A method for arranging collaborative mining of a coal seam group in a rock burst mine

Abstract

A kind of rock burst mine coal seam group collaborative mining arrangement method, the distribution characteristics of coal seam in mine are collected, based on the distribution characteristics of coal seam, the mining sequence of each coal seam in coal seam group is determined;According to the mining conditions of each coal seam, the section coal pillar width and working face size range of each coal seam working face arrangement are determined;According to the physical and mechanical parameters of coal seam and its roof and floor in mining area, a simulation model of coal seam group mining pressure relief protection range is established, and the change trend of coal seam group pressure relief protection range under different parameters is determined;According to the change trend of coal seam group pressure relief protection range, the pressure relief protection range of coal seam in mining area is determined, and the specific working face size of each coal seam arrangement is determined;According to the actual conditions of mine and the mining connection principle, the connection sequence of each coal seam working face in coal seam group is determined.The present application can maximize the use of the pressure relief area of protected layer, effectively reduce the rock burst risk of coal seam group mining.

Description

Technical Field

[0001] This invention relates to a coal seam mining layout method, specifically a method for the coordinated mining layout of coal seam groups in rockburst-prone mines, belonging to the technical field of coordinated mining layout in rockburst-prone mines. Background Technology

[0002] Rockbursts are dynamic disasters that occur during underground coal mining due to the instantaneous release of a large amount of elastic strain energy accumulated in the coal and rock mass within the production space, resulting in severe damage. They are currently the most prominent production safety issue in underground mining. With the shift of coal production centers westward, mining intensity in western mining areas is increasing, leading to more severe rockburst hazards. Especially in western mining areas where coal seam cluster mining is prevalent, the coordinated mining of protective and protected coal seams can effectively reduce the risk of rockbursts in the protected coal seams.

[0003] Currently, the main method for co-mining coal seam groups in mines prone to rockbursts is to determine the pressure relief angle based on engineering experience or theoretical calculations and to calculate the displacement distance within the protected layer roadway to determine the co-mining layout parameters. This method has certain application effects, but it also has certain limitations. The method for co-mining coal seam groups based on engineering experience and theoretical calculations has the advantages of simple operation and easy calculation. However, it is based on empirical parameters and requires a lot of engineering experience. It also differs from the actual conditions of the mine. Especially in the overall layout of large-scale coal seam groups, it cannot take into account the changes in local geological conditions, and the results obtained may have large errors. Furthermore, unreasonable roadway layout parameters may not only reduce or even eliminate the pressure relief protection effect of the protected layer roadway, but may also cause stress concentration in the roadway, increasing the risk of rockburst. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the coordinated mining layout of coal seam groups in mines prone to rockbursts, which can maximize the utilization of the pressure relief area of ​​the protected layer and effectively reduce the risk of rockbursts in coal seam group mining.

[0005] To achieve the above objectives, the present invention provides a method for the coordinated mining layout of coal seam groups in mines prone to rock bursts, comprising the following steps:

[0006] Step 1: Collect coal seam distribution characteristics in the mine. These characteristics include the physical and mechanical parameters of each coal seam in the coal seam group, coal seam thickness, coal seam spacing, lithological distribution between coal seams, and mining conditions.

[0007] Step 2: Based on the coal seam distribution characteristics in Step 1, determine the mining sequence of each coal seam in the coal seam group;

[0008] Step 3: Based on the mining conditions of each coal seam, determine the width of the coal pillars and the range of working face dimensions for each coal seam.

[0009] Step 4: Based on the physical and mechanical parameters of the coal seam and its roof and floor in the mining area, establish a simulation model of the pressure relief protection range of the coal seam group and determine the changing trend of the pressure relief protection range of the coal seam group under different parameters;

[0010] Step 5: Determine the coal seam pressure relief protection range in the mining area based on the changing trend of the coal seam group pressure relief protection range in Step 4, thereby determining the working face size for each coal seam.

[0011] Step Six: Determine the sequence of working faces for each coal seam in the coal seam group based on the actual conditions of the mine and the principles of mining continuity.

[0012] The method for determining the mining sequence of each coal seam in the coal seam group in step two of this invention is as follows:

[0013] Based on the mining thickness of each coal seam in the coal seam group, the height of the caving zone after mining is calculated and compared with the distance between coal seams. If the height of the caving zone is greater than the distance between coal seams, the conditions for mining the lower protective layer are not met, and the upper protective layer is used for mining. If the height of the caving zone is less than the distance between coal seams and the conditions for mining the lower protective layer are met, the impact risk of the upper and lower coal seams is judged, and the coal seam with the lower impact risk is selected as the protective layer for mining.

