Method for on-site parallel three-dimensional grouting reinforcement of advanced disturbance area of working face

Abstract

The invention provides a working face advanced disturbance area on-site parallel three-dimensional grouting reinforcement method which comprises the steps that S1, the geological condition of a coal mine working face is obtained, and structural data of a coal mine working face roof and a coal seam are determined; s2, according to the geological condition of the coal mine working face, coal and rock masses in a disturbance area in front of the working face are partitioned; s3, grouting materials, grouting modes and grouting parameters of the different subareas are determined according to the crack development degrees of the different subareas; s4, on-site grouting drilling parameters and advanced grouting drilling parameters are determined according to the structural data of the coal mine working face roof and the coal seam; carrying out on-site grouting drilling and advanced grouting drilling; and S5, according to the on-site grouting drill holes and the advanced grouting drill holes, grouting is conducted on the working face coal wall and the upper broken roof subareas at the same time. According to the method, the impact effect of sudden caving of the broken roof in the mining dynamic pressure disturbance area and coal wall caving on the working face is reduced, and coal mining safety accidents are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, in particular to an on-site parallel three-dimensional grouting reinforcement method for an advanced disturbance zone of a working face. Background Art

[0002] As my country's coal mining is developing deeper and deeper, the original rock stress of the mine is high. After the working face is mined, due to the dynamic disturbance of mining and the influence of the stress field, the rock mass of the roof above the coal seam is broken and loose. During the mining process, it is easy for the coal mining working face to have roof spalling and roof leakage, causing safety accidents, resulting in greater safety hazards on the working face, and seriously affecting the safety production efficiency. If the broken rock mass suddenly falls and the coal wall spalls during mining, it will cause a large impact ground pressure on the working face, damage the mining equipment, and even cause casualties, which will seriously threaten the safety production operation of the coal mine. Therefore, it is necessary to grout the broken coal seam and roof in the dynamic pressure disturbance zone to consolidate them into a stable whole, improve the mechanical properties of the consolidated body, and avoid sudden spalling.

[0003] Grouting technology is the most commonly used reinforcement method for surrounding rock control in deep mine tunnels. Grouting reinforcement can improve the strength and integrity of the broken rock mass, enhance the mechanical properties of the surrounding medium, control the deformation and damage of the surrounding rock, improve the stability of the broken coal rock mass during the mining process, and avoid roof collapse and slab accidents caused by the collapse of the broken rock mass. Domestic and foreign scholars have conducted many studies on grouting theory, grouting materials, grouting technology and grouting quality detection technology, but mainly focus on single grouting methods, analyze the applicable conditions and grouting effects of various grouting methods. Due to the more complex geological structure and stress field of the surrounding rock of deep tunnels and the harsher environment, the conventional single grouting method can no longer meet the requirements of deep surrounding rock control, resulting in the tunnels after grouting reinforcement still have safety hazards such as roof collapse, support material collapse and falling.

[0004] Therefore, a safer and more efficient technical solution is needed to complete the management of the coal body and broken roof in the dynamic pressure disturbance zone in front of the working face, so as to ensure the safe advancement of the working face and the efficiency of safe production. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a method for on-site parallel three-dimensional grouting reinforcement of the advance disturbance zone of a working face, which can solve the existing problems.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] The present invention is realized by the following technical scheme: a method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face, comprising the following steps:

[0008] S1. Obtain the geological conditions of the coal mine working face and determine the structural data of the coal mine working face roof and coal seam; including the rock layer thickness of the working face roof and the degree of development of cracks inside the rock mass;

[0009] S2. Divide the coal-rock mass in the disturbed area in front of the working face into zones according to the degree of development of cracks inside the rock mass and the stress distribution in the coal-rock mass, including zones of complete crushing, zones of crack development and zones of original rock structure; and correspond the zones to zones of high slurry permeability, zones of medium slurry permeability and zones of low slurry permeability according to the slurry permeability characteristics of each zone of the fractured coal-rock mass;

[0010] S3. Through on-site grouting experiments, determine the grouting materials, grouting methods and grouting parameters for different partitions according to the degree of crack development in different partitions;

[0011] S4, determining on-site grouting drilling parameters and advance grouting drilling parameters according to the structural data of the coal mine working face roof and coal seam; and performing on-site grouting drilling and advance grouting drilling;

[0012] S5. According to the on-site grouting drilling and the advance grouting drilling, grouting is performed on the coal wall of the working face and the upper broken roof partitions at the same time, and the determined grouting material is injected into the corresponding partitions through the determined grouting method to complete the integrated grouting.

