Deep coal seam roof blasting roof control and pressure relief anti-collision method

Abstract

The embodiment of the present application discloses a deep coal seam roof blasting roof caving control and pressure relief anti-collision method, relates to the technical field of deep coal seam roof blasting roof caving control and pressure relief anti-collision. The blasting method comprises the following steps: selecting a key rock stratum; determining a high-position blasting roadway in the key rock stratum; drilling boreholes in the roof, floor and side of the high-position blasting roadway along the longitudinal direction and the transverse direction of the mining working face, the longitudinal boreholes are parallel holes, the transverse boreholes are fan-shaped holes, and the longitudinal boreholes and the transverse boreholes form grid-shaped boreholes; charging the drilled boreholes; simultaneously initiating the transverse boreholes first, a large amount of gas and strong shock waves generated by blasting are utilized to form a group of parallel fracture surfaces; and initiating the longitudinal boreholes hole by hole, in the longitudinal borehole initiation process, the free surface formed by the fracture surfaces is utilized to guide the blasting energy to gather on the free surface to crush rocks. The present application is suitable for the coal seam mining scene.

Description

Technical Field

[0001] This invention relates to the field of deep coal seam roof blasting control and pressure relief and anti-impact technology, and particularly to a method for deep coal seam roof blasting control and pressure relief and anti-impact. Background Technology

[0002] Currently, the common practice is to construct blasting holes upwards from the working face's track and haulage route, combined with deep-hole blasting technology, to cut through the roof strata of the coal seam, control the caving step of the roof, and achieve periodic roof shearing to prevent large-scale roof collapse. However, this method does not consider the impact of the overlying roof's own impact tendency characteristics on mining safety. Especially for critical strata with a strong impact tendency, because these strata themselves store a large amount of deformation energy, the sudden release of this energy during normal caving can easily trigger dynamic disasters such as mine tremors and rock bursts.

[0003] Therefore, a new solution is urgently needed. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method for controlling and depressurizing the roof blasting of deep coal seams, which facilitates the control of the energy stored in key rock strata while controlling the collapse step of the coal seam roof, thereby weakening its impact tendency and ensuring the safety of the working face mining.

[0005] In a first aspect, the deep coal seam roof blasting control and pressure relief anti-scour method provided by the embodiments of the present invention includes the following steps: Based on a coal mine geological survey, determining the lithology and thickness of the strata above the coal seam; combining ground stress testing and microseismic monitoring data, selecting the roof strata with predetermined stress, predetermined strength, and a very thick stratum where the microseismic activity of the predetermined strength exceeds a predetermined frequency as the key stratum; determining a high-level blasting roadway in the key stratum, which can be determined by roadway excavation, wherein the high-level blasting roadway is used for blasting construction; drilling blast holes longitudinally and transversely along the mining face in the roof, floor, and sides of the high-level blasting roadway, wherein the longitudinal blast holes are parallel holes and the transverse blast holes are fan-shaped holes. The longitudinal and transverse boreholes form a grid of boreholes; the drilled boreholes are charged with explosives, and the charging section of the longitudinal boreholes is coupled with explosives; shaped charge is applied to the bottom area of ​​the charging section of the transverse boreholes, and coupled charge is applied to the area near the borehole opening of the charging section of the transverse boreholes; the non-charging sections of the longitudinal and transverse boreholes are sealed and plugged; in the formed grid of boreholes, the transverse boreholes are detonated simultaneously first, using the large amount of gas and powerful shock wave generated by the blast to form a set of parallel fracture surfaces; then the longitudinal boreholes are detonated one by one, and during the detonation of the longitudinal boreholes, the free surface formed by the fracture surface is used to guide the blasting energy to concentrate on the free surface to break the rock.

[0006] Optionally, in the deep coal seam roof blasting control and pressure relief method, the key rock layer is selected as the roof with predetermined stress, predetermined strength, and a very thick rock layer, where the microseismic activity of the predetermined intensity exceeds a predetermined frequency. This includes: the key rock layer has a thickness of 10 meters or more, a uniaxial compressive strength of 70 MPa or more, and the energy level of the event where the microseismic activity of the predetermined intensity exceeds the predetermined frequency is 10. 3 Above joules.

