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

Abstract

The invention provides a grouting anti-seepage reinforcement method for a dam body of a coal mine underground reservoir. The grouting anti-seepage reinforcement method comprises the following steps: determining parameters of a coal pillar dam body and an artificial dam body in the coal mine underground reservoir; the coal pillar dam body is detected, a seepage abnormal area of the coal pillar dam body is delineated, the fracture development condition of the coal pillar dam body is analyzed, and exploration verification is conducted through borehole peeping; around the seepage abnormal area of the coal pillar dam body, a plurality of first grouting drill holes are constructed from the side, close to the roadway, of the coal pillar dam body to the side, close to the water storage goaf, of the coal pillar dam body, and segmented grouting is conducted on the first grouting drill holes; and a plurality of second grouting drill holes are constructed in the artificial dam body, and a polyacrylate modified cement material is used for grouting the second grouting drill holes. By means of the method, cracks in the coal pillar dam body, cracks in the joint of the artificial dam body, the top and bottom plate rock strata and cracks in the joint of the artificial dam body and the coal pillar dam body can be effectively filled, a multi-layer segmented grouting reinforcement anti-seepage structure in the coal pillar dam body and a two-way grouting reinforcement anti-seepage structure between the coal pillar dam body and the artificial dam body are formed, and the compactness and impermeability of the dam body are improved.

Description

Technical Field

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

[0002] In some areas, coal resources are abundant but water resources are scarce. Using coal mine goaf to build underground reservoirs has become an effective way to solve the shortage of water resources. However, the dam of coal mine underground reservoirs is affected by various factors such as mine pressure and water pressure. It is easy to cause leakage during long-term operation, which brings safety hazards to coal mine production. Therefore, grouting and anti-seepage reinforcement of coal mine underground reservoir dams is crucial to the protection and utilization of water resources in coal mining and safe production. However, the existing reinforcement methods have a high risk of leakage and the effect is not ideal. Summary of the invention

[0003] The invention provides a grouting anti-seepage reinforcement method for a dam body of an underground reservoir in a coal mine, so as to reduce the risk of leakage of the dam body and improve safety.

[0004] In order to achieve the above object, the present invention provides a method for grouting anti-seepage reinforcement of a coal mine underground reservoir dam, comprising:

[0005] Determine the width and height of the coal pillar dam in the underground reservoir of the coal mine, the size of the artificial dam, the top rock layer, the bottom rock layer and the depth of the side cut of the coal pillar dam;

[0006] Use high-density electrical method and geological radar to conduct non-destructive detection of coal pillar dam, delineate abnormal seepage area of ​​coal pillar dam, analyze the development of cracks in coal pillar dam, and use drilling to conduct exploration and verification;

[0007] Constructing a plurality of first grouting boreholes around the abnormal seepage area of ​​the coal pillar dam from the tunnel side of the coal pillar dam to the water storage goaf side, and performing segmented grouting on the first grouting boreholes;

[0008] After the grouting in the coal pillar dam body solidifies, a plurality of second grouting boreholes are constructed in the artificial dam body, and the second grouting boreholes are grouted using polyacrylate modified cement material.

[0009] Furthermore, the first grouting boreholes are divided into deep grouting boreholes, middle grouting boreholes and shallow grouting boreholes from deep to shallow; wherein, the deep grouting boreholes are grouted with early-strength quick-setting inorganic grouting material, the middle grouting boreholes are grouted with early-strength slow-setting inorganic grouting material, and the shallow grouting boreholes are grouted with early-strength slow-setting inorganic grouting material.

[0010] Furthermore, the depth of the first grouting borehole is 15.0-20.0 m, the grouting pressure of the deep grouting borehole and the shallow grouting borehole is 3.0-3.5 MPa, and the grouting pressure of the middle grouting borehole is 3.5-5.0 MPa.

[0011] Furthermore, the plurality of the first grouting holes are arranged in two rows, wherein the distance between the opening positions of the upper row of the first grouting holes and the top rock layer is 0.9m to 1.1m, and the distance between the opening positions of the lower row of the first grouting holes and the opening positions of the upper row of the first grouting holes is 1.4m to 1.6m.

[0012] Furthermore, a plurality of the second grouting boreholes are respectively arranged in the roof rock layer above the artificial dam body, the bottom rock layer below the artificial dam body, and the coal pillars on both sides of the artificial dam body.

