Grouting drill hole layout method for advanced area treatment of aquifer of coal seam roof and floor

Abstract

The invention discloses a coal seam roof and floor aquifer advanced area treatment grouting drill hole layout method. The method comprises the steps that an advanced area grouting transformation layer position in a coal seam roof and / or a coal seam floor is determined; the first diffusion radius of the grouting slurry in the water-bearing stratum is obtained through theoretical calculation, the second diffusion radius of the grouting slurry in the water-bearing stratum is obtained through numerical simulation calculation, and the smaller one of the first diffusion radius and the second diffusion radius is the diffusion radius of the grouting slurry; determining hole distribution shapes of the grouting drill holes, wherein the hole distribution shapes of the grouting drill holes comprise a fan shape, a feather shape and a comb shape; determining grouting drilling track design parameters; and directional advanced drilling construction is conducted according to the grouting drilling track design parameters, drilling parameters are obtained in real time through the measurement-while-drilling device in the construction process, and the drilling track is adjusted in real time according to the grouting drilling track design parameters till grouting drilling hole distribution operation is completed. By the adoption of the method, selection of the grouting transformation layer position is more accurate and reasonable; the problems that grouting drill holes in an advanced area are not scientific and inaccurate in layout and low in design efficiency are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine roof and floor water hazard prevention and control, and specifically relates to a method for laying out grouting drilling holes for advanced area treatment of aquifers in coal seam roof and floor. Background Art

[0002] The Carboniferous-Permian coalfields in the central and eastern parts of China and the Jurassic coalfields in the western parts of my country are the main coal producing areas in China. However, the exploitation of Carboniferous-Permian coal resources has long been threatened by water inrush from the underlying Ordovician limestone aquifers, and the development of Jurassic coalfields has long been threatened by water damage from the roof sandstone aquifers. The safe and efficient development of coal resources is severely restricted, especially in the process of extending mining to deep areas. Under the influence of the complex geomechanical environment of high ground stress, high water pressure and strong disturbance, the threat of water damage from the bottom limestone and roof sandstone is more severe. In response to the water damage threat from the bottom limestone and roof sandstone of the above-mentioned coal seams, the ground horizontal hole directional drilling technology has begun to be applied in the aquifer grouting transformation project. By constructing horizontal directional branch holes along the ground layer and grouting in advance to transform the target aquifer in the subsequent mining area, the thickness of the aquiclude is increased and the risk of water inrush is reduced. Although the use of ground horizontal hole directional drilling technology to advance regional grouting and transform aquifers has liberated a large number of coal resources threatened by water disasters, the existing advance grouting drilling trajectory design has the following main defects: it relies on manual design, the determination of the advance regional grouting and transformation layer, and the design of the grouting and transformation drilling spacing mainly rely on engineering practice experience, which is difficult to scientifically quantify, resulting in low efficiency and unsatisfactory results of the advance regional grouting and transformation of coal seam roof and floor aquifers, and even possible transformation failure.

[0003] Therefore, designing a reasonable method for grouting drilling layout for advanced regional management of coal seam roof and floor aquifers is an urgent problem to be solved in the current intelligent prevention and control of coal mine water hazards. Summary of the invention

[0004] In view of the defects and shortcomings in the prior art, the present invention provides a method for arranging grouting drilling holes for the advance zone treatment of the roof and floor aquifers of coal seams, so as to solve the technical problems in the prior art of low efficiency and unsatisfactory effect of grouting transformation for the advance zone treatment of the roof and floor aquifers of coal seams.

[0005] To achieve the above object, the present invention adopts the following technical scheme:

[0006] A method for laying out grouting holes for advanced area treatment of aquifers at the roof and floor of a coal seam, the method comprising the following steps:

[0007] Step 1: collect drilling data and formation geophysical data to determine the advanced area grouting transformation layer in the coal seam roof and / or coal seam floor;

[0008] Step 2: According to the drilling data and formation geophysical data collected in step 1, the mechanical properties of the grouting transformation layer in the advance area are determined, the first diffusion radius of the grouting slurry in the aquifer is obtained by theoretical calculation, and the second diffusion radius of the grouting slurry in the aquifer is obtained by numerical simulation, and the smaller value of the first diffusion radius and the second diffusion radius is used as the diffusion radius of the grouting slurry;

