Mine coal face coal rock mass grouting reinforcement method

Abstract

The invention discloses a coal and rock mass grouting reinforcement method for a coal face of a mine, which is characterized by comprising the following steps: preparing materials, tools and related accessories; performing hole marking by an acceptor; constructing a grouting hole; after the construction of the grouting hole is finished, accepting a drilled hole and sealing the hole; grouting, checking a grouting effect, stopping grouting, and cleaning equipment and a site; wherein in the grouting hole construction step, a plurality of sets of grouting holes are formed in a grouting reinforcement area, the distance between the sets is 3 m, each set comprises two grouting holes, and one grouting hole is formed in the coal face coal wall and one grouting hole is formed in the coal face top plate.

Description

Technical Field

[0001] The invention relates to the technical field of mine coal mining methods, and in particular to a grouting reinforcement method for coal rock mass at a mine coal mining working face. Background Art

[0002] During the early tunnel excavation period of the coal mining working face delineation, the tunnel section is small and less affected by mining. During the structural zone, the tunnel formation and support quality can be guaranteed by adding anti-slab anchors, pre-reserved anchors, using the front exploration beams on the fully-mechanized excavator, increasing the support, and manual excavation. However, during the mining and final withdrawal of the working face, the mine pressure is obvious due to the influence of geological structure, nearby goaf, mining disturbance, etc., especially near faults, folds, soft and broken coal zones, etc., the working face leaks and spalls, and the mining and withdrawal channel cannot be normally made.

[0003] Although the existing methods have adopted a series of measures such as pulling the frame in advance, moving the frame after the machine, driving through rods and anchor rods, and installing half-round logs and bamboo fences, they are all passive measures, with high safety risks during construction, low efficiency, and poor results.

[0004] Therefore, a method for grouting reinforcement of coal rock mass at coal mining working face in a mine is proposed. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a method for grouting reinforcement of coal rock mass at a coal mining working face in a mine.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows: A method for reinforcing coal rock mass by grouting at a coal mining face in a mine, comprising the following steps: preparing materials, tools and related accessories, and installing and debugging → inspectors marking holes → constructing grouting holes → inspecting the holes after the grouting holes are completed and sealing the holes → grouting → checking the grouting effect → stopping grouting → cleaning the equipment and cleaning the site; Among them, in the step of constructing grouting holes, several groups of grouting holes are set in the grouting reinforcement area, with a distance of 3m between groups, two grouting holes in each group, one each in the coal wall and roof of the coal mining working face; Among them, several groups of drill holes are divided into odd groups and even groups. Specifically, the lower holes of the odd group are arranged at the coal wall of the coal mining face 1m below the top plate of the coal mining face, and are constructed at an elevation angle of 8°-15° along the strike direction of the coal seam. The upper holes of the odd group are arranged at the top angle position where the coal wall of the coal mining face and the top plate of the coal mining face meet, and are constructed at an elevation angle of 35°-45° along the strike direction of the coal seam; the lower holes of the even group are arranged at the coal wall of the coal mining face 0.5m below the top plate of the coal mining face, and are constructed at an elevation angle of 8°-15° along the strike direction of the coal seam. The upper holes of the even group are arranged at the top plate of the coal mining face 0.5m away from the coal wall of the coal mining face, and are constructed at an elevation angle of 35°-45° along the strike direction of the coal seam. Each grouting hole is 5m deep, with a grouting volume of 1t and a drilling diameter of 35mm, and is equipped with a sealer matching the drilling diameter.

[0007] Among them, the grouting holes on the roof of the coal mining working face are constructed using an MQT-130 / 3.2 anchor net machine, and the grouting holes on the coal wall of the coal mining working face are constructed using an MQTB-130 / 3.5 auxiliary anchor machine.

[0008] The grouting reinforcement area is the geological structure influence zone and the top broken coal rock mass within 5m nearby. A round of grouting reinforcement operation in claim 1 is carried out every 6m of mining on the working face.