[0013] Furthermore, the geological conditions of the coal mine working face are obtained by using a comprehensive columnar stratification diagram of the coal mine working face or by observing with a borehole peephole.

[0014] Furthermore, the partitions are made to correspond to the slurry high permeability zone, the slurry medium permeability zone and the slurry low permeability zone; including: the slurry high permeability zone corresponds to the completely broken zone, the slurry medium permeability zone corresponds to the fracture development zone, and the slurry low permeability zone corresponds to the original rock structure zone.

[0015] Furthermore, the on-site grouting experiment includes: drilling holes in the grouting target area with a hole depth exceeding the fracture development zone, and using a sealer to conduct a segmented sealing grouting test in the grouting test to determine the grouting materials, grouting methods and grouting parameters for different partitions; the grouting parameters include grouting hole spacing, inclination, grouting pressure and slurry type; grouting methods include filling grouting, penetration grouting and high-pressure splitting grouting; the grouting materials include organic slurry silicate modified polyurethane materials, cement-based grouting materials and ultrafine cement-based grouting materials.

[0016] Furthermore, the on-site grouting drilling and advance grouting drilling include: drilling multiple horizontal parallel on-site grouting holes at preset intervals along the vertical coal wall of the working face according to the on-site grouting drilling parameters, and drilling advance grouting holes at preset angles inclined toward the upper roof in the drilling sites of the air tunnel and the machine tunnel according to the advance grouting drilling parameters.

[0017] Furthermore, the on-site grouting drilling parameters are determined according to the structural data of the coal mine working face roof and coal seam, including: presetting the preset spacing and drilling depth of on-site grouting drilling for the working face according to the structural data of the coal mine working face roof and coal seam.

[0018] Furthermore, the advance grouting drilling parameters are determined according to the structural data of the coal mine working face roof and coal seam, including: the preset advance grouting drilling hole bottom spacing, the distance between the end hole position and the front of the working face mining, the distance above the coal seam roof, the grouting pipe length, and the sealing pipe length; the advance grouting drilling angle, the advance grouting drilling depth, and the distance between the advance grouting position and the coal wall of the working face are calculated;

[0019] The advance grouting drilling angle θ is determined by the following formula:

[0020] tanθ=H 注 / S 2 (1)

[0021] In the above formula (1), θ is the angle between the drilling axis and the horizontal direction; H 注 is the grouting height of the top rock layer, m; S 2 is the horizontal distance from the drilling site of the two tunnels to the advanced grouting position, m;

[0022] The grouting height of the top rock layer is H 注 It can be obtained by the following formula:

[0023] H 注 =M 0 / (K P -1)(2)

[0024] In the above formula (2), H 注 is the grouting height of the top rock layer, m; M 0 is the thickness of the coal seam, m; K P is the average expansion coefficient of the broken rock mass, and the average expansion coefficient of the broken rock mass is 1.45;

[0025] The advance grouting drilling depth L can be obtained by the following formula:

[0026] L=kH 注 / sinθ(3)

[0027] In the above formula (3), L is the advance grouting drilling depth, m; k is the redundancy coefficient, ranging from 1.1 to 1.3; H 注 is the grouting height of the top rock layer, m; θ is the angle between the borehole axis and the horizontal direction;

[0028] The distance S between the advance grouting position and the coal wall of the working face is 1 Determined using the following formula:

[0029]

[0030] In the above formula (4): h 1 is the mining height of the working face; f is the friction coefficient of the contact surface between the coal seam and the roof; α is the friction angle inside the coal body; K is the peak concentration coefficient of the advance support pressure; T is the bearing capacity of the coal body itself; γ is the volume force of the overlying rock layer; h 2 The depth of coal seam.

[0031] Furthermore, the advanced grouting drilling holes are arranged in an umbrella shape in the direction of the cutting eye.

[0032] Furthermore, the preset row spacing of the on-site grouting drilling is 5m, the drilling depth is 6-8m, the preset spacing of the bottom of the advanced grouting drilling is 15m, the final hole position is 30m in front of the working face, the coal seam roof is 15m from the ground, the length of the grouting pipe is not less than 70% of the hole depth, and the length of the sealing pipe is not less than 10m.

