Method of grouting a poor borehole

Abstract

The application provides a grouting method for a poor drilling hole. The grouting method for the poor drilling hole comprises the following steps: S1, obtaining relevant information; S2, calculating a water inrush amount of the poor drilling hole according to geological information, mining information, exploration information and a spatial position relationship, so as to determine a water inrush risk size of the poor drilling hole; S3, performing drilling grouting construction on the poor drilling hole with the water inrush risk according to the geological information, the mining information, a deflection trajectory of the poor drilling hole and the water inrush amount of the poor drilling hole, so that at least part of the poor drilling hole is located within a slurry diffusion radius of a drilling hole drilled in the drilling grouting construction process; and S4, evaluating a plugging effect of the grouting method for the poor drilling hole based on lithology parameters and / or core parameters. The deflection data comprises a deflection angle and an azimuth angle of the poor drilling hole. The application effectively solves the problem of poor plugging reliability of the plugging method for the poor closed drilling hole in the prior art.

Description

Technical Field

[0001] This invention relates to the field of mine water hazard prevention technology, and more specifically, to a grouting method for poorly drilled boreholes. Background Technology

[0002] Currently, drilling is often the most reliable and effective method in geological exploration before coal mining. After mining is completed, the boreholes drilled during exploration must be sealed to prevent mine water hazards. However, due to the age of some coal mine exploration boreholes and poor construction techniques, some boreholes have poor sealing. When the working face is mined and these poorly sealed boreholes are exposed, if the boreholes connect to water bodies in the overlying goaf or the confined aquifer in the floor, water inrush will occur, seriously affecting the safety of coal mining.

[0003] In existing technologies, additional water hazard prevention measures are required for poorly sealed exploration boreholes, such as advance water release, construction of retaining walls, and borehole grouting reinforcement, to guide water or re-seal the poorly sealed exploration boreholes, so as to avoid water inrush during the mining process and thus improve the safety of coal mining. Borehole grouting reinforcement measures have become one of the most commonly used water hazard prevention measures due to their advantages of large coverage area, low cost and short construction period. It mainly involves drilling holes around the poorly sealed borehole and grouting. The grout in the holes seeps into the poorly sealed borehole and seals it after solidification.

[0004] However, due to geological movements and poor construction techniques in exploration boreholes, exploration boreholes often deviate to varying degrees, sometimes even beyond the waterproofing and water-blocking coverage of the borehole grouting reinforcement measures. This can lead to water inrushes in exploration boreholes, seriously affecting the safety of construction workers. Summary of the Invention

[0005] The main objective of this invention is to provide a grouting method for defective boreholes, so as to solve the problem of poor sealing reliability in existing sealing methods for defective boreholes.

[0006] To achieve the above objectives, this invention provides a grouting method for sealing defective boreholes. The grouting method for defective boreholes includes: Step S1: Obtaining geological and mining information of the working face, obtaining exploration information and inclination data of the defective borehole, obtaining the spatial relationship between the defective borehole, the working face, the aquifer on the top of the working face, and the aquifer on the bottom of the working face, and obtaining the deviation trajectory of the defective borehole; Step S2: Calculating the water inflow of the defective borehole based on the geological information, mining information, exploration information, and spatial relationship to determine the magnitude of the water inrush risk of the defective borehole; Step S3: ... Based on geological information, mining information, the deviation trajectory of the faulty borehole, and the water inflow of the faulty borehole, borehole grouting is carried out on faulty boreholes with water inrush risk, so that at least part of the faulty borehole is located within the grout diffusion radius of the borehole drilled during the borehole grouting construction; Step S4: Based on lithological parameters and / or core parameters, the sealing effect of the grouting method on the faulty borehole is evaluated; wherein, at least part of the grout in the borehole penetrates into the faulty borehole to seal the faulty borehole; the exploration information includes the initial borehole location coordinates K of the faulty borehole, and the inclination data includes at least one of the deviation angle and azimuth angle of the faulty borehole.

[0007] Further, step S1 includes: Step S11: Based on trigonometric function theory and / or geographic coordinate offset theory, calculate the position coordinates Kn of the defective borehole at n different depths, n=0,1,2,…N, according to the initial borehole position coordinates K and at least one of the deviation angle and azimuth angle. The trajectory formed by connecting the n coordinates Kn sequentially along the depth direction H of the defective borehole is the deviation trajectory of the defective borehole.

[0008] Furthermore, based on geological information, mining information, and exploration information, the method for obtaining the spatial relationship between unfavorable boreholes, working faces, aquifers on the roof of the working face, and aquifers on the floor of the working face includes: Step S12: Based on geological information, mining information, and exploration information, determine the location and mining depth of the upper coal goaf, the depth of floor damage caused by mining of the upper coal goaf, the location and height of the protective rock pillar, the location and development height of the water-conducting fracture zone of the coal mining face, the location and mining depth of the working face, the depth of floor damage caused by mining of the working face, and the aquifers on the floor of the working face. The location and height of the layer, the location and height of the aquitard, and the location and columnar section of the defective borehole; Step S13: On the columnar section of the defective borehole, mark the upper coal goaf, the depth of damage to the upper coal floor, the protective rock pillar, the water-conducting fracture zone of the coal face, the working face, the depth of damage to the working face floor, the aquifer and aquitard of the working face floor, so as to determine the spatial relationship between the defective borehole, the working face, the aquifer of the working face roof and the aquifer of the working face floor; wherein, the aquifer of the working face roof is the water accumulation in the upper coal goaf.