[0009] Among them, in the grouting step, it is first necessary to carry out slurry mixing, specifically, the polymer curing material group A and group B are mixed in a volume ratio of 1:1 and fully reacted. The curing radius of the curing material is 1.5m, among which the polymer curing material group A is a silicate modified polyurethane material, and the polymer curing material group B is Guant CM-15.

[0010] Wherein, in the grouting step, a ZYBQ-3.8 / 31.5 mining pneumatic injection pump is used for grouting, and the grouting pressure is 4-6MPa.

[0011] Among them, in the grouting step, the following preparations should be made for grouting construction: prepare a power air source with a pressure of 0.4-0.7MPa; equip a DN16 high-pressure hose with a length from the compressed air joint to the grouting pump, and transport the solidified material group A and group B pairs and the grouting equipment to the air inlet chute or the return air chute for classified storage; prepare cleaning agents, emulsions or engine oils; prepare enough cotton yarn and wooden wedges to prevent the raw materials from flowing out through the cracks and causing waste.

[0012] Among them, in the grouting step, the grouting pipe is processed with 1-inch steel pipe, the grouting port is welded as DN10 straight through according to the grouting pipeline interface, and the end is processed with a 2.0m long flower pipe to increase the grouting penetration effect; the hole mouth is sealed with cotton yarn and curing material, and the sealing length is not less than 1.0m; the grouting volume of a single hole is 1000kg, and when the diffusion is poor, the number of grouting holes on the side is increased.

[0013] Among them, in the grouting step, for coal rock mass with medium fissure density, that is, coal rock mass with fissure width greater than 1mm, the interval skipping hole grouting method is adopted to reduce slurry cross-linking and improve the grouting effect; for large areas, the grouting sequence of first the periphery and then the interior is adopted; for the overall reinforcement of broken coal pillars, the combination of deep and shallow holes and the interval skipping hole grouting method are adopted. The grouting begins to solidify within 1-2 minutes after grouting, and the broken and soft coal mass is bonded into a resin cement body with an adhesion of 1MPa. The compressive strength is 3-4h after grouting. Greater than 25MPa, which greatly enhances the overall strength of the coal body and effectively reduces the degree of damage to the coal seam, thereby ensuring safe production; for coal rock masses with a high degree of crack development and crack density, that is, coal rock masses with crack width greater than 1cm or a grouting pressure of 4Mpa and a grouting time of less than 2min, that is, grouting carriers with slurry leakage, shallow grouting is adopted first, and after the slurry diffuses, an overall coal body with a slurry-stopping effect is quickly formed in the shallow part to prevent slurry leakage, and then deep grouting is performed to ensure the deep slurry diffusion range and grouting pressure.

[0014] Among them, in the grouting step, when the following situations occur, the following judgment criteria for stopping grouting should be strictly followed to avoid grouting accidents: a. The designed grouting pressure of 4MPa is reached and the pressure is maintained for more than 3min; although the grouting pressure has not been reached, grouting occurs, and grouting still occurs after intermittent grouting and the amount of grouting is greater than 90% of the grouting amount; during the grouting process, abnormal splitting noises are found in the coal and rock mass in the grouting area; when the grouting amount of a single hole has reached the amount designed in the grouting scheme; b. The grouting amount of each hole should be uniform, and the error of the grouting amount of each hole should be controlled within 150kg; c. The grouting diffusion range reaches 1.5m and above; d. It begins to solidify within 1-2min after grouting, and the broken and soft coal body is bonded into a resin binder with an adhesion of 1MPa. After 3-4h, the compressive strength is greater than 25MPa, which can greatly enhance the strength of the overall coal body and effectively reduce the degree of damage to the coal seam, thereby ensuring safe production.

[0015] Among them, the two steps of constructing grouting holes and grouting both adopt the 3:8 continuous operation mode. Each shift, the construction of grouting holes and grouting operations are divided into 3 groups and carried out simultaneously in sections, with 5-7 people in each group, including 2-3 people for the construction of grouting holes and grouting, and 3-4 people for material transportation and loading. The air supply capacity of the construction site is 3m³ / min, and the air supply pressure is 0.5Mpa. After grouting reinforcement, reinforcing support anchor rods are driven on the top of the local spalling and top crushing locations of the working face for reinforced support. After support, the working face is mined normally.

