Grouting reinforcement anti-seepage method for dam body of underground reservoir of coal mine

Abstract

The invention discloses a grouting reinforcement anti-seepage method for a dam body of a coal mine underground reservoir, which comprises the following steps of: constructing a grouting hole at an artificial dam body position of a dam body to be treated, and performing segmented grouting on the grouting hole; the grouting materials are spread to the interiors of the artificial dam bodies, the interiors of the coal pillar dam bodies, the connecting positions between the artificial dam bodies and the coal pillar dam bodies, the connecting positions between the artificial dam bodies and the top plate rock stratum and the connecting positions between the artificial dam bodies and the bottom plate rock stratum; therefore, micropore cracks in the to-be-treated dam body and the connecting positions between the to-be-treated dam body and the top plate rock stratum and between the to-be-treated dam body and the bottom plate rock stratum can be effectively blocked, the leakproofness and the anti-seepage performance of the coal mine underground reservoir dam body are remarkably improved, and effective anti-seepage reinforcement of the coal mine underground reservoir dam body is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, and in particular to a grouting reinforcement and anti-seepage method for the dam body of an underground coal mine reservoir. Background Technique

[0002] In some areas rich in coal resources but lacking in water resources, the underground coal mine reservoir technology has become an effective way to solve the problem of water shortage. The underground coal mine reservoir uses the goaf for water storage, and uses the dam body formed by connecting the coal pillar dam body and the artificial dam body to block water, and is equipped with a water transfer facility, which is a new type of hydraulic structure. The coal pillar dam body is the reserved protective coal pillar. The artificial dam body is an artificial structure, mostly composed of a brick wall, a concrete wall, and a filling layer. However, the dam body of the underground coal mine reservoir is affected by various factors such as mine pressure and water pressure, and is prone to leakage problems during long-term operation, bringing potential safety hazards to coal mine production.

[0003] The existing reinforcement and anti-seepage methods for the underground reservoir dam body usually carry out the anti-seepage project synchronously with coal mining, and use a combination of a cement protection layer, an anti-seepage geotextile, and a cement anti-seepage layer to form an anti-seepage wall for anti-seepage. However, due to construction limitations, it is difficult for the anti-seepage geotextile to cover the entire roadway wall surface, and there are easily defects after the construction of the anti-seepage geotextile, such as joints formed due to poor splicing quality, being punctured during construction, being broken by the underlying filling layer, being torn due to uneven roadway wall surface, etc., which directly affects the reinforcement and anti-seepage effect of the underground reservoir dam body. Therefore, the existing technology is difficult to effectively reinforce and prevent seepage of the underground reservoir dam body. Summary of the Invention

[0004] The present invention provides a grouting reinforcement and anti-seepage method for the dam body of an underground coal mine reservoir to solve the technical problem that the existing technology is difficult to effectively reinforce and prevent seepage of the underground reservoir dam body.

[0005] To solve the above technical problems, an embodiment of the present invention provides a grouting reinforcement and anti-seepage method for the dam body of an underground coal mine reservoir, including:

[0006] Obtaining the dam body leakage information of the underground coal mine reservoir, and determining the dam body to be treated in the underground coal mine reservoir based on the dam body leakage information; wherein, the dam body to be treated includes an artificial dam body and a coal pillar dam body;

[0007] Determining the structural information of the dam body to be treated according to the engineering information of the underground coal mine reservoir;

[0008] Determining the drilling depth and the segmented grouting requirements according to the geological information and the structural information of the underground coal mine reservoir;

[0009] Constructing grouting holes on the surface of the artificial dam body according to the drilling depth;

[0010] According to the drilling depth and the segmented grouting requirements, segmented grouting is carried out on the grouting holes, so that the grouting material diffuses to the inside of the artificial dam body, the inside of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum.

[0011] As a preferred solution, determining the structural information of the dam body to be treated according to the engineering information of the underground coal mine reservoir specifically includes:

[0012] According to the engineering information, determine the reserved width of the coal pillar dam body, each structural layer of the artificial dam body and the thickness of each structural layer, the cutting depth and cutting width between the artificial dam body and the coal pillar dam body, the cutting depth and cutting width between the artificial dam body and the roof rock stratum, and the cutting depth and cutting width between the artificial dam body and the floor rock stratum.

[0013] As a preferred solution, determining the drilling depth and segmented grouting requirements according to the geological information and the structural information of the underground coal mine reservoir specifically includes:

[0014] According to the geological information, determine the lithology of the roof rock stratum and the lithology of the floor rock stratum;

[0015] According to the reserved width of the coal pillar dam body, the lithology of the roof rock stratum and the lithology of the floor rock stratum, determine the grouting volume and grouting pressure;

[0016] According to each structural layer and the thickness of each structural layer, determine the segmented grouting depth range, the grouting material and the drilling depth;

[0017] According to the grouting volume, the grouting pressure, the segmented grouting depth range and the grouting material, determine the segmented grouting requirements.

