A method for advanced regional treatment of water disaster in coal seam floor

Abstract

The present invention relates to a method for advanced regional treatment of water disasters in coal seam floor. This method focuses on the problem of grouting blind zones between holes that may be caused by too large a spacing of traditional parallel branch holes, fully combines the hydrogeological characteristics of the grouted layer and the grouting technology, and according to the law of gradual linear decrease of the effective grouting pressure in the horizontal section, to eliminate the grouting blind zones to the greatest extent.

Description

Technical Field

[0001] The present invention relates to a method for advanced regional treatment of water disasters in the coal seam floor, belonging to the technical field of prevention and control of water disasters in the coal seam floor in coal mining areas. Background Art

[0002] Grouting reinforcement of the coal seam floor is the main technical means for preventing and controlling water disasters caused by karst confined water in the coal seam floor. It mainly grouts and reforms the water-conducting and water-containing rock layers in the coal seam floor into water-resisting layers, so as to increase the thickness of the water-resisting layer in the coal seam floor and improve the comprehensive water-blocking ability of the rock layers in the coal seam floor, in order to prevent the outburst of karst water from the floor. In recent years, with the rapid development and maturity of the large-capacity directional deviation drilling technology and equipment, the grouting reform and reinforcement of the coal seam floor have changed from local treatment underground to combined regional treatment above and below the well, and the advanced regional grouting treatment technology has been widely applied to the prevention and control of karst water disasters in the floors of North China-type coalfields. The "Detailed Rules for Coal Mine Water Prevention and Control" promulgated in 2018 put forward the promotion suggestion that "when the recharge water source of the confined aquifer is abundant and the conditions for dewatering by pressure reduction and curtain grouting are not available, ground regional treatment, or the method of locally grouting and reinforcing the water-resisting layer of the floor and reforming the aquifer can be adopted".

[0003] The grouting pressure is the driving force to overcome the flow resistance of the slurry, the hydrostatic pressure, and the frictional resistance of the borehole wall, so as to drive the slurry to spread in the fissure. However, due to the cumulative increase of the frictional resistance along the horizontal hole and the frictional resistance of the borehole wall, the grouting pressure along the horizontal hole shows a decreasing trend, so the slurry diffusion distance shows a decreasing trend with the decrease of the grouting pressure along the horizontal section (such as Figure 1 ). At present, in the process of treating water disasters in the coal seam floor, whether it is underground or ground construction of directional grouting treatment boreholes, the equal-spacing parallel hole layout mode is commonly used for the horizontal section of long-distance grouting holes. However, the attenuation of the grouting pressure along the grouting hole in the borehole results in insufficient slurry diffusion distance in the later stage of the horizontal grouting section with the equal-spacing parallel hole layout mode, causing the grouting ranges to be unable to overlap and cross, forming grouting blind areas, and it is difficult to achieve the goal of full coverage of regional treatment.

[0004] Therefore, inventing a reasonable borehole layout mode based on the decreasing effect of grouting pressure is an urgent problem to be solved in the current floor regional grouting reform. Summary of the Invention

[0005] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0006] The main objective of the present invention is to solve the technical problems existing in the prior art, and a method for advanced regional treatment of water disasters in coal seam floor is provided. This method focuses on the problem of grouting blind areas between holes that may be caused by too large spacing of traditional parallel branch holes, and fully combines the hydrogeological characteristics of the grouted layer and the grouting process. According to the law of gradual linear decrease of the effective grouting pressure in the horizontal section, the grouting blind areas are eliminated to the greatest extent.

[0007] To solve the above problems, the solution of the present invention is:

[0008] A method for advanced regional treatment of water disasters in coal seam floor, including:

[0009] Step 1, analyze the hydrogeological characteristics of the grouted rock formation;

[0010] Step 2, determine the extension direction of the branch holes based on the hydrogeological characteristics;

[0011] Step 3, analyze the effective grouting pressure in the horizontal section of the grouting borehole;

[0012] Step 4, determine the maximum length of the horizontal section of the grouting borehole based on the effective grouting pressure in the horizontal section of the grouting borehole;

[0013] Step 5, determine the "conical" grouting diffusion range of the horizontal section of the grouting borehole;

[0014] Step 6, construct the horizontal section of the grouting borehole in the grouted layer based on the grouting diffusion range.

