Anti-impact safety argumentation method for permanent chamber arranged in coal seam

Abstract

The invention relates to the technical field of coal mine safe mining, in particular to an anti-impact safety argumentation method for a permanent chamber arranged in a coal seam, which comprises the following steps of: when the coal seam belongs to a rock burst coal seam, acquiring an anti-impact material of the permanent chamber and an actual anti-impact material value; based on the anti-impact material of the permanent chamber, chamber parameters and anti-impact parameters of the permanent chamber are obtained; calculating a theoretical anti-scour material value based on the chamber parameters and the anti-scour parameters, and determining the anti-scour safety of the permanent chamber based on comparative analysis of the theoretical anti-scour material value and an actual anti-scour material value; and when the anti-scour safety is higher than a safety threshold value, optimizing the anti-scour parameters based on the anti-scour safety. The anti-impact safety of the permanent chamber in the rock burst coal seam can be accurately evaluated, the safety and stability of the chamber are guaranteed, the reliability of the permanent chamber in the coal mining process is improved, and the safety risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mine safety mining, and particularly relates to a permanent chamber anti-burst safety demonstration method arranged in a coal seam. BACKGROUND

[0002] Early mines rarely consider the problem of rock burst in the design due to the backwardness of design concept and design standard, so that the development roadway and permanent chamber are arranged in the rock burst coal seam. In recent years, with the increase of mining depth, the frequency of rock burst accidents also increases, which seriously affects the safety production of the mine and the safety of the life and property of the employees.

[0003] According to the twenty-eighth regulation of the "Regulations for Prevention and Control of Rock Burst in Coal Mines", the development roadway should not be arranged in the serious rock burst coal seam, and the permanent chamber should not be arranged in the rock burst coal seam. When the development roadway and the permanent chamber cannot meet the above requirements and do not have the condition of re-arrangement, safety demonstration is required. After taking comprehensive measures to prevent rock burst and confirming that the impact danger monitoring index is less than the critical value, it can continue to be used, and the monitoring must be strengthened.

[0004] Although the rock burst danger in the permanent chamber is monitored, the rock burst material is not monitored, and the safety problem caused by the rock burst problem cannot be coped with. SUMMARY

[0005] In view of the above shortcomings of the prior art, the present application provides a permanent chamber anti-burst safety demonstration method arranged in a coal seam to solve the above technical problems.

[0006] In the first aspect, the present application provides a permanent chamber anti-burst safety demonstration method arranged in a coal seam, comprising: S1, when the coal seam belongs to a rock burst coal seam, obtaining the anti-burst material and the actual anti-burst material value of the permanent chamber, and obtaining the chamber parameter and the anti-burst parameter of the permanent chamber based on the anti-burst material of the permanent chamber; S2, calculating the theoretical anti-burst material value based on the chamber parameter and the anti-burst parameter, and determining the anti-burst safety of the permanent chamber based on the comparison and analysis of the theoretical anti-burst material value and the actual anti-burst material value; S3, when the anti-burst safety is higher than the safety threshold, optimizing the anti-burst parameter based on the anti-burst safety.

[0007] The historical data and the simulation analysis model are called by the parameter optimization module to comprehensively review and simulate the geological conditions, the rock burst risk level and the characteristics of the rock burst prevention material of the current permanent chamber. Based on the simulation results, the strength grade of part of the rock burst prevention material is reduced or the amount thereof is reduced from the economic cost and resource utilization point of view. For example, the high-strength anchor rod is replaced by an anchor rod with slightly lower strength but still meeting the safety requirements, and the anchor rod spacing is appropriately increased. At the same time, the finite element analysis and other technical means are used to simulate and verify the adjusted rock burst prevention parameters to ensure the stability of the permanent chamber under different working conditions under the new parameters. After multiple rounds of simulation and fine-tuning, the optimized rock burst prevention parameters are finally determined and applied to the actual permanent chamber rock burst prevention project, thereby improving the economic benefits and resource utilization efficiency under the premise of ensuring safety.

[0008] In an optional implementation, the rock burst prevention material of the permanent chamber includes anchor rods, anchor cables and anchoring agents; and step S2 specifically includes: judging whether a first determination condition is met based on the anchor rod length, the anchor rod spacing and the anchor rod diameter calculated according to the anchor rod parameter calculation theory and in combination with the actual anchor rod length, the actual anchor rod spacing and the actual anchor rod diameter; judging whether a second determination condition is met based on the anchor cable length and the anchor cable spacing calculated according to the anchor cable parameter calculation theory and in combination with the actual anchor cable length and the actual anchor cable spacing; respectively calculating the anchor rod anchoring theoretical length, the anchor rod anchoring actual length, the anchor cable anchoring theoretical length and the anchor cable anchoring actual length, and determining that a third determination condition is met when the anchor rod anchoring actual length is not shorter than the anchor rod anchoring theoretical length and the anchor cable anchoring actual length is not shorter than the anchor cable anchoring theoretical length; determining that the permanent chamber has rock burst prevention safety when the first determination condition, the second determination condition and the third determination condition are all met.