[0018] As a preferred solution, each structural layer includes an outer concrete wall layer, an outer brick wall layer, a filling layer, an inner brick wall layer and an inner concrete wall layer which are sequentially stacked, and one side of the inner concrete wall layer is a goaf; the segmented grouting depth range includes a first grouting depth range corresponding to the filling layer and a second grouting depth range corresponding to the outer concrete wall layer and the bonding interface between it and the outer brick wall layer; the grouting material includes a first grouting material corresponding to the first grouting depth range and a second grouting material corresponding to the second grouting depth range;

[0019] Then, according to the drilling depth and the requirements of sectional grouting, sectional grouting is carried out on the grouting holes, so that the grouting material diffuses to the inside of the artificial dam body, the inside of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum, which specifically includes:

[0020] According to the drilling depth, determine the length of the grouting pipe, and based on the first grouting depth range and the second grouting depth range, drill holes on the grouting pipe to form a first drilling area corresponding to the first grouting depth range and a second drilling area corresponding to the second grouting depth range;

[0021] Based on the first drilling area and the second drilling area, arrange a number of water bag rings on the pipe wall of the grouting pipe, and insert the grouting pipe provided with the water bag rings into the grouting hole, so that the water bag rings are arranged between the pipe wall of the grouting pipe and the hole wall of the grouting hole;

[0022] Control the water injection of the water bag rings to form a first grouting space corresponding to the first grouting depth range in the grouting hole;

[0023] According to the grouting volume and the grouting pressure, inject the first grouting material into the first grouting space through the first drilling area, so that the first grouting material diffuses in the filling layer;

[0024] Control the water injection of the water bag rings to form a second grouting space corresponding to the second grouting depth range in the grouting hole;

[0025] According to the grouting volume and the grouting pressure, inject the second grouting material into the second grouting space through the second drilling area, so that the second grouting material diffuses to the inside of the outer concrete wall layer, the bonding interface between the outer concrete wall layer and the outer brick wall layer, the inside of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum.

[0026] As a preferred solution, the first grouting material is a quick-setting inorganic grouting material, the quick-setting inorganic grouting material includes component A and component B, component A is composed of sulfoaluminate cement and an admixture, and component B is composed of a quick-setting agent and an expansive agent; the mass ratio of component A to component B is 4.5:1, and the water-cement ratio of the quick-setting inorganic grouting material is 0.6:1.

[0027] As a preferred solution, the second grouting material is a polyacrylate-modified cement material, which includes polyacrylate emulsion, defoamer, ultra-fine cement, alumina clinker accelerating agent and early strength agent. The water-cement ratio of the polyacrylate-modified cement material is 1:1, and the polymer-cement ratio is 0.2:1.

[0028] As a preferred solution, the difference between the length of the grouting pipe and the drilling depth is greater than or equal to 40 cm.

[0029] As a preferred solution, the grouting pressure corresponding to the first grouting material is 0.5 MPa to 1.0 MPa, and the grouting pressure corresponding to the second grouting material is 1.0 MPa to 2.0 MPa;

[0030] The water injection pressure of the water bag ring bag when forming the first grouting space is greater than the grouting pressure corresponding to the first grouting material; the water injection pressure of the water bag ring bag when forming the second grouting space is greater than the grouting pressure corresponding to the second grouting material.

[0031] As a preferred solution, obtaining the dam body leakage information of the coal mine underground reservoir and determining the dam body to be treated in the coal mine underground reservoir based on the dam body leakage information specifically includes:

[0032] Count the number of leakage points and the leakage volume per unit time of each dam body in the coal mine underground reservoir;

[0033] When it is detected that the number of leakage points of any dam body is greater than the preset leakage point number threshold or the leakage volume per unit time of the leakage point is greater than the preset leakage volume threshold, determine that the any dam body is the dam body to be treated.

[0034] As a preferred solution, the method further includes:

[0035] When the segmented grouting of the grouting hole is completed, seal the grouting hole.

[0036] Compared with the prior art, the beneficial effect of the embodiment of the present invention is that by constructing a grouting hole at the position of the artificial dam body of the dam body to be treated and performing segmented grouting on the grouting hole, the grouting material can be diffused into the interior of the artificial dam body, the interior of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum, so as to effectively seal the micro-pore cracks inside the dam body to be treated and the connection positions between the dam body to be treated and the roof rock stratum and the floor rock stratum, thereby significantly improving the tightness and anti-seepage performance of the coal mine underground reservoir dam body and realizing the effective anti-seepage reinforcement of the coal mine underground reservoir dam body. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic flow chart of the grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir in the embodiment of the present invention;

[0038] Figure 2 It is a front view of the grouting of the dam body of the underground coal mine reservoir in the embodiment of the present invention;

[0039] Figure 3 It is a top view of the grouting of the dam body of the underground coal mine reservoir in the embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of the layout of the grouting holes for the dam body of the underground coal mine reservoir in the embodiment of the present invention;

[0041] Among them, 1. Coal pillar dam body; 2. Roof rock stratum; 3. Floor rock stratum; 4. Artificial dam body; 5. Grouting hole; 6. Stockpiled mine water; 7. Outer concrete wall layer; 8. Outer brick wall layer; 9. Filling layer; 10. Inner concrete wall layer; 11. Inner brick wall layer; 12. Grouting pipe; 13. First water bag ring bag; 14. Second water bag ring bag; 15. Third water bag ring bag; 16. Water pipe; 17. Water pump; 18. Grouting rubber hose; 19. Grouting pump. Specific implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0043] Please refer to Figures 1 to 4 , the embodiment of the present invention provides a grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir, including the following steps S1 to S5:

