Geologic structure treatment and grout burst prevention method under separation layer grouting and filling mining

Abstract

The invention discloses a method for preventing slurry bursting in geological structure treatment under separation layer grouting and filling mining, and belongs to the technical field of coal mine filling mining. Meanwhile, a geophysical prospecting method and a drilling method are adopted to obtain the distribution form of the non-cohesive or weakly-cohesive concealed structure in the stratum; determining an anti-burst grouting area; a grouting treatment scheme is determined according to the buried depth of the coal seam and the development condition of the hidden structure; and the grouting reinforcement effect is detected. The method not only can effectively prevent slurry bursting accidents caused by the fact that slurry flows through the hidden structure, but also can determine the grouting reinforcement area of the hidden structure through theoretical calculation, and compared with grouting reinforcement of the whole hidden structure, the cost can be effectively reduced, and the targeting of grouting reinforcement treatment of the area of the hidden structure is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine filling mining, and in particular to a method for preventing slurry collapse in geological structure management under separation layer grouting filling mining. Background Art

[0002] Separation layer grouting is a technical method to control surface subsidence and movement deformation. Its basic principle is to carry out high-pressure grouting into the separation layer of the overburden rock, use slurry to fill the separation layer space, support the overburden rock layer, block the transmission of mining space, and thus control the overburden rock layer and surface movement. When there are geological structures in the strata, such as non-bonded or weakly bonded hidden structures in the overburden of the working face, the grouting separation layer may be connected to the coal mining working face, causing slurry burst accidents and threatening the production of the working face.

[0003] Among the existing patents, CN201910990300.1-A method for preventing and controlling grouting during delamination grouting, which conducts a tracer test to determine the flow pattern of the tracer in the water-conducting structure, and determines the location of the grouting through theoretical calculation, thereby achieving precise prevention and control of grouting. CN202311201953.XA method for determining the position and pressure of delamination grouting, which obtains the actual grouting pressure and the pressure that the delamination space can bear through theoretical calculation, and then determines the position of the key grouting layer and the grouting layer section, and implements delamination grouting when the grouting layer and grouting pressure are feasible, thereby improving the quality of the project and the degree of safety assurance, and preventing underground grouting accidents. CN202311136823.2-A method for accurately grouting and reducing settlement of mining overburden composite curtains and overburden multi-delamination layers, which injects cement slurry into multiple thick hard rock layers of cracks or weak surfaces of geological structures to reinforce the cracks or weak surfaces, and forms a multi-layer protective curtain on the top of the grouting layer to prevent grouting and slurry leakage during delamination grouting. CN202410723293.X - A method for sealing through cracks by grouting in a delamination layer and a microcapsule dedicated to the method, judging whether cracks appear in the delamination space according to the change of pressure during the delamination grouting process, injecting slurry containing microcapsules into the delamination layer to seal the through cracks, and timely sealing the cracks at the leakage points by microcapsules. The above patent solves the problems of slurry burst and slurry leakage during delamination grouting by theoretical analysis, constructing curtains or adding new plugging materials. When there are geological structures in the stratum, such as non-bonded or weakly bonded hidden structures in the overburden of the working face, if the mining area is not blocked, the slurry will move along the non-bonded or weakly bonded hidden structures, which will not only affect the delamination grouting effect, but also cause the grouting delamination to be connected with the coal mining working face, causing slurry burst accidents and threatening the safe production of the working face. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a method for preventing slurry from breaking under geological structure management under delamination grouting filling mining. The constructed combined sealing dam body can effectively prevent the slurry from flowing and migrating to the remaining space of the target delamination above the mined area during delamination grouting under single-side open conditions, thereby enhancing the delamination grouting effect.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preventing slurry collapse in geological structure management under delamination grouting filling mining, comprising the following steps:

[0006] S1. Determine the distribution of concealed structures: by injecting high-pressure water into the detached layer, geophysical prospecting and drilling methods are used in turn to obtain the distribution of non-cohesive or weakly cohesive concealed structures in the stratum;