[0009] In an optional implementation, in step S2, judging the rock burst prevention safety further includes: calculating the rock burst prevention effect energy absorption of the top anchor rod and the anchor cable, calculating the rock burst prevention effect energy absorption of the roadway sidewall anchor rod and the anchor cable, judging the theoretical vibration event that the rock burst prevention system can resist under the preset vibration parameter based on the energy balance principle in combination with the two kinds of energy absorption, and judging whether a fourth determination condition is met in combination with the theoretical vibration event and the actual vibration event; determining that the permanent chamber has rock burst prevention safety when the first determination condition, the second determination condition, the third determination condition and the fourth determination condition are all met.

[0010] In an optional implementation, the anchor rod length is calculated as:

[0011]

[0012] wherein, is the exposed length; is the effective length of the anchor rod; is the length of the anchor rod into the stable rock formation; is the stability influence coefficient of the surrounding rock, is the span of the roadway; The inter-row spacing of the anchor rods is calculated as:

[0013] wherein, is the inter-row spacing of the anchor rods; is the anchoring force of the anchor rod; is the bulk density of the rock; is the safety factor, is the height of the roof fall; The diameter of the anchor rod is calculated as:

[0014] wherein, is the diameter of the anchor rod; is the tensile strength of the rod material.

[0015] In an alternative embodiment, the length of the anchor cable is calculated as:

[0016] wherein, is the depth of the anchor cable into the stable rock formation; is the exposed length of the anchor cable in the roadway; is the maximum thickness of the unstable coal / rock formation; The spacing and row spacing of the anchor cables is calculated as:

[0017] wherein, is the inter-row spacing of the anchor cables; is the designed anchoring force of the anchor cable; is the gravity density of the suspended rock formation; is the safety factor; is the height of the roof fall.

[0018] In an alternative embodiment, the theoretical anchoring length of the anchor rod / cable is calculated as:

[0019] wherein, is the designed anchoring force; is the diameter of the anchor rod / cable or the anchor rod / cable hole; is the bonding strength of the resin anchoring agent; The actual anchoring length of the anchor rod / cable is calculated as

[0020] wherein, is the anchoring length; is the resin anchoring agent diameter; is the anchor rod or anchor cable diameter; is the anchor rod or anchor cable drilling diameter; is the resin anchoring agent length used in the hole.

[0021] In an optional embodiment, the total energy released by the roof rock after the impact occurs is balanced with the energy absorbed by the anti-impact effect of the roof anchor rod and anchor cable, and the surface displacement velocity of the roof is calculated; The total energy released by the coal body in the sidewall after the impact occurs is balanced with the energy absorbed by the anti-impact effect of the sidewall anchor rod and anchor cable, and the displacement velocity of the sidewall surface is calculated; The peak particle velocity is obtained by combining the surface displacement velocity of the roof and the displacement velocity of the sidewall surface; The theoretical seismic event is calculated based on the peak particle velocity and the preset seismic parameters, specifically including:

[0022] wherein, is the peak particle velocity; is the energy characteristic coefficient of the seismic source; is the anti-impact energy of the theoretical seismic event; is the epicentral distance; is the attenuation coefficient.

[0023] The beneficial effects of the present application are that the permanent chamber anti-impact safety demonstration method arranged in the coal seam provided by the present application can determine the anti-impact safety by comparing the theoretical and actual anti-impact material values by obtaining the anti-impact material, chamber and anti-impact parameters, and can optimize the anti-impact parameters when the anti-impact safety is higher than the threshold value, which is helpful to accurately evaluate the anti-impact safety of the permanent chamber in the coal seam with rock burst, ensures the safety and stability of the chamber, improves the reliability of the permanent chamber in the coal mining process, reduces the safety risk, and provides strong support for the safety production of coal mines.

[0024] In addition, the design principle of the present application is reliable, the structure is simple, and it has very wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below, and obviously, other drawings can also be obtained by those skilled in the art without creative labor on the premise of not paying creative labor.

[0026] Figure 1is a schematic flow chart of a method for demonstrating the safety of a permanent chamber arranged in a coal seam against a rock burst according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to enable persons skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the protection scope of the present application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein only for the purpose of describing specific embodiments and is not intended to limit the present application.

[0029] The method for demonstrating the safety of a permanent chamber arranged in a coal seam against a rock burst provided by the embodiments of the present application is executed by a computer device, and accordingly, a system for demonstrating the safety of a permanent chamber arranged in a coal seam against a rock burst runs in the computer device.

[0030] Figure 1 is a schematic flow chart of a method for demonstrating the safety of a permanent chamber arranged in a coal seam against a rock burst according to an embodiment of the present application. In the flow chart, Figure 1 The execution subject can be a system for demonstrating the safety of a permanent chamber arranged in a coal seam against a rock burst. According to different requirements, the order of steps in the flow chart can be changed, and some steps can be omitted.