[0044] Step S1, obtain the dam body leakage information of the underground coal mine reservoir, and determine the dam body to be treated in the underground coal mine reservoir based on the dam body leakage information; wherein, the dam body to be treated includes the artificial dam body 4 and the coal pillar dam body 1;

[0045] Step S2, determine the structural information of the dam body to be treated according to the engineering information of the underground coal mine reservoir;

[0046] Step S3, determine the drilling depth and segmented grouting requirements according to the geological information and the structural information of the underground coal mine reservoir;

[0047] Step S4, construct grouting holes 5 on the surface of the artificial dam body 4 according to the drilling depth;

[0048] Step S5: According to the drilling depth and the segmented grouting requirement, perform segmented grouting on the grouting holes 5, so that the grouting material diffuses into the interior of the artificial dam body 4, the interior of the coal pillar dam body 1, the connection position between the artificial dam body 4 and the coal pillar dam body 1, the connection position between the artificial dam body 4 and the roof rock stratum 2, and the connection position between the artificial dam body 4 and the floor rock stratum 3.

[0049] Specifically, in this embodiment, it is first necessary to conduct on-site investigation of the underground coal mine reservoir to determine the dam body leakage information, and based on this dam body leakage information, determine the dam body to be treated that needs grouting reinforcement currently. Further, due to different dam body structures, lithologies of the roof rock stratum 2 and the floor rock stratum 3, the corresponding grouting requirements usually also vary. In order to effectively grout and reinforce the dam body to be treated, in this embodiment, according to the engineering information of the underground coal mine reservoir, such as data like borehole columnar diagrams, mining engineering diagrams, and construction drawings of the artificial dam body 4, etc., the structural information of the dam body to be treated is determined. Further, since this embodiment needs to perform segmented grouting on the artificial dam body 4, it is necessary to determine the drilling depth according to the structural information obtained above, so as to be able to drill holes according to the layer thickness of different structural layers. In addition, it is also necessary to determine the segmented grouting requirement based on the geological information and the structural information, which has reference value for the grouting volume, grouting pressure, grouting area, etc.

[0050] Further, according to the determined drilling depth, construct grouting holes 5 on the surface of the artificial dam body 4, and based on the drilling depth and the segmented grouting requirement, perform segmented grouting on the grouting holes 5, so that different grouting materials and grouting parameters can be adopted according to the porosity sizes of different structural layers in the artificial dam body 4, realizing the rapid plugging of cracks and pores, achieving the optimal anti-seepage effect. Based on this grouting method, the grouting material can be made to diffuse into the interior of the artificial dam body 4, the interior of the coal pillar dam body 1, the connection position between the artificial dam body 4 and the coal pillar dam body 1, the connection position between the artificial dam body 4 and the roof rock stratum 2, and the connection position between the artificial dam body 4 and the floor rock stratum 3.

[0051] The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir provided by the embodiment of the present invention, by constructing grouting holes 5 at the position of the artificial dam body 4 of the dam body to be treated and performing segmented grouting on the grouting holes 5, so that the grouting material diffuses into the interior of the artificial dam body 4, the interior of the coal pillar dam body 1, the connection position between the artificial dam body 4 and the coal pillar dam body 1, the connection position between the artificial dam body 4 and the roof rock stratum 2, and the connection position between the artificial dam body 4 and the floor rock stratum 3, can effectively plug the micro-cracks inside the dam body to be treated and the connection positions between the dam body to be treated and the roof rock stratum 2 and the floor rock stratum 3, thereby significantly improving the tightness and anti-seepage performance of the dam body of the underground coal mine reservoir, and realizing the effective anti-seepage reinforcement of the dam body of the underground coal mine reservoir.

[0052] As a preferred solution, determining the structural information of the dam body to be treated according to the engineering information of the underground coal mine reservoir specifically includes:

[0053] According to the engineering information, determine the reserved width of the coal pillar dam body 1, each structural layer of the artificial dam body 4 and the thickness of each structural layer, the cutting depth and cutting width between the artificial dam body 4 and the coal pillar dam body 1, the cutting depth and cutting width between the artificial dam body 4 and the roof rock stratum 2, and the cutting depth and cutting width between the artificial dam body 4 and the floor rock stratum 3.

[0054] Specifically, according to engineering information such as borehole columnar diagrams, mining engineering diagrams, and construction drawings of the artificial dam body 4, the reserved width of the coal pillar dam body 1 can be determined, thereby the plastic zone range of the coal pillar dam body 1 can be determined, providing a reference for determining the grouting pressure and grouting volume. And according to each structural layer of the artificial dam body 4 and the thickness of each structural layer, the drilling depth can be determined.