[0009] Further, step S2 includes: Step S21: Based on geological information, mining information, and exploration information, calculate the maximum inflow rate A at the connection between the faulty borehole and the aquifer on the top of the working face. When the maximum inflow rate A is greater than or equal to 50 m³ / h, determine that the aquifer on the top of the working face poses a risk of water inrush to the working face through the faulty borehole; Step S22: Based on geological information, mining information, and exploration information, calculate the maximum inflow rate B at the connection between the faulty borehole and the aquifer on the bottom of the working face. When the maximum inflow rate B is greater than or equal to 50 m³ / h, determine that the aquifer on the bottom of the working face poses a risk of water inrush to the working face through the faulty borehole; wherein, the formula for calculating the maximum inflow rate Q is: ; ;in, For the Xie Cai coefficient, The roughness of a poorly drilled hole. For hydraulic radius, This refers to the cross-sectional area of ​​the poorly drilled hole. This refers to the hydraulic gradient.

[0010] Further, step S3 includes: Step S31: Determine the location of the grouting layer based on the location of the poorly drilled borehole that poses a risk of water inrush due to the aquifer on the top plate of the working face and / or the location of the poorly drilled borehole that poses a risk of water inrush due to the aquifer on the bottom plate of the working face, the deviation trajectory of the poorly drilled borehole, geological information, and mining information; Step S32: Based on grouting design theory, design the drilling parameters according to the location of the grouting layer and the deviation trajectory of the portion of the poorly drilled borehole that poses a risk of water inrush; Step S33: Carry out drilling construction; Step S34: After the drilling construction is completed, grout is injected into the borehole from the grouting layer.

[0011] Furthermore, in step S31, the method for determining the location of the grouting layer includes: Step S311: When sealing a faulty borehole that poses a risk of water inrush due to the aquifer on the top of the working face, the first grouting layer is selected within the protective rock column.

[0012] Furthermore, in step S31, the method for determining the location of the grouting layer also includes: step S312: when sealing the defective borehole that poses a risk of water inrush due to the aquifer at the bottom of the working face, the second grouting layer is selected below the top interface of the aquifer at the bottom of the working face, and there is a preset distance L between the second grouting layer and the top interface of the aquifer at the bottom of the working face, and the preset distance L satisfies: 0m≤L≤15m.

[0013] Further, step S4 includes: Step S41: After the drilling is completed, with the final borehole center axis as the center, drill a first core sample at any position within a radius r, and analyze the contained material, integrity rock quality index, and lithological mechanical parameters of the first core sample; if the analysis shows that the first core sample contains sealing material from a defective borehole, it is determined that the borehole has exposed a defective borehole; if the analysis shows that the first core sample does not contain sealing material, it is determined that the borehole has not exposed a defective borehole.

[0014] Furthermore, step S4 also includes: step S42: after grouting is completed, a second rock core is drilled at any position within the diameter r range with the final borehole center axis as the center, and the contents, integrity rock quality index and lithological mechanical parameters of the second rock core are analyzed.

[0015] Furthermore, in step S42: if the borehole has revealed a defective borehole and the second core contains a concretion; and / or, the integrity quality index of the second core is greater than that of the first core; and / or, the lithological mechanical parameters of the second core are greater than those of the first core; then the grouting method for the defective borehole is judged to have a good sealing effect.

[0016] The grouting method for defective boreholes, applying the technical solution of this invention, is used to seal defective boreholes. When sealing defective boreholes is required, firstly, geological and mining information of the working face is obtained, along with exploration and inclination data of the defective borehole. The spatial relationships between the defective borehole, the working face, the aquifer on the top of the working face, and the aquifer on the bottom of the working face are also obtained, along with the deviation trajectory of the defective borehole. Then, based on the geological, mining, and exploration information and the spatial relationships, the water inflow of the defective borehole is calculated to determine the magnitude of its water inrush risk. Subsequently, based on the geological, mining, deviation trajectory, and water inflow of the defective borehole, grouting is performed on the defective borehole with water inrush risk to ensure that the defective borehole is within the grout diffusion radius of the borehole drilled during the grouting process. Finally, the sealing effect of the grouting method for defective boreholes is evaluated based on lithological parameters and / or core parameters. In this process, at least a portion of the grout in the borehole seeps into the defective borehole to seal it; the exploration information includes the initial borehole location coordinates K of the defective borehole, and the inclination data includes at least one of the deviation angle and azimuth angle of the defective borehole.

[0017] Compared to existing methods that directly grout defective boreholes, the grouting method in this application analyzes the deviation trajectory of the defective borehole before grouting and incorporates this trajectory during drilling. This ensures the defective borehole remains within the grout diffusion radius of the grout, guaranteeing its waterproofing and water-blocking effectiveness. This significantly improves the reliability of grouting in sealing defective boreholes, addressing the poor sealing reliability of existing methods and enhancing worker safety during mining operations. Furthermore, the water inflow rate of the defective borehole is analyzed before grouting to provide data support for subsequent operations, further enhancing the sealing reliability of the grouting method. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A flowchart illustrating an embodiment of the grouting method for poorly drilled holes according to the present invention is shown.