[0031] As Figure 1 shown, the method comprises: S1, when the coal seam belongs to a rock burst coal seam, obtaining the anti-rock burst material of the permanent chamber and the actual anti-rock burst material value, and obtaining the chamber parameters and the anti-rock burst parameters of the permanent chamber based on the anti-rock burst material of the permanent chamber; S2, calculating the theoretical anti-rock burst material value based on the chamber parameters and the anti-rock burst parameters, and determining the anti-rock burst safety of the permanent chamber based on the comparison and analysis of the theoretical anti-rock burst material value and the actual anti-rock burst material value; S3, when the anti-rock burst safety is higher than a safety threshold, optimizing the anti-rock burst parameters based on the anti-rock burst safety.

[0032] Optionally, as one embodiment of the present application, before the argument of the anti-impact safety is carried out, the coal seam with impact ground pressure is firstly judged, and the judgment of the coal seam with impact ground pressure is specifically: the coal seam with impact ground pressure is the coal seam in which the impact ground pressure phenomenon has occurred in the minefield range, or the coal seam with impact tendency and the evaluation with impact danger are identified.

[0033] If the argument result of the coal seam attribute of the permanent chamber is the non-impact ground pressure coal seam, the anti-impact safety argument of the permanent chamber is not needed, and the permanent chamber is directly determined as “continuable use”; if the argument result of the coal seam attribute of the permanent chamber is the impact ground pressure coal seam, the next step is determined.

[0034] The impact ground pressure influencing factors include the geological influencing factors and the mining technology influencing factors, the geological factors influencing the impact ground pressure include: the coal seam occurrence characteristics, the buried depth, the roof rock characteristics and the key layer, the coal rock impact tendency, the ground stress, the fault, the fold and the like; the mining technology factors influencing the impact ground pressure include: the bottom coal thickness, the roadway group, the coal pillar, the roadway intersection and the like.

[0035] The different scores are set for the geological influencing factors and the mining technology influencing factors, and the comprehensive index method is adopted to obtain the impact danger score by weighting and comprehensively combining the geological influencing factors and the mining technology influencing factors; Based on the comparison between the impact danger score and the danger threshold, when the impact danger score is lower than the danger threshold, it is determined as no impact danger, and when the impact danger score is higher than the danger threshold, it is determined as the impact danger exists.

[0036] Optionally, as one embodiment of the present application, the anti-impact materials of the permanent chamber include the anchor rod, the anchor cable and the anchoring agent; the argument of the compliance of the permanent chamber is carried out, and the argument content is according to the eighth three of the “Regulations for the Prevention and Control of Impact Ground Pressure in Coal Mines”: the rigid anti-impact is strictly prohibited in the impact ground pressure roadway, the anti-impact design is carried out according to the impact danger, the anti-impact anchor rod (anchor cable), the collapsible support and the high-strength and anti-impact roadway hydraulic support and the like are adopted to improve the anti-impact capacity of the roadway. When the anti-impact materials of the permanent chamber do not conform to the above related provisions, the compliance argument result of the permanent chamber is “non-compliance”, the anti-impact parameters are re-optimized until the argument result is “compliance”, and then the next step is carried out. The anti-impact safety argument of the permanent chamber based on the anti-impact parameters specifically includes: The anchor rod length, the anchor rod interval and the anchor rod diameter based on the parameter calculation theory of the anchor rod are combined with the actual anchor rod length, the anchor rod interval and the anchor rod diameter to determine whether the first determination condition is met; The anchor cable length and the anchor cable interval based on the parameter calculation theory of the anchor cable are combined with the actual anchor cable length and the anchor cable interval to determine whether the second determination condition is met; The anchor rod anchoring theoretical length, the anchor rod anchoring actual length, the anchor cable anchoring theoretical length and the anchor cable anchoring actual length are calculated respectively, and when the anchor rod anchoring actual length is not shorter than the anchor rod anchoring theoretical length and the anchor cable anchoring actual length is not shorter than the anchor cable anchoring theoretical length, the third determination condition is determined; The energy absorbed by the anti-blasting effect of the top anchor rod and anchor cable is calculated, the energy absorbed by the anti-blasting effect of the roadway side anchor rod and anchor cable is calculated, the theoretical vibration event that can be resisted by the anti-blasting system under the preset vibration parameter is determined based on the energy balance principle combined with the two kinds of absorbed energy, and whether the fourth determination condition is met is determined combined with the theoretical vibration event and the actual vibration event; When the first determination condition, the second determination condition, the third determination condition and the fourth determination condition are met at the same time, it is determined that the permanent chamber has anti-blasting safety.

[0037] Optionally, as an embodiment of the present application, the anchor rod length is calculated as:

[0038]

[0039] wherein, is the exposed length; is the effective length of the anchor rod; is the length of the anchor rod into the stable rock formation; is the surrounding rock stability influence coefficient, is the roadway span; The anchor rod row spacing is calculated as:

[0040] wherein, is the anchor rod row spacing; is the anchor rod anchoring force; is the unit weight of rock; is the safety factor, is the caving height; The anchor rod diameter is calculated as:

[0041] wherein, is the anchor rod diameter; is the tensile strength of the rod body material.