[0033] Furthermore, the step of injecting the determined grouting material into the corresponding partition by a determined grouting method to complete the integrated grouting includes:

[0034] For the completely broken coal and rock mass areas in front of the working face that are severely disturbed by mining, chemical grouting is carried out by filling grouting through on-site grouting drilling of vertical coal walls, and two-component organic slurry silicate modified polyurethane material is injected; in view of the incomplete coverage of the roof reinforced by long-distance advance grouting, dynamic complementation is carried out in the broken and leaking areas of the roof in the working face, and chemical slurry is injected in front of the local hydraulic support for reinforcement;

[0035] For the roof fissure development area in front of the working face that is disturbed by mining with moderate intensity, the cement-based grouting material with a particle size of 10-70μm is injected through radial umbrella-shaped advance grouting holes by the penetration grouting method;

[0036] For the roof original rock structure area 30m in front of the working face that is slightly disturbed or not affected by mining disturbance, ultra-fine cement-based grouting materials with a particle size of 5-10μm are injected through radial umbrella-shaped advance grouting holes using the high-pressure splitting grouting method with a grouting pressure of not less than 12MPa.

[0037] Compared with the prior art, the beneficial effects of the present invention include:

[0038] The present invention provides a method for on-site parallel three-dimensional grouting reinforcement of the advance disturbance zone of a working face. The method comprises the following steps: drilling a plurality of parallel horizontal on-site grouting holes and radial umbrella-shaped advance grouting holes into the coal seam and the broken roof of the disturbance zone at the working face and the two-lane drilling sites with pre-set drilling parameters, and simultaneously performing grouting operations using different grouting materials and different grouting methods on each partition of the coal wall of the working face and the broken roof above. Different slurries are solidified into a network skeleton structure, so that the broken coal rock mass in the disturbance zone can form a stable whole, thereby achieving the effect of integrated three-dimensional grouting.

[0039] The method for on-site parallel three-dimensional grouting reinforcement of the advance disturbance zone of the working face provided by the present invention not only has a simple process, saves grouting time, has little impact on production operations, has low cost, and has a large grouting range and good reinforcement effect, but also reduces the impact of sudden falling of broken roof and coal wall spalling in the mining dynamic pressure disturbance zone on the working face, reduces coal mining safety accidents, ensures safe and efficient mining of the working face, and has important practical engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them:

[0041] Figure 1 It is a flow chart of a method for on-site parallel three-dimensional grouting reinforcement of a working face advance disturbance zone according to the present invention;

[0042] Figure 2 It is a schematic diagram of a three-dimensional grouting scheme in an implementation case of the present invention;

[0043] Figure 3 It is a stress partition characteristic diagram of the support in front of the working surface in the implementation case of the present invention;

[0044] Figure 4 A three-dimensional design diagram of parallel three-dimensional grouting drilling arrangement in a method for on-site parallel three-dimensional grouting reinforcement of an advanced disturbance zone of a working face provided by an embodiment of the present invention;

[0045] Figure 5 A plan design diagram of parallel three-dimensional grouting drilling arrangement in a method for on-site parallel three-dimensional grouting reinforcement of an advanced disturbance zone of a working face provided by an embodiment of the present invention;

[0046] Figure 6 A cross-sectional design diagram of parallel three-dimensional grouting drilling arrangement in a method for on-site parallel three-dimensional grouting reinforcement of an advance disturbance zone of a working face provided in an embodiment of the present invention.

[0047] As shown in the figure: 1. Coal seam, 2. Working face, 3. Roof, 4. On-site grouting drilling, 5. Air tunnel, 6. Machine tunnel, 7. Drilling site, 8. Advance grouting drilling, 9. Working face support. DETAILED DESCRIPTION

[0048] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0049] The present invention provides a method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of the working face, the process of which is as follows: Figure 1 As shown, the following steps are included:

[0050] S1. Obtain the geological conditions of the coal mine working face and determine the structural data of the coal mine working face roof and coal seam, including the rock layer thickness of the working face roof and the degree of development of cracks inside the rock mass;

[0051] Specifically, in order to ensure that the structural data of the roof overlying the coal seam in a coal mine is reasonable and accurate, the physical parameters such as the rock layer thickness of the roof of the coal mine working face and the degree of development of internal fractures in the rock mass and the structural structure can be determined based on the comprehensive columnar stratification diagram of the working face in the coal mine mining area or through observation with a borehole peephole.

[0052] S2. Divide the coal-rock mass in the disturbed area in front of the working face into zones according to the degree of development of cracks inside the rock mass and the stress distribution in the coal-rock mass, including zones of complete crushing, zones of crack development and zones of original rock structure; and correspond the zones to zones of high slurry permeability, zones of medium slurry permeability and zones of low slurry permeability according to the slurry permeability characteristics of each zone of the fractured coal-rock mass;

[0053] Specifically, on the basis of the zoning of the coal rock mass in the disturbed area in front of the working face, the broken coal rock mass in front of the working face is divided into a high slurry permeability zone, a medium slurry permeability zone and a low slurry permeability zone according to the slurry permeability characteristics of each broken coal rock mass zone; each zone is corresponded to the high slurry permeability zone, the medium slurry permeability zone and the low slurry permeability zone, specifically, the high slurry permeability zone corresponds to the completely broken zone, the medium slurry permeability zone corresponds to the fracture development zone, and the low slurry permeability zone corresponds to the original rock structure zone.