[0013] Furthermore, the second grouting drilling comprises:

[0014] The top plate grouting drill hole is arranged at the center of the top plate rock layer above the artificial dam body, with a horizontal distance of 2.8-3.2m from the front of the artificial dam body, a hole depth of 2.8-3.2m, and a grouting pressure of 0.5-1.0Mpa;

[0015] The bottom plate grouting drill hole is arranged in the center of the bottom plate rock layer below the artificial dam body, with a horizontal distance of 2.8-3.2m from the front of the artificial dam body, a hole depth of 2.8-3.2m, and a grouting pressure of 0.5-1.0Mpa.

[0016] Furthermore, the second grouting drilling comprises:

[0017] The left grouting borehole is arranged at the center of the left coal pillar of the artificial dam body, with a horizontal distance of 4.8-5.2m and a horizontal distance of 3.0-5.0m from the side of the artificial dam body, a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0Mpa;

[0018] The right grouting drill hole arranged at the center of the coal pillar on the right side of the artificial dam body is 4.8-5.2m and 3.0-5.0m away from the side of the artificial dam body, with a hole depth of 5.0-7.0m and a grouting pressure of 0.5-1.0Mpa.

[0019] Furthermore, the early-strength, fast-setting inorganic grouting material comprises component A and component B, wherein component A is composed of sulphoaluminate cement with additives added thereto, and component B is a setting regulator, which is composed of an accelerator and a retarder.

[0020] Furthermore, the early-strength slow-setting inorganic grouting material includes silicate cement, sulphoaluminate cement, fly ash and admixtures.

[0021] Furthermore, the polyacrylate modified cement material consists of polyacrylate emulsion, defoamer, ultrafine cement and alumina clinker accelerator.

[0022] By applying the technical solution of the present invention, a method for grouting anti-seepage reinforcement of a dam body of an underground water reservoir in a coal mine is provided, comprising: determining the width and height of a coal pillar dam body in an underground water reservoir in a coal mine, the size of an artificial dam body, and the depth of the grooves on the roof rock layer, the bottom rock layer and the side of the coal pillar dam body; using high-density electrical method and geological radar to perform non-destructive detection on the coal pillar dam body, delineating the abnormal seepage area of ​​the coal pillar dam body, analyzing the development of cracks in the coal pillar dam body, and performing exploration and verification by drilling peek; constructing a plurality of first grouting boreholes from the coal pillar dam body adjacent to the tunnel side to the coal pillar dam body adjacent to the water storage goaf side around the abnormal seepage area of ​​the coal pillar dam body, and performing segmented grouting on the first grouting boreholes; after the grouting in the coal pillar dam body solidifies, constructing a plurality of second grouting boreholes in the artificial dam body, and grouting the second grouting boreholes using polyacrylate modified cement material. Through this method, the cracks inside the coal pillar dam body, between the artificial dam body and the top and bottom rock layers, and at the connection between the coal pillar dam body can be effectively filled, forming a multi-level segmented grouting reinforcement anti-seepage structure inside the coal pillar dam body, and a two-way grouting reinforcement anti-seepage structure between the coal pillar dam body and the artificial dam body, thereby improving the density and impermeability of the dam body.

[0023] The present invention adopts multi-layer, bidirectional grouting anti-seepage reinforcement technology, which can effectively fill the cracks inside the coal pillar dam body, between the artificial dam body and the top and bottom rock layers, and at the connection between the coal pillar dam body, forming a multi-level segmented grouting reinforcement anti-seepage structure inside the coal pillar dam body, and a bidirectional grouting reinforcement anti-seepage structure between the coal pillar dam body and the artificial dam body, thereby improving the density and impermeability of the dam body, significantly reducing the leakage risk of the dam body of the coal mine underground reservoir, and improving the safety of coal mine production. It has broad application prospects and good economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 It is a flow chart of the grouting anti-seepage reinforcement method for the dam body of a coal mine underground reservoir provided by the present invention;

[0026] Figure 2 It is a front view of grouting of a coal mine underground reservoir dam body using the method of the present invention;

[0027] Figure 3 It is a top view of grouting of a coal mine underground reservoir dam body using the method of the present invention;

[0028] Figure 4 The present invention is a side view of grouting of a dam body of an underground reservoir in a coal mine using the method of the present invention.

