Regional danger grading and solving method under combined fault

Abstract

The invention provides a regional danger grading and solving method under a combined fault, and relates to the technical field of coal mine safety, and the specific steps are as follows: obtaining a fault crustal stress increment matrix and a combined fault, obtaining the influence range and peak influence range of each combined fault structure according to the combined fault and the crustal stress increment matrix, and calculating the regional danger grade; according to the basic data of the fault and the working face, a plastic zone range and an elastic zone range are obtained, according to a combined fault structure influence range, a fault structure peak value range and the like, a combined fault advanced regional danger level is obtained, and corresponding measures are executed according to the danger level. According to the method, the interaction between the faults and the coupling relation between the faults and the advanced supporting stress are dynamically considered, the potential mine pressure impact risk can be accurately evaluated, a fault structure-advanced supporting stress impact danger prevention and treatment system is established, and the contradiction among the roadway advanced pressure relief strength, range and cost is correctly controlled.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine safety, and in particular to a regional hazard level classification and solution under a combined fault. Background Art

[0002] The output of underground coal mines in my country accounts for more than 85% of the total output. Faults, as a geological structure that is commonly found in underground coal mines in a complex combination, often interact with mining activities to induce rock bursts of greater destructive magnitude. Therefore, in actual mining work, the advanced positions of the horizontal tunnels at both ends of the working face need to be strengthened with blasting pressure relief to ensure the safety of mining activities.

[0003] In the production safety planning of multi-fault mines, a single fault system is used to statically judge the hazards of multiple faults. There is a common problem that the coupling between faults and between fault structural stress and advance support stress is not dynamically considered. In the production of multi-fault mines, the combination of faults is complex, and the coupling factors between fault structural stress and advance support stress are diverse, making it difficult to correctly establish a "fault structure-advance support stress" impact hazard prevention system. In the production operations of combined fault mines, the energy released by the impact mine pressure caused by the combined faults and the range of damage are uncertain, while the corresponding advanced pressure relief schemes for the horizontal tunnels at both ends of the working face tend to be mechanized fixed-distance and quantitative designs, making it difficult to correctly control the contradiction between the intensity, range and cost of the advanced pressure relief of the horizontal tunnels.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a regional hazard level classification and solution under a combined fault to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A regional hazard classification and solution under a combined fault, the specific steps include:

[0008] S1. Construct the cross-section and plan view of the combined fault and working face, and collect the basic data of the fault and working face, including the fall of each fault, the original rock stress in the non-structural area, the vertical ground stress around the fault, the horizontal ground stress, the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration factor of the coal rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone of the coal body, the friction angle of the coal body and the lateral pressure coefficient of the coal body;

[0009] S2. According to the cross-sectional view and plan view of the combined fault and the working surface, the vertical geostress, and the horizontal geostress, the calculated dip angle and plane grid matrix of the fault layer of the combined fault are obtained; according to the calculated dip angle and plane grid matrix of the fault layer of the combined fault, the geostress increment matrix of the fault is obtained; according to the geostress increment matrix of the fault, the influence range of each fault is obtained; according to the influence range of each fault, the combination relationship of the fault is determined, and the combined fault is obtained;

[0010] S3. according to the faults and geostress increment matrix included in the combined fault, obtain the geostress increment matrix of the combined fault, and according to the geostress increment matrix of the combined fault, obtain the geostress influence range of the combined fault and the geostress peak influence range of the combined fault;

[0011] S4. according to the drop of each fault and the combined fault, obtain the drop influence range and the drop peak influence range of each combined fault structure; according to the effective drop of the combined fault, obtain the drop influence range and the drop peak influence range of each combined fault structure;

[0012] S5. Obtain the influence range and peak influence range of the combined fault structure according to the combined fault in-situ stress influence range, the in-situ stress peak influence range, the drop influence range of the combined fault structure, and the drop peak influence range;

[0013] S6. Process the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration coefficient of the coal-rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone and the internal friction angle of the coal body to generate the range of the plastic zone, and process the lateral pressure coefficient of the coal body, the coal seam thickness, the stress concentration coefficient and the friction coefficient of the micro-unit in the plastic zone to generate the range of the elastic zone;

[0014] S7. Divide the working face into the facing stage and the diverging stage, and judge the regional danger level of the combined fault advance according to the influence range of the combined fault structure, the peak influence range of the combined fault structure, the plastic zone range and the elastic zone range, and implement corresponding measures according to the danger level.

[0015] Furthermore, a vertical profile with the upper and lower ranges of the fault length is made along the working face lane to obtain the fault profile line. Four inflection points with large slope changes are found in the fault profile line, and the angle and length are counted. The calculation formula is:

[0016]

[0017] Among them, L i is the fault length, θ i is the calculated dip angle of the i-th fault, i is the index of the fault, the value range of i is [1,I], I is the number of faults that pass through the working surface, θi1 ,θ i2 ,θ i3 and θ i4 are the first, second, third and fourth inflection point angles between the fault profile and the horizontal line, h i1 、h i2 、h i3 and h i4 They are the first, second, third and fourth broken line lengths of the fault profile line in the vertical section diagram;

[0018] On the fault profile, a Cartesian coordinate system xoy is established with the horizontal midpoint of the working surface as the center of the circle, the actual relative profile relationship of the I faults, and the advancing direction of the working surface as the positive semi-axis direction of the x-axis, and the moving point M represents any point relative to the fault;