[0007] S2. Determine the anti-break grouting area;

[0008] S3. Determine the grouting treatment plan according to the burial depth of the coal seam and the development of the concealed structure in S1. The grouting treatment plan includes: above-ground grouting treatment, underground grouting treatment, and above-ground and underground combined grouting treatment;

[0009] S4. Test the effect of grouting reinforcement: Carry out high-pressure water injection experiment through the delamination grouting drilling hole again, inspect it through geophysical exploration method, and observe whether there is water dripping or leakage on the coal mining working face; if water dripping occurs on the coal mining working face, stop high-pressure water injection immediately, determine the leakage location based on the geophysical exploration results, and seal it by injecting slurry prepared with cement, plugging agent and quick-setting material through the grouting reinforcement drilling hole until there is no water dripping or leakage on the working face.

[0010] Preferably, in S1, high-pressure water injection is carried out into the delamination area through the surface delamination grouting drilling holes of the coal mining working face, and the water flows along the hidden structure under the action of pressure. At the same time, geophysical methods are used to detect non-bonded or weakly bonded hidden structures in the stratum, and drilling methods are used for auxiliary detection, and finally the distribution morphology of the non-bonded or weakly bonded hidden structures in the stratum is obtained.

[0011] Preferably, in S2, the grouting separation layer is first determined in the longitudinal direction, and then the area between the upper part of the water-conducting fracture zone and the grouting separation layer is determined as the longitudinal grouting area.

[0012] Combined with the distribution of the concealed structure obtained in S1, the scope of the grouting area along the advancing direction and the dip direction of the working face is determined.

[0013] Preferably, the distance from the grouting separation layer to the coal seam is greater than the sum of the height of the water-conducting fracture zone and the height of the isolation maintenance zone, and the calculation formula is:

[0014] H 离 ≥H 导 +(5~8)M

[0015] In the formula, H 离 is the detachment layer height, m; H 导 is the height of the water-conducting fracture zone determined by the properties of the overburden, m; M is the height of the coal seam, m.

[0016] Preferably, the calculation formula for the length of the grouting reinforcement area along the advancing direction of the working face is:

[0017]

[0018] Where, L 横 is the length of the grouting reinforcement area along the advancing direction of the working face, m; H is the distance from the water-conducting fracture zone to the stratum, m; α is the inclination angle of the hidden structure along the advancing direction of the working face, °; L0 is the width of the grouting reinforcement protection zone, m.

[0019] The calculation formula for the length of the grouting reinforcement area along the inclination direction of the working face is:

[0020]

[0021] Where, L 倾 is the length of the grouting reinforcement area along the dip direction of the working face, β is the dip angle of the hidden structure along the dip direction of the working face, °.

[0022] The width of the grouting reinforcement protection zone is determined by the leading influence distance, and its calculation formula is:

[0023] L0=H0cotω

[0024] Where L0 is the width of the grouting reinforcement protection zone, m; H0 is the average mining depth, m; ω is the leading influence angle, °.

[0025] Preferably, in S3, the grouting treatment scheme is divided into above-hole grouting treatment, below-hole grouting treatment and above-hole and below-hole combined grouting treatment.

[0026] When the coal seam is buried below 600 meters, the above-ground grouting treatment scheme is adopted; when the coal seam is buried above 600 meters, the underground grouting treatment scheme is adopted; when the non-bonded or weakly bonded concealed structure is highly close to the surface in the vertical direction and the span in the direction of the working face inclination exceeds the width of the working face, the above-ground and underground combined grouting treatment is adopted.