[0016] The beneficial effects of the present invention are: 1. The present invention aims to solve the problems of soft and broken coal and rock mass, difficult mining and high safety risks during the period when the coal mining working face in the mine passes through the structural zone. By taking active measures, the mining procedures and processes of the coal mining working face are adjusted, and the soft and broken sections of the top coal and rock mass are solidified in advance using reinforcing polymer materials such as Guant and polyurethane. Through the high pressure of the grouting pump, the filling and solidifying materials are fully injected into the soft coal mass on the top and coal side, increasing the strength of the surrounding rock of the top side of the working face, achieving the purpose of reinforcement, reducing spalling and roof collapse, ensuring safe and efficient mining of the working face, and providing safety guarantees for the roof management and retreat passage of the coal mining working face.

[0017] 2. The method of the present invention effectively improves the integrity and stability of the soft coal rock mass near the structural zone of the mine working face, increases the strength of the surrounding surrounding rock, reduces the impact of the structural zone on the mining activities of the working face, and has achieved good results in production practice. It effectively avoids the occurrence of roof accidents such as spalling and roof leakage in the coal mining working face, and is suitable for the safe and smooth passage of the coal mining working face through the structural zone and the production of equipment withdrawal channels in the mine. It has been promoted and applied in the production of false bottoms with large deformation of the working face, the excavation working face passing through the structural zone, and small interlayer spacing.

[0018] 3. The application of the present invention in the process of mining through the structural belt of the coal mining face in the mine avoids the frequent occurrence of top crushing and spalling of the working face, eliminates the occurrence of roof accidents of the coal mining face, and ensures the production task of raw coal at the same time, with the monthly output exceeding the plan by more than 10,000 tons.

[0019] 4. The application of the present invention in determining the stop-mining line of a coal mining working face in a mine can move the designed stop-mining line of the working face outward, increase the output of raw coal, and create more economic benefits.

[0020] 5. The present invention is promoted and applied in the tunnel excavation working face through the structural belt, which improves the integrity of the broken coal and rock mass and creates a high-quality environment for rapid excavation. During the excavation period, the single-head monthly excavation footage of the coal tunnel set a record of 250m. The working face can be delineated in advance, effectively alleviating the tense situation of mining and excavation continuity.

[0021] 6. The promotion and application of the present invention in the air inlet and return chute of the coal mining face in the mine effectively solves the problems of large deformation of the chute, obvious pressure, broken nets and falling bags during the mining process, and ensures the safety of the top and wall of the tunnel during the mining period.

[0022] 7. The present invention is applied to the stratified mining of local coal seams with small spacing in the coal mining working face of a mine. The working face bottom plate is reinforced by grouting to produce a false bottom, which serves as a hard coal mining working face top plate of the upper working face, creating favorable conditions for the management of the coal mining working face top plate during the recovery of the working face.

[0023] 8. The application of the present invention during the production of a withdrawal channel in a coal mining face in a mine improves the quality of anchor net support in the channel through grouting reinforcement technology, shortens the production period of the withdrawal channel, and ensures the safe withdrawal of equipment in the withdrawal channel. At the same time, it effectively alleviates the difficulty of fire prevention and extinguishing management during the closing period of the working face, and provides ample time and space for the rapid closure of the working face. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a schematic diagram of the arrangement of odd-numbered arrays of drilling holes in the construction grouting hole step of the present invention.

[0025] Figure 2 It is a schematic diagram of the arrangement of even-numbered arrays of drilling holes in the construction grouting hole step of the present invention.