[0055] As a preferred solution, determining the drilling depth and segmented grouting requirements according to the geological information and the structural information of the underground coal mine reservoir specifically includes:

[0056] According to the geological information, determine the lithology of the roof rock stratum 2 and the lithology of the floor rock stratum 3;

[0057] According to the reserved width of the coal pillar dam body 1, the lithology of the roof rock stratum 2 and the lithology of the floor rock stratum 3, determine the grouting volume and grouting pressure;

[0058] According to each structural layer and the thickness of each structural layer, determine the segmented grouting depth range, grouting material and the drilling depth;

[0059] According to the grouting volume, the grouting pressure, the segmented grouting depth range and the grouting material, determine the segmented grouting requirements.

[0060] Specifically, based on the lithology of the roof rock stratum 2 and the lithology of the floor rock stratum 3 determined from geological information, it is also possible to provide a reference for the grouting pressure. It can be understood that in this embodiment, corresponding grouting pressures can be preset for different widths of the coal pillar dams 1, the lithology of the roof rock stratum 2, and the lithology of the floor rock stratum 3. Similarly, corresponding grouting volumes are set for different widths of the coal pillar dams 1. Thus, based on the width of the coal pillar dam 1, the lithology of the roof rock stratum 2, and the lithology of the floor rock stratum 3 of the dam to be treated, the corresponding grouting volume and grouting pressure can be directly determined. Of course, it can also be judged based on human experience, and this embodiment does not make specific limitations here. Further, according to each structural layer of the artificial dam 4 and its thickness, the range of the area that needs to be grouted can be determined as the sectional grouting depth range, and at the same time, the drilling depth can also be determined. Moreover, considering that the porosities of different structural layers are different, different grouting materials can be selected based on different porosity sizes.

[0061] As a preferred solution, each of the structural layers includes an outer concrete wall layer 7, an outer brick wall layer 8, a filling layer 9, an inner brick wall layer 11, and an inner concrete wall layer 10 that are sequentially stacked. One side of the inner concrete wall layer 10 is a goaf; the sectional grouting depth range includes a first grouting depth range corresponding to the filling layer 9 and a second grouting depth range corresponding to the outer concrete wall layer 7 and the bonding interface between it and the outer brick wall layer 8; the grouting materials include a first grouting material corresponding to the first grouting depth range and a second grouting material corresponding to the second grouting depth range.

[0062] Then, according to the drilling depth and the sectional grouting requirements, sectional grouting is carried out on the grouting hole 5 so that the grouting material diffuses to the inside of the artificial dam 4, the inside of the coal pillar dam 1, the connection position between the artificial dam 4 and the coal pillar dam 1, the connection position between the artificial dam 4 and the roof rock stratum 2, and the connection position between the artificial dam 4 and the floor rock stratum 3. Specifically, it includes:

[0063] According to the drilling depth, the length of the grouting pipe 12 is determined, and based on the first grouting depth range and the second grouting depth range, holes are drilled in the grouting pipe 12 to form a first hole-drilling area corresponding to the first grouting depth range and a second hole-drilling area corresponding to the second grouting depth range.

[0064] Based on the first hole-drilling area and the second hole-drilling area, a number of water bag rings are arranged on the pipe wall of the grouting pipe 12, and the grouting pipe 12 provided with the water bag rings is inserted into the grouting hole 5 so that the water bag rings are arranged between the pipe wall of the grouting pipe 12 and the hole wall of the grouting hole 5.

[0065] Control the water injection of the water bag ring bag to form a first grouting space corresponding to the first grouting depth range in the grouting hole 5;

[0066] According to the grouting volume and the grouting pressure, inject the first grouting material into the first grouting space through the first punching area, so that the first grouting material diffuses in the filling layer 9;

[0067] Control the water injection of the water bag ring bag to form a second grouting space corresponding to the second grouting depth range in the grouting hole 5;

[0068] According to the grouting volume and the grouting pressure, inject the second grouting material into the second grouting space through the second punching area, so that the second grouting material diffuses into the inside of the outer concrete wall layer 7, the bonding interface between the outer concrete wall layer 7 and the outer brick wall layer 8, the inside of the coal pillar dam body 1, the connection position between the artificial dam body 4 and the coal pillar dam body 1, the connection position between the artificial dam body 4 and the roof rock stratum 2, and the connection position between the artificial dam body 4 and the floor rock stratum 3.

[0069] Specifically, each structural layer in this embodiment includes an outer concrete wall layer 7, an outer brick wall layer 8, a filling layer 9, an inner brick wall layer 11, and an inner concrete wall layer 10 that are sequentially stacked. One side of the inner concrete wall layer 10 is a goaf for storing groundwater. Further, the segmented grouting depth range includes a first grouting depth range corresponding to the filling layer 9 and a second grouting depth range corresponding to the outer concrete wall layer 7 and the bonding interface between it and the outer brick wall layer 8; based on different grouting depth ranges, the grouting materials selected include the first grouting material corresponding to the first grouting depth range and the second grouting material corresponding to the second grouting depth range.