[0027] Preferably, the above-ground grouting treatment scheme specifically includes: grouting areas at intervals of L in the hidden structures on the surface of the coal mining face. j Construct multiple rows of stepped grouting reinforcement holes along the advancing direction of the working face to the grouting reinforcement area, construct the middle hole to the bottom of the grouting reinforcement area, inject slurry prepared by cement, plugging agent and quick-setting material to seal the hidden structure; the remaining grouting reinforcement holes are spaced L apart. jThe holes are arranged in a stepped manner on both sides, with the end holes spaced at a height of h0. Slurry prepared with cement and plugging agent is injected into the grouting reinforcement area in sequence until the grouting reinforcement of the anti-collapse grouting area is completed.

[0028] Preferably, the underground grouting treatment specifically includes: dividing the grouting reinforcement area into three different height layers in the longitudinal direction, and j Construct multiple groups of directional drilling holes to different layers, and inject slurry prepared by cement, plugging agent and quick-setting material into the grouting reinforcement area through the directional drilling holes in the lowest layer to seal the hidden structure; inject slurry prepared by cement and plugging agent into the grouting reinforcement area through the directional drilling holes in the remaining layers until the grouting reinforcement of the anti-collapse grouting area is completed.

[0029] Preferably, the above-ground and underground combined grouting treatment specifically includes: extending the delamination grouting borehole in the grouting reinforcement area to the bottom of the grouting reinforcement area, and at the same time constructing a directional drilling hole in the tunnel on one side of the working face to the same layer, and injecting slurry prepared by cement, plugging agent and quick-setting material into the bottom of the grouting reinforcement area through the delamination grouting borehole and the directional drilling to seal the hidden structure; after the sealing is completed, the delamination grouting borehole is re-drilled for secondary hole expansion, and then the delamination grouting borehole is lifted upward by a certain distance h1, and the slurry prepared by cement and plugging agent is injected, and then it is lifted again by a certain distance h1 until the anti-collapse grouting area is completely reinforced.

[0030] Preferably, in S3, the slurry prepared from cement and plugging agent has a ratio of cement: plugging agent = 7:2;

[0031] In S3 and S4, the slurry prepared from cement, plugging agent and quick-setting material has a ratio of cement: plugging agent: quick-setting material = 7:1:2;

[0032] The water-cement ratio is 1:0.46.

[0033] Compared with the prior art, the present invention provides a method for preventing slurry collapse in geological structure management under delamination grouting filling mining, which has the following beneficial effects:

[0034] (1) A variety of solutions were proposed to treat non-bonded or weakly bonded concealed structures (grouting and reinforcement drilling and grouting treatment in the well construction, directional drilling and grouting treatment in the underground construction, and joint grouting treatment in the well and underground), providing a variety of options for the treatment of concealed structures, which can effectively block the concealed structure area, block the channel between the grouting separation layer and the coal mining face, and ensure the smooth grouting and filling of the separation layer of the coal mining face. During the actual construction, the final grouting treatment plan is determined by comprehensively considering factors such as geological mining conditions and construction costs, so as to achieve effective treatment of non-bonded or weakly bonded concealed structures in the stratum.

[0035] (2) The grouting reinforcement slurry proposed in the present invention is prepared from cement, a leak-proof agent and a quick-setting material. Compared with ordinary cement slurry, it has a higher viscosity and a shorter setting time. After the slurry is injected, it can be concentrated near the grouting reinforcement area and can effectively seal the hidden structure area.

[0036] (3) The present invention determines the grouting reinforcement area of ​​the hidden structure through theoretical calculation. Compared with grouting reinforcement of the entire hidden structure, it can effectively reduce the cost and enhance the targeting of grouting reinforcement management in the hidden structure area. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 A flow chart of a method for preventing slurry collapse in geological structure management under delamination grouting and filling mining proposed in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the distribution of grouting separation layers in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the distribution of the grouting reinforcement area along the advancing direction of the working face in an embodiment of the present invention;

[0041] Figure 4 A schematic diagram of a grouting reinforcement area along the inclination direction of a working face in an embodiment of the present invention;

[0042] Figure 5 It is a schematic diagram of grouting treatment in the well along the advancing direction of the working face in an embodiment of the present invention;