[0026] Figure 3 It is a schematic diagram of the spatial arrangement of odd-numbered arrays of drilling holes and even-numbered arrays of drilling holes in the construction grouting hole step of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0028] Example 1 like Figures 1 to 3 As shown, a method for grouting reinforcement of coal rock mass at a coal mining face in a mine comprises the following steps: preparing materials, tools and related accessories, and installing and debugging → inspectors marking holes → constructing grouting holes → inspecting the holes after the grouting holes are completed and sealing the holes → grouting → checking the grouting effect → stopping grouting → cleaning the equipment and cleaning the site; In the step of constructing grouting holes, several groups of grouting holes are set in the grouting reinforcement area 2, with a distance of 3m between groups, two grouting holes in each group, one each in the coal wall 3 and the roof 5 of the coal mining working face; The plurality of groups of boreholes are divided into an odd group and an even group. Specifically, the lower holes 1-11 of the odd group are arranged at the coal wall (3) of the coal mining face below 1 m from the top plate 5 of the coal mining face, and are constructed at an elevation angle of 8° along the strike direction of the coal seam. The upper holes 1-12 of the odd group are arranged at the top angle position where the coal wall 3 of the coal mining face and the top plate 5 of the coal mining face meet, and are constructed at an elevation angle of 35° along the strike direction of the coal seam. The lower holes 2-11 of the even group are arranged at the coal wall 3 of the coal mining face below 0.5 m from the top plate 5 of the coal mining face, and are constructed at an elevation angle of 8° along the strike direction of the coal seam. The upper holes 2-12 of the even group are arranged at the top plate 5 of the coal mining face 0.5 m from the coal wall 3 of the coal mining face, and are constructed at an elevation angle of 35° along the strike direction of the coal seam. Each grouting hole is 5m deep, with a grouting volume of 1t and a drilling diameter of 35mm, and is equipped with a sealer matching the drilling diameter.

[0029] The grouting holes of the roof 5 of the coal mining face are constructed by using an MQT-130 / 3.2 anchor net machine, and the grouting holes of the coal wall 3 of the coal mining face are constructed by using an MQTB-130 / 3.5 anchor machine.

[0030] The grouting reinforcement area 2 is the geological structure influence zone and the top broken coal rock mass within 5m nearby. A round of grouting reinforcement operation in claim 1 is carried out every 6m of mining on the working face.

[0031] Among them, in the grouting step, it is first necessary to carry out slurry mixing, specifically, the polymer curing material group A and group B are mixed in a volume ratio of 1:1 and fully reacted. The curing radius of the curing material is 1.5m, among which the polymer curing material group A is a silicate modified polyurethane material, and the polymer curing material group B is Guant CM-15.

[0032] Among them, in the grouting step, a ZYBQ-3.8 / 31.5 mining pneumatic injection pump is used for grouting, and the grouting pressure is 4MPa.

[0033] Among them, in the grouting step, the following preparations should be made for grouting construction: prepare a power air source with a pressure of 0.4MPa; equip a DN16 high-pressure hose with a length from the compressed air joint to the grouting pump, and transport the solidified material group A and group B pairs and the grouting equipment to the air inlet chute or the return air chute for classified storage; prepare cleaning agents, emulsions or engine oils; prepare enough cotton yarn and wooden wedges to prevent the raw materials from flowing out through the cracks and causing waste.

[0034] Among them, in the grouting step, the grouting pipe is processed with 1-inch steel pipe, the grouting port is welded as DN10 straight through according to the grouting pipeline interface, and the end is processed with a 2.0m long flower pipe to increase the grouting penetration effect; the hole mouth is sealed with cotton yarn and curing material, and the sealing length is not less than 1.0m; the grouting volume of a single hole is 1000kg, and when the diffusion is poor, the number of grouting holes on the side is increased.

[0035] Among them, in the grouting step, for coal rock mass with medium crack density, that is, coal rock mass with crack width greater than 1mm, the interval jump hole grouting method is adopted to reduce slurry cross-linking and improve the grouting effect; for large areas, the grouting sequence of first the periphery and then the interior is adopted; for the overall reinforcement of broken coal pillars, the combination of deep and shallow holes and the interval jump hole grouting method are adopted. The grouting begins to solidify within 1 minute after grouting, and the broken and soft coal mass is bonded into a resin cement body, and its bonding force reaches 1MPa. After 3h, the compressive strength is greater than 25MPa, which greatly enhances the strength of the overall coal body and effectively reduces the degree of damage to the coal seam, thereby ensuring safe production; for coal rock masses with high fissure development and fissure density, that is, coal rock masses with fissure width greater than 1cm or grouting pressure of 4Mpa, grouting time less than 2min, that is, grouting carriers with slurry leakage, shallow grouting is adopted first, and after the slurry diffuses, an overall coal body with a slurry-stopping effect is quickly formed in the shallow part to prevent slurry leakage, and then deep grouting is performed to ensure the deep slurry diffusion range and grouting pressure.

