Combined pressure relief method of blasting cracking in thick bottom coal with gangue in rock burst mine tunnel

Abstract

The present invention discloses a combined pressure relief method for thick-layer bottom coal and gangue in rock burst mine tunnels, comprising: evenly dividing the gangue-containing area of the thick-layer bottom coal in the mine tunnel into n stages; selecting measuring points in each stage and conducting lithology measurements on the mine tunnel floor to obtain the gangue lithology and thickness of the thick-layer bottom coal in each stage; dividing the gangue-containing area into different regional grades; formulating large-diameter drilling pressure relief program parameters and coal seam blasting pressure relief program parameters for the different graded areas based on the regional grades; and formulating large-diameter drilling and coal seam blasting pressure relief construction procedures for the different graded areas based on the large-diameter drilling pressure relief program parameters and the coal seam blasting pressure relief program parameters to achieve combined pressure relief for thick-layer bottom coal and gangue in the tunnel. This method effectively improves the pressure relief effect of the gangue-containing area of the thick-layer bottom coal in rock burst mine tunnels, reduces the risk of impact dynamic disasters caused by insufficient pressure relief due to gangue inclusions, and improves the life safety factor of underground workers.

Description

Technical Field

[0001] The invention relates to the field of coal mining and coal mine safety technology, in particular to a combined pressure relief method for thick-layer bottom coal with gangue blasting in rock burst mine tunnels. Background Art

[0002] Coal seam tunnels are a prime area for rock burst disasters. Excavation in coal seams with rock burst requires extensive engineering and is highly labor-intensive. Once a rock burst occurs, it can easily lead to tunnel damage and casualties. For thick coal seams, retaining a bottom coal layer in the tunnel is an unavoidable technical challenge. When the coal seam structure is complex, interbedded gangue of varying thicknesses can occur in the tunnel bottom coal, increasing the risk of rock bursts from the tunnel floor. Currently, large-diameter drilling holes in the bottom coal layer are commonly used to decompress the bottom coal layer containing interbedded gangue. While this method is effective for coal seams, it is less effective for rock layers containing interbedded gangue, rendering it ineffective for relieving pressure. Furthermore, the lithology and thickness of interbedded gangue often vary, further inhibiting the effectiveness of conventional pressure-relief methods. Developing an effective bottom coal decompression scheme to mitigate the rock burst risk in the tunnel bottom coal layer, given the constantly changing lithology and thickness of interbedded gangue, is an urgent task. Summary of the Invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a combined pressure relief method for coal-interbedded gangue blasting and fracturing in thick-layer bottom coal of rock burst mine tunnels. The rock burst area of thick-layer bottom coal of rock burst mine tunnels is divided into multiple stages, and two measuring points are selected in each stage to measure the rock burst rock properties and thickness of the rock burst rock by drilling into the tunnel floor. At the same time, the rock burst area of thick-layer bottom coal of rock burst mine tunnels is divided into different rock burst grades according to the rock burst rock properties and thickness of the rock burst rock. Pressure relief parameters for different rock burst grades are formulated, and a pressure relief construction procedure is set. The combined pressure relief of coal seam blasting and large-diameter pressure relief is achieved under different rock burst grades. The method effectively improves the pressure relief effect of the rock burst area of thick-layer bottom coal of rock burst mine tunnels, reduces the risk of impact dynamic disasters caused by insufficient pressure relief due to rock burst rock, and improves the life safety factor of underground workers.

[0004] In order to achieve the above technical objectives, the present invention provides a combined pressure relief method for thick coal and gangue blasting at the bottom of a rock burst mine tunnel, comprising the following steps:

[0005] S1, the thick bottom coal containing gangue area of the mine tunnel is evenly divided into n stages;

[0006] S2, selecting a measuring point in each stage and measuring the lithology of the bottom plate of the mine roadway to obtain the interbedded gangue lithology and thickness of the thick bottom coal in each stage;

[0007] S3, dividing the interbedded gangue area into different regional grades based on the interbedded gangue lithology and the interbedded gangue thickness;

[0008] S4, based on the regional grades, respectively formulating parameters for large-diameter drilling pressure relief schemes and coal seam blasting pressure relief schemes for regions of different grades;

[0009] S5. Based on the parameters of the large-diameter drilling pressure relief scheme and the parameters of the coal seam blasting pressure relief scheme, large-diameter drilling and coal seam blasting pressure relief construction procedures for different grade areas are formulated to achieve combined pressure relief by blasting and fracturing of thick bottom coal with gangue in the tunnel.