[0043] Figure 6 A top view of a ground drilling hole in an embodiment of the present invention;

[0044] Figure 7 It is a schematic diagram of underground grouting treatment along the inclination direction of the working face in an embodiment of the present invention;

[0045] Figure 8 It is a top view of the underground grouting treatment along the advancing direction of the working face in the embodiment of the present invention;

[0046] Fig. 9 It is a schematic diagram of the above-ground and underground combined grouting treatment along the advancing direction of the working face in an embodiment of the present invention;

[0047] Fig.10 It is a schematic diagram of the above-ground and underground combined grouting treatment along the inclination direction of the working face in an embodiment of the present invention;

[0048] Fig.11It is a schematic diagram of the above-ground grouting in the above-ground and underground combined grouting treatment process in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0050] This embodiment proposes a method for preventing slurry from collapsing in geological structures under stratum grouting and filling mining. The detailed steps are as follows: Figures 1 to 11 As shown:

[0051] (1) Determine the distribution of hidden structures

[0052] High-pressure water injection is carried out into the stratum delamination area through the grouting holes on the surface of the coal mining face. In order to prevent accidents such as well flooding during the high-pressure water injection experiment, plugging agents are added to the water to reduce the fluidity of the water. Under the action of pressure, the water will flow along the concealed structure. At the same time, survey lines are laid on the surface above the coal mining face, in the tunnels on both sides of the face, and in the open cuts. Geophysical exploration methods such as transient electromagnetic are used to detect the non-bonded or weakly bonded concealed structures in the stratum, and drilling methods are used for auxiliary detection to obtain the distribution morphology of the non-bonded or weakly bonded concealed structures in the stratum.

[0053] (2) Determine the anti-break grouting area

[0054] 1) Determine the grouting separation layer. The distance from the grouting separation layer to the coal seam should be greater than the sum of the height of the water-conducting fracture zone and the height of the isolation maintenance zone (5 to 8 times the mining height). The calculation formula is:

[0055] H 离 ≥H 导 +(5~8)M

[0056] In the formula, H 离 is the detachment layer height, m; H 导 is the height of the water-conducting fracture zone determined by the properties of the overburden, m; M is the height of the coal seam, m.

[0057] 2) Determine the height of the grouting reinforcement area in the longitudinal direction. Based on the determined grouting layer of the abscission layer, combined with the distribution of the hidden structure determined in step 1, the area above the water-conducting fracture zone to the grouting abscission layer is determined as the longitudinal grouting reinforcement area.

[0058] 3) Based on the distribution of the hidden structure detected in step 1, determine the length of the grouting reinforcement area along the advancing direction of the working face.

[0059]

[0060] Where, L 横 is the length of the grouting reinforcement area along the advancing direction of the working face, m; H is the distance from the water-conducting fracture zone to the stratum, m; α is the inclination angle of the hidden structure along the advancing direction of the working face, °; L0 is the width of the grouting reinforcement protection zone, m.

[0061] Length of grouting reinforcement area along the inclination direction of the working face:

[0062]

[0063] Where, L 倾 is the length of the grouting reinforcement area along the dip direction of the working face, β is the dip angle of the hidden structure along the dip direction of the working face, °.

[0064] The width of the grouting reinforcement protection zone is determined by the leading influence distance, and its calculation formula is:

[0065] L0=H0cotω

[0066] Where L0 is the width of the grouting reinforcement protection zone, m; H0 is the average mining depth, m; ω is the leading influence angle, °.

[0067] (3) Carry out multiple grouting treatment schemes

[0068] The spacing of the grouting holes for separation layer is determined by the diffusion radius of the fly ash slurry. The calculation formula for the distance between adjacent grouting holes for separation layer is:

[0069] L a ≤2kl 粉

[0070] Where, L a is the distance between adjacent separation layer grouting holes, m; k is the safety factor, which is 0.3-0.7; l 粉 is the diffusion radius of fly ash slurry, m

[0071] The calculation formula for the distance between adjacent grouting reinforcement holes is:

[0072] L j ≤2kl

[0073] Where, L jis the distance between adjacent grouting reinforcement holes, m; k is the safety factor, which is 0.3-0.7; l is the diffusion radius of the slurry prepared by cement and plugging agent, m. The spacing between each group of directional drilling holes is the same as the spacing between grouting reinforcement holes.