[0036] Among them, in the grouting step, when the following situations occur, the following judgment criteria for stopping grouting should be strictly followed to avoid grouting accidents: a. The designed grouting pressure of 4MPa is reached and the pressure is maintained for more than 3min; although the grouting pressure has not been reached, grouting occurs, and grouting still occurs after intermittent grouting and the amount of grouting is greater than 90% of the grouting amount; during the grouting process, abnormal splitting noises are found in the coal and rock mass in the grouting area; when the grouting amount of a single hole has reached the amount designed in the grouting scheme; b. The grouting amount of each hole should be uniform, and the error of the grouting amount of each hole should be controlled within 150kg; c. The grouting diffusion range reaches 1.5m and above; d. It begins to solidify within 1min after grouting, and the broken and soft coal body is bonded into a resin binder with an adhesion of 1MPa. After 3h, the compressive strength is greater than 25MPa, which can greatly enhance the strength of the overall coal body and effectively reduce the degree of damage to the coal seam, thereby ensuring safe production.

[0037] Among them, the two steps of constructing grouting holes and grouting both adopt the 3:8 continuous operation mode. Each shift, the construction of grouting holes and grouting operations are divided into 3 groups and carried out simultaneously in sections, with 5 people in each group, including 2 people for the construction of grouting holes and grouting, and 3 people for material transportation and loading; the air supply capacity of the construction site is 3m³ / min, and the air supply pressure is 0.5Mpa; after grouting reinforcement, 4 reinforcing support anchor rods are driven at the top of the local spalling and top crushing locations of the working face for reinforced support, and the working face is mined normally after support.

[0038] Example 2 like Figures 1 to 3 As shown, a method for grouting reinforcement of coal rock mass at a coal mining face in a mine comprises the following steps: preparing materials, tools and related accessories, and installing and debugging → inspectors marking holes → constructing grouting holes → inspecting the holes after the grouting holes are completed and sealing the holes → grouting → checking the grouting effect → stopping grouting → cleaning the equipment and cleaning the site; In the step of constructing grouting holes, several groups of grouting holes are set in the grouting reinforcement area 2, with a distance of 3m between groups, two grouting holes in each group, one each in the coal wall 3 and the roof 5 of the coal mining working face; Among them, several groups of drill holes are divided into odd groups and even groups. Specifically, the lower holes 1-11 of the odd group are arranged at the coal wall 3 of the coal mining face below 1m from the top plate 5 of the coal mining face, and are constructed at an elevation angle of 15° along the strike direction of the coal seam. The upper holes 1-12 of the odd group are arranged at the top angle position where the coal wall 3 of the coal mining face and the top plate 5 of the coal mining face meet, and are constructed at an elevation angle of 45° along the strike direction of the coal seam; the lower holes 2-11 of the even group are arranged at the coal wall 3 of the coal mining face below 0.5m from the top plate 5 of the coal mining face, and are constructed at an elevation angle of 15° along the strike direction of the coal seam. The upper holes 2-12 of the even group are arranged at the top plate 5 of the coal mining face 0.5m from the coal wall 3 of the coal mining face, and are constructed at an elevation angle of 45° along the strike direction of the coal seam. Each grouting hole is 5m deep, with a grouting volume of 1t and a drilling diameter of 35mm, and is equipped with a sealer matching the drilling diameter.

[0039] The grouting holes of the roof 5 of the coal mining face are constructed by using an MQT-130 / 3.2 anchor net machine, and the grouting holes of the coal wall 3 of the coal mining face are constructed by using an MQTB-130 / 3.5 anchor machine.