[0014] The method for calculating the height of the caving zone after coal seam mining is as follows:

[0015]

[0016] In the formula: L k The height of the landslide zone is in meters (m).

[0017] L m The thickness of the coal seam during mining is in meters (m).

[0018] The method for determining the width of the coal pillars and the size range of the working face in step three of this invention is as follows:

[0019] The method for determining the width of the coal pillar in the section is as follows: based on the hydrogeological conditions of the mine, it is determined whether to leave a wide or narrow coal pillar. When the hydrogeological conditions of the mine are complex or extremely complex, a wide coal pillar can be used for roadway protection; when the hydrogeological conditions of the mine are simple or moderate, a narrow coal pillar can be used for roadway protection.

[0020] The minimum width of a wide coal pillar is calculated using the following formula:

[0021] W k =W s +W t +W x (2)

[0022] In the formula: W k Minimum width of a wide coal pillar, in meters;

[0023] W s The width of the plastic zone on the side of the goaf, in meters;

[0024] W t The width of the elastic core region is in meters (m).

[0025] W x The width of the plastic zone on the side of the tunnel, in meters;

[0026] The maximum width of a narrow coal pillar is calculated using the following formula:

[0027] W z =W s +W x (3)

[0028] In the formula: W z The maximum width of the narrow coal pillar is in meters.

[0029] W s The width of the plastic zone on the side of the goaf, in meters;

[0030] W x The width of the plastic zone on the side of the tunnel, in meters;

[0031] The method for determining the working face size range is as follows: the dip length of the working face is determined based on the scraper conveyor equipped in the mine, and the strike length of the working face is determined based on the division of the mining (panel) area and the distribution of geological structures in the mine.

[0032] The simulation model for the pressure relief protection range of coal seam group mining in step four of this invention includes establishing a coal seam pressure relief protection range model under the influence of coal seam thickness, a coal seam pressure relief protection range model under the influence of coal seam spacing, and a coal seam pressure relief protection range model under the influence of inter-coal seam lithology, based on the coal seam distribution characteristics and the physical and mechanical parameters of the coal seam and its roof and floor.

[0033] In step five of this invention, determining the coal seam pressure relief protection range in the mining area should be based on simulation results of different parameters under three schemes: the coal seam pressure relief protection range model under the influence of coal seam thickness, the coal seam pressure relief protection range model under the influence of coal seam spacing, and the coal seam pressure relief protection range model under the influence of inter-coal seam lithology. The fitting relationship between the pressure relief protection range and different parameters of different schemes should be analyzed and obtained.

[0034] The fitting equations for the pressure relief protection range of the present invention under different schemes and parameters in the three schemes are as follows:

[0035] Fitting equation for the coal seam pressure relief protection range under the influence of coal seam thickness:

[0036] y = -0.1875x 2 +3.75x+468.19 (4)

[0037] Fitting equation for the coal seam pressure relief protection range under the influence of coal seam spacing:

[0038] y = 0.051x 2 -0.8167x+478.14 (5)

[0039] Fitting equation for the coal seam stress relief protection range under the influence of inter-seam lithology and strength:

[0040] y = 0.1939x 3 -2.9196x 2 +10.448x+445.65 (6)

[0041] The method for determining the specific working face dimensions for each coal seam according to the present invention is as follows:

[0042] Based on the evolution formula of the coal seam pressure relief protection range in the mining area obtained in step five, with different parameters of different schemes, the pressure relief protection range under all geological exploration boreholes in the mining area is calculated respectively, and the minimum value is taken as the standard pressure relief protection range. The dip length of the working face should be less than or equal to the standard pressure relief protection range. Combined with the aforementioned working face size range, the dip length of the working face is finally determined. The minimum internal displacement distance of the roadway is calculated based on the standard pressure relief protection range. The horizontal distance between the boundaries of the goaf of the internal displacement protection layer of the two roadways of the working face should be greater than the minimum internal displacement distance of the roadway. Based on the minimum internal displacement distance of the roadway, the layout positions of the opening cut and the stop line are determined, and the strike length of the working face is finally determined.

[0043] The method for calculating the minimum internal displacement distance of the roadway is as follows:

[0044]

[0045] In the formula: L n The minimum internal displacement distance of the tunnel, in meters;

[0046] L c The protective layer mining range is in meters (m).

[0047] L x The standard pressure relief protection range of the protected layer is in meters (m).