[0020] Figure 2 A schematic diagram of the overall structure after selecting the first grouting layer position is shown in the grouting method for poorly drilled holes according to the present invention.

[0021] Figure 3 A schematic diagram of the overall structure after selecting the second grouting layer position is shown in the grouting method for poorly drilled holes according to the present invention.

[0022] The above figures include the following reference numerals:

[0023] 1. Poorly drilled borehole; 2. Upper coal seam goaf; 3. Depth of damage to the floor of the upper coal seam caused by mining; 4. Protective rock pillar; 41. Medium sandstone aquifer; 5. Water-conducting fracture zone of the coal face; 6. Working face; 61. Depth of damage to the floor of the working face caused by mining; 7. Aquifer on the floor of the working face; 81. First grouting layer; 82. Second grouting layer; 9. Water-retaining layer; 10. First borehole group; 11. Second borehole group. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] In this invention, unless otherwise stated, directional terms such as "up" and "down" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" are generally used in relation to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0027] To address the issue of poor sealing reliability in existing methods for sealing faulty boreholes, this application provides a grouting method for faulty boreholes.

[0028] like Figures 1 to 3 As shown, the grouting method for defective boreholes is used to seal defective borehole 1. The grouting method for defective boreholes includes:

[0029] Step S1: Obtain geological and mining information of working face 6, obtain exploration information and inclination data of defective borehole 1, obtain the spatial relationship between defective borehole 1, working face 6, aquifer on the top plate of working face and aquifer 7 on the bottom plate of working face, and obtain the deviation trajectory of defective borehole 1.

[0030] Step S2: Based on geological information, mining information, exploration information and spatial location, calculate the water inflow of the faulty borehole 1 to determine the magnitude of the water inrush risk of the faulty borehole 1;

[0031] Step S3: Based on geological information, mining information, the deviation trajectory of the defective borehole 1 and the water inflow of the defective borehole 1, perform borehole grouting construction on the defective borehole with water inrush risk, so that at least part of the defective borehole 1 is located within the grout diffusion radius of the borehole drilled during the borehole grouting construction.

[0032] Step S4: Evaluate the sealing effect of grouting methods for poor boreholes based on lithological parameters and / or core parameters;

[0033] In this process, at least a portion of the grout in the borehole permeates into the defective borehole 1 to seal it; the exploration information includes the initial borehole location coordinates K of the defective borehole 1, and the inclination data includes at least one of the deviation angle and azimuth angle of the defective borehole 1.

[0034] Applying the technical solution of this embodiment, the grouting method for defective boreholes is used to seal defective borehole 1. When sealing defective borehole 1 is required, firstly, the geological and mining information of the working face are obtained, along with the exploration and inclination data of defective borehole 1. The spatial relationships between defective borehole 1, the working face 6, the aquifer on the top of the working face, and the aquifer on the bottom of the working face 7 are also obtained. The deviation trajectory of defective borehole 1 is also obtained. Then, based on the geological, mining, and exploration information and the spatial relationships, the water inflow of defective borehole 1 is calculated to determine the magnitude of its water inrush risk. Afterward, based on the geological, mining, deviation trajectory, and water inflow of defective borehole 1, grouting is performed on the defective borehole with water inrush risk to ensure that defective borehole 1 is within the grout diffusion radius of the borehole drilled during the grouting process. Finally, the sealing effect of the grouting method for defective boreholes is evaluated based on lithological parameters and / or core parameters. In this process, at least a portion of the grout in the borehole seeps into the defective borehole 1 to seal it. The exploration information includes the initial borehole location coordinates K of the defective borehole 1, and the inclination data includes at least one of the deviation angle and azimuth angle of the defective borehole 1.

[0035] Compared to existing methods that directly grout defective boreholes, the grouting method in this application analyzes the deviation trajectory of the defective borehole 1 before grouting and incorporates this trajectory during drilling. This ensures the defective borehole 1 is within the grout diffusion radius of the borehole, guaranteeing its location within the waterproofing and water-blocking range of the grouting measures. This significantly improves the sealing reliability of the grouting method for the defective borehole 1, solving the problem of poor sealing reliability in existing methods for sealing defective boreholes and enhancing worker safety during backfilling. Furthermore, the water inflow rate of the defective borehole 1 is analyzed before grouting to provide data support for subsequent grouting operations, further improving the sealing reliability of the grouting method for defective boreholes.

[0036] In this embodiment, defective borehole 1 is a borehole that has been plugged, but the plugging effect is poor.

[0037] In this embodiment, working face 6 is a coal mining working face.

[0038] In this embodiment, the geological information includes a comprehensive stratigraphic columnar section of the working face and a comprehensive hydrogeological columnar section of the working face.

