an irregular rock slope (1-2), and the other side of the anti-seepage boundary line (9) is a regular rock slope (1-1), characterized in that This is done using the following steps: S1 anti-seepage gelled composite spray filler preparation The solidified cementitious material, building sand / tailings sand and water are mixed and configured to prepare an anti-seepage cementitious composite spray filler. When the total mass of the anti-seepage cementitious composite spray filler is 100%, the proportions of the components are: 19% to 26% of the solidified cementitious material, 53% to 62% of the building sand / tailings sand, and 16% to 21% of water; S2 anti-seepage gelled composite spray filler wet spray The anti-seepage gelled composite sprayed filler prepared in step S1 is wet-sprayed on the irregular rock slope (1-2), and the wet-spraying length L1 is extended to the regular rock slope (1-1) on the other side of the anti-seepage boundary (9), thereby forming an anti-seepage gelled composite sprayed filler layer (2) on the surface of the anti-seepage transition section; the surface of the anti-seepage gelled composite sprayed filler layer (2) sprayed on the irregular rock slope (1-2) is uniform and straight, and the thickness of the anti-seepage gelled composite sprayed filler layer (2) sprayed in the L1 length section is uniformly transitioned to 0; S3 anti-seepage geomembrane laying An anti-seepage geomembrane (3) is laid from a regular rock slope (1-1), and is extended along an anti-seepage boundary line (9) to an irregular rock slope (1-2) by a length of L2, so that the anti-seepage gelled composite spraying material layer (2) and the anti-seepage geomembrane (3) extend in both directions to form an overlap section; S4 Rubber pad, thin steel plate laying, fixing According to the designed hole diameter and spacing, holes are drilled in the rubber pad (7) and the thin steel plate (6), and then the rubber pad (7) and the thin steel plate (6) are laid on the anti-seepage geomembrane (3) from the inside to the outside, and the drilling positions on the rubber pad (7) and the thin steel plate (6) correspond to each other; the hollow grouting anchor rod (4) is self-drilled through the drilling holes of the thin steel plate (6) and the rubber pad (7), and penetrates into the rock in the anti-seepage gelled composite sprayed filling material layer (2), and the rock penetration angle is α and the rock penetration depth is La; S5 anti-seepage plugging agent trimming After the hollow grouting anchor rod (4) is fixed, the excess part of the extended laying section of the anti-seepage geomembrane (3) is cut off, and the gaps between the thin steel plate (6), the rubber pad (7), the anti-seepage geomembrane (3) and the anti-seepage gel composite spraying material layer (2) are filled and bonded with an anti-seepage plugging agent (8), and the anti-seepage plugging agent (8) is evenly applied along the periphery of the thin steel plate (6).

2. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill as claimed in claim 1, characterized in that: The solidified cementitious material used in step S1 is a solidified cementitious material for tailings filling, and an anti-seepage cementitious composite spray filler with a specified anti-seepage effect is prepared in accordance with the "General Industrial Solid Waste Storage and Landfill Pollution Control Standard" (GB 18599-2020).

3. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill as claimed in claim 1, characterized in that: The solidified cementitious material used in step S1 is mixed with a stabilizer, a composite powder, water glass and cement, and the content of each component when the total mass is calculated as 100% is: 9% to 15% of the stabilizer, 9% to 15% of the composite powder, 28% to 45% of the water glass, and 28% to 47% of the cement; the mass percentage of the stabilizer is 50% to 60% of calcium chloride and 40% to 50% of sodium borate tetrahydrate; the composite powder is mixed with carbide slag powder, desulfurized gypsum, fly ash and blast furnace slag, and the mass percentage is 29% to 37% of carbide slag powder, 15% to 20% of desulfurized gypsum, 19% to 24% of fly ash, and 20% to 26% of blast furnace slag.

4. A method for fixing an anti-seepage transition section on an irregular rock slope in a mine landfill as claimed in claim 2 or 3, characterized in that: The construction sand / tailings sand used in step S1 is medium sand, the mass of particles with a particle size greater than 0.25 mm exceeds 50% of the total weight, and the average particle size is 0.5 mm to 0.25 mm.

5. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill as claimed in claim 4, characterized in that: In step S2, the thickness of the anti-seepage gelled composite spraying filling material layer (2) formed by wet spraying on the irregular rock slope (1-2) is δ=5cm-15cm, and the wet spraying length L1=1.0m-2.0m is extended on the regular rock slope (1-1).

6. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill as claimed in claim 5, characterized in that: In step S3, the anti-seepage geomembrane (3) laid is a HDPE geomembrane with a specification of 1.5 mm to 2.0 mm, and the extended laying length L2 is 0.8 m to 1.5 m.

7. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill as claimed in claim 6, characterized in that: In step S4, the hollow grouting anchor rod (4) is a full-length corrugated thread, equipped with a fixing nut (5) and a special quick grouting joint, the specification model of the hollow grouting anchor rod (4) is R20~25, the drilling depth into the rock La=50cm~1.5m, the plane spacing of the borehole along the axial direction M=30cm~50cm, and the hollow grouting anchor rod (4) has an inclination angle α of 15°~25° into the rock.

8. A method for fixing an anti-seepage transition section on an irregular rock slope in a mine landfill as claimed in claim 7, characterized in that: In step S4, the nut (5) is matched with the size of the hollow grouting anchor rod (4), and the size of the nut (5) is M16 to M20.

9. A method for fixing an anti-seepage transition section of an irregular rock slope in a mine landfill as claimed in claim 8, characterized in that: The thin steel plate (6) is a steel plate with a thickness of less than 3 mm, a specification size of 2 mm to 3 mm, a width B of 30 cm to 50 cm, an axis length L3 of 1 to 2 m, a surface pre-drilled hole processing, the hole diameter matches the specification of the hollow grouting anchor rod (4), the hole spacing M2 is 30 cm to 50 cm, and the inner lining is a rubber pad (7); the rubber pad (7) is a high-pressure resistant rubber pad with a thickness of 3 mm to 5 mm.

10. A method for fixing an anti-seepage transition section on an irregular rock slope in a mine landfill as claimed in claim 9, characterized in that: In step S5, the anti-seepage plugging agent (8) is an inorganic waterproof plugging material, code-named FDⅡGB 23440-2009.

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