[0040] The grouting reinforcement area 2 is the geological structure influence zone and the top broken coal rock mass within 5m nearby. A round of grouting reinforcement operation in claim 1 is carried out every 6m of mining on the working face.

[0041] Among them, in the grouting step, it is first necessary to carry out slurry mixing, specifically, the polymer curing material group A and group B are mixed in a volume ratio of 1:1 and fully reacted. The curing radius of the curing material is 1.5m, among which the polymer curing material group A is a silicate modified polyurethane material, and the polymer curing material group B is Guant CM-15.

[0042] Among them, in the grouting step, a ZYBQ-3.8 / 31.5 mining pneumatic injection pump is used for grouting, and the grouting pressure is 6MPa.

[0043] Among them, in the grouting step, the following preparations should be made for grouting construction: prepare a power air source with a pressure of 0.7MPa; equip a DN16 high-pressure hose with a length from the compressed air joint to the grouting pump, and transport the solidified material group A and group B pairs and the grouting equipment to the air inlet chute or the return air chute for classified storage; prepare cleaning agents, emulsions or engine oils; prepare enough cotton yarn and wooden wedges to prevent the raw materials from flowing out through the cracks and causing waste.

[0044] Among them, in the grouting step, the grouting pipe is processed with 1-inch steel pipe, the grouting port is welded as DN10 straight through according to the grouting pipeline interface, and the end is processed with a 2.0m long flower pipe to increase the grouting penetration effect; the hole mouth is sealed with cotton yarn and curing material, and the sealing length is not less than 1.0m; the grouting volume of a single hole is 1000kg, and when the diffusion is poor, the number of grouting holes on the side is increased.

[0045] Among them, in the grouting step, for coal rock mass with medium fissure development degree and fissure density, that is, coal rock mass with fissure width greater than 1mm, the interval skipping hole grouting method is adopted to reduce slurry cross-linking and improve the grouting effect; for large areas, the grouting sequence of first the periphery and then the interior is adopted; for the overall reinforcement of broken coal pillars, the combination of deep and shallow holes and the interval skipping hole grouting method are adopted. The grouting begins to solidify within 2 minutes after grouting, and the broken and soft coal mass is bonded into a resin cement body with an adhesion of 1MPa. After 4 hours, the compressive strength is greater than 25MPa, which greatly enhances the strength of the overall coal body and effectively reduces the degree of damage to the coal seam, thereby ensuring safe production; for coal rock masses with a high degree of crack development and crack density, that is, coal rock masses with crack width greater than 1cm or grouting pressure of 4Mpa, grouting time of less than 2min, that is, grouting carriers with slurry leakage, shallow grouting is adopted first, and after the slurry diffuses, an overall coal body with a slurry-stopping effect is quickly formed in the shallow part to prevent slurry leakage, and then deep grouting is performed to ensure the deep slurry diffusion range and grouting pressure.

[0046] Among them, in the grouting step, when the following situations occur, the following judgment criteria for stopping grouting should be strictly followed to avoid grouting accidents: a. The designed grouting pressure of 4MPa is reached and the pressure is maintained for more than 3min; although the grouting pressure has not been reached, grouting occurs, and grouting still occurs after intermittent grouting and the amount of grouting is greater than 90% of the grouting amount; during the grouting process, abnormal splitting noises are found in the coal and rock mass in the grouting area; when the grouting amount of a single hole has reached the amount designed in the grouting scheme; b. The grouting amount of each hole should be uniform, and the error of the grouting amount of each hole should be controlled within 150kg; c. The grouting diffusion range reaches 1.5m and above; d. It begins to solidify within 2min after grouting, and the broken and soft coal body is bonded into a resin binder with an adhesion of 1MPa. After 4h, the compressive strength is greater than 25MPa, which can greatly enhance the strength of the overall coal body and effectively reduce the degree of damage to the coal seam, thereby ensuring safe production.