[0039] In this embodiment, the mining information includes the working face layout diagram (working face slope length, routing length, etc.), coal seam mining thickness, mining depth, depth of floor damage caused by mining, development height of water-conducting fracture zone 5 in the coal mining face, distribution range of water threatened by the overlying strata of the working face penetrated by the faulty borehole 1 (water level, water pressure, etc.), location of the confined aquifer in the floor of the working face penetrated by the faulty borehole 1 (water pressure, etc.), columnar section of the faulty borehole 1, location of the faulty borehole 1, and inclination data of the faulty borehole 1 (skew angle, azimuth angle, etc.). If the development height of the water-conducting fracture zone 5 and the depth of floor damage caused by mining are not measured, reference can be made to specifications or empirical formulas for the region.

[0040] In this embodiment, the depth of the mining floor includes the depth of the mining floor of the upper coal group (3) and the depth of the mining floor of the working face (61).

[0041] In this embodiment, the aquifer on the top of the working face is a water body threatened by the overlying rock of the working face.

[0042] In this embodiment, the water-bearing layer 7 of the working face bottom plate is a pressure-bearing water-bearing layer of the working face bottom plate.

[0043] In this embodiment, step S1 includes: Step S11: Based on trigonometric function theory and / or geographic coordinate offset theory, according to the initial borehole location coordinates K and at least one of the deviation angle and azimuth angle, calculate the location coordinates Kn of the defective borehole 1 at n different depths, n=0,1,2,…N. Connect the n coordinates Kn sequentially along the depth direction H of the defective borehole 1 to form the deviation trajectory of the defective borehole 1. In this way, workers can use this method to calculate the location coordinates Kn of the defective borehole 1 at different depths to determine the deviation distance of the defective borehole 1 at different depths, and thus determine the deviation trajectory of the defective borehole 1, providing data support for subsequent borehole grouting construction.

[0044] like Figure 2 and Figure 3 As shown, the methods for obtaining the spatial relationships between the unfavorable borehole 1, the working face 6, the aquifer on the top of the working face, and the aquifer on the bottom of the working face, based on geological information, mining information, and exploration information, include:

[0045] Step S12: Based on geological information, mining information, and exploration information, determine the location and mining depth of the upper coal goaf 2, the depth of the upper coal mining floor damage 3, the location and height of the protective rock pillar 4, the location and development height of the water-conducting fracture zone 5 in the coal mining face, the location and mining depth of the working face 6, the depth of the working face floor damage 61, the location and height of the aquifer 7 in the working face floor, the location and height of the water-retaining layer 9, and the location and columnar section of the defective borehole 1;

[0046] Step S13: On the columnar section of the defective borehole 1, mark the following: the upper coal goaf 2, the depth of damage to the upper coal floor 3, the protective rock pillar 4, the water-conducting fracture zone 5 of the working face 5, the working face 6, the depth of damage to the working face floor 61, the aquifer 7 of the working face floor 7, and the aquitard 9, to determine the spatial relationship between the defective borehole 1, the working face 6, the aquifer on the working face roof, and the aquifer 7 on the working face floor. The aquifer on the working face roof is the accumulated water within the upper coal goaf 2.

[0047] In this embodiment, the aquifer on the roof of the working face is the water accumulated in the upper coal goaf 2, that is, the water body threatened by the overlying rock of the working face.

[0048] like Figure 1 As shown, step S2 includes:

[0049] Step S21: Based on geological information, mining information and exploration information, calculate the maximum water inflow A at the connection between the faulty borehole 1 and the aquifer on the top of the working face. When the maximum water inflow A is greater than or equal to 50 m³ / h, it is determined that the aquifer on the top of the working face poses a risk of water inrush to the working face 6 through the faulty borehole 1.

[0050] Step S22: Based on geological information, mining information and exploration information, calculate the maximum water inflow B at the point where the faulty borehole 1 connects with the aquifer 7 at the bottom of the working face. When the maximum water inflow B is greater than or equal to 50 m³ / h, it is determined that the aquifer 7 at the bottom of the working face poses a risk of water inrush to the working face 6 through the faulty borehole 1.

[0051] The formula for calculating the maximum inflow rate Q is as follows:

[0052] ;

[0053] ;

[0054] in, For the Xie Cai coefficient, For the roughness of defective borehole 1, For hydraulic radius, The cross-sectional area of ​​defective borehole 1. The hydraulic gradient is used. By calculating the maximum inflow rate at the connection point between the faulty borehole 1 and the aquifer on the roof of the working face (water accumulation in the upper coal goaf 2) and the aquifer 7 on the floor of the working face (confined aquifer on the floor of the working face), we can, on the one hand, identify the faulty borehole 1 with the risk of water inrush. This avoids the need for workers to seal the portion of faulty borehole 1 with a maximum inflow rate less than 50 m³ / h (i.e., this portion does not pose a risk of water inrush), thus preventing a large amount of unnecessary construction during borehole grouting and increasing the speed of borehole grouting, saving significant manpower and resources. On the other hand, the maximum inflow rate provides data support for subsequent borehole grouting, further improving the reliability of sealing during borehole grouting.

[0055] In this embodiment, The value is half the radius of the defective borehole 1. The value is the ratio of the change in water head to the thickness of the impermeable layer.

