Coal roadway outburst prevention method for blocking coal seam supporting body

Abstract

The invention provides a coal roadway outburst prevention method for blocking a coal seam supporting body, which belongs to the technical field of comprehensive development and utilization of coal mine gas and comprises the following steps of: performing gas concentration detection on a coal seam to obtain gas concentrations of different areas of the coal seam, and performing mechanical analysis on the coal seam to obtain relative ground stress of the coal seam; dividing the gas grade of the coal seam according to the gas concentration of different areas of the coal seam, and dividing the stress grade of the coal seam according to the relative ground stress of different areas of the coal seam to obtain a stress gas grade area of the coupled coal seam; according to the coal seam inclination angle, a protection range is defined, and conventional strip outburst elimination measures are implemented; within the range of the strip protection area, cement mortar is injected into the coal body through the bottom drainage roadway for reinforcement, and anchor rods are driven into the coal seam to support the coal seam according to the stress gas grade area of the coal seam; according to the method, the dangerous level areas are divided, strip coal body reinforcement is carried out on the basis of strip outburst elimination, the possibly deformed areas are protected, and therefore reasonable utilization of coal mine gas is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive development and utilization of coal mine gas, and in particular to a coal laneway outburst prevention method for blocking a coal seam support body. Background Art

[0002] Coal tunnel outburst prevention refers to a series of preventive measures taken during coal mining against possible coal and gas outbursts in coal seams. Coal and gas outburst refers to a dynamic phenomenon in which the coal body suddenly ruptures and is accompanied by the release of a large amount of gas due to the combined effect of ground stress and gas pressure during coal mining. This outburst phenomenon is extremely destructive and dangerous.

[0003] Coal and gas outbursts are affected by three factors: ground stress, gas, and mechanical properties of coal. The existing coal tunnel outburst prevention technology mainly focuses on coal seam gas extraction, and pays less attention to the role of these two factors: ground stress and mechanical properties of coal. There is a lack of technical methods to use different measures to block the coal seam support in different danger zones to solve the problem of soft coal damage under high stress conditions. As a result, in recent years, there have been many low gas content / pressure accidents under high stress and low strength coal conditions, causing a large number of casualties. Especially with the continuous increase in the mining depth of coal mines, such accidents will become more and more common. It is very necessary to control the damage of coal under different stress conditions. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for preventing coal roadway outbursts by blocking coal seam support bodies. By dividing the dangerous level areas, strip coal body reinforcement is carried out on the basis of strip outburst elimination, and the areas where deformation may occur are protected, thereby avoiding the occurrence of outbursts. Specifically, it includes:

[0005] A method for preventing coal roadway outbursts by blocking a coal seam support body, comprising:

[0006] Before coal seam excavation, gas concentration detection is performed on the coal seam to obtain the gas concentration in different areas of the coal seam, and mechanical analysis is performed on the coal seam to obtain the relative ground stress of the coal seam;

[0007] Dividing the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, and dividing the stress grade of the coal seam according to the relative ground stress in different areas of the coal seam, to obtain the stress gas grade area of ​​the coal seam after coupling;

[0008] According to the inclination of the coal seam, the protection range is delineated and conventional strip outburst elimination measures are implemented;

[0009] In the strip protection zone, cement mortar is injected into the coal body through the bottom pumping tunnel for reinforcement, and anchor bolts are driven into the coal seam through the bottom pumping tunnel according to the stress gas grade area of ​​the coal seam to support the coal seam;

[0010] Start gas extraction operations;

[0011] Before mining operations begin, the installed anchor bolts are removed.

[0012] Optionally, the detecting of gas concentration in the coal seam to obtain gas concentrations in different areas of the coal seam includes:

[0013] Before coal seam excavation, structural detection of the working face is carried out through drilling detection technology, and combined with gas parameter testing, the gas concentration in different areas of the coal seam is evaluated to obtain the gas concentration in different areas of the coal seam.