[0042] Optionally, as an embodiment of the present application, the anchor cable length is calculated as:

[0043] wherein, is the anchor cable anchoring depth into the stable rock formation; is the exposed length of the anchor cable in the roadway; Maximum thickness of unstable coal / rock stratum; Anchor cable spacing, row spacing calculation is:

[0044] Wherein, Anchor cable row spacing; Anchor cable design anchoring force; Gravity density of suspended rock stratum; Safety factor; Height of caving arch.

[0045] Optionally, as an embodiment of the present application, the theoretical anchoring length of anchor rod / anchor cable is calculated as:

[0046] Wherein, Design anchoring force; Anchor rod / anchor cable hole or anchor rod / anchor cable diameter; Resin anchoring agent bonding strength; The actual anchoring length of anchor rod / anchor cable is calculated as

[0047] Wherein, Anchoring length; Resin anchoring agent diameter; Anchor rod or anchor cable diameter; Anchor rod or anchor cable drilling diameter; Resin anchoring agent length used in hole.

[0048] Optionally, as an embodiment of the present application, the energy absorption calculation of the anti-collision effect of roof anchor rod and anchor cable is:

[0049] Wherein, Number of roof anchor cables; Number of roof anchor rods; a Roadway net depth; b Anti-collision row spacing; Energy consumption of roof anchor rod before limit deformation breakage; Energy consumption of roof anchor cable before limit deformation breakage; The energy absorption calculation of the anti-collision effect of roadway side anchor rod and anchor cable is:

[0050] Wherein, Number of roadway side anchor cables; Number of roadway side anchor rods; Roadway side net depth; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage;

[0051] wherein, Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage;

[0052] wherein, Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage, specifically including:

[0053] wherein, Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage; Energy consumption of the roof anchor before the limit deformation and breakage.

[0054] Optionally, as one embodiment of the present application, a single-track hoist chamber of a certain mine is located in a 3rd mining area, with a buried depth of 909.64-933.73 m. The chamber is arranged along the roof of the coal seam, and the average thickness of the bottom coal is 3.5 m.

[0055] Firstly, the coal seam property of the impact ground pressure of the coal seam where the permanent chamber is located is demonstrated, and the identification result shows that the 3rd coal seam and its roof and floor of the single-track hoist chamber of the 3rd mining area of the mine have weak impact tendency. It is considered that the 3rd coal seam of the mine belongs to the impact ground pressure coal seam.

[0056] Based on the actual geological conditions and mining technical conditions of the single-track hoist chamber in the third mining area, the main impact factors of rock burst in the single-track hoist chamber in the third mining area are determined as follows: the coal seam and the roof and floor have weak impact tendency; the burial depth, roof thickness characteristic parameters, thick and hard roof, ground stress, coal seam thickness, coal pillar, roadway intersection, fault, etc.

[0057] Based on the geological factors and mining technical factors of the single-track hoist chamber in the third mining area, the impact of rock burst index is calculated to be 0.57 by using the comprehensive index method, and the impact of rock burst index is determined to be 0.5 by mining technical factors. The comprehensive determination of the rock burst danger level of the single-track hoist chamber in the third mining area is "medium rock burst danger".

[0058] Article 56 of the "Provisions for Prevention and Control of Rock Burst in Coal Mines" stipulates that rock burst mines must adopt regional and local rock burst prevention measures. Regional rock burst prevention measures should be taken first at the design stage of mine design and mining (panel, belt) area; timely follow-up local rock burst measures should be taken mainly for the formed mining and excavation faces. The single-track hoist chamber in the third mining area is an existing roadway, and local rock burst measures are mainly used. According to the provisions of Article 56 of the "Provisions for Prevention and Control of Rock Burst in Coal Mines", the rock burst prevention scheme for the single-track hoist chamber in the third mining area is as follows: ① Before the expansion and repair of the single-track hoist chamber in the third mining area, large-diameter pressure relief boreholes are drilled in the coal seam to provide pressure relief protection for expansion and repair construction and prevent rock burst during expansion and repair. The pressure relief boreholes are arranged perpendicular to the roadway sides, the borehole diameter is 150 mm, the borehole depth is 20 m, and the borehole spacing is 2 m.

[0059] ② During the expansion and repair of the single-track hoist chamber in the third mining area, the floor is constructed, and the two sides are strengthened to prevent rock burst, to ensure that the roadway cross section meets the requirements and ensures the stability of the roadway. The roadway height must be ensured to be 3.6 m, and the specific depth is dynamically adjusted according to the deformation of the roadway. The maximum floor depth is 2.0 m. When the floor depth is 0.5~1 m, one anchor rod is needed on each side of the roadway; when the floor depth is 1~2 m, two anchor rods are needed on each side of the roadway.