[0056] In this embodiment, in order to calculate the maximum water inflow of the faulty borehole 1, it is assumed that no sealing has been carried out in the faulty borehole 1, that is, the faulty borehole 1 is assumed to be a pipe. Based on this, the maximum water inflow of the borehole is calculated by combining the Chezy formula in groundwater dynamics.

[0057] In this embodiment, step S2 further includes:

[0058] Step S23: Analyze the water conductivity between the defective borehole 1 and the aquifer on the top plate of the working face.

[0059] In step S23, for the aquifer in the roof of the working face (the water accumulation in the upper coal goaf 2), according to the "Specifications for the Retention of Coal Pillars for Buildings, Water Bodies, Railways and Main Shafts and Coal Mining", the maximum thickness of the waterproof safety rock pillar (protective rock pillar 4) is calculated (generally 7 times the coal seam mining thickness). The vertical distance between the top of the water-conducting fracture zone 5 of the coal mining face and the bottom of the upper coal goaf 2 is compared. If the vertical distance between the top of the water-conducting fracture zone 5 of the coal mining face and the bottom of the upper coal goaf 2 is less than the maximum thickness of the waterproof safety rock pillar (protective rock pillar 4), then the roof of the working face 6 has a risk of water inrush during the mining process, and the presence of the defective borehole 1 will further aggravate the risk of water inrush. If the vertical distance between the bottom of the water-conducting fracture zone 5 of the coal mining face and the bottom of the upper coal goaf 2 is greater than the maximum thickness of the waterproof safety rock pillar (protective rock pillar 4), then the roof of the working face 6 does not have a risk of water inrush during the mining process. However, considering the impact of the faulty borehole 1, even if the top plate of the working face 6 does not pose a risk of water inrush, it should still be considered as such in order to ensure the personal safety of the workers to the greatest extent possible.

[0060] Step S24: Analyze the water conductivity between the defective borehole 1 and the aquifer 7 at the bottom of the working face.

[0061] In step S24, for the aquifer 7 (confined aquifer) at the bottom of the working face, calculations are performed according to the "Detailed Rules for Water Prevention and Control in Coal Mines". If the water inrush coefficient (i.e., the ratio between the vertical distance between the depth of damage to the working face floor 61 and the top interface of the confined aquifer at the bottom of the working face and the water pressure of the confined aquifer at the bottom of the working face) is greater than 0.06 MPa / m, then the bottom of the working face 6 is at risk of water inrush during mining operations, and the presence of the faulty borehole 1 will further exacerbate the risk of water inrush. If the water inrush coefficient is less than 0.06 MPa / m, then the bottom of the working face 6 is not at risk of water inrush during mining operations. However, considering the impact of the faulty borehole 1, even if the bottom of the working face 6 is not at risk of water inrush, it should still be considered as such to ensure the safety of the workers to the greatest extent possible.

[0062] like Figures 1 to 3 As shown, step S3 includes:

[0063] Step S31: Determine the location of the grouting layer based on the location of the defective borehole 1 that poses a risk of water inrush due to the aquifer on the top plate of the working face and / or the location of the defective borehole 1 that poses a risk of water inrush due to the aquifer 7 on the bottom plate of the working face, the deviation trajectory of the defective borehole 1, geological information and mining information.

[0064] Step S32: Based on the grouting design theory, and according to the location of the grouting layer and the deflection trajectory of the part of the faulty borehole 1 that has the risk of water inrush, design the borehole parameters;

[0065] Step S33: Perform drilling operations;

[0066] Step S34: After the drilling is completed, grout is injected into the borehole from the grouting layer.

[0067] like Figure 2 As shown, in step S31, the method for determining the location of the grouting layer includes:

[0068] Step S311: When sealing the faulty borehole 1 that poses a risk of water inrush due to the aquifer on the top of the working face, the first grouting layer 81 is selected inside the protective rock column 4.

[0069] In this embodiment, since a water-conducting fracture zone 5 is formed in the overlying rock after the working face 6 is mined, the first grouting layer 81 is selected in the protective rock pillar 4 located between the water-conducting fracture zone 5 and the aquifer (upper coal goaf 2) on the top of the working face.

[0070] In this embodiment, considering the injectability of the grouting strata of the protective rock pillar 4, and in conjunction with the comprehensive hydrogeological columnar section of the working face, the first grouting layer 81 is often selected within the aquifer strata of the protective rock pillar 4. Combined with the deviation trajectory of the portion of the poor borehole 1 near the aquifer of the working face roof, the deviation state of the first grouting layer 81 and the projection position of the first grouting layer 81 on the coal seam floor (working face 6 floor) are determined, providing data support for borehole grouting construction.

[0071] Specifically, the first grouting layer 81 is selected in the medium sandstone aquifer 41 within the aquifer strata. In this way, the medium sandstone aquifer 41 is not only easy for workers to grout, but also facilitates the diffusion of the grout, thereby reducing the difficulty of grouting construction and increasing the waterproofing and water-blocking range of the borehole grouting measures.

[0072] In step S32, the method for designing borehole parameters based on the location of the grouting layer and the deflection trajectory of the portion of the faulty borehole 1 with a risk of water inrush includes:

[0073] Step S321: Design drilling parameters for the portion of defective borehole 1 near the aquifer on the top plate of the working face.