[0014] Optionally, dividing the stress level of the coal seam according to the relative ground stress of different areas of the coal seam includes:

[0015] The relative ground stress of the coal seam is determined using a stress gauge within 50 m of the selected target area.

[0016] Optionally, the classifying the gas grade of the coal seam according to the gas concentration in different areas of the coal seam includes:

[0017] When Q min ≤Q<(Q min + Q max ) / 2, the current area is a low-gas area;

[0018] When Q ≥ (Q min + Q max ) / 2, the current area is a high-gas area;

[0019] Among them, Q min is the gas concentration of the area with the lowest gas concentration, Q is the gas concentration of the current area, and Q max The gas concentration is the area with the highest gas concentration.

[0020] Optionally, dividing the stress levels of the coal seam according to the relative ground stresses of different areas of the coal seam includes:

[0021] When σ min ≤σ<(σ min + σ max ) / 2, the current area is a low stress area;

[0022] When σ≥(σ min + σ max ) / 2, the current area is a high stress area;

[0023] Among them, σ min is the stress of the area with the lowest stress, σ is the stress of the current area, and σ max is the stress in the area with the highest stress.

[0024] Optionally, the stress gas grade area of ​​the coal seam after the coupling includes:

[0025] Low stress and low gas area, high stress and low gas area, low stress and high gas area and high stress and high gas area.

[0026] Optionally, the protection range is delineated according to the coal seam inclination, and conventional strip outburst elimination measures are implemented, including:

[0027] When the coal seam inclination ∈ [0°, 15°], the protection zone is 20 m;

[0028] When the coal seam inclination is greater than 15°, the protection zone is 30 m;

[0029] According to the working face design, multiple drill holes are arranged along the tunnel, evenly distributed at the edge of the strip protection zone, and conventional strip outburst elimination measures are implemented.

[0030] Optionally, within the strip protection zone, cement mortar is injected into the coal body through the bottom pumping tunnel for reinforcement, and according to the stress gas grade area of ​​the coal seam, anchor bolts are driven into the coal seam through the bottom pumping tunnel to support the coal seam, which includes:

[0031] Before the grouting operation, drill holes are arranged in the bottom extraction tunnel, and then cement mortar is injected into the coal body for reinforcement;

[0032] The grouting pressure should be controlled within the range of 1 / 2-2 / 3 of the ground-to-ground stress in the current area;

[0033] Among them, the grouting pressure gradually increases;

[0034] Determine the anchor length for each stress gas grade area according to the coal seam thickness;

[0035] The distance between each anchor rod is determined according to the stress gas grade area.

[0036] Optionally, determining the anchor rod length of each stress gas grade area according to the coal seam thickness includes:

[0037] The bolt length in low-stress low-gas areas and low-stress high-gas areas is 1.5 times the thickness of the coal seam;

[0038] The bolt length in high stress low gas area and high stress high gas area is 2.5 times the coal seam thickness;

[0039] Determining the distance between the anchor rods according to the stress gas grade area includes:

[0040] Multiple rows of anchors are evenly arranged in each area, in a single area:

[0041] When the area is a low-stress and low-gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 10m;

[0042] When the area is a low stress and high gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 7m;

[0043] When the area is a high stress and low gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 4m;

[0044] When the area is a high-stress and high-gas area, the distance between two adjacent anchor rods in any horizontal row or any vertical column in this area is 1m.