[0070] Further, before grouting, the construction of the grouting hole 5 will be carried out based on the drilling depth. In this embodiment, the drilling depth is the total layer thickness of the outer concrete wall layer 7, the outer brick wall layer 8, and the filling layer 9. Then, determine the length of the grouting pipe 12 according to the drilling depth, and cut the grouting pipe 12 based on this length. Then, based on the first grouting depth range and the second grouting depth range, punch holes in the grouting pipe 12. Preferably, punch flower holes in the grouting pipe 12 to form a first punching area corresponding to the first grouting depth range and a second punching area corresponding to the second grouting depth range, so as to ensure that after the grouting pipe 12 extends into the grouting hole 5, the punching positions respectively correspond to the first grouting depth range and the second grouting depth range, and ensure that the grouting material enters the corresponding grouting depth range.

[0071] Further, in order to achieve segmented grouting inside the artificial dam body 4, in this embodiment, based on the first drilling area and the second drilling area, a plurality of water bag rings are arranged on the pipe wall of the grouting pipe 12. It can be understood that the water bag ring is a ring-shaped water bag, which is arranged around the pipe wall of the grouting pipe 12 and is also connected to the water pump 17 through the water pipe 16, so as to be able to inject water into the water bag ring. After inserting the grouting pipe 12 provided with the water bag ring into the grouting hole 5, the water bag ring is arranged between the pipe wall of the grouting pipe 12 and the hole wall of the grouting hole 5. By injecting water into the water bag ring, the water bag ring can be inflated to tightly adhere to the pipe wall of the grouting pipe 12 and the hole wall of the grouting hole 5, playing a role in stopping grout, so as to be able to carry out segmented grouting reinforcement. Among them, the grouting pipe 12 is connected to the grouting pump 19 through the grouting rubber hose 18. Preferably, the grouting pipe 12 is made of a 2-point seamless steel pipe.

[0072] When performing the first-stage grouting, first control the water injection of the water bag ring to form a first grouting space corresponding to the first grouting depth range in the grouting hole 5, ensuring that at this time, the first grouting material can only enter the first grouting space and diffuse within the first grouting depth range, and cannot enter the second grouting depth range. Then, according to the pre-determined grouting volume and grouting pressure, inject the first grouting material into the first grouting space through the first drilling area, so that the first grouting material first diffuses along the filling layer 9 and then diffuses into the inside of the coal pillar dam body 1 through the cut-out connection parts with the coal pillar dam body 1, the roof rock stratum 2, and the floor rock stratum 3. When the grouting pressure rises, indicating that the first grouting material has fully diffused, the grouting can be stopped at this time, so as to form an anti-seepage barrier inside the filling layer 9 and on the surface of the inner brick wall layer 11 to prevent the grout from flowing into the goaf during the second-stage grouting.

[0073] During the second-stage grouting, it is also necessary to control the water injection of the water bag ring bag to form a second grouting space corresponding to the second grouting depth range in the grouting hole 5, ensuring that the second grouting material can only enter this second grouting space and spread within the second grouting depth range at this time, and cannot enter the first grouting depth range. Then, according to the pre-determined grouting volume and grouting pressure, the second grouting material is injected into the second grouting space through the second drilling area, so that the second grouting material spreads to the inside of the outer concrete wall layer 7, the bonding interface between the outer concrete wall layer 7 and the outer brick wall layer 8, the inside of the coal pillar dam body 1, the connection position between the artificial dam body 4 and the coal pillar dam body 1, the connection position between the artificial dam body 4 and the roof rock stratum 2, and the connection position between the artificial dam body 4 and the floor rock stratum 3. When the grouting pressure rises, indicating that the second grouting material has spread sufficiently, the grouting can be stopped at this time, thus forming a grouting reinforcement and anti-seepage area at the connection positions inside the artificial dam body 4, inside the coal pillar dam body 1, between the artificial dam body 4 and the coal pillar dam body 1, between the artificial dam body 4 and the roof rock stratum 2, and between the artificial dam body 4 and the floor rock stratum 3, realizing the reinforcement and anti-seepage of the dam body to be treated.

[0074] It should be noted that in this embodiment, the setting position of the water bag ring bag is not specifically limited, and it only needs to ensure that the first grouting space corresponding to the first grouting depth range and the second grouting space corresponding to the second grouting depth range can be formed in the grouting hole 5 respectively through water injection control. In addition, the method of segmented grouting realized by water injection of the water bag ring bag is not limited by the grouting pressure and will not cause grout leakage due to excessive grouting pressure.

[0075] As a preferred solution, the first grouting material is a quick-setting inorganic grouting material, which includes component A and component B. Component A is composed of sulphoaluminate cement and additives, and component B is composed of a quick-setting agent and an expansion agent; the mass ratio of component A to component B is 4.5:1, and the water-cement ratio of the quick-setting inorganic grouting material is 0.6:1.

[0076] Specifically, in this embodiment, the grouting material is selected comprehensively considering the pore characteristics of the grouting horizon, the performance of the grouting material, and the expected purpose of grouting. The first grouting horizon is the filling layer 9, which has a large porosity and is relatively close to the goaf on the water storage side. Using a high-strength quick-setting inorganic grouting material can quickly seal the fissure pores and ensure that the slurry will not spread into the water storage goaf. In addition, the quick-setting inorganic grouting material in this embodiment has fine particles and very high injectability, which is convenient for filling into the micro-cracks of the dam body and, along with the solidification of the grouting material, effectively seals the micro-pores and cracks, which can significantly reduce the leakage risk of the coal mine underground reservoir dam body and improve the safety of coal mine production. Moreover, the components of the grouting material are non-toxic and harmless and have no pollution to the water body, ensuring the safety of the water quality.