[0015] Preferably, in the above method for advanced regional treatment of water disasters in coal seam floor, the extension direction of the branch holes is parallel to the isohyet.

[0016] Preferably, in the above method for advanced regional treatment of water disasters in coal seam floor, the extension direction of the branch holes is perpendicular to the fault strike direction.

[0017] A method for advanced regional treatment of water disasters in coal seam floor, including:

[0018] Construct a first grouting borehole leading to the grouted layer, and construct a plurality of first branch hole horizontal sections at the bottom end of the first grouting borehole. One end of each first branch hole horizontal section is connected to the first grouting borehole, and the other end extends in the grouted layer;

[0019] Construct a second grouting borehole leading to the grouted layer, and construct a plurality of second branch hole horizontal sections at the bottom end of the second grouting borehole. One end of each second branch hole horizontal section is connected to the second grouting borehole, and the other end extends towards the direction of the first grouting borehole;

[0020] Among them, the grouting diffusion ranges of the first branch hole horizontal sections and the second branch hole horizontal sections partially overlap.

[0021] Preferably, in the above method for advanced regional treatment of water disaster in coal seam floor, it includes: the horizontal sections of the first branch holes and the horizontal sections of the second branch holes are alternately arranged in the injection target layer.

[0022] Preferably, in the above method for advanced regional treatment of water disaster in coal seam floor, it includes: the grouting range at the end of the horizontal section of the first branch holes overlaps with the grouting range at the end of the horizontal section of the second branch holes.

[0023] Preferably, in the above method for advanced regional treatment of water disaster in coal seam floor, at least part of the horizontal section of the first branch holes is arranged in parallel with at least part of the horizontal section of the second branch holes.

[0024] A method for advanced regional treatment of water disaster in coal seam floor includes:

[0025] Construct a first grouting hole leading to the injection target layer, and construct a plurality of horizontal sections of the first branch holes at the bottom end of the first grouting hole. One end of each horizontal section of the first branch holes is connected to the first grouting hole, and the other end extends in the injection target layer;

[0026] Construct a second grouting hole leading to the injection target layer, and construct a plurality of horizontal sections of the second branch holes at the bottom end of the second grouting hole. One end of each horizontal section of the second branch holes is connected to the second grouting hole, and the other end extends towards the direction of the first grouting hole;

[0027] Wherein, the spacing between the horizontal sections of the first branch holes gradually decreases in the direction towards the second grouting hole; the spacing between the horizontal sections of the second branch holes gradually decreases in the direction towards the first grouting hole; and the grouting diffusion ranges of the horizontal sections of the first branch holes and the horizontal sections of the second branch holes overlap.

[0028] Preferably, in the above method for advanced regional treatment of water disaster in coal seam floor, the horizontal sections of the first branch holes and the horizontal sections of the second branch holes form a grouting diffusion area in the injection target layer. The horizontal sections of the first branch holes and / or the horizontal sections of the second branch holes include an arc section, and the radian of the arc section located inside the grouting diffusion area in the injection target layer is greater than the radian near the grouting diffusion area in the injection target layer.

[0029] Preferably, in the above method for advanced regional treatment of water disaster in coal seam floor, the horizontal sections of the first branch holes and the horizontal sections of the second branch holes are arranged in central symmetry.

[0030] Therefore, compared with the prior art, the present invention focuses on the problem of grouting blind zones between holes that may be caused by too large a spacing of traditional parallel branch holes. According to the "conical" grouting diffusion pattern of the horizontal section of the grouting borehole, the long-distance staggered parallel branch hole mode and the long-distance reverse complementary arc branch hole mode are adopted, which can eliminate the grouting blind zones to the greatest extent, ensure the effect of grouting transformation in the coal seam floor area and effectively prevent and control the water hazard of the coal seam floor, and realize the safe mining of coal resources, which has practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings incorporated herein and forming a part of the specification illustrate embodiments of the present invention, and together with the specification further serve to explain the principles of the present invention and enable those skilled in the art to make and use the present disclosure.