[0009] Step 3, determining the hole arrangement shape of the grouting boreholes according to the determined mechanical properties of the grouting transformation layer in the advanced area, wherein the hole arrangement shape of the grouting boreholes includes fan-shaped, feather-shaped and comb-shaped;

[0010] Step 4, determining the grouting drilling trajectory design parameters according to the advanced area grouting transformation layer determined in step 1, the drilling grouting slurry diffusion radius determined in step 2, and the grouting drilling hole layout shape determined in step 3;

[0011] Step 5: Perform directional advance drilling construction according to the determined grouting drilling trajectory design parameters. During the construction process, use the drilling measurement device to obtain the drilling parameters in real time, and adjust the drilling trajectory in real time according to the grouting drilling trajectory design parameters until the grouting drilling layout operation is completed.

[0012] The present invention also has the following technical features:

[0013] Specifically, the step 1 specifically includes:

[0014] When the advanced zone grouting reconstruction layer is located in the coal seam floor, based on the "lower three zones" theory, the depth values ​​of the three coal seam floor mining water-conducting damage zones are obtained through theoretical calculation, physical similarity simulation test and numerical simulation calculation. The maximum value of the three coal seam floor mining water-conducting damage zone depth values ​​is taken as the standard value, and the aquifer with the smallest difference between the depth value and the standard value is taken as the floor grouting reconstruction layer;

[0015] When the advanced zone grouting transformation layer is located in the coal seam roof, based on the "upper three zones" theory, the theoretical calculation of the coal seam roof water-conducting fracture zone, physical similarity simulation test and numerical simulation calculation are used to obtain the three coal seam roof water-conducting fracture zone development height values. The maximum value of the three coal seam roof water-conducting fracture zone development height values ​​is taken as the standard value, and the aquifer with the smallest difference between the height value and the standard value is taken as the roof grouting transformation layer.

[0016] Furthermore, the first diffusion radius of the grouting slurry in the aquifer is determined by the following formula:

[0017]

[0018] Where: r1 is the first diffusion radius, in m; K is the permeability coefficient of the aquifer, in m / s; z is the grouting pressure head, in m; t is the grouting time, in s; is the porosity of the rock mass in the grouting layer; λ is the ratio of the viscosity of the grouting slurry to the viscosity of water; r0 is the radius of the grouting borehole, in m.

[0019] Furthermore, in step 3, determining the hole arrangement shape of the grouting drilling according to the determined grouting transformation layer characteristics specifically includes:

[0020] When the drilling rate of grouting reformed formation is greater than or equal to 85%, the hole arrangement shape of grouting drilling is comb-shaped;

[0021] When the drilling hole formation rate of the grouting reformation formation is greater than or equal to 60% and less than 85%, the hole arrangement shape of the grouting drilling hole is feather-shaped;

[0022] When the drilling hole formation rate of the grouting transformation formation is less than 60%, the hole distribution shape of the grouting drilling holes is fan-shaped.

[0023] Furthermore, the drilling trajectory design parameters described in step 4 include the opening position, the final hole position, the branch hole opening position, the drilling spacing, the drilling depth, the drilling inclination, the drilling azimuth, the drilling inclination point position, the drilling stable inclination point position and the drilling bending strength.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] (1) When designing grouting drilling, the method of the present invention firstly combines theoretical calculation, physical similarity simulation calculation and numerical simulation calculation to obtain the depth of the water-conducting damage zone of the coal seam floor and the height of the water-conducting fracture zone of the coal seam roof, respectively. Then, the grouting transformation layer in the coal seam roof and / or coal seam floor is determined according to the obtained calculation results. Since the calculated value is closer to the true value, the selection of the grouting transformation layer is more accurate and reasonable. The grouting drilling trajectory design parameters are determined in combination with the determined grouting transformation layer, the grouting slurry diffusion radius and the grouting drilling hole layout shape, thereby solving the problems of unscientific and inaccurate grouting drilling layout in the advanced area and low design efficiency.