[0074] In step S321, considering the grouting target, a first group of boreholes 10 is drilled around the defective borehole 1 in the first grouting layer 81 in the "front, back, left and right" directions to form a "small curtain" to ensure that the defective borehole 1 is within the waterproof and water-blocking range of the grouting borehole measures, thereby cutting off the defective borehole 1 channel between the water-bearing layer (the water accumulation in the upper coal goaf 2) on the top of the working face and the working face 6.

[0075] In this embodiment, the first borehole group 10 includes five first boreholes, which are spaced apart around the defective borehole 1.

[0076] It should be noted that the number of first boreholes is not limited to this and can be adjusted according to working conditions and usage requirements. Optionally, the first borehole can be one, two, three, four, six, seven, eight, or more.

[0077] In this embodiment, the distance between the opening of the first borehole and the bottom plate of the working surface 6 is 1.2m.

[0078] Specifically, based on data such as the vertical distance between the first grouting layer 81 and the drilling hole of the working face, the grout diffusion radius, and the projection position of the first grouting layer 81 on the coal seam floor (the floor of the working face 6), the grouting borehole orientation, the angle between the vacancy and the horizontal plane, and the borehole length should be designed according to the grouting design theory.

[0079] like Figure 3 As shown, in step S31, the method for determining the location of the grouting layer further includes:

[0080] Step S312: When sealing the defective borehole 1 that poses a risk of water inrush due to the aquifer 7 at the bottom of the working face, the second grouting layer 82 is selected below the top interface of the aquifer 7 at the bottom of the working face. A preset distance L exists between the second grouting layer 82 and the top interface of the aquifer 7 at the bottom of the working face, satisfying: 0m ≤ L ≤ 15m. Thus, because the second grouting layer 82 is located below the top interface of the aquifer 7 at the bottom of the working face, the borehole grouting measure increases the thickness of the waterproof layer 9 while sealing the defective borehole 1, further reducing the risk of water inrush at the bottom of the working face 6 and ensuring the safety of the workers. Simultaneously, the above setting allows for more flexible and diverse values ​​for the preset distance L to adapt to different working conditions and sealing requirements, and also improves the processing flexibility of the workers.

[0081] In this embodiment, L is 8m.

[0082] It should be noted that the value of L is not limited to this and can be adjusted according to the working conditions and sealing requirements. Optionally, L can be 1m, 3m, 9m, 12m, or 15m.

[0083] In this embodiment, by combining the deviation trajectory of the defective borehole 1 near the aquifer 7 of the working face floor and the comprehensive hydrogeological columnar section of the working face, the second grouting layer 82 is determined to be within 15m below the top interface of the aquifer 7 (the confined aquifer of the working face floor) (often the final borehole location of the grouting borehole). The deviation state of the second grouting layer 82 and its projection position on the coal seam floor (the floor of the working face 6) are determined to provide data support for borehole grouting construction.

[0084] In step S32, the method for designing borehole parameters based on the location of the grouting layer and the deflection trajectory of the portion of the faulty borehole 1 with a risk of water inrush further includes:

[0085] Step S322: Design drilling parameters for the portion of defective borehole 1 near the aquifer 7 on the bottom plate of the working face.

[0086] In step S322, taking into account the grouting target and the final grouting hole position, a second group of boreholes 11 is drilled around the defective borehole 1 in the second grouting layer 82 in the "front, back, left and right" directions to form a "small curtain" to ensure that the defective borehole 1 can be located within the waterproof and water-blocking range of the grouting borehole, thereby cutting off the channel of the defective borehole 1 between the water-bearing layer 7 of the working face bottom plate and the working face 6.

[0087] In this embodiment, the second borehole group 11 includes five second boreholes, which are spaced apart around the defective borehole 1.

[0088] It should be noted that the number of second boreholes is not limited to this and can be adjusted according to working conditions and usage requirements. Optionally, the number of second boreholes may be one, two, three, four, six, seven, eight, or more.

[0089] Specifically, based on data such as the vertical depth of the grouting modification layer, the grout diffusion radius, and the projection position of the second grouting layer 82 on the coal seam floor (the floor of working face 6), parameters such as the grouting borehole orientation, the angle between the vacancy and the horizontal plane, and the borehole length are designed according to the grouting design theory.

[0090] In this embodiment, step S4 includes:

[0091] Step S41: After drilling is completed, with the final borehole center axis as the center, drill a first core sample at any position within a radius r, and analyze the contained material, integrity rock quality indicators, and lithological mechanical parameters of the first core sample. If the analysis shows that the first core sample contains sealing material from the defective borehole 1, it is determined that the borehole has exposed the defective borehole 1. If the analysis shows that the first core sample does not contain sealing material, it is determined that the borehole has not exposed the defective borehole 1.

[0092] In this embodiment, step S4 further includes:

[0093] Step S42: After grouting is completed, take the final borehole center axis as the center and drill a second core at any position within the diameter r range. Analyze the contents, integrity, rock quality indicators, and lithological mechanical parameters of the second core.

[0094] Optionally, 5m≤r≤10m.

[0095] In this embodiment, in step S42:

[0096] If the borehole has already exposed a faulty borehole 1 and the second core sample contains concretions; and / or

[0097] The integrity quality index of the second core is greater than that of the first core; and / or;

[0098] The lithological and mechanical parameters of the second core are greater than those of the first core.