[0032] Figure 1 Illustrates a schematic diagram of the grouting pressure and diffusion radius of the horizontal section of the horizontal grouting hole in the embodiment of the present invention. In the figure, (a) shows the attenuation of the grouting pressure along the way, and (b) shows the diffusion range of the grout;

[0033] Figure 2 Illustrates a schematic diagram of grouting of the horizontal grouting hole in the embodiment of the present invention (section);

[0034] Figure 3 Illustrates the spatial relationship between the horizontal section of the grouting hole, the water level line of the grouted rock formation and the water-conducting structure in the embodiment of the present invention. In the figure, (a) the directional hole is perpendicular to the isohyet, and (b) the directional hole is nearly horizontal to the isohyet;

[0035] Figure 4 Illustrates a schematic diagram of the plane layout of the branch holes in the horizontal section of grouting in the embodiment of the present invention. In the figure, (a) traditional long-distance parallel branch holes, (b) long-distance staggered parallel branch holes, and (c) long-distance reverse complementary arc branch holes;

[0036] Embodiments of the present invention will be described with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] This embodiment provides a method for advanced regional treatment of water hazard in the coal seam floor, including:

[0038] Step 1: Analyze the hydrogeological characteristics of the grouted rock formation. According to the spatial relationship between the grouting borehole and the grouted rock formation, as well as the distribution information such as the underground water level h w and thickness of the grouted formation, analyze the spatial distribution and hydrostatic pressure distribution characteristics of the grouted rock formation around the grouting borehole in the grouting area ( Figure 2 ).

[0039] Step 2: Determine the extension direction of the branch holes. It can be seen from the grouting pressure formula that since the slurry needs to overcome the hydrostatic pressure and the comprehensive viscous resistance in the borehole and fissures when diffusing and flowing in the rock formation, when the extension direction of the horizontal grouting section of the directional borehole is perpendicular to the increasing section of the equipotential line ( Figure 3 a), that is, as the borehole extends, the hydrostatic pressure gradually increases, which further exacerbates the attenuation of the effective grouting pressure in the horizontal section of the branch hole, and the advanced grouting treatment efficiency is not high. Therefore, according to the distribution characteristics of the hydrodynamic field of the grouted layer in the treatment area, the main extension direction of each hole of the horizontal section of the branch hole for grouting treatment should be parallel to the equipotential line as much as possible ( Figure 3 b), which can reduce the attenuation ability of the effective grouting pressure in the horizontal section of the branch hole and achieve better treatment efficiency.

[0040] In addition, the water-conducting structures (faults, fissures) in the coal seam floor are the main objects of grouting treatment, which often control the permeability and the main seepage direction of the strata. The void medium in the fault zone has good openness, strong connectivity, and small grouting resistance, and the slurry diffusion ability in the fault is better than that in the normal rock formation outside the fault zone. Therefore, the extension direction of each hole of the horizontal section of the branch hole for grouting treatment should be orthogonal to the fault strike direction as much as possible. Since a single-branch grouting hole is easy to expose the water-conducting channel and the grouting resistance to be overcome is small, it is possible to achieve better grouting efficiency for the water-conducting fault with fewer grouting holes and horizontal section lengths.

[0041] Step 3: Analyze the effective grouting pressure in the horizontal section of the grouting borehole. According to the formula:

[0042] ,

[0043] Determine the effective pressure along the horizontal section according to the above formula. In the formula, P 0 is the reading of the pressure gauge at the orifice of the grouting hole, l is the length of the horizontal section of the grouting hole; γ g and γ w is the specific gravity of the slurry and water; h 1 is the vertical distance between the orifice of the grouting hole and the horizontal section; h w is the height of the hydrostatic pressure water column of the grouted layer; ξ is the comprehensive resistance coefficient when the slurry flows in the hole wall and the fissures exposed by the hole wall.