[0026] (2) The method of the present invention has the advantages of high drilling design efficiency, small error, and fast drilling design adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of the method of the present invention;

[0028] Figure 2 The physical similarity model of coal seam mining in Example 1;

[0029] Figure 3 The physical similarity simulation result of coal seam mining in Example 1;

[0030] Figure 4 The three-dimensional numerical calculation model of coal seam mining in Example 1;

[0031] Figure 5 The results of three-dimensional numerical simulation of coal seam mining;

[0032] Figure 6 It is a schematic diagram of the calculation result of the second diffusion radius of the grouting slurry in Example 1;

[0033] Figure 7 Schematic diagram of the hole shape of grouting drilling, where (a) is fan-shaped, (b) is feather-shaped, and (c) is comb-shaped;

[0034] The present invention is described in detail below with reference to the accompanying drawings and specific implementation methods. DETAILED DESCRIPTION

[0035] In accordance with the above technical solution, the following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention. The present invention is further described in detail below in conjunction with the embodiments.

[0036] Example 1

[0037] Following the above technical solution, Figure 1 As shown, this embodiment discloses a method for laying out grouting holes for advanced area treatment of aquifers at the roof and floor of a coal seam, the method comprising the following steps:

[0038] Step 1: collect drilling data and formation geophysical data to determine the advanced area grouting transformation layer in the coal seam roof and / or coal seam floor;

[0039] The drilling data includes a columnar diagram of the formation, which can show the lithology, rock color, structure, mineral composition, etc. from the surface to different depths underground. The mechanical properties that can be obtained from the drilling data include: formation porosity, formation permeability, inclined length of the working face, mining depth, average bulk density of the bottom rock layer, compressive strength of the bottom rock mass, internal friction angle of the bottom rock mass, etc.

[0040] The stratigraphic geophysical data is obtained by arranging seismic sources and receivers on the surface. It is necessary to record the propagation and reflection of seismic waves underground, and then infer the structure and properties of underground rock formations. The data obtained mainly include seismic wave field data, velocity information data, geological structure information data and bottom interface data. These data can determine the location, trend, dip and fault distance of underground faults, and can also reflect the bending and deformation of underground strata; through analysis, the interfaces between different strata, the thickness of each stratum, lithology and the interface between the top and bottom plates can be obtained.

[0041] Based on the obtained data, the advanced area grouting transformation layer in the coal seam roof and / or coal seam floor can be determined, including:

[0042] When the advanced zone grouting reconstruction layer is located in the coal seam floor, based on the "lower three zones" theory, the depth values ​​of the three coal seam floor mining water-conducting damage zones are obtained through theoretical calculation, physical similarity simulation test and numerical simulation calculation. The maximum value of the three coal seam floor mining water-conducting damage zone depth values ​​is taken as the standard value, and the aquifer with the smallest difference between the depth value and the standard value is taken as the floor grouting reconstruction layer;

[0043] The calculation of the depth of the water-conducting damage zone caused by mining in the coal seam floor specifically includes:

[0044] According to the theoretical formula of plastic mechanics, a theoretical value of the depth of the water-conducting damage zone of the coal seam floor is obtained:

[0045]

[0046] Where: H is the mining depth, in m; is the internal friction angle of the bottom rock mass, in degrees.

[0047] When the advanced zone grouting transformation layer is located in the coal seam roof, based on the "upper three zones" theory, the theoretical calculation of the coal seam roof water-conducting fracture zone, physical similarity simulation test and numerical simulation calculation are used to obtain the three coal seam roof water-conducting fracture zone development height values. The maximum value of the three coal seam roof water-conducting fracture zone development height values ​​is taken as the standard value, and the aquifer with the smallest difference between the height value and the standard value is taken as the roof grouting transformation layer.

[0048] For the height of the water-conducting fracture zone in the coal seam roof, the calculation formula in the "Coal Mine Water Prevention and Control Manual" (Table 1) is used to obtain the theoretical calculated value of the height of the water-conducting fracture zone in the coal seam roof.

[0049] Table 1

[0050]

[0051] In Table 1, H1 is the theoretical value of the development height of the water-conducting fracture zone in the coal seam roof (m); M is the mining thickness (m).

[0052] Using the formula in the above table, we can calculate the theoretical value of the development height of the water-conducting fracture zone in the coal seam roof.