[0099] This indicates that the grouting method used to seal poorly drilled holes has a good sealing effect.

[0100] Specifically, taking Mine 061405 as an example, there is a geological borehole No. 506 within its working face area. The construction of borehole No. 506 occurred in the 1950s, and the borehole was simply sealed with yellow mud, which was insufficient to meet the requirements for water isolation. During exploration, it was discovered that borehole No. 506 connected to the accumulated water (aquifer in the roof of the working face) in the upper coal goaf 2, where the water accumulation area is 1.38 km². 2 The accumulated water volume reached 380,000 cubic meters. 3 Geological borehole No. 506 also connected to the confined aquifer at the bottom of the working face (aquifer 7 at the bottom of the working face), where the water pressure reached 0.64 MPa.

[0101] Grouting was carried out on geological borehole No. 506 according to the grouting method for this poor borehole. First, geological borehole No. 506 has potential water inrush channels between it and the aquifer on the top and bottom of the working face, and the maximum water inrush at the connection between geological borehole No. 506 and the aquifer on the top of the working face reaches 150m³. 3 / h, the maximum inflow at the point where it connects with the aquifer 7 at the bottom of the working face reaches 136m³ / h. 3 Based on this, grouting was required for the portions of geological borehole No. 506 near the aquifer on the top of the working face and aquifer 7 on the bottom of the working face. After completion, the grouting sealing effect was evaluated as good. This method not only has good practicality but also has clear basis, is simple and easy to implement, and can effectively prevent mine water hazards caused by poorly sealed boreholes, providing a theoretical reference for safe coal mining.

[0102] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0103] Grouting methods for sealing faulty boreholes are used to plug them. When sealing faulty boreholes is necessary, the following steps are taken: First, obtain geological and mining information of the working face, exploration information and inclination data of the faulty borehole, the spatial relationships between the faulty borehole, the working face, the aquifer on the top of the working face, and the aquifer on the bottom of the working face, and obtain the deviation trajectory of the faulty borehole. Then, based on the geological, mining, and exploration information and spatial relationships, calculate the water inflow of the faulty borehole to determine its risk of water inrush. Next, based on the geological, mining, deviation trajectory, and water inflow of the faulty borehole, grouting is performed on the faulty borehole with the risk of water inrush, ensuring that the faulty borehole is within the grout diffusion radius of the borehole drilled during the grouting process. Finally, the sealing effect of the grouting method is evaluated based on lithological parameters and / or core parameters. In this process, at least a portion of the grout in the borehole seeps into the defective borehole to seal it; the exploration information includes the initial borehole location coordinates K of the defective borehole, and the inclination data includes at least one of the deviation angle and azimuth angle of the defective borehole.

[0104] Compared to existing methods that directly grout defective boreholes, the grouting method for defective boreholes in this application analyzes the deviation trajectory of the defective borehole before grouting and incorporates this trajectory during drilling. This ensures the defective borehole remains within the grout diffusion radius of the grout, guaranteeing its waterproofing and water-blocking capabilities. This significantly improves the reliability of grouting in sealing defective boreholes, addressing the poor sealing reliability of existing methods and enhancing worker safety during mining operations. Furthermore, the water inflow of the defective borehole is analyzed before grouting to provide data support for subsequent operations, further improving the sealing reliability. Clearly, the embodiments described above are merely some examples of this invention, not all examples. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0105] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0106] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A grouting method for sealing defective boreholes (1), characterized in that, The grouting method for the poorly drilled borehole includes: Step S1: Obtain geological information and mining information of the working face (6), obtain exploration information and inclination data of the defective borehole (1), obtain the spatial positional relationship between the defective borehole (1), the working face (6), the aquifer on the top plate of the working face and the aquifer on the bottom plate of the working face (7), and obtain the deviation trajectory of the defective borehole (1). Step S2: Based on the geological information, the mining information, the exploration information and the spatial location relationship, calculate the water inflow of the unfavorable borehole (1) to determine the magnitude of the water inrush risk of the unfavorable borehole (1); Step S3: Based on the geological information, the mining information, the deviation trajectory of the defective borehole (1) and the water inflow of the defective borehole (1), borehole grouting construction is carried out on the defective borehole (1) with water inrush risk, so that at least part of the defective borehole (1) is located within the grout diffusion radius of the borehole drilled during the borehole grouting construction. Step S4: Evaluate the sealing effect of the grouting method for the defective borehole based on lithological parameters and / or core parameters; Wherein, at least part of the slurry in the borehole seeps into the defective borehole (1) to seal the defective borehole (1); the exploration information includes the initial borehole location coordinate point K of the defective borehole (1), and the inclination data includes at least one of the deviation angle and azimuth angle of the defective borehole (1); Step S2 includes: Step S21: Based on the geological information, the mining information and the exploration information, calculate the maximum water inflow A at the point where the defective borehole (1) connects with the aquifer on the top of the working face. When the maximum water inflow A is greater than or equal to 50 m³ / h, determine that the aquifer on the top of the working face poses a risk of water inrush to the working face (6) through the defective borehole (1). Step S22: Based on the geological information, the mining information and the exploration information, calculate the maximum water inflow B at the point where the defective borehole (1) connects with the aquifer (7) at the bottom of the working face. When the maximum water inflow B is greater than or equal to 50 m³ / h, determine that the aquifer (7) at the bottom of the working face poses a risk of water inrush to the working face (6) through the defective borehole (1). The formula for calculating the maximum inflow rate Q is as follows: ； ； in, For the Xie Cai coefficient, For the roughness of the poorly drilled hole (1), For hydraulic radius, The cross-sectional area of ​​the defective borehole (1) is... This refers to the hydraulic gradient.