[0047] Among them, the two steps of constructing grouting holes and grouting both adopt the 3:8 continuous operation mode. The construction of grouting holes and grouting operations in each shift are divided into 3 groups and carried out simultaneously in sections, with 7 people in each group, including 3 people for the construction of grouting holes and grouting, and 4 people for material transportation and loading; the air supply capacity of the construction site is 3m³ / min, and the air supply pressure is 0.5Mpa; after grouting reinforcement, 4 reinforcing support anchor rods are driven at the top of the local spalling and top crushing locations of the working face for reinforced support, and the working face is mined normally after support.

[0048] The above-mentioned embodiments effectively improved the integrity and stability of the soft coal rock mass near the structural zone of the working face, increased the strength of the surrounding surrounding rock, reduced the impact of the structural zone on the mining activities of the working face, and effectively avoided the occurrence of roof accidents such as spalling and roof leakage; the average monthly raw coal output exceeded the plan by 12,000 tons; the designed stop-mining line of the working face was moved outward by 25 meters, the raw coal production increased by nearly 15,000 tons, and the additional benefits created were up to 11 million yuan; during the production of the withdrawal channel, through the implementation of this method, the quality of the anchor net support in the channel was improved, and the production period of the withdrawal channel was shortened by nearly 8 days. The total construction period of the working face withdrawal channel production, equipment withdrawal, closure of the working face and other finishing withdrawal work was 36 days, which ensured the safe withdrawal of the equipment in the withdrawal channel while effectively alleviating the difficulty of fire prevention and extinguishing management during the finishing period of the working face, and provided ample time and space for the rapid closure of the working face.

[0049] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine, characterized in that: The following steps are involved: Prepare materials, tools and related accessories, and install and debug → inspectors mark holes → construct grouting holes → inspect and seal holes after grouting holes are completed → grouting → check grouting effect → stop grouting → clean equipment and clean up the site; In the step of constructing grouting holes, a plurality of groups of grouting holes are arranged in the grouting reinforcement area (2), with a spacing of 3 m between groups, and two grouting holes in each group, one each in the coal wall (3) and the roof (5) of the coal mining working face; The plurality of groups of boreholes are divided into an odd group and an even group. Specifically, the lower holes (1-11) of the odd group are arranged at the coal wall (3) of the coal mining face 1 m below the top plate (5) of the coal mining face, and are constructed at an elevation angle of 8°-15° along the strike direction of the coal seam. The upper holes (1-12) of the odd group are arranged at the top angle position where the coal wall (3) of the coal mining face and the top plate (5) of the coal mining face meet, and are constructed at an elevation angle of 35°-45° along the strike direction of the coal seam. The lower holes (2-11) of the even group are arranged at the coal wall (3) of the coal mining face 0.5 m below the top plate (5) of the coal mining face, and are constructed at an elevation angle of 8°-15° along the strike direction of the coal seam. The upper holes (2-12) of the even group are arranged at the coal wall (3) of the coal mining face 0.5 m above the top plate (5) of the coal mining face, and are constructed at an elevation angle of 35°-45° along the strike direction of the coal seam. Each grouting hole is 5m deep, with a grouting volume of 1t and a drilling diameter of 35mm, and is equipped with a sealer matching the drilling diameter.

2. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 1, characterized in that: The grouting holes of the coal mining face roof (5) are constructed using an MQT-130 / 3.2 anchor net machine, and the grouting holes of the coal mining face coal wall (3) are constructed using an MQTB-130 / 3.5 anchor machine.

3. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 1, characterized in that: The grouting reinforcement area (2) is the geological structure influence zone and the top broken coal rock mass within a range of 5m nearby. A round of grouting reinforcement operation in claim 1 is carried out every 6m of mining on the working face.

4. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 1, characterized in that: In the grouting step, the slurry ratio needs to be carried out first, specifically, the polymer curing material group A and group B are mixed in a volume ratio of 1:1 and fully reacted. The curing radius of the curing material is 1.5m, among which the polymer curing material group A is a silicate modified polyurethane material, and the polymer curing material group B is Guant CM-15.

5. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 4, characterized in that: In the grouting step, a ZYBQ-3.8 / 31.5 mining pneumatic injection pump is used for grouting, and the grouting pressure is 4-6MPa.

6. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 5, characterized in that: In the grouting step, the following preparations should be made for the grouting construction: prepare a power air source with a pressure of 0.4-0.7MPa; equip a DN16 high-pressure hose with a length from the compressed air joint to the grouting pump, and transport the solidified material group A and group B pairs and the grouting equipment to the air inlet chute or the return air chute for classified storage; prepare cleaning agents, emulsions or engine oils; prepare enough cotton yarn and wooden wedges to prevent the raw materials from flowing out through the cracks and causing waste.

7. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 6, characterized in that: In the grouting step, the grouting pipe is processed using a 1-inch steel pipe, the grouting port is welded as a DN10 straight-through according to the grouting pipeline interface, and the end is processed with a 2.0m long flower pipe to increase the grouting penetration effect; the hole mouth is sealed with cotton yarn and curing material, and the sealing length is not less than 1.0m; the grouting volume of a single hole is 1000kg, and when the diffusion is poor, the number of grouting holes on the side is increased.

8. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 7, characterized in that: In the grouting step, for coal rock mass with medium fissure density, that is, coal rock mass with a fissure width greater than 1 mm, an interval skip hole grouting method is used to reduce slurry cross-linking and improve the grouting effect; for a large area, a grouting sequence of first the periphery and then the interior is adopted; for the overall reinforcement of the broken coal pillar, a combination of deep and shallow holes and an interval skip hole grouting method are adopted. The grouting begins to solidify within 1-2 minutes after grouting, and the broken soft coal mass is bonded into a resin cement body, and its bonding force reaches 1MPa. After 3-4 hours, the compressive strength is high. The pressure is higher than 25MPa, which greatly enhances the overall strength of the coal body and effectively reduces the degree of damage to the coal seam, thereby ensuring safe production; for coal rock masses with high fissure development and fissure density, that is, coal rock masses with fissure width greater than 1cm or grouting pressure of 4Mpa and grouting time of less than 2min, that is, grouting carriers with slurry leakage, shallow grouting is adopted first, and after the slurry diffuses, an overall coal body with a slurry-stopping effect is quickly formed in the shallow part to prevent slurry leakage, and then deep grouting is performed to ensure the deep slurry diffusion range and grouting pressure.

9. A method for grouting reinforcement of coal rock mass at a coal mining face in a mine according to claim 8, characterized in that: In the grouting step, when the following situations occur, the following judgment criteria for stopping grouting should be strictly followed to avoid grouting accidents: a. The designed grouting pressure of 4MPa is reached and the pressure is maintained for more than 3min; although the grouting pressure has not been reached, grouting occurs, and grouting still occurs after intermittent grouting and the grouting amount is greater than 90% of the grouting amount; during the grouting process, abnormal splitting noises are found in the coal and rock mass in the grouting area; when the grouting amount of a single hole has reached the amount designed in the grouting scheme; b. The grouting amount of each hole should be uniform, and the error of the grouting amount of each hole should be controlled within 150kg; c. The grouting diffusion range is 1.5m or more; d. It begins to solidify within 1-2min after grouting, and the broken and soft coal body is bonded into a resin binder with an adhesion of 1MPa. After 3-4h, the compressive strength is greater than 25MPa, which can greatly enhance the strength of the overall coal body and effectively reduce the degree of damage to the coal seam, thereby ensuring safe production.

10. A method for grouting reinforcement of coal and rock mass at a coal mining face in a mine according to claim 1, characterized in that: The two steps of constructing the grouting holes and grouting are both carried out in a three-eighth continuous operation mode. The construction of the grouting holes and grouting operations are divided into three groups for each shift and are carried out simultaneously in sections, with 5-7 people in each group, including 2-3 people for the construction of the grouting holes and grouting, and 3-4 people for material transportation and loading. The air supply capacity of the construction site is 3m³ / min, and the air supply pressure is 0.5Mpa. After grouting reinforcement, reinforcing support anchor rods (4) are installed at the top of the local spalling and top crushing locations of the working face for reinforcement support. After support, the working face is mined normally.

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