[0007] Optionally, in the deep coal seam roof blasting control and pressure relief and anti-impact method, the high-level blasting roadway can be a rectangular roadway or a straight-wall semi-circular arch roadway, the width of the high-level blasting roadway is 4.5 meters to 5 meters, the height of the high-level blasting roadway is 4 meters to 4.5 meters, and the cross-sectional area of ​​the high-level blasting roadway is greater than 17 square meters.

[0008] Optionally, in the deep coal seam roof blasting control and pressure relief and anti-impact method, the number of high-level blasting roadways is determined according to the thickness and width of the key rock strata, the width of the key rock strata is determined according to the width of the longwall face, the high-level blasting roadways are arranged at the horizontal centerline of the key rock strata, and the blasting holes constructed in a single high-level blasting roadway cover a rock mass interval 140 meters wide and 30 meters high.

[0009] Optionally, in the deep coal seam roof blasting control and pressure relief and anti-impact method, the longitudinal blast holes are arranged in the sidewalls of the high-level blasting roadway; the transverse blast holes are arranged in the roof, floor and sidewalls of the high-level blasting roadway.

[0010] Optionally, the deep coal seam roof blasting control and pressure relief method, wherein blast holes are drilled longitudinally and laterally along the longwall face, the longitudinal blast holes are parallel holes and the transverse blast holes are fan-shaped holes, including: the diameter of a single blast hole is R, the blasting radius formed by the single blast hole is R1; the blasting spacing b of the parallel holes is aR1, where a is 2; and the bottom distance of the fan-shaped holes is less than 5R1.

[0011] Optionally, in the deep coal seam roof blasting control and pressure relief method, the explosion fracture radius R1 formed by a single blast hole can be 8 to 12 times the diameter R of the single blast hole.

[0012] Optionally, in the deep coal seam roof blasting control and pressure relief method, the loading of the drilled blast holes includes: the depth of the blast hole is L, the length of the loading section L1 of the blast hole accounts for 65% to 75% of the total length L of the blast hole, and the length of the plugging section L2 for sealing the non-loading section accounts for 25% to 35% of the total length L of the blast hole.

[0013] Optionally, the deep coal seam roof blasting control and pressure relief method, wherein the charging section of the transverse borehole is charged with shaped charge at the bottom and the charging section of the transverse borehole is coupled with charge near the borehole opening, includes:

[0014] The spacing between two adjacent fan-shaped holes in the transverse borehole gradually increases along the depth direction. The range of the shaped charge is from the distance of 2R1 between the two adjacent fan-shaped holes along the depth direction to the bottom of the hole. The range of the coupling charge is from the blocking section to the distance of 2R1 between the two adjacent fan-shaped holes along the depth direction.

[0015] Optionally, the deep coal seam roof blasting control and pressure relief method includes the following: sequential detonation of longitudinal blast holes, which are arranged in order of increasing distance from the fan-shaped holes.

[0016] The deep coal seam roof blasting control and pressure relief method provided in this embodiment of the invention selects a roof with predetermined stress, predetermined strength, a thick rock stratum, and microseismic activity exceeding a predetermined frequency as the key rock stratum; a high-level blasting roadway is determined in the key rock stratum for blasting construction; blast holes are drilled longitudinally and transversely along the roof, floor, and sides of the high-level blasting roadway, the longitudinal blast holes being parallel holes and the transverse blast holes being fan-shaped holes, forming a grid of blast holes; explosives are loaded into the drilled blast holes, and the longitudinal blast holes are... The charging section is coupled with charging; and, the bottom range of the charging section of the transverse blast hole is charged with shaped charge, and the range near the orifice of the charging section of the transverse blast hole is coupled with charging; the non-charging sections of the longitudinal blast hole and the transverse blast hole are sealed and plugged; in the formed grid of blast holes, the transverse blast holes are detonated simultaneously first, and a set of parallel fracture surfaces are formed by using the large amount of gas and powerful shock wave generated by the blast; then the longitudinal blast holes are detonated one by one, and during the detonation of the longitudinal blast holes, the free surface formed by the fracture surface is used to guide the blasting energy to accumulate on the free surface to break the rock. By setting up a high-level blasting roadway in the key rock strata, and constructing longitudinal parallel blast holes and transverse fan-shaped blast holes in the roof, floor and sidewalls of the high-level blasting roadway, a crisscrossing blasting network is formed, and the blast holes are detonated in a gradient manner, forming a grid-like fracture field along the mining face in the thick key rock strata. The longitudinal fracture network is used to release the deformation energy of the rock mass stored in the key rock strata, causing damage and deterioration of the rock mass. The transverse fracture network is used to control the caving step. First, transverse blast holes are detonated simultaneously. The large amount of gas and powerful shock wave generated by the blasting create a set of parallel fracture surfaces. The transverse blast fracture zone ensures the safe caving of the key rock strata, ensuring safe mining. Then, longitudinal blast holes are detonated one by one. During the detonation of the longitudinal blast holes, the free surface formed by the fracture surfaces guides the blasting energy to concentrate on this free surface to break the rock. The longitudinal blast fracture zone allows the energy stored in the key rock strata to be rapidly released as deformation energy, weakening the mechanical properties of the rock mass and thus reducing the rock strata's impact tendency. In this way, while controlling the caving step of the coal seam roof, the energy stored in the key rock strata is controlled, and its impact tendency is weakened, thereby ensuring the safety of the working face mining. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the process for controlling and depressurizing the roof blasting of deep coal seams and preventing erosion, provided for an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of a key rock stratum and a high-level blasting tunnel provided for an embodiment of the present invention;