[0074] Scheme 1: grouting treatment on the well, grouting area of ​​hidden structure on the surface of coal mining working face at intervals of L j Construct multiple rows of stepped grouting reinforcement boreholes along the working face advancement direction to the grouting reinforcement area, construct the middle borehole to the bottom of the grouting reinforcement area, and inject slurry prepared by cement, plugging agent and quick-setting material to seal the non-bonded or weakly bonded hidden structure, blocking the channel between the grouting separation layer and the coal mining working face. The plugging agent can increase the viscosity of the cement slurry, and the quick-setting material can accelerate the solidification of the cement slurry. The interval between the remaining grouting reinforcement boreholes is L j It is arranged in a stepped manner on the left and right sides, with the final hole positions spaced at a height of h0. After the grouting of the bottom area is completed, slurry prepared by cement and plugging agent is injected into the grouting reinforcement area in sequence through the grouting reinforcement holes on both sides until the grouting reinforcement of the anti-collapse grouting area is completed.

[0075] Solution 2: Underground grouting treatment, the grouting reinforcement area is divided into three different height layers in the vertical direction, and the intervals of L in the tunnel on one side of the working face j Construct multiple groups of directional drilling holes to different layers in the grouting reinforcement area. The grouting casing of the directional drilling holes in the grouting reinforcement area is a flower pipe. Slurry prepared by cement, plugging agent and quick-setting material is injected into the grouting reinforcement area through the directional drilling holes in the lowest layer. The plugging agent can increase the viscosity of the cement slurry, and the quick-setting material can accelerate the solidification of the cement slurry. After the slurry is injected, it can quickly enter the cracks in the hidden structure area, and can effectively seal the non-bonded or weakly bonded hidden structure, block the channel between the grouting detachment layer and the coal mining working face, and then inject the slurry prepared by cement and plugging agent into the grouting reinforcement area through the directional drilling holes in the remaining layers until the grouting reinforcement of the anti-collapse grouting area is completed.

[0076] Solution 3: Combined grouting treatment above and below the ground, extending the separation layer grouting borehole in the grouting reinforcement area to the bottom of the grouting reinforcement area, and constructing a directional borehole in the tunnel on one side of the working face to the same layer. The grouting casing of the directional borehole in the grouting reinforcement area is a flower pipe. The slurry prepared by cement, plugging agent and quick-setting material is injected into the bottom of the grouting reinforcement area through the separation layer grouting borehole and the directional borehole at the same time. The plugging agent can increase the viscosity of the cement slurry, and the quick-setting material can accelerate the solidification of the cement slurry. After the slurry is injected, it can quickly enter the cracks in the hidden structure area, which can effectively block the non-bonded or weakly bonded hidden structure and block the passage between the grouting separation layer and the coal mining working face. After the plugging is completed, the separation layer grouting borehole is re-drilled for secondary expansion, and the separation layer grouting borehole is lifted up a certain distance h1, and the slurry prepared by cement and plugging agent is injected, and then it is lifted again by a certain distance h1, and the slurry is continued to be injected until the anti-collapse grouting area is completely reinforced.

[0077] When the above three plans are implemented, when the coal seam is shallow, that is, the coal seam is buried below 600 meters, the control method of Plan 1 can be adopted; when the coal seam is deep, that is, the coal seam is buried above 600 meters, the control method of Plan 2 can be adopted; if the non-bonded or weakly bonded concealed structure has a large development space and a wide impact range, that is, the non-bonded or weakly bonded concealed structure is highly close to the surface in the vertical direction, and the span in the dip direction of the working face exceeds the width of the working face, the control method of Plan 3 shall be adopted.