[0060] ③ After the expansion and repair of the single-track hoist chamber in the third mining area, the remaining floor coal in the roadway is treated by pressure relief (referred to as "floor coal turning"), to eliminate the impact of hidden dangers in the floor coal. According to the maximum floor depth of 2.0 m, the minimum thickness of the floor coal after the floor is turned is estimated to be 1.5 m, and the maximum is close to 3.5 m. In order to maintain the same height of the roadway and ensure the stability of the roadway after the floor is turned, the broken coal body needs to be transported to the deep pit behind and re-flattened, and then pushed forward.

[0061] ④ In order to ensure the stability of the high-side roadway, the roadway needs to be strengthened to prevent rock burst. U29 retractable steel sheds are used for strengthening and preventing rock burst, with a shed distance of not more than 1.2 m, and the two shed legs are worn shoes to prevent drilling the floor.

[0062] To demonstrate the effectiveness of the local anti-bumping measures of the monorail chamber in the third mining area, the original pressure relief scheme of the monorail chamber in the third mining area is compared with the above-mentioned pressure relief scheme by using the method of engineering analogy. The monorail chamber in the third mining area took the last danger relief and pressure relief measures in 2022, which has been more than 2 years, and no rock burst has occurred during this period. The specific implementation scheme is as follows: ①Large-diameter borehole in coal seam The large-diameter borehole in coal seam is adopted for pressure relief in the two sides of the monorail chamber in the third mining area. The borehole diameter is 150 mm; the borehole depth is 15 m; and the borehole spacing is 2 m.

[0063] ②Prevention scheme in the area with residual coal When the thickness of the residual coal is less than 2 m, large-diameter borehole is used to break the floor. In the direction perpendicular to the centerline of the roadway, 4-5 floor holes are arranged on average in each row, the two holes in the middle are vertically drilled, and the two holes on the sides are drilled downward at an angle of 45° to the bottom corner. The row spacing is not greater than 1 m, the diameter is 150 mm, and the borehole depth reaches the hard rock layer at the coal seam floor.

[0064] When the thickness of the residual coal is greater than or equal to 2 m, blasting is used for pressure relief. Not less than 4 boreholes are arranged in each row, the row spacing is not greater than 3 m, the hole depth reaches the coal seam floor, and the charge weight is not less than the design requirement.

[0065] Through analogy analysis, it can be known that the large-diameter borehole pressure relief measures currently designed for the two sides of the monorail chamber in the third mining area maintain consistency with the original scheme in terms of borehole diameter and spacing, and the borehole depth is greater than the original scheme. However, considering that the monorail chamber in the third mining area has an average of 3.5 m of residual coal, the developed pressure relief scheme is to flip the residual coal, which can maximize the reduction of floor stress concentration and thus reduce the possibility of rock burst. In addition, according to the planning of the mining face connection in the mine, the mining time of the 3304 working face in the west wing of the third mining area is from November 1, 2024 to July 15, 2025, and the service time of the monorail chamber in the third mining area is less than 2 years by the end of 2025. Therefore, through engineering analogy, it is considered that the anti-bumping measures developed for the monorail chamber in the third mining area are effective.

[0066] According to the provisions of Article 46 of the "Provisions for Prevention and Control of Rock Burst in Coal Mines", microseismic monitoring and stress monitoring methods are used for rock burst prevention and monitoring in the monorail chamber in the third mining area. The main method for danger relief is large-diameter borehole pressure relief. The borehole diameter is 150 mm, and the depth is 25 m. First, 1 m spaced boreholes are drilled. If the first round of drilling does not eliminate the danger of rock burst, additional boreholes are drilled in the middle of the first round of drilling for the second round of drilling. If the danger of rock burst is still not eliminated after three rounds of drilling, blasting pressure relief can be used. The blasting hole depth is 15 m, the diameter is 42 mm, and the spacing is 5 m.

[0067] The permanent chamber anti-blast safety demonstration includes four aspects: first, to carry out compliance demonstration of permanent chamber anti-blast; second, to carry out rationality demonstration of permanent chamber anti-blast; third, to carry out anti-impact capacity demonstration of permanent chamber anti-blast; and fourth, to develop monitoring scheme of permanent chamber anti-blast.

[0068] 1) Compliance demonstration of single-track hoist chamber anti-blast in three mining areas Article 83 of the "Regulations on Prevention and Control of Coal Mine Rock Burst" provides that rigid anti-blast shall be strictly prohibited in rock burst roadway, and anti-blast design shall be carried out according to the risk of rock burst, and anchor rod (anchor cable), collapsible support and high-strength, anti-impact roadway hydraulic support, etc. can be used to improve the anti-impact capacity of the roadway.

[0069] The following anti-blast materials are used in the single-track hoist chamber in the three mining areas of the mine: ① Anchor rod, anchor cable and anchoring agent High-strength prestressed anchor rod specification: MSGLW-500 / 22 (Φ22mm x 2800mm), rod yield strength ≥ 500MPa, rod tensile strength ≥ 630MPa, rod elongation rate ≥ 15%. The exposed nut length of the anchor rod is 10-50mm, 1 CK2535 type (yellow) and 1 M2550 type anchoring agent (white) are used in combination during anchoring, the design anchoring force is 190kN, and the pretightening torque is not less than 400N·m.