[0048] The principle for determining the working face sequence in this invention is as follows:

[0049] ① The sequence of the first mining face should avoid leaving isolated coal pillars as much as possible;

[0050] ② When the working face of the protected layer is connected, it should be ensured that the working face is completely within the pressure relief protection range of the protective layer;

[0051] ③ When the working face of the protected layer is connected, care should be taken to avoid mining disturbance between the working face of the protective layer and the working face of the protected layer.

[0052] Compared with existing technologies, this invention determines the mining sequence of each coal seam in a coal seam group by collecting the distribution characteristics of coal seams in the mine. Based on the mining conditions of each coal seam, it determines the range of section coal pillar width and working face size for each working face. It then establishes a simulation model of the pressure relief protection range for coal seam group mining, thereby determining the changing trend of the pressure relief protection range of the coal seam group under different parameters. This allows for the determination of the specific working face size for each coal seam. Finally, based on the actual mine conditions and mining continuity principles, the continuity sequence of each working face in the coal seam group is determined. The collaborative mining layout method designed in this invention can maximize the utilization of the pressure relief area of ​​the protected layer and effectively reduce the risk of rockburst during coal seam group mining. Attached Figure Description

[0053] Figure 1 This is a schematic flowchart of the method for coordinating the mining of coal seam groups in mines prone to rock bursts, as described in an embodiment of the present invention.

[0054] Figure 2 This is a schematic diagram of the geological structure of a panel area in an embodiment of the present invention;

[0055] Figure 3 This is a fitting curve of the coal seam pressure relief protection range under the influence of coal seam thickness in an embodiment of the present invention;

[0056] Figure 4 This is a fitting curve of the coal seam pressure relief protection range under the influence of coal seam spacing in an embodiment of the present invention;

[0057] Figure 5 This is a fitting curve of the coal seam pressure relief protection range under the influence of inter-seam lithology and strength in an embodiment of the present invention;

[0058] Figure 6 This is a schematic diagram of the working face layout of the 2-1 coal seam in an embodiment of the present invention;

[0059] Figure 7 This is a schematic diagram of the working face layout of the 2-2 coal seam in an embodiment of the present invention. Detailed Implementation

[0060] The invention will now be further described with reference to the accompanying drawings.

[0061] like Figure 1 As shown, a method for the coordinated mining layout of coal seam groups in a rockburst-prone mine includes the following steps:

[0062] Step 1: Collect coal seam distribution characteristics in the mine. These characteristics include the physical and mechanical parameters of each coal seam in the coal seam group, coal seam thickness, coal seam spacing, lithological distribution between coal seams, and mining conditions.

[0063] Step 2: Based on the coal seam distribution characteristics in Step 1, determine the mining sequence of each coal seam in the coal seam group;

[0064] Based on the mining thickness of each coal seam in the coal seam group, the height of the caving zone after mining is calculated and compared with the distance between coal seams. If the height of the caving zone is greater than the distance between coal seams, the conditions for mining the lower protective layer are not met, and the upper protective layer is used for mining. If the height of the caving zone is less than the distance between coal seams, and the conditions for mining the lower protective layer are met, the rockburst hazard of the upper and lower coal seams is judged (rockburst mines will conduct a rockburst hazard assessment of the coal seams, and the judgment of the rockburst hazard of the upper and lower coal seams is based on the comparison of the assessment results. This judgment method is the basic principle for selecting protective layers in the national standard GB-T / 25217.12-2019). The coal seam with the lower rockburst hazard is selected as the protective layer for mining.

[0065] The method for calculating the height of the caving zone after coal seam mining is as follows:

[0066]

[0067] In the formula: L k The height of the landslide zone is in meters (m).

[0068] L m The thickness of the coal seam during mining is in meters (m).

[0069] Step 3: Based on the mining conditions of each coal seam, determine the width of the coal pillars and the range of working face dimensions for each coal seam.

[0070] The method for determining the width of the coal pillar in the section is as follows: based on the hydrogeological conditions of the mine, it is determined whether to leave a wide or narrow coal pillar. When the hydrogeological conditions of the mine are complex or extremely complex, a wide coal pillar can be used for roadway protection; when the hydrogeological conditions of the mine are simple or moderate, a narrow coal pillar can be used for roadway protection.

[0071] The minimum width of a wide coal pillar is calculated using the following formula:

[0072] W k =W s +W t +W x (2)

[0073] In the formula: W k Minimum width of a wide coal pillar, in meters;

[0074] W s The width of the plastic zone on the side of the goaf, in meters;

[0075] W t The width of the elastic core region is in meters (m).