[0010] Optionally, in S1, the length of the stage is 30 to 60 m.

[0011] Optionally, in S2, the rock properties are measured on the bottom plate of the mine tunnel by coring with a vertical depth of 15 m.

[0012] Optionally, in S3, the calculation formula of the area level is:

[0013] W=KH

[0014] Where W represents the impact hazard index of the thick bottom coal containing interbedded gangue area in the mine tunnel; K represents the rock type of interbedded gangue, which is 0.5 for sandstone, 1.0 for sandy mudstone, and 1.5 for mudstone; H represents the thickness of interbedded gangue.

[0015] Optionally, when 0<W≤1.5, the region grade of the region containing interbedded gangue is Grade I;

[0016] When 1.5<W≤4.5, the area grade of the area containing interbedded gangue is Grade II;

[0017] When 4.5<W≤9, the area grade of the area containing interbedded gangue is Grade III;

[0018] When W>9, the area grade of the area containing interbedded gangue is Grade IV.

[0019] Optionally, in S4, the process of formulating the parameters of the large-diameter drilling pressure relief scheme and the parameters of the coal seam blasting pressure relief scheme is as follows:

[0020] When the area grade of the gangue-containing area is Grade I: the diameter of the large-diameter drill hole is 150 mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine tunnel, the drilling strike spacing is 2.0 m, and the drilling depth is D1;

[0021] When the area grade of the area containing interbedded gangue is grade II: the large diameter drilling hole is 150 mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine roadway, and the drilling depth is D1; the coal seam blasting hole is 42 mm, four holes are arranged, the drilling depth is D2, the single hole charge is 0.5~1.0 kg, and the drilling angle is α=-45~60° along the direction of the mine roadway;

[0022] When the area grade of the area containing interbedded gangue is Grade III: the large diameter drill hole is 150 mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine roadway, and the drilling depth is D1; the coal seam blasting hole is 42 mm, four holes are arranged, the drilling depth is D2, the single hole charge is 1.0~2.0 kg, and the drilling angle is α=-45~60° along the direction of the mine roadway;

[0023] When the area grade of the area containing interbedded gangue is Grade IV: the diameter of the coal seam blasting hole is 42 mm, three holes are arranged, the drilling depth is D2, the charge of a single hole is 2.5 kg, and the drilling angle is α=-45~60° along the direction of the mine tunnel.

[0024] Optionally, the calculation formula of D1 is:

[0025]

[0026] Wherein, S is the thickness of the thick bottom coal, and α is the drilling angle.

[0027] Optionally, the calculation formula of D2 is:

[0028]

[0029] Where S1 is the distance between the gangue and the mine roadway floor, H is the thickness of the gangue, and α is the drilling angle.

[0030] The present invention has the following technical effects:

[0031] The thick coal-interbedded areas in the mine roadway were divided into multiple stages. Within each stage, two measuring points were selected to measure the interbedded lithology and thickness of the interbedded lithology by drilling and coring the roadway floor. Furthermore, the thick coal-interbedded areas in the mine roadway were divided into different interbedded lithology and thickness levels based on the interbedded lithology. Pressure relief parameters for different interbedded lithology levels were developed, and a pressure relief construction procedure was established. This combined pressure relief using coal seam blasting and large-diameter pressure relief was achieved under different interbedded lithology levels. This approach effectively improved the pressure relief effect in the thick coal-interbedded areas of rock burst mine roadways, reduced the risk of impact dynamic hazards caused by insufficient pressure relief due to interbedded lithology, and improved the safety of underground workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a flow chart of a combined pressure relief method for thick-layer bottom coal and gangue blasting in rock burst mine tunnels according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic cross-sectional view of the result of the grade classification of different interbedded gangue areas in an embodiment of the present invention;

[0035] Figure 3 This is a schematic cross-sectional diagram of the arrangement of the Level I interbedded gangue combined pressure relief drilling holes in an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of a top view of a mine tunnel with a Class I gangue combined pressure relief drilling arrangement according to an embodiment of the present invention;

[0037] Figure 5 Schematic diagram of the strike cross section of the arrangement of the II-level gangue blasting combined with pressure relief drilling in an embodiment of the present invention;