[0070] The roof anchor cable uses Φ21.8mm x 8300mm anchor cable, and 3 K2550 type resin anchoring agents (blue) are used for anchoring per hole. The exposed lock length of the anchor cable is 150-250mm, the initial anchoring force of the anchor cable is not less than 280kN, and the anchoring length is not less than 2000mm.

[0071] Three-diameter matching: anchor rod (cable) drilling uses φ30mm drill bit to drill, and anchor rod (cable) uses φ25mm resin anchoring agent to anchor; the difference between the diameter of anchor rod (cable) and the drill hole is 6mm-10mm, and the difference between the diameter of the drill hole and the resin anchoring agent is 4mm-8mm, which meets the specified requirements.

[0072] ② Woven welded mesh Diameter φ5.0mm woven welded mesh is used, with a grid of 100mm x 100mm, specifications: long x wide = 3000mm x 1100mm, 1700mm x 1100mm, or anti-blast woven welded mesh is used.

[0073] The anti-blast woven welded mesh is made of φ6.0mm cold-drawn steel, with length x width = 2800mm x 1040mm, 1520mm x 1040mm, 1680mm x 1040mm, 1400mm x 1000mm, and the grid is 80mm x 80mm (welded), and the longitudinal and transverse rib ends exceed the first vertical edge by 80mm. Adjacent meshes are connected by inserting and connecting the connecting rods made of φ6mm cold-drawn steel.

[0074] ③T-shaped steel belt: width 140mm, thickness 10mm; length 4.4m, 1.2m, 2.0m.

[0075] ④Anchor rod and anchor cable tray Anchor rod tray specifications: steel material Q345B, length x width x thickness = 150mm x 150mm x 12mm, hole diameter φ28mm, spherical diameter 100mm, arc height 30-40mm.

[0076] Anchor cable tray specifications: steel material Q345B, length x width x thickness = 300mm x 300mm x 18mm, hole diameter φ32mm, spherical diameter 200mm, arc height 50-60mm.

[0077] The above anti-blast material meets the requirements of the "Regulations for Prevention and Control of Coal Mine Rock Burst".

[0078] In the calculation of anchor rod length: the exposed length is 0.1m; the surrounding rock stability influence coefficient is generally 0.9-1.2, and the coefficient is 1.0; the roadway span is 5.2m; the anchor rod depth into the stable rock layer is 0.5m according to the empirical formula. The effective length of the anchor rod is calculated to be 1.62m, and the length of the anchor rod is 2.22m, therefore, the length of the anchor rod should not be less than 2.22m, and the current length of the anchor rod is 2.8m.

[0079] In the calculation of anchor rod spacing: the anchor rod anchoring force is 190kN per root; the rock bulk density is 25kN / m³; the safety factor is generally taken as K =3; the caving height is 1.61m. The anchor rod spacing is calculated to be 1.25m, and the design roof anchor rod spacing is 0.8m x 1.0m, and the anchor rod spacing of the side part is 0.8m x 1.0m.

[0080] In the calculation of anchor rod diameter: the tensile strength of the rod body material is 630MPa; the anchoring force is 190kN. The anchor rod diameter is calculated to be 20mm, while the anchor rod diameter used in the field is 22mm. In summary, it meets the first determination condition.

[0081] In the anchor cable length calculation, the anchor cable anchor into the stable rock depth is 1.5m; the exposed length of anchor cable in roadway is 0.25m; the maximum thickness of unstable coal (rock) layer, the roof is taken as the direct roof thickness 1.61m. The roof anchor cable length is calculated as 3.36m, and the current anchor cable length is 8.3m.

[0082] In the anchor cable spacing calculation: the anchor cable design anchoring force is taken as 350kN / root; the falling arch height is taken as the direct roof thickness 1.61m; the gravity density of the suspended rock layer is taken as 25kN / m; the safety factor is taken as 3. The anchor cable spacing is calculated as 1.7m, and the design roof anchor cable spacing is 1.3m x 1.0m. In summary, the second determination condition is met. K

[0083] In the anchor rod / anchor cable theoretical anchoring length calculation: the anchor rod is taken as 190kN; the anchor cable is taken as 350kN; the anchor rod (cable) hole or anchor rod (cable) diameter is taken as 22m; the resin anchoring agent bonding strength, the resin anchoring agent and coal body bonding strength is taken as 2.0MPa, and the resin anchoring agent and rock bonding strength is taken as 3.5MPa. The anchor rod anchoring length is calculated as 0.78m, and the anchor cable anchoring length is calculated as 1.46m.