[0029] The above drawings include the following reference numerals:

[0030] 1. Roof rock layer; 2. Bottom rock layer; 3. Coal pillar dam body; 4. Artificial dam body; 5. First grouting borehole; 6. Shallow grouting borehole; 7. Middle grouting borehole; 8. Deep grouting borehole; 9. Grouting stopper; 10. Left grouting borehole; 11. Right grouting borehole; 12. Roof grouting borehole; 13. Bottom grouting borehole. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] like Figures 1 to 4 As shown, an embodiment of the present invention provides a method for grouting anti-seepage reinforcement of a dam body of an underground water reservoir in a coal mine, comprising: determining the width and height of a coal pillar dam body 3 in an underground water reservoir in a coal mine, the size of an artificial dam body 4, and the depth of the grooves on the roof rock layer 1, the bottom rock layer 2, and the side of the coal pillar dam body 3; using high-density electrical method and geological radar to perform non-destructive detection on the coal pillar dam body 3, delineate the abnormal seepage area of ​​the coal pillar dam body 3, analyze the development of cracks in the coal pillar dam body 3, and use borehole peeping to perform exploration and verification; around the abnormal seepage area of ​​the coal pillar dam body 3, construct a plurality of first grouting boreholes 5 from the coal pillar dam body 3 facing the tunnel side to the water storage goaf side, and perform segmented grouting on the first grouting boreholes 5; after the grouting in the coal pillar dam body 3 solidifies, construct a plurality of second grouting boreholes in the artificial dam body 4, and use polyacrylate modified cement material to grout the second grouting boreholes.

[0033] Through this method, the cracks inside the coal pillar dam body, between the artificial dam body and the top and bottom rock layers, and at the connection between the coal pillar dam body can be effectively filled, forming a multi-level segmented grouting reinforcement anti-seepage structure inside the coal pillar dam body, and a two-way grouting reinforcement anti-seepage structure between the coal pillar dam body and the artificial dam body, thereby improving the density and impermeability of the dam body.

[0034] Specifically, Figure 3As shown, the first grouting borehole 5 is divided into a deep grouting borehole 8, a middle grouting borehole 7 and a shallow grouting borehole 6 from deep to shallow; wherein, the deep grouting borehole 8 is grouted with an early-strength quick-setting inorganic grouting material, the middle grouting borehole 7 is grouted with an early-strength slow-setting inorganic grouting material, and the shallow grouting borehole 6 is grouted with an early-strength slow-setting inorganic grouting material. Adjacent grouting borehole sections are spaced apart by grouting stoppers 9.

[0035] The early-strength quick-setting inorganic grouting materials, early-strength slow-setting inorganic grouting materials, and polyacrylate modified cement materials are fine-grained and highly injectable, which are easy to fill into the micro-cracks of the dam body. As the grouting materials solidify, they effectively block the micro-porous cracks, which can significantly reduce the leakage risk of the dam body of the underground reservoir of the coal mine and improve the safety of coal mine production. The grouting materials are non-toxic and harmless, and have no pollution to the water body, which can ensure the safety of water quality.

[0036] Among them, the hole depth of the first grouting borehole 5 is 15.0-20.0m, the grouting pressure of the deep grouting borehole 8 and the shallow grouting borehole 6 is 3.0-3.5MPa, and the grouting pressure of the middle grouting borehole 7 is 3.5-5.0MPa.

[0037] like Figure 2 As shown, the plurality of first grouting boreholes 5 are arranged in two rows, wherein the distance between the opening position of the first grouting boreholes 5 in the upper row and the roof rock layer 1 is 0.9m to 1.1m, and the distance between the opening position of the first grouting boreholes 5 in the lower row and the opening position of the first grouting boreholes 5 in the upper row is 1.4m to 1.6m. This improves the reinforcement effect of the coal pillar dam body 3.

[0038] Among them, a plurality of second grouting boreholes are respectively arranged in the roof rock layer 1 above the artificial dam body 4 , the bottom rock layer 2 below the artificial dam body 4 , and the coal pillars on both sides of the artificial dam body 4 .