[0053] Physical similarity experiments can intuitively show the development characteristics of the floor damage zone and the roof water-conducting fracture zone during coal mining, such as Figure 2As shown, the existing physical similarity model of coal seam mining is used to simulate the depth of the bottom plate damage zone and the height of the water-conducting fracture zone during coal seam mining. Specifically, according to the basic similarity theory, similar materials such as river sand, fly ash, gypsum, and calcium carbonate are selected: mixed according to the preset ratio, added with water and stirred, and loaded into the model frame after being evenly mixed to build a physical similarity model with geometric similarity, stress similarity, and bulk density similarity. The model size is: length × width × height = 3000mm × 1000mm × 200mm. After the physical similarity model is built, the development process of the bottom plate mining-induced water-conducting damage zone and the roof plate water-conducting fracture zone during coal seam mining is simulated. By measuring the height of the fractures generated on the surface of the physical model, the depth value of the bottom plate mining-induced water-conducting damage zone and the height value of the roof plate water-conducting fracture zone after coal seam mining are obtained. Through the similarity ratio conversion, the depth value of the coal seam bottom plate mining-induced water-conducting damage zone and the height value of the coal seam roof water-conducting fracture zone development are obtained. The simulation results are shown as follows Figure 3 shown.

[0054] Numerical simulation is another effective means to obtain the development characteristics of the floor damage zone and the roof water-conducting fracture zone during coal mining. Figure 4 As shown in the figure, the existing numerical simulation software is used to establish a three-dimensional numerical calculation model according to the actual working conditions and actual engineering geological conditions. The depth of the floor damage zone and the height of the water-conducting fracture zone in the coal seam mining process are numerically simulated and calculated to obtain the depth of the floor damage zone and the height of the water-conducting fracture zone in the roof during coal seam mining. The numerical simulation results are shown in Figure 5 shown.

[0055] Through the above-mentioned theoretical calculations, physical similarity experiments and numerical simulation calculations, the depth values ​​of the three coal seam floor mining-induced water-conducting damage zones and the development height values ​​of the three coal seam roof water-conducting fracture zones were obtained. The maximum value of the three coal seam floor mining-induced water-conducting damage zone depth values ​​was taken as the standard value, and the aquifer with the smallest difference between the depth value and the standard value was taken as the floor grouting transformation layer; the maximum value was taken as the standard value in order to select the grouting transformation layer above the water-conducting fracture zone as much as possible, to avoid the development of the water-conducting fracture zone to the grouting transformation layer after the coal seam is mined, causing cracks in the grouting transformation layer, thereby affecting the grouting transformation effect.

[0056] Step 2: according to the determined mechanical properties of the grouting transformation layer, the first diffusion radius of the grouting slurry in the aquifer is obtained by theoretical calculation, and the second diffusion radius of the grouting slurry in the aquifer is obtained by numerical simulation, and the smaller value of the first diffusion radius and the second diffusion radius is used as the diffusion radius of the grouting slurry;

[0057] Specifically, in theoretical calculations, the slurry enters the underground aquifer through the grouting hole. The aquifer can be regarded as a porous medium. Therefore, the grouting slurry enters the underground aquifer by infiltration. The infiltration grouting theory can be used to determine the first diffusion radius through the following formula:

[0058]

[0059] Where: r1 is the first diffusion radius, in m; K is the permeability coefficient of the aquifer, in m / s; z is the grouting pressure head, in m; t is the grouting time, in s; is the porosity of the rock mass in the grouting layer; λ is the ratio of the viscosity of the grouting slurry to the viscosity of water; r0 is the radius of the grouting borehole, in meters. -5 m / s; z = 250m; λ=97.2;r0=0.076m,the grouting time t is 1h, 60h and 120h respectively.

[0060] In this embodiment, through calculation, when the grouting time is 1h, 60h and 120h, the first diffusion radius is 1.11m, 6.64m and 9.08m respectively.

[0061] With the help of the fluid mechanics module in COMSOL Multiphysics finite element software, numerical simulation was performed to determine the second diffusion radius.

[0062] Specifically, it includes: according to the actual grouting operation conditions, setting numerical simulation calculation parameters and conditions, simulating the diffusion process of slurry in aquifers. Grouting in aquifers is essentially the process of slurry displacing groundwater. The flow of slurry and groundwater in aquifers belongs to two-phase flow. The volume fraction is used in the numerical simulation calculation results to characterize the diffusion radius of slurry in aquifers. The slurry diffusion form is circular diffusion centered on the grouting hole. Figure 6 The red part in the graph represents the slurry concentration, and its volume fraction is close to 100%. The blue part represents groundwater, and its slurry volume fraction is close to 0, that is, the volume fraction of groundwater is close to 100%.