[0054] S3. Through on-site grouting experiments, determine the grouting materials, grouting methods and grouting parameters for different partitions according to the degree of crack development in different partitions;

[0055] Specifically, drilling is performed in the target area for grouting, the hole depth should exceed the fracture development area, and a hole sealer is used in the grouting test to perform segmented hole sealing grouting test to determine the grouting materials, grouting methods and grouting parameters of different partitions; the grouting parameters include grouting hole spacing, inclination, grouting pressure and slurry type, etc.; the grouting methods include filling grouting, penetration grouting and high-pressure splitting grouting; the grouting materials include organic slurry silicate modified polyurethane materials, cement-based grouting materials and ultra-fine cement-based grouting materials;

[0056] S4, determining on-site grouting drilling parameters and advance grouting drilling parameters according to the structural data of the coal mine working face roof and coal seam; and performing on-site grouting drilling and advance grouting drilling;

[0057] Exemplarily, according to the structural data of the roof and coal seam of the coal mine working face, preset spacing and drilling depth of on-site grouting drilling holes of the working face are preset;

[0058] Specifically, according to the structural data of the coal mine working face roof and coal seam, the parameters of the advance grouting drilling are determined, including the preset spacing of the hole bottom of the preset advance grouting drilling, the spacing between the end hole position and the front of the working face mining, the distance from the top of the coal seam roof, the length of the grouting pipe, and the length of the sealing pipe; the advance grouting drilling angle, the advance grouting drilling depth, and the distance between the advance grouting position and the coal wall of the working face are calculated;

[0059] The advance grouting drilling angle θ is determined by the following formula:

[0060] tanθ=H 注 / S 2 (1)

[0061] In the above formula (1), θ is the angle between the drilling axis and the horizontal direction; H 注 is the grouting height of the top rock layer, m; S 2 is the horizontal distance from the drilling site of the two tunnels to the advanced grouting position, m;

[0062] The grouting height of the top rock layer is H 注 It can be obtained by the following formula:

[0063] H 注 =M 0 / (K P -1)(2)

[0064] In the above formula (2), H 注 is the grouting height of the top rock layer, m; M 0 is the thickness of the coal seam, m; K P is the average expansion coefficient of the broken rock mass, and the average expansion coefficient of the broken rock mass is 1.45;

[0065] The advance grouting drilling depth L can be obtained by the following formula:

[0066] L=kH 注 / sinθ(3)

[0067] In the above formula (3), L is the advance grouting drilling depth, m; k is the redundancy coefficient, ranging from 1.1 to 1.3; H 注 is the grouting height of the top rock layer, m; θ is the angle between the borehole axis and the horizontal direction;

[0068] The distance S between the advance grouting position and the coal wall of the working face is 1 Determined using the following formula:

[0069]

[0070] In the above formula (4): h 1 is the mining height of the working face; f is the friction coefficient of the contact surface between the coal seam and the roof; α is the friction angle inside the coal body; K is the peak concentration coefficient of the advance support pressure; T is the bearing capacity of the coal body itself; γ is the volume force of the overlying rock layer; h 2 The depth of coal seam.

[0071] Then, multiple horizontal parallel on-site grouting holes are drilled along the vertical coal wall at preset intervals on the working face according to the on-site grouting drilling parameters, and advance grouting holes are drilled at the drilling sites of the ventilation tunnel and the machine tunnel according to the advance grouting drilling parameters at a preset angle inclined toward the roof above;

[0072] In the working face and the two-tunnel drilling sites, holes are drilled multiple times into the coal seam and the broken roof of the disturbed area above the coal seam at pre-set intervals, elevations and preset depths to obtain the multiple parallel-arranged on-site grouting boreholes and multiple radial umbrella-shaped advance grouting boreholes.

[0073] The advanced grouting drilling hole is designed in the direction of the eye cutting and is generally arranged in an umbrella shape. The umbrella-shaped hole arrangement is simple and the construction is convenient. The drilling rig only needs to adjust the elevation angle and azimuth angle to construct different grouting holes.