[0078] (4) Test the effect of grouting reinforcement

[0079] After steps (1) to (3) are completed, the grouting reinforcement effect is tested in the following manner:

[0080] High-pressure water injection experiments are carried out through delamination grouting drilling, and inspections are carried out through geophysical methods. At the same time, it is observed whether there is water dripping or leakage on the coal mining working face; if water dripping occurs on the coal mining working face, high-pressure water injection is stopped immediately, and the leakage location is determined in combination with the geophysical exploration results, and the slurry prepared by cement, plugging agent and quick-setting material is injected into the grouting reinforcement drilling hole for sealing; the high-pressure water injection experiment and injection and sealing are repeated until there is no water dripping or leakage on the working face.

[0081] In addition, it should be noted that the ratio of the slurry prepared from cement, plugging agent and quick-setting material mentioned above is cement: plugging agent: quick-setting material = 7:1:2; the ratio of the slurry prepared from cement and plugging agent is cement: plugging agent = 7:2, and the water-cement ratio is 1:0.46.

[0082] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0083] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preventing slurry from collapsing in geological structures under mining by grouting and filling in delamination, characterized in that: The following steps are involved: S1. Determine the distribution of concealed structures: By injecting high-pressure water into the detached layer, geophysical exploration and drilling methods are used to obtain the distribution of non-bonded or weakly bonded concealed structures in the stratum; S2. Determine the anti-break grouting area; S3. Determine the grouting treatment plan according to the burial depth of the coal seam and the development of the concealed structure in S1. The grouting treatment plan includes: above-ground grouting treatment, underground grouting treatment, and above-ground and underground combined grouting treatment; S4. Test the effect of grouting reinforcement: Carry out high-pressure water injection experiment through the delamination grouting drilling hole again, inspect it through geophysical exploration method, and observe whether there is water dripping or leakage on the coal mining working face; if water dripping occurs on the coal mining working face, stop high-pressure water injection immediately, determine the leakage location based on the geophysical exploration results, and seal it by injecting slurry prepared with cement, plugging agent and quick-setting material through the grouting reinforcement drilling hole until there is no water dripping or leakage on the working face.

2. The method for preventing slurry collapse during grouting filling mining of geological structures under separation layer according to claim 1 is characterized in that: In S1, high-pressure water injection is carried out into the stratum delamination area through the grouting holes on the surface of the coal mining face. Under the action of pressure, water flows along the concealed structure. At the same time, geophysical methods are used to detect the non-bonded or weakly bonded concealed structures in the stratum, and drilling methods are used for auxiliary detection. Finally, the distribution morphology of the non-bonded or weakly bonded concealed structures in the stratum is obtained.

3. The method for preventing slurry collapse during grouting filling mining of geological structures under separation layer according to claim 2 is characterized in that: In S2, the grouting separation layer is first determined in the longitudinal direction, and then the area between the water-conducting fracture zone and the grouting separation layer is determined as the longitudinal grouting area; Combined with the distribution of the concealed structure obtained in S1, the scope of the grouting area along the advancing direction and the dip direction of the working face is determined.

4. A method for preventing slurry collapse in geological structure management under delamination grouting filling mining according to claim 3, characterized in that: The distance from the grouting separation layer to the coal seam is greater than the sum of the height of the water-conducting fracture zone and the height of the isolation maintenance zone. The calculation formula is: H 离 ≥H 导 +(5~8)M In the formula, H 离 is the detachment layer height, m; H 导 is the height of the water-conducting fracture zone determined by the properties of the overburden, m; M is the height of the coal seam, m.