[0063] Monitoring points are set in the numerical software to monitor the mixing zone between the slurry and groundwater in different time periods. At this time, the length of the mixed zone from the grouting hole obtained by monitoring is the diffusion radius of the slurry.

[0064] like Figure 6 As shown, when t=60h, the monitoring obtained that the length of the slurry-water mixing zone from the grouting hole was 6.78m, that is, the slurry diffusion radius r was 6.78m.

[0065] Therefore, the second diffusion radius calculated by numerical simulation after grouting for 1 h, 60 h and 120 h is 1.16 m, 6.78 m and 9.23 m, respectively.

[0066] The smaller value of the first diffusion radius and the second diffusion radius is used as the diffusion radius of the grouting slurry.

[0067] In summary, the final diffusion radius of the grouting slurry determined is 1.11m for 1h, 6.64m for 60h, and 9.08m for 120h.

[0068] Step 3: According to the determined grouting transformation layer characteristics, determine the hole layout shape of the grouting boreholes, the hole layout shape of the grouting boreholes includes fan-shaped, feather-shaped and comb-shaped; the hole layout shape of the grouting boreholes is as follows: Figure 7 shown.

[0069] The characteristics of fan-shaped drilling are low construction difficulty, high drilling efficiency, and flexible drilling and injection coordinated construction, but there are disadvantages of concentrated and repeated engineering work;

[0070] The characteristics of feather drilling are uniform hole distribution, fewer blind areas for grouting, and less repeated engineering, but the construction difficulty is moderate, the drilling efficiency is moderate, and the coordinated construction of drilling and grouting is not flexible enough;

[0071] The characteristics of comb-shaped drilling are uniform hole arrangement, basically no blind area for grouting, and no repeated engineering work, but the construction is difficult and the coordinated construction of drilling and grouting is difficult. According to the characteristics of the grouting transformation stratum and the specific conditions of the on-site drilling construction, the appropriate drilling hole arrangement shape is selected for construction, including:

[0072] When the drilling rate of grouting reformed formation is greater than or equal to 85%, the hole arrangement shape of grouting drilling is comb-shaped;

[0073] When the drilling hole formation rate of the grouting reformation formation is greater than or equal to 60% and less than 85%, the hole arrangement shape of the grouting drilling hole is feather-shaped;

[0074] When the drilling hole formation rate of the grouting reformation formation is less than 60%, the hole arrangement shape of the grouting drilling hole is fan-shaped to ensure the drilling efficiency under the formation condition with low porosity.

[0075] Step 4, determining the grouting drilling trajectory design parameters according to the drilling grouting slurry diffusion radius determined in step 2 and the grouting drilling hole shape determined in step 3;

[0076] The drilling trajectory design parameters include the opening position, the final hole position, the branch hole opening position, the drilling spacing, the drilling depth, the drilling inclination angle, the drilling azimuth angle, the drilling inclination point position, the drilling stable inclination point position and the drilling bending strength.

[0077] Step 5: Carry out directional advance drilling construction according to the determined grouting drilling trajectory design parameters. During the construction process, use the downhole measurement device to obtain the drilling parameters in real time, and adjust the drilling trajectory in real time according to the grouting drilling trajectory design parameters. That is, adjust the trajectory of the drilling process in time according to the design parameters, correct the actual construction drilling trajectory, and make the drilling as close to the design trajectory as possible until the grouting drilling operation is completed.

[0078] The method of the present invention combines theoretical calculation, physical similarity simulation calculation and numerical simulation calculation when designing grouting drilling, respectively obtaining the depth of the water-conducting damage zone of the coal seam floor and the height of the water-conducting fracture zone of the coal seam roof, and then determines the grouting transformation layer according to the obtained calculation results. Since the calculated value is closer to the real value, the selection of the grouting transformation layer is more accurate and reasonable.

[0079] In the above description, unless otherwise clearly specified and limited, the terms "set", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integrated connection; it can be a direct connection or an indirect connection, etc. For ordinary technicians in this field, the specific meanings of the above terms in this technical solution can be understood according to specific circumstances.