[0076] W x The width of the plastic zone on the side of the tunnel, in meters;

[0077] The maximum width of a narrow coal pillar is calculated using the following formula:

[0078] W z =W s +W x (3)

[0079] In the formula: W z The maximum width of the narrow coal pillar is in meters.

[0080] W s The width of the plastic zone on the side of the goaf, in meters;

[0081] W x The width of the plastic zone on the side of the tunnel is in meters (m).

[0082] The method for determining the working face size range is as follows: the dip length of the working face is determined based on the scraper conveyor equipped in the mine, and the strike length of the working face is determined based on the division of the mining (panel) area and the distribution of geological structures in the mine.

[0083] Step 4: Based on the physical and mechanical parameters of the coal seam and its roof and floor in the mining area, establish a simulation model of the pressure relief protection range of the coal seam group and determine the changing trend of the pressure relief protection range of the coal seam group under different parameters;

[0084] The simulation model for the pressure relief protection range of coal seam group mining includes establishing models based on the coal seam distribution characteristics and the physical and mechanical parameters of the coal seam and its roof and floor, respectively, for the coal seam pressure relief protection range under the influence of coal seam thickness, the coal seam pressure relief protection range under the influence of coal seam spacing, and the coal seam pressure relief protection range under the influence of inter-coal seam lithology.

[0085] Step 5: Determine the coal seam pressure relief protection range in the mining area based on the changing trend of the coal seam group pressure relief protection range in Step 4, thereby determining the working face size for each coal seam.

[0086] To determine the coal seam pressure relief protection range in the mining area, we should analyze and obtain the fitting relationship between the pressure relief protection range and different parameters under three schemes: the coal seam pressure relief protection range model under the influence of coal seam thickness, the coal seam pressure relief protection range model under the influence of coal seam spacing, and the coal seam pressure relief protection range model under the influence of inter-coal seam lithology.

[0087] The fitting equations for the pressure relief protection range of the present invention under different schemes and parameters in the three schemes are as follows:

[0088] Fitting equation for the coal seam pressure relief protection range under the influence of coal seam thickness:

[0089] y = -0.1875x 2 +3.75x+468.19 (4)

[0090] Fitting equation for the coal seam pressure relief protection range under the influence of coal seam spacing:

[0091] y = 0.051x 2 -0.8167x+478.14 (5)

[0092] Fitting equation for the coal seam stress relief protection range under the influence of inter-seam lithology and strength:

[0093] y = 0.1939x 3 -2.9196x 2 +10.448x+445.65 (6)

[0094] The method for determining the specific layout and dimensions of the working face for each coal seam is as follows:

[0095] Based on the evolution formula of the coal seam pressure relief protection range in the mining area obtained in step five, with different parameters of different schemes, the pressure relief protection range under all geological exploration boreholes in the mining area is calculated respectively, and the minimum value is taken as the standard pressure relief protection range. The dip length of the working face should be less than or equal to the standard pressure relief protection range. Combined with the aforementioned working face size range, the dip length of the working face is finally determined. The minimum internal displacement distance of the roadway is calculated based on the standard pressure relief protection range. The horizontal distance between the boundaries of the goaf of the internal displacement protection layer of the two roadways of the working face should be greater than the minimum internal displacement distance of the roadway. Based on the minimum internal displacement distance of the roadway, the layout positions of the opening cut and the stop line are determined, and the strike length of the working face is finally determined.

[0096] The method for calculating the minimum internal displacement distance of the roadway is as follows:

[0097]

[0098] In the formula: L n The minimum internal displacement distance of the tunnel, in meters;

[0099] L c The protective layer mining range is in meters (m).

[0100] L x The standard pressure relief protection range of the protected layer is in meters (m).

[0101] Step Six: Determine the sequence of working faces for each coal seam in the coal seam group based on the actual conditions of the mine and the principles of mining succession;

[0102] The principle for determining the working face succession sequence is as follows:

[0103] ① The sequence of the first mining face should avoid leaving isolated coal pillars as much as possible;

[0104] ② When the working face of the protected layer is connected, it should be ensured that the working face is completely within the pressure relief protection range of the protective layer;

[0105] ③ When the working face of the protected layer is connected, care should be taken to avoid mining disturbance between the working face of the protective layer and the working face of the protected layer. The following is a specific embodiment of the method for coordinated mining of coal seam groups in mines prone to rock bursts, according to the present invention, including the following steps:

[0106] Taking the coordinated mining layout of coal seams 2-1 and 2-2 in a certain mine as an example, the distribution characteristics of coal seams in the mine were collected. These characteristics include the physical and mechanical parameters of each coal seam in the coal seam group, coal seam thickness, coal seam spacing, inter-coal seam lithological distribution, and mining conditions. The coal seam thickness, coal seam spacing, and inter-coal seam lithological distribution are shown in Tables 1 to 4.