5. The method for preventing slurry collapse during grouting filling mining of geological structures under separation layer according to claim 4 is characterized in that: The calculation formula for the length of the grouting reinforcement area along the advancing direction of the working face is: Where, L 横 is the length of the grouting reinforcement area along the advancing direction of the working face, m; H is the distance from the water-conducting fracture zone to the stratum, m; α is the inclination angle of the hidden structure along the advancing direction of the working face, °; L0 is the width of the grouting reinforcement protection zone, m. The calculation formula for the length of the grouting reinforcement area along the inclination direction of the working face is: Where, L 倾 is the length of the grouting reinforcement area along the working face dip direction, β is the dip angle of the hidden structure along the working face dip direction, °; The width of the grouting reinforcement protection zone is determined by the leading influence distance, and its calculation formula is: L0=H0cotω Where L0 is the width of the grouting reinforcement protection zone, m; H0 is the average mining depth, m; ω is the leading influence angle, °.

6. The method for preventing slurry collapse during grouting filling mining of geological structures under separation layer according to claim 1 is characterized in that: In S3, the grouting treatment scheme is divided into above-ground grouting treatment, below-ground grouting treatment and above-ground and below-ground combined grouting treatment; When the coal seam is buried below 600 meters, the above-ground grouting treatment scheme is adopted; when the coal seam is buried above 600 meters, the underground grouting treatment scheme is adopted; when the non-bonded or weakly bonded concealed structure is highly close to the surface in the vertical direction and the span in the direction of the working face dip exceeds the width of the working face, the above-ground and underground combined grouting treatment is adopted.

7. The method for preventing slurry collapse during grouting filling mining of a geological structure under separation layer according to claim 1 is characterized in that: The above-ground grouting treatment plan specifically includes: grouting area of ​​hidden structure on the surface of coal mining working face at intervals of L j Construct multiple rows of stepped grouting reinforcement holes along the advancing direction of the working face to the grouting reinforcement area, construct the middle hole to the bottom of the grouting reinforcement area, inject slurry prepared by cement, plugging agent and quick-setting material to seal the hidden structure; the remaining grouting reinforcement holes are spaced L apart. j The holes are arranged in a stepped manner on both sides, with the end holes spaced at a height of h0. Slurry prepared with cement and plugging agent is injected into the grouting reinforcement area in sequence until the grouting reinforcement of the anti-collapse grouting area is completed.

8. The method for preventing slurry collapse by grouting and filling in the delamination layer according to claim 7 is characterized in that: The specific underground grouting treatment includes: dividing the grouting reinforcement area into three different height layers in the vertical direction, and j Construct multiple groups of directional drilling holes to different layers, and inject slurry prepared by cement, plugging agent and quick-setting material into the grouting reinforcement area through the directional drilling holes in the lowest layer to seal the hidden structure; inject slurry prepared by cement and plugging agent into the grouting reinforcement area through the directional drilling holes in the remaining layers until the grouting reinforcement of the anti-collapse grouting area is completed.

9. A method for preventing slurry collapse in geological structure management under delamination grouting filling mining according to claim 8, characterized in that: The above-ground and underground joint grouting treatment specifically includes: extending the delamination grouting borehole in the grouting reinforcement area to the bottom of the grouting reinforcement area, and constructing a directional drill hole in the tunnel on one side of the working face to the same layer, and injecting slurry prepared by cement, plugging agent and quick-setting material into the bottom of the grouting reinforcement area through the delamination grouting borehole and directional drilling to seal the hidden structure; after the sealing is completed, the delamination grouting borehole is re-drilled for secondary hole expansion, and then the delamination grouting borehole is lifted upward by a certain distance h1, and the slurry prepared by cement and plugging agent is injected, and then it is lifted again by a certain distance h1 until the anti-collapse grouting area is completely reinforced.

10. A method for preventing slurry collapse in geological structure management under delamination grouting filling mining according to claim 9, characterized in that: In S3, the slurry prepared from cement and plugging agent has a ratio of cement: plugging agent = 7:2; In S3 and S4, the slurry prepared from cement, plugging agent and quick-setting material has a ratio of cement: plugging agent: quick-setting material = 7:1:2; The water-cement ratio is 1:0.46.

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