[0039] like Figure 4 As shown, the second grouting boreholes include: a top plate grouting borehole 12 arranged at the center of the top plate rock layer 1 above the artificial dam body 4, with a horizontal distance of 2.8-3.2m from the front of the artificial dam body 4, a hole depth of 2.8-3.2m, and a grouting pressure of 0.5-1.0Mpa; a bottom plate grouting borehole 13 arranged at the center of the bottom plate rock layer 2 below the artificial dam body 4, with a horizontal distance of 2.8-3.2m from the front of the artificial dam body 4, a hole depth of 2.8-3.2m, and a grouting pressure of 0.5-1.0Mpa.

[0040] like Figure 3As shown, the second grouting boreholes include: a left grouting borehole 10 arranged at the center of the left coal pillar of the artificial dam body 4, at a horizontal distance of 4.8-5.2m from the side of the artificial dam body 4, at a horizontal distance of 3.0-5.0m from the side of the artificial dam body 4, a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0Mpa; a right grouting borehole 11 arranged at the center of the right coal pillar of the artificial dam body 4, at a horizontal distance of 4.8-5.2m from the side of the artificial dam body 4, at a horizontal distance of 3.0-5.0m from the side of the artificial dam body 4, a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0Mpa.

[0041] Among them, the early-strength and fast-setting inorganic grouting material includes component A and component B, wherein component A is composed of sulphoaluminate cement with additives added, and component B is a setting regulator, which is composed of an accelerator and a retarder.

[0042] Specifically, the early strength slow setting inorganic grouting material includes silicate cement, sulphoaluminate cement, fly ash and admixtures. The polyacrylate modified cement material is composed of polyacrylate emulsion, defoamer, ultrafine cement and alumina clinker accelerator.

[0043] In order to clearly understand the present invention, the present invention is further described below in conjunction with the accompanying drawings:

[0044] like Figure 2 As shown, the coal mine underground water reservoir applied by the present invention includes a roof rock layer 1 above the artificial dam body, a floor rock layer 2 below the artificial dam body, a coal pillar dam body 3, an artificial dam body 4, a first grouting borehole 5, a left grouting borehole 10 arranged at the center of the left coal pillar part of the artificial dam body, and a right grouting borehole 11 arranged at the center of the right coal pillar part of the artificial dam body.

[0045] like Figure 3 As shown, the first grouting borehole 5 of the present invention is constructed from the coal pillar dam body facing the roadway to the side facing the water storage goaf, and the shallow grouting borehole 6, the middle grouting borehole 7, and the deep grouting borehole 8 are divided by the grouting stopper 9, and grouting is performed in sections. After the grouting of the first grouting borehole 5 is completed and solidified, the left grouting borehole 10 arranged at the center of the left coal pillar of the artificial dam body and the right grouting borehole 11 arranged at the center of the right coal pillar of the artificial dam body are constructed, and grouting is performed.

[0046] like Figure 4 As shown, a top plate grouting borehole 12 is arranged at the center of the top plate rock layer above the artificial dam body of the present invention, and a bottom plate grouting borehole 13 is arranged at the center of the bottom plate rock layer below the artificial dam body, which are constructed respectively on the top plate and bottom plate in front of the artificial dam body.

[0047] The specific steps are as follows:

[0048] (1) Based on the coal mine geological data, drilling columnar diagram, mining engineering drawings and artificial dam construction drawings, the width and height of the coal pillar dam 3 of the coal mine underground reservoir, the size of the artificial dam 4, and the embedded depth of the artificial dam in the upper roof rock layer 1, the lower bottom rock layer 2 and the coal pillar dam 3 are determined.

[0049] (2) Use high-density electrical method and geological radar to conduct non-destructive detection of the coal pillar dam, delineate the abnormal seepage area of ​​the coal pillar dam, analyze the development of cracks in the coal pillar dam 3, and use the first grouting borehole 5 for peek inspection and verification.

[0050] (3) Around the abnormal seepage area of ​​the coal pillar dam body 3, multiple first grouting boreholes are constructed from the coal pillar dam body 3 adjacent to the tunnel side to the side adjacent to the water storage goaf area, and early-strength fast-setting inorganic grouting materials and early-strength slow-setting inorganic grouting materials are used in turn to perform segmented grouting on the deep grouting borehole 8, the middle grouting borehole 7, and the shallow grouting borehole 6.

[0051] (4) After the multi-layer grouting of the coal pillar dam body 3 solidifies, the second grouting borehole is constructed in the top rock layer 1 above the artificial dam body, the bottom rock layer 2 below, and the coal pillar dam body 3 on both sides, and grouting is performed using polyacrylate modified cement.