[0045] The present invention reinforces the coal body in strips in areas with different danger levels, protects the areas where deformation may occur, and thus avoids the occurrence of outbursts. Compared with the prior art, the above technical scheme has at least the following beneficial effects: (1) It changes the idea of ​​focusing on gas extraction in the traditional coal tunnel outburst prevention technology, proposes a strip coal body reinforcement technology, effectively enhances the stability of the coal seam support body, protects the areas where deformation may occur in advance, reduces the risk of coal and gas outbursts, and provides new ideas for the prevention and control of coal and gas outbursts. (2) Comprehensively consider the control effect of the three elements of ground stress, gas, and coal body mechanical properties on outbursts, carefully divide the outburst danger level, and implement control measures of different strengths on this basis, so as to achieve precise control of coal body destruction under different stress and gas pressure conditions and improve the outburst prevention effect. (3) With the increase of coal mining depth, coal and gas outburst accidents under high stress and low strength coal body conditions will become more and more frequent. Compared with traditional gas control technology, this technology has stronger pertinence. (4) By controlling the destruction of strip coal bodies, coal and gas outburst disasters can be prevented and controlled. The workload is lower than that of traditional gas extraction technology, which can reduce the cost of outburst prevention and thus ensure the rational use of coal mine gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of 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 creative work.

[0047] Figure 1 This is the anchor rod arrangement diagram of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "one" or "the" do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0050] It should be noted that the terms "up", "down", "left", "right", "front" and "back" used in the present invention are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0051] In order to solve the problems existing in the prior art, this embodiment provides a coal tunnel anti-burst method for blocking the coal seam support body. The main implementation contents include: before coal seam excavation, structural detection and gas parameter testing are carried out on the working face to determine the gas distribution; mechanical analysis is carried out on the working face to determine the stress distribution; the gas concentration is increased from the minimum value Q min To the maximum value Q max , divided into two grade areas, and the stress is also increased from the lowest value σ min To the maximum value σ maxDivide into 2 levels, and form four level areas by superimposing gas pressure and stress distribution: high stress and high gas area, low stress and high gas area, high stress and low gas area, low stress and low gas area; according to the inclination of the coal seam, define the protection range and implement conventional strip outburst elimination measures; within the strip protection range, inject cement mortar into the coal body through the bottom pumping lane for reinforcement; drive anchor rods into the coal seam in the bottom pumping lane to further support the coal seam; after completing the support and grouting, start the gas extraction operation; after the roadway gas outburst elimination measures are completed, implement the working face outburst prevention measures, and remove the installed anchor rods before the start of the mining operation, so as to further carry out the mining of the coal seam. The present invention divides the dangerous level area, and reinforces the strip coal body on the basis of strip outburst elimination, protects the area where deformation may occur, and thus avoids the occurrence of outburst.

[0052] The specific implementation is as follows:

[0053] A method for preventing coal roadway outbursts by blocking a coal seam support body, comprising:

[0054] S1. Before coal seam excavation, gas concentration detection is performed on the coal seam to obtain the gas concentration in different areas of the coal seam, and mechanical analysis is performed on the coal seam to obtain the relative ground stress of the coal seam:

[0055] Before coal seam excavation, structural detection of the working face is carried out through drilling detection technology, and combined with gas parameter testing, the gas concentration in different areas of the coal seam is evaluated to obtain the gas concentration in different areas of the coal seam.

[0056] The relative ground stress of the coal seam is determined using a stress gauge within 50 m of the selected target area.

[0057] In this step, the working face is structurally detected by drilling detection technology, and the gas concentration in the coal seam is evaluated by combining gas parameter testing. Through these detection data, the gas content is identified so that high-gas and low-gas areas can be determined later;

[0058] The numerical simulation method is used to study the influence of factors such as mining layout, ground height and coal seam structure on the stress field. The data measured by stress gauge and numerical simulation are combined to subsequently determine the high-stress and low-stress areas of the working face.

[0059] S2, dividing the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, dividing the stress grade of the coal seam according to the relative ground stress in different areas of the coal seam, and obtaining the stress gas grade area of ​​the coal seam after coupling;

[0060] Wherein, the gas grade of the coal seam according to the gas concentration in different areas of the coal seam includes:

[0061] When Q min ≤Q<(Qmin + Q max ) / 2, the current area is a low-gas area;

[0062] When Q ≥ (Q min + Q max ) / 2, the current area is a high-gas area;

[0063] Among them, Q min is the gas concentration of the area with the lowest gas concentration, Q is the gas concentration of the current area, and Q max The gas concentration is the area with the highest gas concentration.