[0020] Figure 3 A schematic diagram of longitudinal and transverse blast holes in key rock strata provided for embodiments of the present invention;

[0021] Figure 4 A schematic diagram of the parallel hole spacing arrangement provided in an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of a fan-shaped borehole charging structure provided for an embodiment of the present invention. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] In deep coal mining, traditional methods involve drilling blast holes upwards from the working face's track and haulage route, combined with deep-hole blasting technology, to cut through the roof strata and control the roof's caving step, achieving periodic roof collapse and preventing large-scale roof falls. However, this method does not consider the impact of the overlying roof's inherent impact tendency on mining safety. Especially for critical strata with a strong impact tendency, these strata themselves store a large amount of deformation energy. During normal caving, the sudden release of this energy can easily trigger dynamic disasters such as mine tremors and rock bursts.

[0027] To facilitate the control of the energy stored in key rock strata while simultaneously controlling the caving step of the coal seam roof, thereby reducing its impact tendency and ensuring the safety of the working face mining, embodiments of the present invention provide a method for controlling and depressurizing the roof blasting of deep coal seams to prevent shove. See also... Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of the process for controlling and depressurizing the roof blasting of deep coal seams and preventing erosion, provided as an embodiment of the present invention. Figure 2 This is a schematic diagram of a key rock stratum and a high-level blasting tunnel provided for an embodiment of the present invention. Figure 2The left side of the diagram shows a transverse cross-section of the coal seam and rock strata, while the right side shows a longitudinal cross-section. The arrow below the coal seam in the longitudinal cross-section indicates the direction of coal seam mining. The methods for controlling and depressurizing the roof blasting and preventing shoveling in deep coal seams include:

[0028] S01. Based on the geological survey of the coal mine, the lithology and thickness of the rock strata above coal seam 1 are determined. Combined with the data from the geostress test and microseismic monitoring, the roof strata with predetermined stress, predetermined strength, and a very thick rock stratum, and with microseismic activity of predetermined strength exceeding the predetermined frequency, are selected as the key rock stratum 2.

[0029] In some embodiments, the deep coal seam roof blasting control and pressure relief method, wherein selecting the roof with predetermined stress, predetermined strength, and a very thick rock stratum, and where the microseismic activity of the predetermined intensity exceeds a predetermined frequency, as the key rock stratum, includes: the thickness of the key rock stratum being more than 10 meters, the uniaxial compressive strength of the rock being more than 70 MPa, and the energy level of the event where the microseismic activity of the predetermined intensity exceeds the predetermined frequency being 10. 3 Above joules.

[0030] S02. Determine the high-level blasting roadway 3 in the key rock strata. The high-level blasting roadway 3 can be determined by the roadway excavation method, wherein the high-level blasting roadway 3 is used for blasting construction.