2. The grouting method for poorly drilled holes according to claim 1, characterized in that, Step S1 includes: Step S11: Based on trigonometric function theory and / or geographic coordinate offset theory, calculate the position coordinates Kn of the defective borehole (1) at n different depths, n=0,1,2,…N, according to the initial borehole position coordinates K and at least one of the skew angle and the azimuth angle. The trajectory formed by connecting the n coordinates Kn sequentially along the depth direction H of the defective borehole (1) is the skew trajectory of the defective borehole (1).

3. The grouting method for poorly drilled holes according to claim 1, characterized in that, The method for obtaining the spatial relationship between the defective borehole (1), the working face (6), the aquifer on the top of the working face, and the aquifer on the bottom of the working face (7) based on the geological information, the mining information, and the exploration information includes: Step S12: Based on the geological information, the mining information and the exploration information, determine the location and mining depth of the upper coal goaf (2), the depth of the upper coal mining floor damage (3), the location and height of the protective rock pillar (4), the location and development height of the water-conducting fracture zone (5) of the coal mining face, the location and mining depth of the working face (6), the depth of the working face floor damage (61), the location and height of the aquifer (7) of the working face floor, the location and height of the water-retaining layer (9), and the location and columnar section of the defective borehole (1); Step S13: On the columnar diagram of the defective borehole (1), mark the upper coal goaf (2), the depth of damage to the upper coal mining floor (3), the protective rock pillar (4), the water-conducting fracture zone of the coal mining face (5), the working face (6), the depth of damage to the working face floor (61), the aquifer (7) of the working face floor, and the water-resistant layer (9) to determine the spatial relationship between the defective borehole (1), the working face (6), the aquifer on the working face roof, and the aquifer (7) of the working face floor; The aquifer on the roof of the working face is the water accumulated in the upper coal goaf (2).

4. The grouting method for poorly drilled holes according to claim 3, characterized in that, Step S3 includes: Step S31: Determine the location of the grouting layer based on the location of the defective borehole (1) that causes water inrush danger due to the aquifer on the top plate of the working face and / or the location of the defective borehole (1) that causes water inrush danger due to the aquifer (7) on the bottom plate of the working face, the deviation trajectory of the defective borehole (1), the geological information and the mining information; Step S32: Based on the grouting design theory, design the drilling parameters according to the location of the grouting layer and the deflection trajectory of the part of the defective borehole (1) with the risk of water inrush; Step S33: Perform drilling operations; Step S34: After the drilling is completed, grout is injected into the borehole from the grouting layer.

5. The grouting method for poorly drilled holes according to claim 4, characterized in that, In step S31, the method for determining the location of the grouting layer includes: Step S311: When sealing the defective borehole (1) that poses a risk of water inrush due to the aquifer on the top of the working face, the first grouting layer (81) is selected within the protective rock column (4).

6. The grouting method for poorly drilled holes according to claim 4, characterized in that, In step S31, the method for determining the location of the grouting layer further includes: Step S312: When sealing the defective borehole (1) that poses a risk of water inrush due to the water-bearing layer (7) of the working face bottom plate, the second grouting layer (82) is selected below the top interface of the water-bearing layer (7) of the working face bottom plate. The second grouting layer (82) and the top interface of the water-bearing layer (7) of the working face bottom plate have a preset distance L, and the preset distance L satisfies: 0m≤L≤15m.

7. The grouting method for poorly drilled holes according to claim 1, characterized in that, Step S4 includes: Step S41: After the drilling is completed, take the center axis of the final borehole as the center and drill the first core at any position within the radius r. Analyze the contents, integrity, rock quality indicators, and lithological mechanical parameters of the first core. If the analysis shows that the first core contains the sealing material from the defective borehole (1), it is determined that the borehole has exposed the defective borehole (1). If the analysis shows that the first core does not contain the sealing material, it is determined that the borehole has not exposed the defective borehole (1).

8. The grouting method for poorly drilled holes according to claim 7, characterized in that, Step S4 further includes: Step S42: After grouting is completed, a second rock core is drilled at any position within the diameter r range, with the final borehole center axis as the center. The contents, integrity rock quality indicators and lithological mechanical parameters of the second rock core are analyzed.

9. The grouting method for poorly drilled holes according to claim 8, characterized in that, In step S42: If the borehole has exposed the defective borehole (1) and the second core contains a concretion; and / or, The integrity quality index of the second core is greater than that of the first core; and / or; The lithological and mechanical parameters of the second core are greater than those of the first core. Therefore, it is determined that the grouting method for the defective borehole has a good sealing effect.

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