[0084] In the anchor rod / anchor cable actual anchoring length calculation: the resin anchoring agent diameter is taken as 25mm; the anchor rod diameter is taken as 22mm, and the anchor cable diameter is taken as 21.8mm; the drilling diameter of anchor rod is taken as 30mm. For anchor rod, the anchoring agent length is 850mm, and the anchor rod anchoring length is calculated as 1277mm. For anchor cable, the anchoring agent length is 1500mm, and the anchor cable anchoring length is calculated as 2207mm. It can be seen that one CK2535 type (yellow) and one M2550 type anchoring agent (white) are used for each anchor rod in the field, and three K2550 type resin anchoring agents (blue) are used for anchoring each anchor cable. The anchor rod and anchor cable anchoring lengths meet the lengthening anchoring requirements. The third determination condition is met.

[0085] In the roof anchor net (cable) anti-blasting effect energy absorption calculation: the number of roof anchor cables is taken as 3; the number of roof anchor rods is taken as 7; the roadway net is taken as 5.2m; the anti-blasting spacing of anchor rods and anchor cables is taken as 1.0m. The roof anchor net (cable) anti-blasting effect energy absorption is calculated as 5kJ / m2.

[0086] In the total energy absorption calculation of roadway side anchor rod and cable anti-blasting structure, the number of roadway side anchor cables is taken as 0; the number of roadway side anchor rods is taken as 5; the roadway side net is taken as 3.6m; the anti-blasting spacing is taken as 1.0m. The total energy absorption of roadway side anchor rod and cable anti-blasting structure is calculated as 2.78kJ / m2.

[0087] ​The yield thickness of the rock mass surrounding the roadway is approximately 0.5–1 m. Assuming the yielding rock mass range is equal to the range of rock mass fractures, and taking the fracture thickness of the rock mass as 1 m, the rock layer density as 2.5 × 10³ kg / m³, and the coal seam density as 1.4 × 10³ kg / m³, the kinetic energy released by the surface rock mass of the roadway surrounding rock after a major seismic event is calculated as follows: .

[0088] For the tunnel roof, the potential energy released due to the tensile extension displacement of the anchor cables during the vibration of the roof rock mass must also be considered. The elongation rate is taken as 10%, and the free section length is 2.8 - 0.1 - 1.277 = 1423 mm. The ultimate displacement of the anchor bolt... △h Taking a thickness of 142mm, the potential energy released by the sliding of the top rock block due to impact is 3.55kJ / m. 2 .

[0089] According to energy balance analysis, the total energy released by the roof rock mass after the impact is as follows: +3.55 = 5; The total energy released by the coal seam at the flank after the impact, according to energy balance analysis, is: 0.7 =2.78; Calculations show that It is 1.08 m / s. Given that the velocity is 1.99 m / s, and based on the relationship that the rock ejection velocity is twice the peak velocity of the particle as pointed out by K. Hino, the peak velocity of the vibrating particles in the surrounding rock is calculated to be v = 0.54 m / s.

[0090] In the microseismic energy calculation: the peak mass velocity is taken as v = 0.54 m / s, the energy characteristic coefficient of the seismic source is taken as 3.19, the source distance is taken as 20 m, and the attenuation coefficient is taken as 1.5. The rock bolt anti-scour system includes the anti-scour body (rock bolts, anchor cables) and the protective body (metal mesh, steel strip). Its impact resistance is systematic and cannot be calculated solely based on the number of rock bolts and anchor cables. The weakening effect of the weaker stiffness of the protective body relative to the anti-scour body on the overall anti-scour system's impact resistance must be considered. The calculated theoretical impact resistance energy for the seismic event is 2.29 × 10⁻⁶. 5 J, meaning the anti-impact system can withstand an impact of 2.29 × 10⁻⁶ ohms from 20m away. 5 J is a vibration event. If the current vibration event value is less than this value, the fourth condition is met.

[0091] In some embodiments, the safety demonstration system for the erosion prevention of permanent chambers arranged in coal seams may include multiple functional modules composed of computer program segments. The computer programs of each program segment in the safety demonstration system for the erosion prevention of permanent chambers arranged in coal seams may be stored in the memory of a computer device and executed by at least one processor to perform the function of demonstrating the safety of the erosion prevention of permanent chambers in coal mines.

[0092] In several embodiments provided by the present application, it should be understood that the disclosed system and method can be implemented in other manners. For example, the system embodiments described above are merely schematic. For example, the division of the modules is merely a logical function division. For another example, a plurality of modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, and electrical, mechanical or other forms.

[0093] The modules illustrated as separated components can or can not be physically separated, and the components illustrated as modules can or can not be physical modules, i.e., can be located in one place, or can be distributed on a plurality of network modules. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment.

[0094] In addition, each functional module in each embodiment of the present application can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0095] Although the present application has been described in detail by referring to the preferred embodiments thereof, it should be understood that the present application is not limited to the above-mentioned embodiments. Various equivalent modifications and replacements to the embodiments of the present application can be made by those skilled in the art without departing from the spirit and scope of the present application. Any modifications or replacements made by those skilled in the art within the technical scope disclosed by the present application should be covered by the protection scope of the present application.