[0031] In some embodiments, the deep coal seam roof blasting control and pressure relief method describes a high-level blasting roadway 3 that can be a rectangular roadway or a straight-walled semi-circular arch roadway. The width of the high-level blasting roadway 3 is 4.5 to 5 meters, the height is 4 to 4.5 meters, and the cross-sectional area is greater than 17 square meters. It is understood that, for ease of blasting operations, the width and height of the high-level blasting roadway are set to 4.5 to 5 meters, and the cross-sectional area is greater than 17 square meters.

[0032] In some embodiments, the method for controlling and relieving pressure during deep coal seam roof blasting and caving, wherein the number of high-level blasting roadways 3 is determined based on the thickness and width of the key rock stratum 2, the width of the key rock stratum 2 is determined based on the width of the longwall face, the high-level blasting roadways 3 are arranged at the horizontal centerline of the key rock stratum 2, and the blasting holes constructed in a single high-level blasting roadway 3 cover a rock mass interval 140 meters wide and 30 meters high. Specifically, multiple high-level blasting roadways can be determined based on the thickness and width of the key rock stratum.

[0033] S03. In the high-level blasting roadway 3, blast holes are drilled in the longitudinal and transverse directions along the mining face of the roof 31, floor 32 and sidewall. The longitudinal blast holes 4 are parallel holes and the transverse blast holes 5 are fan-shaped holes. The longitudinal blast holes 4 and the transverse blast holes 5 form a grid of blast holes 6.

[0034] Specifically, a high-level blasting tunnel 3 is set up in the key rock stratum 2, and longitudinal parallel blast holes 4 and transverse fan-shaped blast holes 5 are constructed in the roof 31, floor 32 and sidewalls of the high-level blasting tunnel 3 to form a crisscrossing blasting network. For example, Figure 3 As shown, Figure 3 This is a schematic diagram of longitudinal and transverse blast holes in a key rock stratum provided for an embodiment of the present invention. It is understood that the longitudinal blast holes 4 and the transverse blast holes 5 must satisfy a certain spatial relationship. The longitudinal blast holes 4 and the transverse blast holes 5 form a grid of parallel and fan-shaped holes 6, facilitating the formation of a larger blast fracture network. The transverse fan-shaped holes 7 are a schematic diagram from another angle of the transverse blast holes 5. Blasting operations are carried out in the determined key rock stratum to form a blast fracture network along the longitudinal and transverse directions of the mining face. The longitudinal fracture network is used to release the deformation energy of the rock mass stored in the key rock stratum, causing rock mass damage and deterioration. The transverse fracture network is used to control the caving step.

[0035] S04. The drilled borehole is loaded with explosives, and the loading section of the longitudinal borehole 4 is coupled with explosives.

[0036] It is understandable that coupled charging along the longitudinal blast hole charging section of the longwall face can form a large-scale fracture zone. The longitudinal blast fracture zone allows the stored energy of the key rock strata to be rapidly released as deformation energy, weakening the mechanical properties of the rock mass and thus reducing the rock strata's impact tendency.

[0037] S05, and, shaped charge is applied to the bottom area of ​​the charge section of the transverse borehole 5, coupled charge is applied to the area near the borehole opening of the charge section of the transverse borehole 5; the non-charge sections of the longitudinal borehole 4 and the transverse borehole 5 are sealed and plugged.

[0038] It is understandable that shaped charge is applied at the bottom of the blast hole along the transverse blast hole charging section of the longwall face, and coupled charge is applied near the hole opening. The transverse blasting fracture zone ensures that the key rock strata can collapse safely, thus ensuring the safety of longwall mining.

[0039] S06. In the formed gridded blast holes, the transverse blast holes 5 are detonated simultaneously first, and a set of parallel fracture surfaces are formed by using the large amount of gas and powerful shock wave generated by the explosion.

[0040] Specifically, the transverse blast holes are detonated simultaneously. The large amount of gas and powerful shock wave generated by the blasting create a set of parallel fracture surfaces. The transverse blasting fracture zone ensures that the key rock strata can collapse safely, thus ensuring safe mining.

[0041] S07. Then, the longitudinal borehole 4 is detonated one hole at a time. During the detonation of the longitudinal borehole 4, the blasting energy is guided to concentrate on the free surface formed by the fracture surface to break the rock.