[0052] (5) Multiple first grouting holes 5 are divided into two rows, upper and lower, in a three-flower arrangement. The opening height of the upper row of holes is 1.0m from the top plate, the opening height of the lower row of holes is 1.5m from the upper row of holes, and the spacing between adjacent holes is 3m.

[0053] (6) The second grouting boreholes include: top plate grouting boreholes 12 arranged in the top plate rock layer 1 above the artificial dam body, bottom plate grouting boreholes arranged in the bottom plate rock layer 2 below the artificial dam body, left side grouting boreholes arranged in the left coal pillar of the artificial dam body, and right side grouting boreholes arranged in the right coal pillar of the artificial dam body.

[0054] (7) The first grouting drilling hole has an inclination angle of 0 degrees, a hole depth of 15.0-20.0 m, and a grouting pressure of 3.0-5.0 MPa.

[0055] (8) In the second grouting drilling, a top plate grouting drilling hole 12 is arranged at the center of the top plate rock layer 1 above the artificial dam body, with a horizontal distance of 3.0m from the front of the artificial dam body, an upward inclination of 0.16 degrees, a hole depth of 3m, and a grouting pressure of 0.5-1.0MPa.

[0056] (9) In the second grouting drilling, a bottom plate grouting drilling hole 13 is arranged at the center of the bottom plate rock layer 2 below the artificial dam body, with a horizontal distance of 3.0 m from the front of the artificial dam body, a downward inclination of 0.16 degrees, a hole depth of 3.0 m, and a grouting pressure of 0.5-1.0 MPa.

[0057] (10) In the second grouting borehole, a left grouting borehole 10 is arranged at the center of the left coal pillar of the artificial dam body, with a horizontal distance of 5.0m from the side of the artificial dam body and a horizontal distance of 3.0-5.0m from the side of the artificial dam body, an angle of 0.54-0.78 degrees with the surface side of the coal pillar dam body, a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0MPa.

[0058] (11) In the second grouting borehole, the right grouting borehole 11 is arranged at the center of the coal pillar on the right side of the artificial dam body, with a horizontal distance of 5.0m from the side of the artificial dam body and a horizontal distance of 3.0-5.0m from the side of the artificial dam body, an angle of 0.54-0.78 degrees with the surface side of the coal pillar dam body, a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0MPa.

[0059] (12) The lengths of the deep grouting borehole 8, the middle grouting borehole 7, and the shallow grouting borehole 6 are respectively 1 / 3 of the length of the first grouting borehole 5. The deep and shallow grouting pressures are 3.0-3.5 MPa, and the middle grouting pressure is 3.5-5.0 MPa.

[0060] (13) The early strength and quick setting inorganic grouting material is divided into component A and component B. Component A is mainly composed of sulphoaluminate cement with additives, and component B is a setting regulator composed of an accelerator and a retarder.

[0061] (14) The main raw materials of the early strength slow setting inorganic grouting material are silicate cement, sulphoaluminate cement, fly ash and admixtures.

[0062] (15) The polyacrylate modified cement material is mainly composed of polyacrylate emulsion, defoamer, ultrafine cement and alumina clinker accelerator.

[0063] In a specific embodiment, the coal pillar dam of a coal mine underground reservoir is set with a width of 20m and a height of 3.5m. The artificial dam is 4.0m wide and 4.5m high, and is embedded in the top and bottom rock layers and the coal pillars on both sides to a depth of 0.5m.

[0064] The high-density electrical method and geological radar were used to conduct non-destructive detection of the coal pillar dam, delineate the abnormal seepage area of ​​the coal pillar dam, analyze the development of the cracks in the coal pillar dam 3, and construct a first grouting borehole 5 for peek inspection and verification.

[0065] Around the abnormal seepage area of ​​the coal pillar dam body 3, multiple first grouting boreholes 5 are constructed from the coal pillar dam body 3 facing the tunnel side to the side facing the water storage goaf area. The boreholes are divided into two rows, upper and lower, and arranged in a three-flower pattern. The opening height of the upper row of boreholes is 1.0m from the top plate, and the opening height of the lower row of holes is 1.5m from the upper row of holes. The spacing between adjacent boreholes is 3m. The grouting boreholes are constructed in sequence from left to right and from top to bottom, with an inclination of 0 degrees and a hole depth of 15.0m.