Claims

1. A method for demonstrating the safety of a permanent chamber against a burst in a coal seam, characterized in that, The method comprises the following steps: S1, when the coal seam belongs to a rock burst coal seam, obtaining the anti-rock burst material of the permanent chamber and the actual anti-rock burst material value, obtaining the chamber parameters and the anti-rock burst parameters of the permanent chamber based on the anti-rock burst material of the permanent chamber; S2, calculating the theoretical anti-rock burst material value based on the chamber parameters and the anti-rock burst parameters, and determining the anti-rock burst safety of the permanent chamber based on the comparison and analysis of the theoretical anti-rock burst material value and the actual anti-rock burst material value; S3, when the anti-rock burst safety is higher than the safety threshold, optimizing the anti-rock burst parameters based on the anti-rock burst safety.

2. The permanent chamber safety demonstration method arranged in a coal seam according to claim 1, characterized in that, The anti-rock burst material of the permanent chamber comprises an anchor rod, an anchor cable and an anchoring agent; step S2 specifically comprises: calculating the theoretical anchor rod length, the anchor rod spacing and the anchor rod diameter based on the parameters of the anchor rod, and combining the actual anchor rod length, the anchor rod spacing and the anchor rod diameter to determine whether the first determination condition is met; calculating the theoretical anchor cable length and the anchor cable spacing based on the parameters of the anchor cable, and combining the actual anchor cable length and the anchor cable spacing to determine whether the second determination condition is met; respectively calculating the anchor rod anchoring theoretical length, the anchor rod anchoring actual length, the anchor cable anchoring theoretical length and the anchor cable anchoring actual length, and when the anchor rod anchoring actual length is not shorter than the anchor rod anchoring theoretical length and the anchor cable anchoring actual length is not shorter than the anchor cable anchoring theoretical length, determining that the third determination condition is met; when the first determination condition, the second determination condition and the third determination condition are met at the same time, determining that the permanent chamber has the anti-rock burst safety.

3. The permanent chamber safety demonstration method arranged in a coal seam according to claim 2, characterized in that, In step S2, determining the anti-rock burst safety further comprises: calculating the anti-rock burst effect energy absorption of the roof anchor rod and the anchor cable, calculating the anti-rock burst effect energy absorption of the roadway side anchor rod and the anchor cable, determining the theoretical shock event that the anti-rock burst system can resist under the preset shock parameter based on the energy balance principle and combining the two kinds of energy absorption, and determining whether the fourth determination condition is met by combining the theoretical shock event and the actual shock event; when the first determination condition, the second determination condition, the third determination condition and the fourth determination condition are met at the same time, determining that the permanent chamber has the anti-rock burst safety.

4. The permanent chamber safety demonstration method arranged in a coal seam according to claim 3, characterized in that, The anchor rod length is calculated as: wherein, is the exposed length; is the effective length of the anchor rod; is the length of the anchor rod into the stable rock formation; is the stability influence coefficient of the surrounding rock, is the span of the roadway; The anchor rod spacing is calculated as: wherein, is the spacing between the anchor rods; is the anchoring force of the anchor rod; is the bulk density of the rock; is the safety factor, is the caving height; The anchor rod diameter is calculated as: wherein is the anchor rod diameter; is the tensile strength of the rod material.

5. The permanent chamber safety demonstration method arranged in a coal seam according to claim 3, characterized in that, The anchor cable length is calculated as: wherein, is the depth of anchor cable anchoring into stable strata; is the exposed length of anchor cable in the roadway; is the maximum thickness of unstable coal / strata; The anchor cable spacing and the anchor cable spacing are calculated as: wherein, is the spacing between the anchor lines; is the design anchoring force for the anchor lines; is the gravity density of the suspended rock formation; is the safety factor; is the height of the roof fall arch.

6. The method for verifying the anti-rock burst safety of the permanent chamber arranged in the coal seam according to claim 3, wherein The anchor rod / anchor cable theoretical anchoring length is calculated as: wherein, is the design anchoring force; is the anchor rod / anchor cable hole or anchor rod / anchor cable diameter; is the resin anchoring agent bond strength; The anchor rod / anchor cable actual anchoring length is calculated as wherein, is the anchoring length; is the resin anchor diameter; is the anchor rod or cable diameter; is the anchor rod or cable hole diameter; is the in-hole resin anchor length.

7. The method for verifying the anti-rock burst safety of the permanent chamber arranged in the coal seam according to claim 3, wherein the total energy released by the roof rock mass after the impact occurs is balanced with the anti-rock burst effect energy absorption of the roof anchor rod and the anchor cable, and the surface displacement velocity of the roof is calculated; the total energy released by the side coal mass after the impact occurs is balanced with the anti-rock burst effect energy absorption of the roadway side anchor rod and the anchor cable, and the surface displacement velocity of the roadway side is calculated; the particle peak velocity is obtained by combining the surface displacement velocity of the roof and the surface displacement velocity of the roadway side; the theoretical shock event is calculated based on the particle peak velocity and the preset shock parameter, and specifically comprises: wherein, is the peak particle velocity; is the energy characteristic coefficient of the source; is the theoretical shock event impact energy; is the hypocentral distance; is the attenuation coefficient.

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