[0042] In some embodiments, the deep coal seam roof blasting control and pressure relief method, wherein the sequential detonation of longitudinal blast holes includes: detonating each hole sequentially in order of increasing distance from the fan-shaped holes.

[0043] For example, electronic detonators can be used to detonate the blast holes in a gradient manner. Specifically, when detonating the blast holes in a gradient manner, the transverse blast holes are detonated simultaneously first, followed by the longitudinal blast holes one by one, forming a crisscrossing grid-like fracture field in the thick critical rock strata. During the detonation of the longitudinal blast holes, the free surface formed by the fracture surface is used to guide the blasting energy to accumulate on the free surface, thereby breaking the rock. The longitudinal blasting fracture zone allows the energy stored in the critical rock strata to be rapidly released as deformation energy, weakening the mechanical properties of the rock mass and thus reducing the impact tendency of the rock strata.

[0044] The deep coal seam roof blasting control and pressure relief method provided in this embodiment of the invention selects a roof with predetermined stress, predetermined strength, a thick rock stratum, and microseismic activity exceeding a predetermined frequency as the key rock stratum; a high-level blasting roadway is determined in the key rock stratum for blasting construction; blast holes are drilled longitudinally and transversely along the roof, floor, and sides of the high-level blasting roadway, the longitudinal blast holes being parallel holes and the transverse blast holes being fan-shaped holes, forming a grid of blast holes; explosives are loaded into the drilled blast holes, and the longitudinal blast holes are... The charging section is coupled with charging; and, the bottom range of the charging section of the transverse blast hole is charged with shaped charge, and the range near the orifice of the charging section of the transverse blast hole is coupled with charging; the non-charging sections of the longitudinal blast hole and the transverse blast hole are sealed and plugged; in the formed grid of blast holes, the transverse blast holes are detonated simultaneously first, and a set of parallel fracture surfaces are formed by using the large amount of gas and powerful shock wave generated by the blast; then the longitudinal blast holes are detonated one by one, and during the detonation of the longitudinal blast holes, the blasting energy is guided to accumulate on the free surface formed by the fracture surface to break the rock. By setting up a high-level blasting roadway in the key rock strata, and constructing longitudinal parallel blast holes and transverse fan-shaped blast holes in the roof, floor and sidewalls of the high-level blasting roadway, a crisscrossing blasting network is formed along the longwall face, and the blast holes are detonated in a gradient manner, forming a crisscrossing grid-like fracture field in the thick key rock strata. The longitudinal fracture network is used to release the deformation energy of the rock mass stored in the key rock strata, causing damage and deterioration of the rock mass. The transverse fracture network is used to control the caving step. First, transverse blast holes are detonated simultaneously. The large amount of gas and powerful shock wave generated by the blasting create a set of parallel fracture surfaces. The transverse blast fracture zone ensures the safe caving of the key rock strata, ensuring safe mining. Then, longitudinal blast holes are detonated one by one. During the detonation of the longitudinal blast holes, the free surface formed by the fracture surfaces guides the blasting energy to concentrate on this free surface to break the rock. The longitudinal blast fracture zone allows the energy stored in the key rock strata to be rapidly released as deformation energy, weakening the mechanical properties of the rock mass and thus reducing the rock strata's impact tendency. In this way, while controlling the caving step of the coal seam roof, the energy stored in the key rock strata is controlled, and its impact tendency is weakened, thereby ensuring the safety of the working face mining.

[0045] In some embodiments, the deep coal seam roof blasting control and pressure relief method comprises longitudinal blast holes arranged in the sidewalls of the high-level blasting roadway; and transverse blast holes arranged in the roof, floor and sidewalls of the high-level blasting roadway.

[0046] Specifically, in the roof, floor, and sides of the high-level blasting roadway, blast holes are drilled longitudinally and laterally along the mining face. Longitudinal blast holes are located in the sides of the high-level blasting roadway and are arranged in parallel configurations; transverse blast holes are located in the roof, floor, and sides of the high-level blasting roadway and are arranged in a fan-shaped configuration. The longitudinal and transverse blast holes must meet certain spatial relationships, forming a grid of parallel and fan-shaped holes to facilitate the formation of a larger blasting fracture network.