[0107] Table 1

[0108] 2-1 Coal Thickness 0～1.0m 1.0～2.0m 2.0～3.0m 3.0～4.0m 4.0～5.0m 5.0～6.0m Number of holes 10 31 49 25 5 10 percentage 7.9％ 24.6％ 38.9％ 19.8％ 4.0％ 7.9％

[0109] Table 2

[0110] 2-2 Coal Thickness 0～1.5m 1.5～3.0m 3.0～4.5m 4.5～6.0m 6.0～7.5m Number of holes 17 34 42 23 9 percentage 13.5％ 27.0％ 33.3％ 18.3％ 7.1％

[0111] Table 3

[0112] Coal seam spacing 4～14m 14～24m 24～34m 34～44m Number of holes 12 56 50 2 percentage 9.5％ 44.4％ 39.7％ 1.6％

[0113] Table 4

[0114] Lithology of the thickest rock layer siltstone Sandy mudstone fine-grained sandstone medium-grained sandstone other Number of holes 20 51 37 10 2 percentage 15.9％ 40.5％ 29.4％ 7.9％ 1.6％

[0115] Based on the coal seam distribution characteristics, the mining sequence of each coal seam in the coal seam group is determined;

[0116] Based on the mining thickness of each coal seam in the coal seam group, the height of the caving zone after coal seam mining is calculated. The method for calculating the height of the coal seam caving zone is as follows:

[0117]

[0118] In the formula: L k The height of the landslide zone is in meters (m).

[0119] L m The thickness of the coal seam being mined is expressed in meters (m).

[0120] According to statistics, the maximum mining thickness of coal seam 2-1 is 6m, and the maximum mining thickness of coal seam 2-2 is 7.5m. Therefore:

[0121]

[0122]

[0123] According to statistics, the distance between coal seam 2-1 and coal seam 2-2 is between 4 and 44 meters. In some areas, the height of the caving zone after mining coal seam 2-2 is greater than the distance between coal seams. Therefore, it can be considered that it does not meet the conditions for mining the lower protective layer. Thus, the mining method of the coal seam group in this mine is determined to be upper protective layer mining, that is, priority is given to mining coal seam 2-1, and coal seam 2-2 is mined after the protective layer is formed by mining coal seam 2-1.

[0124] Based on the mining conditions of each coal seam, determine the width of the coal pillars and the size range of the working face for each coal seam. The method for determining the width of the coal pillars is to determine whether to leave wide or narrow coal pillars based on the hydrogeological conditions of the mine. When the hydrogeological conditions of the mine are complex or extremely complex, wide coal pillars can be used for roadway protection; when the hydrogeological conditions of the mine are simple or moderate, narrow coal pillars can be used for roadway protection.

[0125] According to the assessment, the hydrogeological conditions of the mine are complex, and wide coal pillars can be used for roadway protection. However, considering that 2-1 coal seam is the first coal seam to be mined, in order to avoid leaving isolated coal pillars in the overlying goaf, narrow coal pillars are used for roadway protection in 2-1 coal seam, while wide coal pillars are used for 2-2 coal seam.

[0126] The minimum width of a wide coal pillar can be calculated using the following formula:

[0127] W k =W s +W t +W x (4)

[0128] In the formula: W k Minimum width of a wide coal pillar, in meters;

[0129] W s Width of the plastic zone on the side of the goaf, in meters;

[0130] W t Width of the elastic core region, in meters;

[0131] W x The width of the plastic zone on the side of the tunnel, in meters.

[0132] Based on the actual conditions of the mine, the width of the plastic zone on the goaf side is about 8m, the width of the elastic core zone is about 6m, the width of the plastic zone on the roadway side is about 4m, and the minimum width of the wide coal pillar is 18m. Therefore, the width of the wide coal pillar in this mine is determined to be 30m.

[0133] The maximum width of a narrow coal pillar can be calculated using the following formula:

[0134] W z =W s +W x (5)

[0135] In the formula: Wz This represents the maximum width of a narrow coal pillar, in meters (m).

[0136] W s Width of the plastic zone on the side of the goaf, in meters;

[0137] W x The width of the plastic zone on the side of the tunnel, in meters.