[0066] Each time the construction is completed, one first grouting borehole 5 is completed, and the grouting plug 9 is used to divide the borehole into three parts, namely the shallow grouting borehole 6, the middle grouting borehole 7, and the deep grouting borehole 8, for segmented grouting. First, the deep grouting borehole 8 is grouted with early-strength and fast-setting inorganic grouting material, with component A: component B being 4.5:1, the water-cement ratio being 0.6:1, and the grouting pressure being 3.0MPa. Then, the middle grouting borehole 7 is grouted with early-strength and slow-setting inorganic grouting material, with a water-cement ratio of 0.3:1 and a grouting pressure of 4.0MPa. Finally, the shallow grouting borehole 6 is grouted with early-strength and slow-setting inorganic grouting material, with a water-cement ratio of 0.3:1 and a grouting pressure of 3.0MPa. Drilling and grouting are carried out in this construction order.

[0067] After the first grouting drilling hole 5 is completed and the grouting material solidifies, the left grouting drilling hole 10 is constructed on the left coal pillar dam of the artificial dam body. The horizontal distance between the drilling hole and the side of the artificial dam body is 5.0m, the horizontal distance between the drilling hole and the side of the artificial dam body is 5.0m, the angle between the drilling hole and the surface of the coal pillar dam body is 0.78 degrees, and the hole depth is 7.0m. After the drilling hole construction is completed, polyacrylate modified cement is used for grouting. The water-cement ratio is 1:1, the poly-cement ratio is 0.2:1, and the grouting pressure is 0.5MPa.

[0068] The right side grouting drilling hole 11 was constructed on the right side of the coal pillar dam of the artificial dam body. The horizontal distance between the drilling hole and the side of the artificial dam body was 5.0m, and the angle between the drilling hole and the surface of the coal pillar dam body was 0.78 degrees. The hole depth was 7.0m. After the drilling construction was completed, polyacrylate modified cement was used for grouting. The water-cement ratio was 1:1, the poly-cement ratio was 0.2:1, and the grouting pressure was 0.5MPa.

[0069] A top plate grouting borehole 12 is constructed at the center of the top plate rock layer 1 above the artificial dam body, with a horizontal distance of 3.0m from the front of the artificial dam body, an upward inclination of 0.16 degrees, and a hole depth of 3m. After the drilling construction is completed, polyacrylate modified cement is used for grouting. The water-cement ratio is 1:1, the poly-cement ratio is 0.2:1, and the grouting pressure is 0.5MPa.

[0070] A bottom plate grouting borehole 13 is constructed at the center of the bottom plate rock layer 2 below the artificial dam body, with a horizontal distance of 3.0m from the front of the artificial dam body, a downward inclination of 0.16 degrees, and a hole depth of 3.0m. After the drilling construction is completed, polyacrylate modified cement is used for grouting. The water-cement ratio is 1:1, the poly-cement ratio is 0.2:1, and the grouting pressure is 0.5MPa.

[0071] The present invention adopts multi-layer, bidirectional grouting anti-seepage reinforcement technology, which can effectively fill the cracks inside the coal pillar dam body, the artificial dam body and the top and bottom rock layers and the coal pillar dam body, forming a multi-level segmented grouting reinforcement anti-seepage structure inside the coal pillar dam body, and a bidirectional grouting reinforcement anti-seepage structure between the coal pillar dam body and the artificial dam body, thereby improving the density and impermeability of the dam body. At the same time, the selected early-strength rapid-setting inorganic grouting material, early-strength slow-setting inorganic grouting material, and polyacrylate modified cement material have fine particles and very high injectability, which are easy to fill into the micro-cracks of the dam body, and with the solidification of the grouting material, the microporous cracks are effectively blocked, which can significantly reduce the leakage risk of the dam body of the underground reservoir of the coal mine and improve the safety of coal mine production. In addition, the grouting material components are non-toxic and harmless, and have no pollution to the water body, which can ensure the safety of water quality.

[0072] The above are only optional embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0073] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0074] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of this solution. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being only exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0075] In the description of this scheme, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing this scheme and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the scope of protection of this scheme; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0076] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0077] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only to facilitate the distinction between corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this scheme.