[0077] As a preferred solution, the second grouting material is a polyacrylate-modified cement material, which includes polyacrylate emulsion, defoamer, ultrafine cement, aluminous clinker accelerator and early strength agent. The water-cement ratio of the polyacrylate-modified cement material is 1:1, and the polymer-cement ratio is 0.2:1.

[0078] Specifically, the second-stage grouting layer is the outer concrete wall layer 7 and the bonding interface between it and the outer brick wall layer 8. The slurry will diffuse along the bonding interface between the outer concrete wall layer 7 and the outer brick wall layer 8, and then diffuse into the interior of the coal pillar dam 1 through the cut connection with the coal pillar dam 1, roof rock stratum 2 and floor rock stratum 3. A grouting material with good fluidity and strong adhesion to different medium materials is required. High-strength polyacrylate-modified cement material is selected to achieve better anti-seepage effect.

[0079] As a preferred solution, the difference between the length of the grouting pipe 12 and the drilling depth is greater than or equal to 40 cm.

[0080] As a preferred solution, the grouting pressure corresponding to the first grouting material is 0.5 MPa to 1.0 MPa, and the grouting pressure corresponding to the second grouting material is 1.0 MPa to 2.0 MPa;

[0081] The water injection pressure of the water bag ring bag when forming the first grouting space is greater than the grouting pressure corresponding to the first grouting material; the water injection pressure of the water bag ring bag when forming the second grouting space is greater than the grouting pressure corresponding to the second grouting material.

[0082] Specifically, in this embodiment, by limiting that the water injection pressure of the water bag ring bag when forming the first grouting space is greater than the grouting pressure corresponding to the first grouting material, and the water injection pressure when forming the second grouting space is greater than the grouting pressure corresponding to the second grouting material, it is possible to prevent slurry leakage caused by excessive grouting pressure.

[0083] As a preferred solution, obtaining the dam leakage information of the underground coal mine reservoir and determining the dam to be treated in the underground coal mine reservoir based on the dam leakage information specifically includes:

[0084] Counting the number of leakage points and the leakage volume per unit time of the leakage points of each dam in the underground coal mine reservoir;

[0085] When it is detected that the number of leakage points of any dam is greater than the preset leakage point number threshold or the leakage volume per unit time of the leakage points is greater than the preset leakage volume threshold, it is determined that the any dam is the dam to be treated.

[0086] Specifically, when the number of leakage points of any dam body is greater than the preset leakage point number threshold or the leakage volume per unit time of the leakage points is greater than the preset leakage volume threshold, it indicates that the number of leakage points of the dam body is excessive or the leakage volume per unit time of the leakage points is too large, that is, there is a relatively serious leakage problem. Therefore, it is determined that the dam body is a dam body to be treated.

[0087] As an optimal solution, the method further includes:

[0088] When the segmented grouting of the grouting hole 5 is completed, the grouting hole 5 is closed.

[0089] In order to fully reflect the grouting reinforcement and anti-seepage process for the dam body of the underground coal mine reservoir provided by the embodiments of the present invention, a specific embodiment will be described below.

[0090] Taking the underground reservoir of a certain coal mine in Shendong Mining Area as an example, referring to Figures 2 to 4 , the grouting reinforcement and anti-seepage process is as follows:

[0091] (1) On-site investigation. Conduct on-site inspection of the underground coal mine reservoir, determine the leakage situation of the dam body, and select the dam body with leakage problems for grouting reinforcement and anti-seepage.

[0092] (2) Data query. Consult data such as coal mine geological data, borehole columnar diagrams, mining engineering diagrams, and construction drawings of the artificial dam body 4 to determine the reserved width of the coal pillar dam body 1, the structural composition of the artificial dam body 4 and the thickness of each component structural layer, the cutting depth and width, and the lithology of the roof and floor rocks. The width of the coal pillar dam body 1 of the underground reservoir of this coal mine is 20 m, and the lithology of the roof rock layer 2 and the floor rock layer 3 is siltstone. The artificial dam body 4 is a composite structure, wherein: the thickness of the outer concrete wall layer 7 is 1.0 m; the thickness of the outer brick wall layer 8 is 0.5 m; the filling layer 9 is cobblestones and reinforcement materials, with a thickness of 0.5 m; the thickness of the inner concrete wall layer 10 is 0.75 m; the thickness of the inner brick wall layer 11 is 0.75 m and it is in contact with the stored mine water 6; the cutting depth of the coal pillar dam body 1 is 0.5 m, the cutting depth of the floor rock layer 3 is 0.2 m, and the cutting depth of the roof rock layer 2 is 0.3 m.

[0093] (3) Borehole construction. Construct a borehole at the midline of the artificial dam body 4, 2.0 m above the ground. The borehole is perpendicular to the surface of the artificial dam body 4 and has a depth of 2.0 m, reaching the surface of the inner brick wall layer 11.