[0138] Based on the actual conditions of the mine, the width of the plastic zone on the side of the goaf is about 8m, the width of the plastic zone of the surrounding rock in the roadway is about 4m, and the maximum width of the narrow coal pillar is 12m. Therefore, the width of the narrow coal pillar in this mine is determined to be 6m.

[0139] The method for determining the working face size range is as follows: the dip length of the working face is determined based on the scraper conveyor equipped in the mine; the strike length of the working face is determined based on the division of the mining (panel) area and the distribution of geological structures in the mine.

[0140] Based on the actual equipment model equipped in the mine, the scraper conveyor model is SGZ1000 / 3×1000 scraper conveyor. The design length of this conveyor is 300-400m. Therefore, the minimum working face inclination length is 300m and the maximum is 400m.

[0141] According to the division of the mine panel, the maximum working face length of the designed panel is 4150m.

[0142] The method for establishing a simulation model of the pressure relief protection range in coal seam group mining and determining the variation trend of the pressure relief protection range under different parameters is as follows:

[0143] Among them, the establishment of a simulation model for the pressure relief protection range of coal seam group mining mainly includes, based on the coal seam distribution characteristics and according to the physical and mechanical parameters of the coal seam and its roof and floor, establishing a coal seam pressure relief protection range model under the influence of coal seam thickness, a coal seam pressure relief protection range model under the influence of coal seam spacing, and a coal seam pressure relief protection range model under the influence of inter-coal seam lithology.

[0144] Among them, the changing trend of the pressure relief protection range of the coal seam group under different parameters should be analyzed based on the simulation results of different parameters under the above three schemes, and the evolution formula of the pressure relief protection range with different parameters of different schemes should be obtained.

[0145] Calculation model for coal seam pressure relief protection effect parameters:

[0146] A three-dimensional model was constructed based on the borehole columnar section. The model is 1000m long, 840m wide, and 171m high, with a mesh size of 5m. Models for the coal seam stress relief protection range under the influence of coal seam thickness, coal seam spacing, and inter-coal seam lithology were established and calculated to equilibrium. The equilibrium calculation for this part was performed using a built-in algorithm in the numerical simulation software, with the maximum unbalanced force as the criterion, which is 1×10-5 by default. This is basic knowledge that users of this software should have.

[0147] Based on the statistical characteristics of coal seam distribution according to the borehole columnar section, and based on the statistical results, the simulation schemes for coal seam thickness are shown in Table 5, the simulation schemes for coal seam spacing are shown in Table 6, and the simulation schemes for lithological strength between coal seams are shown in Table 7.

[0148] Table 5

[0149]

[0150] Table 6

[0151]

[0152] Table 7

[0153]

[0154]

[0155] The model mesh is divided into 5m sections. Based on the measured physical and mechanical parameters of the coal and rock mass, the physical parameters of each rock layer in the model are assigned and calculated until equilibrium is reached. The mechanical parameters of the model are shown in Table 8.

[0156] Table 8

[0157]

[0158] The working face of the model was then simulated and excavated, and the model was calculated to reach an equilibrium state after excavation.

[0159] The coal seam depressurization protection range under different schemes is shown in Tables 9 to 11.

[0160] Table 9

[0161] Coal seam thickness 1m 3m 5m 7m Pressure relief range 472m 477m 483m 485m

[0162] Table 10

[0163] Coal seam spacing 5m 10m 15m 20m 25m 30m 35m Pressure relief range 474m 475m 481m 483m 486m 498m 514m

[0164] Table 11

[0165] Inter-coal seam lithology Option 1 Option 2 Option 3 Option 4 Option 5 Option Six Average tensile strength / MPa 9.53 2.12 1.77 6.94 4.47 4.36 Pressure relief range 448m 454m 458m 442m 450m 454m

[0166] The fitted curves of the changing trends of the coal seam pressure relief protection range under various factors are shown below. Figures 3-5 As shown;

[0167] Fitting equation for the coal seam pressure relief protection range under the influence of coal seam thickness:

[0168] y = -0.1875x 2 +3.75x+468.19 (6)

[0169] Fitting equation for the coal seam pressure relief protection range under the influence of coal seam spacing:

[0170] y = 0.051x 2 -0.8167x+478.14 (7)

[0171] Fitting equation for the coal seam stress relief protection range under the influence of inter-seam lithology and strength:

[0172] y = 0.1939x 3 -2.9196x 2 +10.448x+445.65 (8)

[0173] The specific method for determining the working surface dimensions is as follows:

[0174] Based on the fitting relationship between the pressure relief protection range and different parameters of different schemes obtained above, the pressure relief protection range under all geological exploration boreholes in the mining area is calculated respectively, and the smaller value is taken as the standard pressure relief protection range. The dip length of the working face should not be greater than the standard pressure relief protection range. Combined with the aforementioned working face size range, the dip length of the working face is finally determined. The minimum internal displacement distance of the roadway is calculated based on the standard pressure relief protection range. The horizontal distance between the boundaries of the goaf of the internal displacement protection layer of the two roadways of the working face should be greater than the minimum internal displacement distance of the roadway. Based on the minimum internal displacement distance of the roadway, the layout positions of the opening cut and the stop line are determined, and the strike length of the working face is finally determined.