[0047] In some embodiments, the deep coal seam roof blasting control and pressure relief method, wherein drilling blast holes along the longitudinal and transverse sides of the longwall face, wherein the longitudinal blast holes are parallel holes and the transverse blast holes are fan-shaped holes, includes: the diameter of a single blast hole is R, the blasting radius formed by the single blast hole is R1; the blasting spacing b of the parallel holes is aR1, where a is 2; and the bottom distance of the fan-shaped holes is less than 5R1.

[0048] For example, see Figure 4 As shown, Figure 4 This is a schematic diagram of the parallel hole spacing arrangement provided in an embodiment of the present invention. The value of the hole radius 8 is half the diameter R of a single hole, the length of the blasting fracture zone 9 of a single hole is R1, and the value of the spacing 10 between two parallel holes is 2R1.

[0049] In some embodiments, in the deep coal seam roof blasting control and pressure relief method, the explosion fracture radius R1 formed by a single blast hole can be 8 to 12 times the diameter R of the single blast hole.

[0050] Furthermore, the explosive fracture radius R1 formed by a single borehole is taken as:

[0051]

[0052] Where, σ cd , σ ld — Uniaxial dynamic compressive strength and uniaxial dynamic tensile strength of the rock mass, MPa; ρ0 — Density of the explosive, Kg / m³ 3 ;D c —Detonation velocity of the explosive, m / s; K—Radial decoupled charge coefficient; l c —Axial charge coefficient; n—Pressure increase coefficient when explosive products expand and collide with the borehole wall; η—Expansion adiabatic index of detonation products; r b Here is the borehole radius, in mm; b = μ d / 1-μ d μ d The dynamic Poisson's ratio of the rock mass is given by μ, and the static Poisson's ratio of the rock mass is given by μ. α and β are the load propagation attenuation indices, where α = 2 + μ. d / 1-μ d β=2-μd / 1-μ d .

[0053] In some embodiments, the deep coal seam roof blasting control and pressure relief method, wherein the loading of the drilled blast holes includes: the depth of the blast hole is L, the length of the loading section L1 of the blast hole accounts for 65% to 75% of the total length L of the blast hole, and the length of the plugging section L2 for sealing the non-loading section accounts for 25% to 35% of the total length L of the blast hole.

[0054] In some embodiments, the deep coal seam roof blasting control and pressure relief method, wherein the shaped charge is applied to the bottom of the charging section of the transverse blast hole, and the coupling charge is applied to the area near the orifice of the charging section of the transverse blast hole, includes: the spacing between two adjacent fan-shaped holes in the transverse blast hole 5 gradually increases along the depth direction; the range of the shaped charge is from the spacing between the two adjacent fan-shaped holes along the depth direction of 2R1 to the bottom of the hole; the range of the coupling charge is from the blocking section to the position where the spacing between the two adjacent fan-shaped holes along the depth direction of 2R1.

[0055] For example, see Figure 5 As shown, Figure 5 This is a schematic diagram of a fan-shaped borehole charging structure provided in an embodiment of the present invention. The depth 11 of the fan-shaped borehole is L. The entire fan-shaped borehole is provided with a charging section 12 and a plugging section 13. The length of the charging section 12 is L1, and the length of the plugging section 13 is L2. The charging section 12 includes a coupling charging section 14 and a shaped charge section 15. Shaped charge is performed along the bottom range of the transverse borehole 5 of the longwall face, and coupling charge is performed within the borehole opening range. The boundary of the shaped charge range should meet the following requirement: the distance between two adjacent fan-shaped boreholes gradually increases along the depth direction. When it increases to 2R1, shaped charge is performed. That is, the shaped charge range is from the distance between two adjacent fan-shaped boreholes along the depth direction of 2R1 to the bottom of the borehole, and the coupling charge range is from the plugging section to the distance between two adjacent fan-shaped boreholes along the depth direction of 2R1.