[0094] (4) Install the grouting pipe 12. Cut a 2.5-meter-long seamless steel pipe with a diameter of 2 fen as the grouting pipe 12 according to the drilling depth, and make perforated holes in the range of 1.3 - 1.5 m and 2.0 m - 2.5 m of the grouting pipe 12. According to the requirements of segmented grouting, put the first water bag ring bag 13 on the area of 1.8 m - 2.2 m of the grouting pipe 12, the second water bag ring bag 14 on the area of 1.3 - 1.5 m, and the third water bag ring bag 15 on the area of 0.5 - 0.7 m, and connect the water pipe 16. Finally, put the grouting pipe 12 into the grouting hole 5.

[0095] (5) Equipment connection. Connect the water pipe 16 to the water pump 17, and connect the grouting pipe 12 to the grouting pump 19 through the grouting rubber hose 18. Turn on the water pump 17 and inject water into the first water bag ring bag 13, the second water bag ring bag 14, and the third water bag ring bag 15, with the water pressure being 2.5 Mpa. After the water bag ring bag is inflated with water, it clings to the wall of the grouting hole 5 and the wall of the grouting pipe 12 to play a role in stopping grout, realizing segmented grouting for seepage prevention.

[0096] (6) First-stage grouting for seepage prevention. Prepare the first grouting material, and select a high-strength and quick-setting inorganic grouting material for this section. This material is divided into component A and component B. The main material of component A is composed of sulfoaluminate cement added with additives, and component B is a setting regulator, composed of a quick-setting agent and an expansion agent. The ratio of component A to component B is 4.5:1, and the water-cement ratio is 0.6:1, with the grouting pressure being 1.0 MPa.

[0097] Turn on the grouting pump 19, and the prepared first grouting material enters the grouting pipe 12 through the grouting rubber hose 18, and then enters the grouting hole 5 through the perforated holes in the range of 2.0 m - 2.5 m of the grouting pipe 12. The slurry first diffuses along the filling layer 9 of the artificial dam body 4, and then diffuses into the interiors of the coal pillar dam body 1, the roof rock stratum 2, and the floor rock stratum 3 through the cut connection. Stop grouting when the grouting pressure rises above 1.0 MPa, indicating that the slurry has fully diffused. After the first-stage grouting is completed, an anti-seepage barrier is formed inside the filling layer 9 and on the surface of the inner brick wall layer 11 to prevent the slurry from flowing into the goaf during the second-stage grouting. Then start the second-stage grouting.

[0098] (7) Second-stage grouting for seepage prevention. Prepare the second grouting material, and select a high-strength polyacrylate-modified cement material for this section, which is mainly composed of polyacrylate emulsion, defoamer, ultra-fine cement, alumina clinker setting accelerator, early strength agent, expansion agent, etc. The water-cement ratio is 1:1, and the poly-cement ratio is 0.2:1, with the grouting pressure being 2.0 MPa. Before grouting, the pressure of the second high-pressure water bag ring bag needs to be released to avoid blocking the perforated holes in this depth range.

[0099] Turn on the grouting pump 19. The prepared second grouting material enters the grouting pipe 12 through the grouting rubber hose 18 and then enters the grouting hole 5 through the perforated holes within the range of 1.3 - 1.5 m of the grouting pipe 12. The grout first diffuses along the outer concrete wall layer 7 of the artificial dam body 4 and the bonding interface between it and the outer brick wall layer 8, and then diffuses into the interiors of the coal pillar dam body 1, the roof rock stratum 2, and the floor rock stratum 3 through the cut connection. Stop grouting when the grouting pressure rises above 2.0 MPa, indicating that the grout has fully diffused. After the second-stage grouting is completed, a grouting reinforcement and anti-seepage area can be formed inside the artificial dam body 4, at the joints between it and the coal pillar dam body 1, the roof rock stratum 2, and the floor rock stratum 3, and inside the coal pillar dam body 1 to achieve three-dimensional reinforcement and anti-seepage of the dam body.

[0100] (8) After the grouting is completed, wait for the grout to solidify, relieve the pressure of the water pump 17, disconnect the equipment connection, and seal the mouth of the grouting pipe 12.

[0101] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A grouting reinforcement and anti-seepage method for the dam body of an underground coal mine reservoir, characterized in that, Including: Obtaining the dam body leakage information of the underground coal mine reservoir, and determining the dam body to be treated in the underground coal mine reservoir based on the dam body leakage information; wherein, the dam body to be treated includes an artificial dam body and a coal pillar dam body; Determining the structural information of the dam body to be treated according to the engineering information of the underground coal mine reservoir; Determining the drilling depth and segmented grouting requirements according to the geological information and the structural information of the underground coal mine reservoir; Constructing grouting holes on the surface of the artificial dam body according to the drilling depth; Carrying out segmented grouting on the grouting holes according to the drilling depth and the segmented grouting requirements, so that the grouting material diffuses to the inside of the artificial dam body, the inside of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum.

2. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 1, characterized in that, The determining the structural information of the dam body to be treated according to the engineering information of the underground coal mine reservoir specifically includes: Determining the reserved width of the coal pillar dam body, each structural layer of the artificial dam body and the thickness of each structural layer, the cut depth and cut width between the artificial dam body and the coal pillar dam body, the cut depth and cut width between the artificial dam body and the roof rock stratum, and the cut depth and cut width between the artificial dam body and the floor rock stratum according to the engineering information.

3. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 2, characterized in that, The determining the drilling depth and segmented grouting requirements according to the geological information and the structural information of the underground coal mine reservoir specifically includes: Determining the lithology of the roof rock stratum and the lithology of the floor rock stratum according to the geological information; Determining the grouting volume and grouting pressure according to the reserved width of the coal pillar dam body, the lithology of the roof rock stratum and the lithology of the floor rock stratum; Determining the segmented grouting depth range, the grouting material and the drilling depth according to each structural layer and the thickness of each structural layer; Determining the segmented grouting requirements according to the grouting volume, the grouting pressure, the segmented grouting depth range and the grouting material.

4. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 3, characterized in that, Each structural layer includes an outer concrete wall layer, an outer brick wall layer, a filling layer, an inner brick wall layer and an inner concrete wall layer which are sequentially stacked; one side of the inner concrete wall layer is a goaf; the segmented grouting depth range includes a first grouting depth range corresponding to the filling layer and a second grouting depth range corresponding to the outer concrete wall layer and the bonding interface between it and the outer brick wall layer; the grouting material includes a first grouting material corresponding to the first grouting depth range and a second grouting material corresponding to the second grouting depth range; Then the carrying out segmented grouting on the grouting holes according to the drilling depth and the segmented grouting requirements, so that the grouting material diffuses to the inside of the artificial dam body, the inside of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum specifically includes: Determine the length of the grouting pipe according to the drilling depth, and based on the first grouting depth range and the second grouting depth range, drill holes in the grouting pipe to form a first drilling area corresponding to the first grouting depth range and a second drilling area corresponding to the second grouting depth range; Based on the first drilling area and the second drilling area, arrange a number of water bag rings on the pipe wall of the grouting pipe, and insert the grouting pipe provided with the water bag rings into the grouting hole so that the water bag rings are arranged between the pipe wall of the grouting pipe and the hole wall of the grouting hole; Control the water injection of the water bag rings to form a first grouting space corresponding to the first grouting depth range in the grouting hole; According to the grouting volume and the grouting pressure, inject the first grouting material into the first grouting space through the first drilling area so that the first grouting material diffuses in the filling layer; Control the water injection of the water bag rings to form a second grouting space corresponding to the second grouting depth range in the grouting hole; According to the grouting volume and the grouting pressure, inject the second grouting material into the second grouting space through the second drilling area so that the second grouting material diffuses into the interior of the outer concrete wall layer, the bonding interface between the outer concrete wall layer and the outer brick wall layer, the interior of the coal pillar dam body, the connection position between the artificial dam body and the coal pillar dam body, the connection position between the artificial dam body and the roof rock stratum, and the connection position between the artificial dam body and the floor rock stratum.

5. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 4, characterized in that, The first grouting material is a quick-setting inorganic grouting material, the quick-setting inorganic grouting material includes component A and component B, component A is composed of sulfoaluminate cement and additives, and component B is composed of a quick-setting agent and an expansion agent; the mass ratio of component A to component B is 4.5:1, and the water-cement ratio of the quick-setting inorganic grouting material is 0.6:

1.

6. The grouting reinforcement and seepage prevention method for the dam body of the underground coal mine reservoir according to claim 4, characterized in that The second grouting material is a polyacrylate-modified cement material, the polyacrylate-modified cement material includes polyacrylate emulsion, defoaming agent, ultrafine cement, aluminous clinker accelerator and early strength agent, the water-cement ratio of the polyacrylate-modified cement material is 1:1, and the poly-ash ratio of the polyacrylate-modified cement material is 0.2:

1.

7. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 4, characterized in that The difference between the length of the grouting pipe and the drilling depth is greater than or equal to 40 cm.

8. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 4, characterized in that, The grouting pressure corresponding to the first grouting material is 0.5 MPa to 1.0 MPa, and the grouting pressure corresponding to the second grouting material is 1.0 MPa to 2.0 MPa; The water injection pressure of the water bag rings when forming the first grouting space is greater than the grouting pressure corresponding to the first grouting material; the water injection pressure of the water bag rings when forming the second grouting space is greater than the grouting pressure corresponding to the second grouting material.

9. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 1, characterized in that, The obtaining of the dam body leakage information of the underground coal mine reservoir and determining the dam body to be treated in the underground coal mine reservoir based on the dam body leakage information specifically includes: Statistically count the number of leakage points and the leakage volume per unit time of each dam body in the underground coal mine reservoir; When it is detected that the number of leakage points of any one dam body is greater than the preset leakage point number threshold or the leakage volume per unit time of the leakage points is greater than the preset leakage volume threshold, determine that the any one dam body is the dam body to be treated.

10. The grouting reinforcement and anti-seepage method for the dam body of the underground coal mine reservoir according to claim 1, characterized in that, The method further includes: When the segmented grouting of the grouting hole is completed, seal the grouting hole.

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