[0175] Secondly, based on the above fitting relationship, calculate as follows: Figure 2 The columnar section of each borehole in the panel shown in Table 12 illustrates the coal seam pressure relief protection range.

[0176] Table 12

[0177]

[0178] Therefore, the working face inclination length should be less than 455m. Considering the aforementioned minimum working face inclination length of 300m and maximum of 400m, the working face inclination length is determined to be 320m.

[0179] The minimum internal displacement distance of the tunnel is:

[0180]

[0181] Therefore, the distance between the boundaries of the goaf of the protective layer in the two roadways is 100m, and the distance between the boundaries of the protective layer in the open cut and the stop line is 75m, that is, the working face strike length is 4000m.

[0182] The principle for determining the working face succession sequence is as follows:

[0183] ① The sequence of the first mining face should avoid leaving isolated coal pillars as much as possible;

[0184] ② When the working face of the protected layer is connected, it should be ensured that the working face is completely within the pressure relief protection range of the protective layer;

[0185] ③ When the working face of the protected layer is connected, care should be taken to avoid mining disturbance between the working face of the protective layer and the working face of the protected layer.

[0186] The No. 2-1 coal seam in this mine is the first coal seam to be mined, and mining proceeds sequentially. Its working face layout is as follows: Figure 6 As shown, coal seam 2-2 is the protected coal seam and is mined sequentially. Its working face layout is as follows. Figure 7 As shown, the sequence of coal seam group collaborative mining is as follows: 21102 working face → 21103 working face → 21104 working face → 21105 / 22103 working face → 21106 / 22104 working face → 21107 / 22105 working face → 21108 / 22106 working face → 21109 / 22107 working face → 21110 / 22108 working face → 22109 working face → 22110 working face.

[0187] Table 13

[0188]

[0189]

[0190]

[0191] In summary, the present invention provides a method for the coordinated mining layout of coal seam groups in mines prone to rockbursts. By collecting data on the distribution characteristics of coal seams in the mine, the mining sequence of each coal seam in the coal seam group is determined. Based on the mining conditions of each coal seam, the width of the coal pillar section and the size range of the working face in each coal seam are determined. A simulation model of the pressure relief protection range of the coal seam group is established, and the changing trend of the pressure relief protection range of the coal seam group under different parameters is determined. The specific working face size of each coal seam is determined, and the sequence of working faces of each coal seam in the coal seam group is determined based on the actual mine conditions and mining continuity principles. The designed coordinated mining layout can maximize the utilization of the pressure relief area of ​​the protected layer, effectively reducing the risk of rockbursts during coal seam group mining.