[0074] For example, the preset spacing of the on-site grouting drilling holes on the working face is 5m, and the drilling depth is 8m;

[0075] The preset spacing between the bottom holes of the radial umbrella-shaped advance grouting boreholes in the two tunnels is 15m. The terminal hole position is about 30m in front of the working face and 15m above the coal seam roof. The preset elevation angle is θ and the depth is Lm. The length of the grouting pipe is not less than 70% of the hole depth, and the length of the sealing pipe is not less than 10m. The elevation angle θ and the depth Lm are obtained by the above formulas (1) and (3).

[0076] S5. According to the on-site grouting drilling and the advance grouting drilling, grouting is performed on the coal wall of the working face and the upper broken roof partitions at the same time, and the determined grouting material is injected into the corresponding partitions through the determined grouting method to complete the integrated grouting.

[0077] Specifically, for the completely broken coal and rock mass areas in front of the working face that are severely disturbed by mining, chemical grouting is carried out by filling grouting through on-site grouting holes in the vertical coal wall, and two-component organic slurry silicate modified polyurethane materials are injected. In view of the possible incomplete coverage of the roof reinforced by long-distance advanced grouting, dynamic complementation is carried out in the broken and leaking areas of the roof within the face, and chemical slurry is injected in front of the local hydraulic support for reinforcement to achieve cyclic stub grouting;

[0078] For the roof fissure development area in front of the working face that is disturbed by mining with moderate intensity, the cement-based grouting material with a particle size of 10-70μm is injected through radial umbrella-shaped advance grouting holes by the penetration grouting method;

[0079] For the original rock structure area of ​​the roof about 30m in front of the working face that is slightly disturbed or not affected by mining disturbance, through radial umbrella-shaped advance grouting drilling holes, the high-pressure splitting grouting method with a grouting pressure of not less than 12MPa is adopted to inject ultra-fine cement-based grouting materials with a particle size of 5-10μm, so as to achieve advance grouting of cracks in the mining-affected range of the working face.

[0080] The present invention will be explained in detail below with reference to the accompanying drawings and implementation examples.

[0081] The embodiment of the present invention is aimed at the area that is not excavated and disturbed by the dynamic pressure of mining. As the working face advances forward, after the direct roof collapses, the basic roof breaks and sinks, forming a vertical fracture zone, a separation zone and a fissure. The coal seam and the roof above are broken and loose, and there are safety hazards such as caving and spalling on the working face, which leads to the situation that the working face support cannot move forward normally. Directional arrangement of drilling holes can be used to grout and reinforce the coal seam and the overlying broken roof of the working face. By constructing directional drilling holes in the working face and the two-lane drilling site, and grouting the directional drilling holes at the same time, the loose rock mass of the overlying roof of the working face can be consolidated into a network skeleton structure. The fracture zone, spalling zone and fissure are treated to form a complete bearing body, achieving the effect of integrated three-dimensional grouting, thereby reducing the stress squeeze on the coal seam, reducing spalling accidents, and ensuring the speed of safe forward advancement of the working face support. After grouting the coal seam and the broken roof above the working face, the mining workers are in an effectively protected state within the range covered by the slurry diffusion.

[0082] The operation steps in the embodiment of the present invention are as follows: Figure 2To illustrate, step 1: first obtain the geological conditions of the coal mine working face to determine the structural data of the roof 3 and coal seam 1 above the working face 2, including physical parameters such as the rock layer thickness of the coal mine working face roof and the degree of fracture development and structural structure inside the rock body. Specifically, in order to ensure that the structural data of the overlying roof 3 of the coal seam 1 is reasonable and accurate, the physical parameters such as the rock layer thickness of the roof 3 of the coal mine working face 2 and the degree of fracture development and structural structure data can be determined based on the comprehensive columnar layered diagram of the mining area working face or through observation with a borehole peep instrument.

[0083] Step 2: Divide the coal rock mass in the disturbed area in front of the working face into zones according to the degree of development of cracks inside the rock mass and the stress distribution in the coal rock mass, including zones of complete crushing, zones of fracture development and zones of original rock structure; on the basis of the zones of coal rock mass in the disturbed area in front of the working face 2, divide the broken coal rock mass in front of the working face into zones of high slurry permeability, zones of medium slurry permeability and zones of low slurry permeability according to the slurry permeability characteristics of each zone of broken coal rock mass. Specifically, the zones of high slurry permeability correspond to the zones of complete crushing, the zones of medium slurry permeability correspond to the zones of fracture development, and the zones of low slurry permeability correspond to the zones of original rock structure; Figure 3 shown.

[0084] Step 3: Conduct on-site grouting tests to determine the grouting methods, grouting materials and grouting parameters for different zones. Specifically, drill holes in the target area for grouting, the hole depth must exceed the fracture development zone, and use a sealer to conduct segmented sealing grouting tests during the grouting test. The grouting parameters include grouting hole spacing, inclination, grouting pressure and slurry type.