[0064] Wherein, the classification of the stress levels of the coal seam according to the relative ground stresses of different areas of the coal seam includes:

[0065] When σ min ≤σ<(σ min + σ max ) / 2, the current area is a low stress area;

[0066] When σ≥(σ min + σ max ) / 2, the current area is a high stress area;

[0067] Among them, σ min is the stress of the area with the lowest stress, σ is the stress of the current area, and σ max is the stress in the area with the highest stress.

[0068] Among them, the stress gas grade areas of the coal seam after the coupling include: low stress and low gas area, high stress and low gas area, low stress and high gas area and high stress and high gas area.

[0069] In this step, the gas concentration is mainly increased from the minimum value Q min To the maximum value Q max , divided into two grade areas, and the stress is also increased from the lowest value σ min To the maximum value σ max Divided into 2 levels, by superimposing gas pressure and stress distribution, four level areas are formed, including:

[0070] According to the measured gas pressure, it is increased from the minimum value Q min to the average value (Q min + Q max ) / 2, average value (Q min +Q max ) / 2 to the maximum value Q max , divided into two levels of areas: high gas area and low gas area;

[0071] Similarly, based on the measured stress, it is reduced from the minimum value σmin to the mean value (σ min + σ max ) / 2, average value (σ min +σ max ) / 2 to the maximum value σ max , divided into 2 levels of areas: high stress area and low stress area;

[0072] The gas pressure and stress distribution are superimposed to form four grade zones: high stress and high gas zone, low stress and high gas zone, high stress and low gas zone, and low stress and low gas zone.

[0073] S3. Delineate the protection range according to the coal seam inclination and implement conventional strip outburst elimination measures:

[0074] When the coal seam inclination ∈ [0°, 15°], the protection zone is 20 m;

[0075] When the coal seam inclination is greater than 15°, the protection zone is 30 m;

[0076] According to the working face design, multiple drill holes are arranged along the tunnel, evenly distributed at the edge of the strip protection zone, and conventional strip outburst elimination measures are implemented.

[0077] In this step, when the coal seam inclination is small (0°-15°), the width of the strips on both sides is small, the protection range is 10-20 m, and the protection range is 20 m; when the coal seam inclination increases (15°-30° or greater), the width of the strips on both sides needs to be increased, the protection range is 20-30 m, and the protection range is 30 m;

[0078] According to the working face design, multiple drill holes are arranged along the tunnel, evenly distributed at the edge of the strip protection zone, and conventional strip outburst elimination measures are implemented.

[0079] Conventional strip burst elimination measures are existing technologies, such as gas extraction, drilling pressure relief, hydraulic punching, etc.

[0080] S4. Inject cement mortar into the coal body through the bottom pumping tunnel to reinforce it within the strip protection zone, and according to the stress gas grade area of ​​the coal seam, drive anchor rods into the coal seam through the bottom pumping tunnel to support the coal seam;

[0081] Before the grouting operation, drill holes are arranged in the bottom extraction tunnel, and then cement mortar is injected into the coal body for reinforcement; the grouting pressure should be controlled within the range of 1 / 2-2 / 3 of the ground stress in the current area, and the grouting pressure increases gradually.

[0082] During this operation, the grouting pressure should be controlled within the range of 1 / 2-2 / 3 of the ground stress in the current area. When the grouting starts, the grouting pressure needs to be gradually increased (still controlled within the range of 1 / 2-2 / 3 of the ground stress) to ensure effective reinforcement of the coal seam.