Claims

1. A method for the coordinated mining layout of coal seam groups in mines prone to rock bursts, characterized in that, Includes the following steps: Step 1: Collect coal seam distribution characteristics in the mine. These characteristics include the physical and mechanical parameters of each coal seam in the coal seam group, coal seam thickness, coal seam spacing, lithological distribution between coal seams, and mining conditions. Step 2: Based on the coal seam distribution characteristics in Step 1, determine the mining sequence of each coal seam in the coal seam group; Step 3: Based on the mining conditions of each coal seam, determine the width of the coal pillars and the size range of the working face for each coal seam. Step 4: Based on the physical and mechanical parameters of the coal seam and its roof and floor in the mining area, establish a simulation model of the pressure relief protection range of the coal seam group and determine the changing trend of the pressure relief protection range of the coal seam group under different parameters; Step 5: Determine the coal seam pressure relief protection range in the mining area based on the changing trend of the coal seam group pressure relief protection range in Step 4, thereby determining the working face size for each coal seam. Step Six: Determine the sequence of working faces for each coal seam in the coal seam group based on the actual conditions of the mine and the principles of mining succession; Step four involves establishing a simulation model for the pressure relief protection range of coal seam mining. This includes establishing models based on the coal seam distribution characteristics and the physical and mechanical parameters of the coal seam and its roof and floor, respectively, for the coal seam pressure relief protection range under the influence of coal seam thickness, the coal seam spacing, and the coal seam pressure relief protection range under the influence of inter-coal seam lithology. In step five, determining the coal seam pressure relief protection range in the mining area should be based on simulation results of different parameters under three schemes: the coal seam pressure relief protection range model under the influence of coal seam thickness, the coal seam pressure relief protection range model under the influence of coal seam spacing, and the coal seam pressure relief protection range model under the influence of inter-coal seam lithology. The fitting relationship between the pressure relief protection range and different parameters of different schemes should be analyzed and obtained. The three fitting relationships are as follows: Fitting equation for the coal seam pressure relief protection range under the influence of coal seam thickness: Fitting equation for the coal seam pressure relief protection range under the influence of coal seam spacing: Fitting equation for the coal seam stress relief protection range under the influence of inter-seam lithology and strength: 。 2. The method for coordinated mining of coal seam groups in a rockburst mine according to claim 1, characterized in that, The method for determining the mining sequence of each coal seam in step two is as follows: Based on the mining thickness of each coal seam in the coal seam group, the height of the caving zone after mining is calculated and compared with the distance between coal seams. If the height of the caving zone is greater than the distance between coal seams, the conditions for mining the lower protective layer are not met, and the upper protective layer is used for mining. If the height of the caving zone is less than the distance between coal seams and the conditions for mining the lower protective layer are met, the impact risk of the upper and lower coal seams is judged, and the coal seam with the lower impact risk is selected as the protective layer for mining. The method for calculating the height of the caving zone after coal seam mining is as follows: In the formula: L k The height of the landslide zone is in meters (m). L m The thickness of the coal seam during mining is in meters (m).

3. The method for coordinated mining of coal seam groups in a rockburst mine according to claim 1, characterized in that, The method for determining the width of the coal pillars and the range of working face dimensions for each coal seam in step three is as follows: The method for determining the width of the coal pillar in the section is as follows: based on the hydrogeological conditions of the mine, determine whether to leave a wide or narrow coal pillar. When the hydrogeological conditions of the mine are complex or extremely complex, a wide coal pillar is used for roadway protection; when the hydrogeological conditions of the mine are simple or moderate, a narrow coal pillar is used for roadway protection. The minimum width of a wide coal pillar is calculated using the following formula: In the formula: W k Minimum width of a wide coal pillar, in meters; W s The width of the plastic zone on the side of the goaf, in meters; W t The width of the elastic core region is in meters (m). W x The width of the plastic zone on the side of the tunnel, in meters; The maximum width of a narrow coal pillar is calculated using the following formula: In the formula: W z The maximum width of the narrow coal pillar is in meters. The method for determining the working face size range is as follows: the dip length of the working face is determined based on the scraper conveyor equipped in the mine, and the strike length of the working face is determined based on the division of the mining area and the distribution of geological structures.

4. The method for coordinated mining layout of coal seam groups in a rockburst mine according to claim 3, characterized in that, The method for determining the specific working face dimensions for each coal seam is as follows: Based on the evolution formula of the coal seam pressure relief protection range in the mining area obtained in step five, with different parameters of different schemes, the pressure relief protection range under all geological exploration boreholes in the mining area is calculated respectively, and the minimum value is taken as the standard pressure relief protection range. The dip length of the working face should be less than or equal to the standard pressure relief protection range. Combined with the aforementioned working face size range, the dip length of the working face is finally determined. The minimum internal displacement distance of the roadway is calculated based on the standard pressure relief protection range. The horizontal distance between the boundaries of the goaf of the internal displacement protection layer of the two roadways of the working face is greater than the minimum internal displacement distance of the roadway. Based on the minimum internal displacement distance of the roadway, the layout positions of the opening cut and the stop line are determined, and the strike length of the working face is finally determined. The method for calculating the minimum internal displacement distance of the roadway is as follows: In the formula: L n The minimum internal displacement distance of the tunnel, in meters; L c The protective layer mining range is in meters (m). L x The standard pressure relief protection range of the protected layer is in meters (m).

5. The method for coordinated mining layout of coal seam groups in a rockburst mine according to claim 4, characterized in that, The principle of continuation is as follows: ①The sequence of the first mining face should avoid leaving isolated coal pillars as much as possible; ② When connecting the working surfaces of the protected layer, it is important to ensure that the working surfaces are completely within the pressure relief protection range of the protective layer; ③ When the working face of the protected layer is connected, care should be taken to avoid mining disturbance between the working face of the protected layer and the working face of the protected layer.

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