[0044] Step 4: Determine the maximum length of the horizontal section of the grouting borehole. When the maximum grouting pressure at the orifice is constant (the orifice grouting pressure is determined by the capacity of the grouting pump), the comprehensive resistance ξ * h 1 in the vertical section and the hydrostatic resistance γ w*h w is relatively fixed, and as the horizontal section of the grouting hole l extends, the frictional resistance along the way ξ * l increases linearly. When P( l ) = 0, the length of the horizontal section l max is the maximum length of the horizontal section of the grouting borehole.

[0045] Step Five: Determine the "conical" grouting diffusion range of the horizontal section of the grouting borehole. According to the effective grouting pressure formula, as Figure 1 shown, starting from the maximum diffusion radius r max at the orifice, with the maximum length of the horizontal section of the maximum grouting borehole lmax as the terminal, and taking the horizontal section as the axis, connecting lines can obtain the "conical" grouting diffusion range of the horizontal section of the grouting borehole.

[0046] Step Six: Consider the layout of boreholes with the attenuation of the grouting pressure along the horizontal holes. Aiming at the problem of blind areas between grouting holes that may be caused by too large spacing of traditional parallel branch holes ( Figure 4 a)), fully combining the hydrogeological characteristics of the grouted layer and the grouting technology, according to the maximum length of the horizontal section of the maximum grouting hole determined in Step Four l max design the maximum length of the horizontal section ， According to the "conical" grouting diffusion range of the horizontal section of the grouting borehole determined in Step Five, with the goal of eliminating the grouting blind area to the greatest extent, two efficient borehole layout modes for advanced regional treatment can be adopted:

[0047] (1) Long-distance staggered parallel branch hole mode ( Figure 4 b)), reduce the length of the horizontal section of the branch holes in the first-order holes, construct the second-order holes staggeredly on the opposite side, and form an overlapping area in the grouting diffusion blind area of the horizontal section of each branch hole in the first-order holes to eliminate the grouting blind area.

[0048] (2) Long-distance reverse complementary arc-shaped branch hole mode ( Figure 4 c)), fully relying on the directional drilling ability, according to the reduced form of the grouting diffusion range of the horizontal section of the grouting borehole, construct the horizontal sections of each branch hole in both the first-order and second-order holes in an "arc" shape and carry out grouting treatment to eliminate the grouting blind area.

[0049] From the above, it can be seen that a borehole layout method for advanced regional treatment of water disasters in coal seam floor considering the attenuation of grouting pressure along horizontal holes of the present invention has the following effects:

[0050] Focusing on the problem of grouting blind zones between holes that may be caused by the too large spacing of traditional parallel branch holes, according to the "conical" grouting diffusion pattern of the horizontal section of the grouting borehole, two hole layout design methods, namely the long-distance staggered parallel branch hole pattern and the long-distance reverse complementary arc branch hole pattern, are invented and proposed. This can eliminate the grouting blind zone to the greatest extent, ensure the grouting reform effect in the coal seam floor area and effectively prevent and control the water hazard of the coal seam floor, realize the safe mining of coal resources, and has practical significance.

[0051] Note that references in the specification to "an embodiment", "embodiments", "exemplary embodiments", "some embodiments", etc. indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include the specific features, structures, or characteristics. Moreover, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure, or characteristic is described in connection with an embodiment, whether or not explicitly described, implementing such a feature, structure, or characteristic in connection with other embodiments will be within the knowledge of those skilled in the art.