[0083] like Figure 1 As shown, the anchor length of each stress gas grade area is determined according to the coal seam thickness:

[0084] The bolt length in low-stress low-gas areas and low-stress high-gas areas is 1.5 times the thickness of the coal seam;

[0085] The bolt length in high stress low gas area and high stress high gas area is 2.5 times the coal seam thickness;

[0086] That is: the anchor length is determined according to the coal seam thickness (H). The anchor length is generally 1.5 times the coal seam thickness. In high stress areas, the anchor length is 2.5 times the coal seam thickness.

[0087] like Figure 1 As shown, the distance between anchor rods is determined according to the stress gas level area:

[0088] Multiple rows of anchors are evenly arranged in each area, in a single area:

[0089] When the area is a low-stress and low-gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 10m;

[0090] When the area is a low stress and high gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 7m;

[0091] When the area is a high stress and low gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 4m;

[0092] When the area is a high-stress and high-gas area, the distance between two adjacent anchor rods in any horizontal row or any vertical column in this area is 1m.

[0093] The specific operation is as follows: determine the length and spacing of the anchor rods according to the four areas divided above. The length of the anchor rods in the high stress and high gas area is 2.5H, and the spacing is 1 m; the length of the anchor rods in the high stress and low gas area is 2.5H, and the spacing is 4 m; the length of the anchor rods in the low stress and high gas area is 1.5H, and the spacing is 7 m; the length of the anchor rods in the low stress and low gas area is 1.5H, and the spacing is 10 m; according to the determined parameters, drive the anchor rods into the coal seam in the bottom extraction tunnel.

[0094] S5. Start gas extraction operation:

[0095] After completing support and grouting, gas extraction operations are started, and the gas extraction system is reasonably arranged to gradually reduce the gas pressure in the coal seam;

[0096] S6. Before the start of mining operations, remove the installed anchor bolts:

[0097] After the tunnel gas outburst prevention measures are completed, the working face gas outburst prevention measures are implemented, and before the start of mining operations, the installed anchor bolts are removed to further carry out coal seam mining operations, including:

[0098] After the gas burst prevention measures in the tunnel are completed, the effectiveness of the measures is evaluated to ensure that the gas concentration meets the standard, and then the gas burst prevention measures are implemented on the working face;

[0099] Before the mining operation begins, the installed anchor bolts are removed to allow further mining work to be carried out on the coal seam.

[0100] The present invention changes the idea of ​​traditional coal tunnel outburst prevention technology that focuses on gas extraction. By reinforcing the strip coal body, the area where deformation may occur is protected in advance, effectively enhancing the stability of the coal seam support body, reducing the risk of coal and gas outbursts, thereby avoiding the occurrence of outbursts, and providing new ideas for coal and gas outburst prevention and control technology. Since the present invention comprehensively considers the control effects of the three elements of ground stress, gas, and coal body mechanical properties on outbursts, it can achieve precise control of coal body destruction under different stress and gas pressure conditions, and improve the outburst prevention effect. Under deep coal mining conditions, compared with traditional gas control technology, this technology is more targeted at coal tunnel outburst prevention and control problems, and can reduce construction workload and outburst prevention costs, thereby ensuring the rational use of coal mine gas.

[0101] The following points need to be explained:

[0102] (1) The drawings of the embodiments of the present invention only involve structures related to the embodiments of the present invention. Other structures may refer to conventional designs.

[0103] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present invention, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0104] (3) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0105] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preventing coal roadway outbursts by blocking a coal seam support, characterized in that: include: Before coal seam excavation, gas concentration detection is performed on the coal seam to obtain the gas concentration in different areas of the coal seam, and mechanical analysis is performed on the coal seam to obtain the relative ground stress of the coal seam; Dividing the gas grade of the coal seam according to the gas concentration in different areas of the coal seam, and dividing the stress grade of the coal seam according to the relative ground stress in different areas of the coal seam, to obtain the stress gas grade area of ​​the coal seam after coupling; According to the inclination of the coal seam, the protection range is delineated and conventional strip outburst elimination measures are implemented; In the strip protection zone, cement mortar is injected into the coal body through the bottom pumping tunnel for reinforcement, and anchor bolts are driven into the coal seam through the bottom pumping tunnel according to the stress gas grade area of ​​the coal seam to support the coal seam; Start gas extraction operations; Before mining operations begin, the installed anchor bolts are removed.

2. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 1, characterized in that: The gas concentration detection of the coal seam to obtain the gas concentration of different areas of the coal seam includes: Before coal seam excavation, structural detection of the working face is carried out through drilling detection technology, and combined with gas parameter testing, the gas concentration in different areas of the coal seam is evaluated to obtain the gas concentration in different areas of the coal seam.

3. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 2, characterized in that: Classifying the stress levels of the coal seam according to the relative ground stresses in different areas of the coal seam includes: The relative ground stress of the coal seam is determined using a stress gauge within 50 m of the selected target area.

4. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 3, characterized in that: The gas grade of the coal seam according to the gas concentration in different areas of the coal seam includes: When Q min ≤Q<(Q min + Q max ) / 2, the current area is a low-gas area; When Q ≥ (Q min + Q max ) / 2, the current area is a high-gas area; Among them, Q min is the gas concentration of the area with the lowest gas concentration, Q is the gas concentration of the current area, and Q max The gas concentration is the area with the highest gas concentration.

5. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 4, characterized in that: The classification of the stress levels of the coal seam according to the relative ground stresses in different areas of the coal seam includes: When σ min ≤σ<(σ min + σ max ) / 2, the current area is a low stress area; When σ≥(σ min + σ max ) / 2, the current area is a high stress area; Among them, σ min is the stress of the area with the lowest stress, σ is the stress of the current area, and σ max is the stress in the area with the highest stress.

6. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 5, characterized in that: The stress gas grade area of ​​the coal seam after the coupling includes: Low stress and low gas area, high stress and low gas area, low stress and high gas area and high stress and high gas area.

7. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 6, characterized in that: According to the coal seam inclination, the protection range is delineated and conventional strip outburst elimination measures are implemented, including: When the coal seam inclination ∈ [0°, 15°], the protection zone is 20 m; When the coal seam inclination is greater than 15°, the protection zone is 30 m; According to the working face design, multiple drill holes are arranged along the tunnel, evenly distributed at the edge of the strip protection zone, and conventional strip outburst elimination measures are implemented.

8. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 7, characterized in that: In the strip protection zone, cement mortar is injected into the coal body through the bottom pumping tunnel for reinforcement, and anchor rods are driven into the coal seam through the bottom pumping tunnel to support the coal seam according to the stress gas grade area of ​​the coal seam, including: Before the grouting operation, drill holes are arranged in the bottom extraction tunnel, and then cement mortar is injected into the coal body for reinforcement; The grouting pressure should be controlled within the range of 1 / 2-2 / 3 of the ground stress in the current area; Among them, the grouting pressure gradually increases; Determine the anchor length for each stress gas grade area according to the coal seam thickness; The distance between each anchor rod is determined according to the stress gas grade area.

9. The method for preventing coal roadway outbursts by blocking a coal seam support according to claim 8, characterized in that: Determining the anchor rod length in each stress gas grade area according to the coal seam thickness includes: The bolt length in low-stress low-gas areas and low-stress high-gas areas is 1.5 times the thickness of the coal seam; The bolt length in high stress low gas area and high stress high gas area is 2.5 times the coal seam thickness; Determining the distance between the anchor rods according to the stress gas grade area includes: Multiple rows of anchors are evenly arranged in each area, in a single area: When the area is a low-stress and low-gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 10m; When the area is a low stress and high gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 7m; When the area is a high stress and low gas area, the distance between two adjacent anchors in any horizontal row or any vertical column in this area is 4m; When the area is a high-stress and high-gas area, the distance between two adjacent anchor rods in any horizontal row or any vertical column in this area is 1m.

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