[0056] It should be noted that while the various embodiments described herein have different focuses, they are also interconnected. When understanding the present invention, reference can be made between the various embodiments. Furthermore, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling and depressurizing the roof during deep coal seam roof blasting and preventing shove, characterized in that, Including the following steps: Based on the geological survey of the coal mine, the lithology and thickness of the rock strata above the coal seam were determined. Combined with the geostress test and microseismic monitoring data, the roof strata with predetermined stress, predetermined strength, thick rock strata, and microseismic activity of predetermined strength exceeding predetermined frequency were selected as the key rock strata. A high-level blasting roadway is determined in the key rock strata, and the high-level blasting roadway is determined by the roadway excavation method, wherein the high-level blasting roadway is used for blasting construction; In the high-level blasting roadway, blast holes are drilled longitudinally and laterally along the mining face in the roof, floor, and sidewalls. The longitudinal blast holes are parallel holes, and the transverse blast holes are fan-shaped holes, forming a grid of blast holes. The longitudinal blast holes are located in the sidewalls of the high-level blasting roadway, and the transverse blast holes are located in the roof, floor, and sidewalls of the high-level blasting roadway. The drilled borehole is loaded with explosives, and the loading section of the longitudinal borehole is coupled with the explosives. In addition, shaped charge is applied to the bottom area of ​​the charge section of the transverse borehole, and coupled charge is applied to the area near the borehole opening of the charge section of the transverse borehole; the non-charge sections of the longitudinal borehole and the transverse borehole are sealed and plugged. In the formed gridded blast holes, the transverse blast holes are detonated simultaneously first, and a set of parallel fracture surfaces are formed by using the large amount of gas and powerful shock wave generated by the explosion. Then, the longitudinal blast holes are detonated one by one. During the detonation of the longitudinal blast holes, the blasting energy is guided to concentrate on the free surface formed by the fracture surface to break the rock. The drilling of blast holes along the longitudinal and transverse directions of the longwall face, wherein the longitudinal blast holes are parallel holes and the transverse blast holes are fan-shaped holes, includes: The diameter of a single borehole is R, and the explosive fracture radius formed by the single borehole is R1; the value of the blasting spacing b of the parallel holes is aR1, where a is 2; the bottom distance of the fan-shaped holes is less than 5R1; the explosive fracture radius R1 formed by the single borehole is 8 to 12 times the diameter R of the single borehole. The loading of explosives into the drilled borehole includes: The depth of the borehole is L, the length of the charging section L1 of the borehole accounts for 65% to 75% of the total length L of the borehole, and the length of the plugging section L2 for sealing the non-charging section accounts for 25% to 35% of the total length L of the borehole. The process of performing shaped charge on the bottom portion of the charging section of the transverse borehole and coupling charge on the portion of the charging section near the borehole opening includes: The spacing between two adjacent fan-shaped holes in the transverse borehole gradually increases along the depth direction. The range of the shaped charge is from the distance of 2R1 between the two adjacent fan-shaped holes along the depth direction to the bottom of the hole. The range of the coupling charge is from the blocking section to the distance of 2R1 between the two adjacent fan-shaped holes along the depth direction.

2. The method for controlling and depressurizing the roof blasting and preventing shoveling in deep coal seams according to claim 1, characterized in that, The selected key rock strata are the top plate containing predetermined stress, predetermined strength, thick rock layers, and microseismic activity exceeding a predetermined frequency. These include: The key rock strata are more than 10 meters thick, have a uniaxial compressive strength of more than 70 MPa, and the energy level of microseismic activity exceeding a predetermined frequency is 10. 3 Above joules.

3. The method for controlling and depressurizing the roof blasting and preventing shoveling in deep coal seams according to claim 1, characterized in that, The high-level blasting tunnel is a rectangular tunnel or a straight-walled semi-circular arch tunnel. The width of the high-level blasting tunnel is 4.5 meters to 5 meters, the height of the high-level blasting tunnel is 4 meters to 4.5 meters, and the cross-sectional area of ​​the high-level blasting tunnel is greater than 17 square meters.

4. The method for controlling and depressurizing the roof blasting and preventing shoveling in deep coal seams according to claim 1, characterized in that, The number of high-level blasting roadways is determined based on the thickness and width of the key rock strata. The width of the key rock strata is determined based on the width of the longwall face. The high-level blasting roadways are arranged at the horizontal centerline of the key rock strata, and the blasting holes constructed in a single high-level blasting roadway cover a rock mass interval that is 140 meters wide and 30 meters high.

5. The method for controlling and depressurizing the roof blasting and preventing shoveling in deep coal seams according to claim 1, characterized in that, The sequential detonation longitudinal borehole includes: Detonation was carried out hole by hole in order of increasing distance from the fan-shaped holes.

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