[0085] Step 4: Determine the parameters for on-site grouting drilling and advanced grouting drilling and start drilling; according to the structural data of the roof 3 and the coal seam 1 obtained in step 1, find the disturbed and broken roof 3 area and coal seam 1 area, drill multiple parallel on-site grouting holes 4 along the working face 2 perpendicular to the coal wall toward the coal seam 1, and drill advanced grouting holes 8 obliquely toward the roof 3 above in the drilling sites 7 of the air tunnel 5 and the machine tunnel 6.

[0086] Drilling holes into the coal seam 1 affected by the disturbance zone and the broken roof 3 above it multiple times at a preset row spacing, elevation angle and preset depth to obtain multiple parallel arranged on-site grouting boreholes 4 and multiple radial umbrella-shaped advance grouting boreholes 8;

[0087] Specifically, the preset spacing of the on-site grouting boreholes 4 of the working face 2 is 5m, and the drilling depth is 8m. The preset spacing of the bottom of the radial umbrella-shaped advance grouting boreholes 8 in the two lanes is 15m. The final hole position is about 30m in front of the working face 2 mining and 15m above the coal seam roof. The preset elevation angle is θ and the depth is Lm. The length of the grouting pipe is not less than 70% of the hole depth, and the length of the sealing pipe is not less than 10m.

[0088] The advanced grouting drilling hole is designed in the direction of the eye cutting and is generally arranged in an umbrella shape. The umbrella-shaped hole arrangement is simple and the construction is convenient. The drilling rig only needs to adjust the elevation angle and azimuth angle to construct different grouting holes.

[0089] Step 5: Grouting is performed on the coal wall of the working face 2 and the upper broken roof 3 at the same time, and different grouting materials are injected into the corresponding partitions through different grouting methods.

[0090] Specifically, for the completely broken coal and rock mass areas in front of the working face that are severely disturbed by mining, chemical grouting is performed by filling grouting through the on-site grouting borehole 4 of the vertical coal wall, and two-component organic slurry silicate modified polyurethane material is injected. In view of the possible incomplete coverage of the long-distance advanced grouting reinforcement of the roof 3, dynamic complementation is performed in the broken and leaking areas of the roof in the face, and chemical slurry is injected in front of the local working face support 9 for reinforcement to achieve cyclic stub grouting;

[0091] In the fissure development area of ​​the roof 3 in front of the working face which is disturbed by the medium intensity of mining, a cement-based grouting material with a particle size of 10-70 μm is injected through the radial umbrella-shaped advance grouting boreholes 8 by the penetration grouting method;

[0092] For the original rock structure area of ​​the roof 3 about 30m in front of the working face which is slightly disturbed or not affected by mining disturbance, ultrafine cement-based grouting materials with a particle size of 5-10μm are injected through radial umbrella-shaped advance grouting boreholes 8 by adopting a high-pressure splitting grouting method with a grouting pressure of not less than 12MPa, so as to achieve advance grouting of the cracks in the mining-affected range of the working face;

[0093] Different slurries penetrate into the cracks of the coal seam and roof 3. The on-site chemical slurry seals the cracks in the coal wall, which can avoid leakage of grouting in the working face 2. Different slurries solidify into a network skeleton structure, changing the effective stress of the rock mass. After treatment, the fracture zone, leakage zone and cracks form a stable bearing whole, achieving the effect of integrated three-dimensional grouting, reducing the squeezing of stress on the coal seam, and reducing roof collapse and rock spalling accidents in the coal mining working face.

[0094] During the mining process, as the working face 2 moves forward, the three-dimensional grouting reinforcement also moves forward. By continuing the above operation, the workers mining the working face 2 are always in an effective protection state of the three-dimensional grouting reinforcement, ensuring that the working face support 9 can move forward safely and efficiently. For example, Figure 2 As shown, the completely broken area (A) is filled with chemical grouting, and a two-component organic slurry silicate modified polyurethane material is injected; the fracture development area (B) is injected with a cement-based grouting material with a particle size of 10-70μm by the infiltration grouting method; the original rock structure area (c) is injected with a high-pressure splitting grouting method with a grouting pressure of not less than 12MPa, and an ultra-fine cement-based grouting material with a particle size of 5-10μm is injected.