[0038] Figure 6 Schematic diagram of a top view of a mine tunnel with a II-level gangue blasting combined with pressure relief drilling arrangement according to an embodiment of the present invention;

[0039] Figure 7 Schematic diagram of the strike cross section of the drill hole arrangement for the combined pressure relief of Grade III gangue blasting in an embodiment of the present invention;

[0040] Figure 8 Schematic diagram of a top view of a mine tunnel with Class III gangue blasting combined with pressure relief drilling arrangement in an embodiment of the present invention;

[0041] Figure 9 Schematic diagram of the cross-section of the IV-level gangue blasting combined with pressure relief drilling arrangement in an embodiment of the present invention;

[0042] Figure 10 This is a schematic top view of a mine tunnel with a Class IV gangue blasting combined with pressure relief drilling arrangement in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] Example

[0045] like Figure 1 As shown, the present invention discloses a combined pressure relief method for thick-layer bottom coal and gangue blasting in rock burst mine tunnels, comprising:

[0046] S1, the thick bottom coal containing gangue area of the mine tunnel is divided into n stages, each stage length is L n , L n It is 30 to 60 meters.

[0047] S2, two measuring points are selected in each stage, and the lithology is measured by coring at the bottom of the mine roadway to obtain the interbedded gangue lithology and gangue thickness of the thick bottom coal in each stage, the thickness S of the thick bottom coal and the distance S1 between the interbedded gangue and the bottom of the mine roadway. The vertical depth of coring is 15m.

[0048] S3, based on the interlayer lithology and thickness of interlayer, the interlayer area is divided into different regional grades. The regional grade division results are as follows: Figure 2 The calculation formula of regional level is:

[0049] W=KH

[0050] Where W represents the impact hazard index of the thick bottom coal containing interbedded gangue area in the mine tunnel; K represents the rock type of interbedded gangue, which is 0.5 for sandstone, 1.0 for sandy mudstone, and 1.5 for mudstone; H represents the thickness of interbedded gangue.

[0051] When 0<W≤1.5, the area grade of the area containing interbedded gangue is Grade I;

[0052] When 1.5<W≤4.5, the area grade of the area containing interbedded gangue is Grade II;

[0053] When 4.5<W≤9, the area grade of the area containing interbedded gangue is Grade III;

[0054] When W>9, the area grade of the area containing interbedded gangue is Grade IV.

[0055] S4, based on the regional level, formulate the parameters of large-diameter drilling pressure relief scheme and coal seam blasting pressure relief scheme for different level areas;

[0056] When the area grade of the area containing interbedded gangue is Grade I: the diameter of the large diameter drill hole is 150mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine tunnel, the drilling spacing is 2.0m, and the drilling depth is

[0057] When the area grade of the area containing interbedded gangue is Grade II: the diameter of the large diameter drilling hole is 150mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine roadway, and the drilling depth is The diameter of the coal seam blasting hole is 42mm, with four holes arranged and the drilling depth is The charge per hole is 0.5-1.0 kg, and the drilling angle is α=-45-60° along the direction of the mine tunnel;

[0058] When the area grade of the area containing interbedded gangue is grade III: the diameter of the large diameter drilling hole is 150mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine tunnel, and the drilling depth is The diameter of the coal seam blasting hole is 42mm, with four holes arranged and the drilling depth is The charge per hole is 1.0-2.0 kg, and the drilling angle is α=-45-60° along the direction of the mine tunnel;

[0059] When the area grade of the area containing interbedded gangue is Grade IV: the diameter of the coal seam blasting hole is 42mm, three holes are arranged, and the drilling depth is The charge for a single hole is 2.5 kg, and the drilling angle is α = -45 to 60° along the direction of the mine tunnel.

[0060] S5. Based on the parameters of the large-diameter drilling and coal seam blasting unloading schemes, develop the large-diameter drilling and coal seam blasting unloading construction procedures for different grade areas to achieve combined unloading of thick bottom coal and gangue blasting. The specific construction procedures are as follows:

[0061] When the area grade of the area containing interbedded gangue is Grade I: large diameter drilling is used to relieve pressure, coal seam blasting is not used; the construction layout is as follows: Figure 3 and Figure 4 shown.

[0062] When the area grade of the area containing interbedded gangue is Grade II: first implement large diameter drilling to relieve pressure, and then implement coal seam blasting to relieve pressure on both sides of the large diameter drilling hole; the construction layout is as follows: Figure 5 and Figure 6 shown.