[0080] The various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for laying out grouting holes for the advanced area treatment of aquifers at the roof and floor of a coal seam, characterized in that: The method comprises the following steps: Step 1: collect drilling data and formation geophysical data to determine the advanced area grouting transformation layer in the coal seam roof and / or coal seam floor; Step 2: According to the drilling data and formation geophysical data collected in step 1, the mechanical properties of the grouting transformation layer in the advance area are determined, the first diffusion radius of the grouting slurry in the aquifer is obtained by theoretical calculation, and the second diffusion radius of the grouting slurry in the aquifer is obtained by numerical simulation, and the smaller value of the first diffusion radius and the second diffusion radius is used as the diffusion radius of the grouting slurry; Step 3, determining the hole arrangement shape of the grouting boreholes according to the determined mechanical properties of the grouting transformation layer in the advanced area, wherein the hole arrangement shape of the grouting boreholes includes fan-shaped, feather-shaped and comb-shaped; Step 4, determining the grouting drilling trajectory design parameters according to the advanced area grouting transformation layer determined in step 1, the drilling grouting slurry diffusion radius determined in step 2, and the grouting drilling hole layout shape determined in step 3; Step 5: Perform directional advance drilling construction according to the determined grouting drilling trajectory design parameters. During the construction process, use the drilling measurement device to obtain the drilling parameters in real time, and adjust the drilling trajectory in real time according to the grouting drilling trajectory design parameters until the grouting drilling layout operation is completed.

2. The method for laying out grouting holes for advanced area treatment of aquifers at the roof and floor of a coal seam as claimed in claim 1, characterized in that: The step 1 specifically includes: when the advanced area grouting and transformation layer is located in the coal seam floor, based on the "lower three zones" theory, three depth values ​​of the coal seam floor mining water-conducting damage zone are obtained through theoretical calculation, physical similarity simulation test and numerical simulation calculation, the maximum value of the three coal seam floor mining water-conducting damage zone depth values ​​is used as the standard value, and the aquifer with the smallest difference between the depth value and the standard value is used as the floor grouting and transformation layer; When the advanced zone grouting reconstruction layer is located in the coal seam roof, based on the "upper three zones" theory, the theoretical calculation of the coal seam roof water-conducting fracture zone, physical similarity simulation test and numerical simulation calculation are used to obtain the three coal seam roof water-conducting fracture zone development height values. The maximum value of the three coal seam roof water-conducting fracture zone development height values ​​is taken as the standard value, and the aquifer with the smallest difference between the height value and the standard value is taken as the roof grouting reconstruction layer.

3. The method for laying out grouting holes for advanced area treatment of aquifers at the roof and floor of a coal seam as claimed in claim 1, characterized in that: The first diffusion radius described in step 2 is determined by the following formula: Where: r1 is the first diffusion radius, in m; K is the permeability coefficient of the aquifer, in m / s; z is the grouting pressure head, in m; t is the grouting time, in seconds; is the porosity of the rock mass in the grouting layer; λ is the ratio of the viscosity of the grouting slurry to the viscosity of water; r0 is the radius of the grouting borehole, in m.

4. The method for laying out grouting holes for advanced area treatment of aquifers at the roof and floor of a coal seam as claimed in claim 1, characterized in that: The step 3 of determining the hole arrangement shape of the grouting boreholes according to the mechanical properties of the grouting transformation layer in the advanced area specifically includes: When the drilling rate of grouting reformed formation is greater than or equal to 85%, the hole arrangement shape of grouting drilling is comb-shaped; When the drilling hole formation rate of the grouting reformation formation is greater than or equal to 60% and less than 85%, the hole arrangement shape of the grouting drilling hole is feather-shaped; When the drilling hole formation rate of the grouting transformation formation is less than 60%, the hole distribution shape of the grouting drilling holes is fan-shaped.

5. The method for laying out grouting holes for advanced area treatment of aquifers at the roof and floor of a coal seam as claimed in claim 1, characterized in that: The drilling trajectory design parameters described in step 4 include the opening position, the final hole position, the branch hole opening position, the drilling spacing, the drilling depth, the drilling inclination angle, the drilling azimuth angle, the drilling inclination point position, the drilling stable inclination point position and the drilling bending strength.

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