Claims

1. A method for grouting anti-seepage reinforcement of underground reservoir dam in coal mine, characterized in that: include: Determine the width and height of the coal pillar dam body (3) in the underground water reservoir of the coal mine, the size of the artificial dam body (4), the depth of the top rock layer (1), the bottom rock layer (2) and the side cutting of the coal pillar dam body (3); The coal pillar dam (3) is non-destructively detected by high-density electrical method and geological radar, the abnormal seepage area of ​​the coal pillar dam (3) is delineated, the development of cracks in the coal pillar dam (3) is analyzed, and exploration and verification are carried out by drilling peek; Constructing a plurality of first grouting boreholes (5) around the abnormal seepage area of ​​the coal pillar dam body (3) from the tunnel side of the coal pillar dam body (3) to the water storage goaf side, and performing segmented grouting on the first grouting boreholes (5); After the grouting in the coal pillar dam body (3) solidifies, a plurality of second grouting boreholes are constructed in the artificial dam body (4), and grouting is performed in the second grouting boreholes using a polyacrylate modified cement material.

2. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 1, characterized in that: The first grouting borehole (5) is divided into a deep grouting borehole (8), a middle grouting borehole (7) and a shallow grouting borehole (6) from deep to shallow; wherein, the deep grouting borehole (8) is grouted with an early-strength, fast-setting inorganic grouting material, the middle grouting borehole (7) is grouted with an early-strength, slow-setting inorganic grouting material, and the shallow grouting borehole (6) is grouted with an early-strength, slow-setting inorganic grouting material.

3. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 2, characterized in that: The hole depth of the first grouting borehole (5) is 15.0-20.0 m, the grouting pressure of the deep grouting borehole (8) and the shallow grouting borehole (6) is 3.0-3.5 MPa, and the grouting pressure of the middle grouting borehole (7) is 3.5-5.0 MPa.

4. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 1, characterized in that: The plurality of first grouting boreholes (5) are arranged in two rows, wherein the distance between the opening positions of the first grouting boreholes (5) in the upper row and the top rock layer (1) is 0.9 m to 1.1 m, and the distance between the opening positions of the first grouting boreholes (5) in the lower row and the opening positions of the first grouting boreholes (5) in the upper row is 1.4 m to 1.6 m.

5. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 1, characterized in that: The plurality of second grouting boreholes are respectively arranged in the top rock layer (1) above the artificial dam body (4), the bottom rock layer (2) below the artificial dam body (4), and the coal pillars on both sides of the artificial dam body (4).

6. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 5, characterized in that: The second grouting drilling comprises: A top plate grouting drill hole (12) is arranged at the center of the top plate rock layer (1) above the artificial dam body (4), with a horizontal distance of 2.8-3.2 m from the front of the artificial dam body (4), a hole depth of 2.8-3.2 m, and a grouting pressure of 0.5-1.0 MPa; The bottom plate grouting drill hole (13) is arranged at the center of the bottom plate rock layer (2) below the artificial dam body (4), with a horizontal distance of 2.8-3.2m from the front of the artificial dam body (4), a hole depth of 2.8-3.2m, and a grouting pressure of 0.5-1.0Mpa.

7. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 5, characterized in that: The second grouting drilling comprises: The left grouting borehole (10) is arranged at the center of the left coal pillar of the artificial dam body (4), with a horizontal distance of 4.8-5.2m from the side of the artificial dam body (4), a horizontal distance of 3.0-5.0m from the side of the artificial dam body (4), a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0Mpa; The right grouting borehole (11) is arranged at the center of the right coal pillar of the artificial dam body (4), with a horizontal distance of 4.8-5.2m from the side of the artificial dam body (4), a horizontal distance of 3.0-5.0m from the side of the artificial dam body (4), a hole depth of 5.0-7.0m, and a grouting pressure of 0.5-1.0Mpa.

8. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 2, characterized in that: The early-strength, fast-setting inorganic grouting material comprises component A and component B, wherein component A is composed of sulphoaluminate cement with additives, and component B is a setting regulator, which is composed of an accelerating setting agent and a retarding setting agent.

9. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 2, characterized in that: The early-strength slow-setting inorganic grouting material comprises silicate cement, sulphoaluminate cement, fly ash and admixtures.

10. The method for anti-seepage reinforcement of coal mine underground reservoir dam body by grouting according to claim 1, characterized in that: The polyacrylate modified cement material consists of polyacrylate emulsion, defoamer, superfine cement and alumina clinker accelerator.

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