[0063] When the area grade of the area containing interbedded gangue is Grade III: first implement coal seam blasting to relieve pressure, implement large diameter drilling to relieve pressure at the original position of the coal seam blasting to relieve pressure, and perform secondary expansion of the coal seam blasting hole; the construction layout is as follows: Figure 7 and Figure 8 shown.

[0064] When the area with interbedded gangue is of Grade IV: coal seam blasting is used for pressure relief instead of large diameter drilling. The construction layout is as follows: Figure 9 and Figure 10 shown.

[0065] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A combined pressure relief method for thick coal and gangue blasting in rock burst mine tunnels, characterized by: The following steps are involved: S1, dividing the thick bottom coal and gangue-containing area of the mine tunnel into n stages; the length of each stage is 30 to 60 m; S2, selecting a measuring point in each stage and measuring the lithology of the bottom plate of the mine roadway to obtain the interbedded gangue lithology and thickness of the thick bottom coal in each stage; S3, dividing the interbedded gangue area into different regional grades based on the interbedded gangue lithology and the interbedded gangue thickness; S4, based on the regional grades, respectively formulating parameters for large-diameter drilling pressure relief schemes and coal seam blasting pressure relief schemes for regions of different grades; The process of formulating the parameters of the large-diameter drilling pressure relief scheme and the coal seam blasting pressure relief scheme parameters is as follows: When the area grade of the gangue-containing area is Grade I: the diameter of the large-diameter drill hole is 150 mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine tunnel, the drilling strike spacing is 2.0 m, and the drilling depth is D1; When the area grade of the area containing interbedded gangue is grade II: the large diameter drilling hole is 150 mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine roadway, and the drilling depth is D1; the coal seam blasting hole is 42 mm, four holes are arranged, the drilling depth is D2, the single hole charge is 0.5~1.0 kg, and the drilling angle is α=-45~60° along the direction of the mine roadway; When the area grade of the area containing interbedded gangue is Grade III: the large diameter drill hole is 150 mm, three holes are arranged, the drilling angle is α=-45~60° along the direction of the mine roadway, and the drilling depth is D1; the coal seam blasting hole is 42 mm, four holes are arranged, the drilling depth is D2, the single hole charge is 1.0~2.0 kg, and the drilling angle is α=-45~60° along the direction of the mine roadway; When the area grade of the area containing interbedded gangue is Grade IV: the diameter of the coal seam blasting hole is 42 mm, three holes are arranged, the drilling depth is D2, the charge of a single hole is 2.5 kg, and the drilling angle is α=-45~60° along the direction of the mine roadway; The calculation formula of D1 is: Where S is the thickness of the thick bottom coal, and α is the drilling angle; The calculation formula of D2 is: Where S1 is the distance between the gangue and the mine roadway floor, H is the thickness of the gangue, and α is the drilling angle; S5. Based on the parameters of the large-diameter drilling pressure relief scheme and the parameters of the coal seam blasting pressure relief scheme, large-diameter drilling and coal seam blasting pressure relief construction procedures for different grade areas are formulated to achieve combined pressure relief by blasting and fracturing of thick bottom coal with gangue in the tunnel.

2. The rock burst mine tunnel thick layer coal mixed with gangue blasting cracking combined pressure relief method according to claim 1, characterized in that: In S2, the rock properties of the mine tunnel floor are measured by coring with a vertical depth of 15 m.

3. The rock burst mine tunnel thick layer coal mixed with gangue blasting cracking combined pressure relief method according to claim 1, characterized in that: In S3, the calculation formula of the area level is: W=KH Where W represents the impact hazard index of the thick bottom coal containing interbedded gangue area in the mine tunnel; K represents the rock type of interbedded gangue, which is 0.5 for sandstone, 1.0 for sandy mudstone, and 1.5 for mudstone; H represents the thickness of interbedded gangue.

4. The rock burst mine tunnel thick layer coal mixed with gangue blasting cracking combined pressure relief method according to claim 3, characterized in that: When 0<W≤1.5, the area grade of the area containing interbedded gangue is Grade I; When 1.5<W≤4.5, the area grade of the area containing interbedded gangue is Grade II; When 4.5<W≤9, the area grade of the area containing interbedded gangue is Grade III; When W>9, the area grade of the area containing interbedded gangue is Grade IV.

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