[0052] The foregoing description of the disclosure has been provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for advanced regional treatment of water disasters in the coal seam floor, characterized in that including: Step 1, analyzing the hydrogeological characteristics of the grouted rock stratum; Step 2, determining the extension direction of the branch holes based on the hydrogeological characteristics; Step 3, analyzing the effective grouting pressure of the horizontal section of the grouting holes; Step 4, determining the maximum length of the horizontal section of the grouting holes based on the effective grouting pressure of the horizontal section of the grouting holes; Step 5, determining the "conical" grouting diffusion range of the horizontal section of the grouting holes; Step 6, constructing the horizontal section of the grouting holes in the grouted layer based on the grouting diffusion range; specifically, adopting the long-distance staggered parallel branch hole mode or the long-distance reverse complementary arc branch hole mode for hole layout, where: The long-distance staggered parallel branch hole mode reduces the length of the horizontal section of the first-order hole branch holes, constructs the second-order holes in a staggered manner on the opposite side, and forms an overlapping area in the grouting diffusion blind area of each horizontal section of the first-order hole branch holes to eliminate the grouting blind area; The long-distance reverse complementary arc branch hole mode fully relies on the directional drilling ability, and according to the reduced form of the grouting diffusion range of the horizontal section of the grouting holes, both the first-order and second-order holes construct the horizontal sections of each branch hole in an "arc" shape and carry out grouting treatment to eliminate the grouting blind area.

2. The advanced regional treatment method for water disaster in coal seam floor according to claim 1, characterized in that The extension direction of the branch holes is parallel to the isohyet.

3. The advanced regional treatment method for water disaster in coal seam floor according to claim 1, characterized in that, The extension direction of the branch holes is perpendicular to the fault strike direction.

4. A method for advanced regional treatment of water disaster in coal seam floor, characterized in that, including: Constructing the first grouting hole leading to the grouted layer, and constructing multiple first branch hole horizontal sections at the bottom end of the first grouting hole. One end of each first branch hole horizontal section is connected to the first grouting hole, and the other end extends in the grouted layer; Constructing the second grouting hole leading to the grouted layer, and constructing multiple second branch hole horizontal sections at the bottom end of the second grouting hole. One end of each second branch hole horizontal section is connected to the second grouting hole, and the other end extends in the direction of the first grouting hole; wherein, the grouting diffusion ranges of the first branch hole horizontal sections and the second branch hole horizontal sections partially overlap.

5. The advanced regional treatment method for water disaster in coal seam floor according to claim 4, characterized in that including: The first branch hole horizontal sections and the second branch hole horizontal sections are alternately arranged in the grouted layer.

6. The advanced regional treatment method for water disaster of coal seam floor according to claim 4, characterized in that including: The grouting ranges at the ends of the first branch hole horizontal sections and the grouting ranges at the ends of the second branch hole horizontal sections overlap.

7. The advanced regional treatment method for water disaster in coal seam floor according to claim 4, characterized in that, At least part of the first branch hole horizontal sections is arranged in parallel with at least part of the second branch hole horizontal sections.

8. A method for advanced regional treatment of water hazards in coal seam floor, characterized in that, including: Constructing the first grouting hole leading to the grouted layer, and constructing multiple first branch hole horizontal sections at the bottom end of the first grouting hole. One end of each first branch hole horizontal section is connected to the first grouting hole, and the other end extends in the grouted layer; Constructing the second grouting hole leading to the grouted layer, and constructing multiple second branch hole horizontal sections at the bottom end of the second grouting hole. One end of each second branch hole horizontal section is connected to the second grouting hole, and the other end extends in the direction of the first grouting hole; wherein, the spacing between each first branch hole horizontal section gradually decreases in the direction towards the second grouting hole; the spacing between each second branch hole horizontal section gradually decreases in the direction towards the first grouting hole; and the grouting diffusion ranges of the first branch hole horizontal sections and the second branch hole horizontal sections overlap.

9. A method for advanced regional treatment of water disasters in the coal seam floor according to claim 8, characterized in that, The horizontal section of the first branch hole and the horizontal section of the second branch hole form a grouting diffusion area of the grouting-receiving layer. The horizontal section of the first branch hole and / or the horizontal section of the second branch hole includes an arc section, and the radian of the arc section located inside the grouting diffusion area of the grouting-receiving layer is greater than the radian close to the grouting diffusion area of the grouting-receiving layer.

10. A method for advanced regional treatment of water disasters in the coal seam floor according to claim 8, characterized in that, The horizontal sections of the first branch holes and the horizontal sections of the second branch holes are arranged in central symmetry.

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