[0095] In summary, if Figure 4-Figure 6 As shown, the method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of the working face of this embodiment includes the following steps: obtaining the geological conditions of the coal mine working face 2, determining the structural data and the degree of fissure development of the roof 3 and the coal seam 1 in front of the working face 2; partitioning the coal seam 1 and the broken roof 3 disturbed by dynamic pressure in front of the working face 2 according to the data of the roof 3 and the coal seam 1 obtained in step 1; conducting on-site grouting tests to determine the grouting methods, grouting materials and grouting parameters for different partitions; and repeatedly grouting the coal seam 1 with preset spacing, elevation angle and preset depth in the working face 2 and the two-lane drilling site 7. and drilling holes in the broken roof 3 of the disturbance zone above to obtain multiple parallel arranged on-site grouting holes 4 and radial umbrella-shaped advance grouting holes 8; synchronously, the coal wall of the working face 2 and the broken roof 3 above are divided into different areas for construction operations using different grouting materials and different grouting methods, and the slurry is solidified into a stable load-bearing whole to achieve the effect of integrated three-dimensional grouting; during mining, the working face 2 is pushed forward, and the three-dimensional grouting reinforcement is also pushed forward accordingly, and the above operation is continued, so that the mining staff are continuously in an effective protection state of the three-dimensional grouting reinforcement, ensuring that the working face support 9 can be pushed forward safely and efficiently.

[0096] The embodiment of the present invention is to implement integrated three-dimensional grouting reinforcement of the coal seam and the broken roof in front of the working face that are disturbed by the dynamic pressure of mining, so as to achieve integrated three-dimensional grouting of the broken coal seam and the roof, ensure the safe and efficient advancement of the working face support, and also enable the workers within the grouting coverage area to be in a state of continuous and effective protection, so that coal mining can be carried out in a safe and orderly manner. The on-site parallel three-dimensional grouting reinforcement technology for the advanced disturbance area of ​​the working face avoids the main shortcomings of the traditional single grouting method. It adopts integrated three-dimensional grouting, the construction process is relatively simple, the impact on production operations is small, leakage of slurry is avoided, the slurry diffusion range is large, and the reinforcement effect is good. It can effectively solve the problem that the broken roof in the disturbance area above the unexcavated coal seam suddenly collapses and collapses during the mining process due to the influence of mining, and the working face has safety hazards and cannot ensure safe and efficient mining.

[0097] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0098] In the several embodiments provided herein, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0099] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of this article.

[0100] In addition, each functional unit in each embodiment of this invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional unit.

[0101] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this article is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of this article. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0102] Specific embodiments are used in this article to illustrate the principles and implementation methods of this article. The description of the above embodiments is only used to help understand the methods and core ideas of this article. At the same time, for general technicians in this field, according to the ideas of this article, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on this article.

Claims

1. A method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face, characterized in that: The following steps are involved: S1. Obtain the geological conditions of the coal mine working face and determine the structural data of the coal mine working face roof and coal seam; Including the thickness of the rock layer on the top of the working face and the degree of development of cracks inside the rock mass; S2. Divide the coal-rock mass in the disturbed area in front of the working face into zones according to the degree of development of cracks inside the rock mass and the stress distribution in the coal-rock mass, including zones of complete crushing, zones of crack development and zones of original rock structure; and correspond the zones to zones of high slurry permeability, zones of medium slurry permeability and zones of low slurry permeability according to the slurry permeability characteristics of each zone of the fractured coal-rock mass; S3. Through on-site grouting experiments, determine the grouting materials, grouting methods and grouting parameters for different partitions according to the degree of crack development in different partitions; S4, determining on-site grouting drilling parameters and advance grouting drilling parameters according to the structural data of the coal mine working face roof and coal seam; and performing on-site grouting drilling and advance grouting drilling; S5. According to the on-site grouting drilling and the advance grouting drilling, grouting is performed on the coal wall of the working face and the upper broken roof partitions at the same time, and the determined grouting material is injected into the corresponding partitions through the determined grouting method to complete the integrated grouting.

2. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 1 is characterized in that: The method of obtaining the geological conditions of the coal mine working face includes: using a comprehensive columnar stratification diagram of the coal mine working face or observing through drilling with a borehole peep instrument.

3. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 1, characterized in that: The partitions are made to correspond to the high slurry permeability zone, the medium slurry permeability zone and the low slurry permeability zone, including: the high slurry permeability zone corresponds to the completely broken zone, the medium slurry permeability zone corresponds to the fracture development zone, and the low slurry permeability zone corresponds to the original rock structure zone.

4. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 1 is characterized in that: The on-site grouting experiment includes: drilling holes in the grouting target area with a hole depth exceeding the fracture development area, and using a sealer to conduct a segmented sealing grouting test in the grouting test to determine the grouting materials, grouting methods and grouting parameters for different partitions; the grouting parameters include grouting hole spacing, inclination, grouting pressure and slurry type; the grouting methods include filling grouting, penetration grouting and high-pressure splitting grouting; the grouting materials include organic slurry silicate modified polyurethane materials, cement-based grouting materials and ultra-fine cement-based grouting materials.

5. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 1, characterized in that: The on-site grouting drilling and advance grouting drilling include: drilling multiple horizontal parallel on-site grouting holes at a preset interval vertically along the coal wall of the working face according to the on-site grouting drilling parameters, and drilling advance grouting holes inclined toward the upper roof at a preset angle in the drilling sites of the air tunnel and the machine tunnel according to the advance grouting drilling parameters.

6. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 5, characterized in that: Determining on-site grouting drilling parameters according to the structural data of the coal mine working face roof and coal seam includes: presetting the preset spacing and drilling depth of on-site grouting drilling for the working face according to the structural data of the coal mine working face roof and coal seam.

7. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 6, characterized in that: Determine the advance grouting drilling parameters according to the structural data of the coal mine working face roof and coal seam, including: preset advance grouting drilling hole bottom spacing, the distance between the end hole position and the front of the working face mining, the distance above the coal seam roof, the grouting pipe length, the sealing pipe length; calculate the advance grouting drilling angle, the advance grouting drilling depth and the distance between the advance grouting position and the coal wall of the working face; The advance grouting drilling angle θ is determined by the following formula: <h2 style=";text-align:left;direction:ltr">tanθ = H<h2 style=";text-align:left;direction:ltr"> 注 <h2 style=";text-align:left;direction:ltr"> / S2 (1) In the above formula (1), θ is the angle between the drilling axis and the horizontal direction; H 注 is the grouting height of the roof rock layer, m; S2 is the horizontal distance from the two tunnel drilling sites to the advance grouting position, m; The grouting height of the top rock layer is H 注 It can be obtained by the following formula: H 注 =M0 / (K P -1) (2) In the above formula (2), H 注 is the grouting height of the roof rock layer, m; M0 is the thickness of the coal seam, m; K P is the average expansion coefficient of the broken rock mass, and the average expansion coefficient of the broken rock mass is 1.45; The advance grouting drilling depth L can be obtained by the following formula: L=kH 注 / sinθ(3) In the above formula (3), L is the advance grouting drilling depth, m; k is the redundancy coefficient, ranging from 1.1 to 1.3; H 注 is the grouting height of the top rock layer, m; θ is the angle between the borehole axis and the horizontal direction; The distance S1 between the advance grouting position and the coal wall of the working face is determined by the following formula: In the above formula (4), h1 is the mining height of the working face; f is the friction coefficient of the contact surface between the coal seam and the roof; α is the internal friction angle of the coal body; K is the peak concentration coefficient of the advance support pressure; T is the bearing capacity of the coal body itself; γ is the volume force of the overlying rock stratum; and h2 is the buried depth of the coal seam.

8. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 7 is characterized in that: The advanced grouting drilling holes are arranged in an umbrella shape in the direction of the cutting eye.

9. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 8, characterized in that: The preset row spacing of the on-site grouting drilling is 5m, the drilling depth is 6-8m, the preset spacing of the bottom of the advanced grouting drilling is 15m, the final hole position is 30m in front of the working face mining, the coal seam roof is 15m from the ground, the length of the grouting pipe is not less than 70% of the hole depth, and the length of the sealing pipe is not less than 10m.

10. The method for on-site parallel three-dimensional grouting reinforcement of the advanced disturbance zone of a working face according to claim 1, characterized in that: The step of injecting the determined grouting material into the corresponding partition by a determined grouting method to complete the integrated grouting includes: For the completely broken coal and rock mass areas in front of the working face that are severely disturbed by mining, chemical grouting is carried out by filling grouting through on-site grouting drilling of vertical coal walls, and two-component organic slurry silicate modified polyurethane material is injected; in view of the incomplete coverage of the roof reinforced by long-distance advance grouting, dynamic complementation is carried out in the broken and leaking areas of the roof in the working face, and chemical slurry is injected in front of the local hydraulic support for reinforcement; For the roof fissure development area in front of the working face that is disturbed by mining with moderate intensity, the cement-based grouting material with a particle size of 10-70μm is injected through radial umbrella-shaped advance grouting holes by the penetration grouting method; For the roof original rock structure area 30m in front of the working face that is slightly disturbed or not affected by mining disturbance, ultra-fine cement-based grouting materials with a particle size of 5-10μm are injected through radial umbrella-shaped advance grouting holes using the high-pressure splitting grouting method with a grouting pressure of not less than 12MPa.

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