[0019] Establish 6 plane grid matrices of the same size and corresponding to the Cartesian coordinate system, the number of rows and columns of the plane grid matrix are both m, the plane grid matrix includes a distance matrix and an angle matrix, and the elements of the 6 plane grid matrices correspond to the Cartesian coordinate system planes;

[0020] Among them, the elements of the 6 plane grid matrices are:

[0021]

[0022] Among them, the matrix element a mm The position of is (m, m);

[0023] The correspondence between the element positions of the plane grid matrix and the coordinates in the Cartesian coordinate system is:

[0024]

[0025] Where (x,y) M is the coordinate of point M in the Cartesian coordinate system, x and y are the horizontal and vertical coordinates of point M in the Cartesian coordinate system, respectively. is the element position of the plane grid matrix, and are the horizontal and vertical coordinates of point M in the plane grid matrix, m The size of the fault length L i twice the maximum value in L1, L2, ..., L i );

[0026] l i1 , l i2 , l i3 In the Cartesian coordinate system, the moving point M(x, y) is respectively at the fault point D i1 , D i2 , D i3distance, using l i1 , l i2 , l i3 , get the distance matrix;

[0027] α i1 , α i2 , α i3 In the Cartesian coordinate system, the moving point M(x, y) is respectively at the fault point D i1 , D i2 , D i3 The angle between the line connecting the two and the positive direction of the x-axis is calculated using α i1 , α i2 , α i3 , get the angle matrix;

[0028] D i1 , D i2 , D i3 They are respectively the upper endpoint, midpoint and lower endpoint of the i-th fault in the profile.

[0029] Furthermore, the incremental matrix of the in-situ stress of the i-th fault is calculated according to the following formula:

[0030] Vσ i =Max(Vσ xi |,|Vσ yi |,|Vσ xyi |)

[0031] Vσ xi =-σ i (A i -B i -1)

[0032] Vσ yi =-σ i (1-A i -B i )

[0033] Vσ xyi =-σ i C i

[0034]

[0035]

[0036] Among them, Vσ i is the incremental matrix of the ground stress of the ith fault, Vσ xi is the stress increment along the x direction on the i-th fault, Vσ yi is the stress increment along the y direction on the i-th fault, Vσ xyiis the increment of shear stress on the i-th fault, σ i is the simulated inclination of the ith fault ignoring shear stress, A i From moving point M to fault point D i3 The distance from the moving point M to the fault point D i1 and D i2 The ratio parameter between the distances, B i From the moving point M to the fault point D i3 The ratio parameter of the distance and the corresponding angle, C i From moving point M to fault point D i2 The proportionality parameter between the distance and the angle, σ hi is the horizontal stress of the i-th fault, σ vi is the vertical stress of the ith fault.

[0037] Furthermore, according to the i-th fault in-situ stress increment matrix, the influence range of each fault is obtained. The specific steps are as follows:

[0038] According to the i-th fault ground stress increment matrix Vσ i , obtain the stress increment curve of the working surface under the influence of I faults, and obtain the influence range of each fault according to the stress increment curve, according to the following formula:

[0039] x i =(x i1 +x i2 ) / 2

[0040] Among them, x i is the influence range of the i-th fault, x i1 and x i2 are the influence ranges on both sides of the i-th fault, respectively, and are defined as the two critical distances from both sides of the i-th fault to the time when the stress increment reaches the original rock stress σ0, where σ0 refers to the stress borne by the rock itself when no external force is applied;

[0041] According to the influence range x of the i-th fault i The relative position of the faults is used to determine the combination relationship of the faults. The specific process is as follows:

[0042] satisfy:

[0043] L dtc <(x a +x b )

[0044] x a =(x a1 +x a2 ) / 2

[0045] x b =(xb1 +x b2 ) / 2

[0046] L dtc =Min(L dtc1 ,L dtc2 ,L dtc3 ,L dtc4 ,L dtc5 )

[0047] x a is the influence range of fault a, x b is the influence range of fault b, x a1 and x a2 are the two critical distances from the two sides of fault a to the time when the stress increment reaches the original rock stress σ0, x b1 and x b2 are the two critical distances from the two sides of fault b to the time when the stress increment reaches the original rock stress σ0, L dtc1 , L dtc2 , L dtc3 , L dtc4 , L dtc5 L is the length of the segment of the propulsion line sandwiched between the two fault planes, dtc is the minimum value among them;

[0048] The distance L between fault a and fault b dtc If it is smaller than the sum of the influence ranges of the two faults, then the fault a and fault b are combined faults;

[0049] By combining and judging all the faults, the combined relationship of the faults can be obtained, and J combined faults can be obtained.

[0050] Furthermore, the incremental matrix of the ground stress of the jth combined fault is obtained:

[0051] VΦ j =Max(Vσ xa +Vσ xb |,|Vσ ya +Vσ yb |,Vσ xya +Vσ xyb |)

[0052] Among them, VΦ j is the geostress increment matrix of the jth combined fault, a∈[1,I]∩b∈[1,I]∩a≠b, Vσ xa , Vσ ya , Vσ xya are the stress increment along the x direction, the stress increment along the y direction, and the shear stress increment on the ath fault, respectively, Vσ xb , Vσ yb , Vσ xybare the stress increment along the x direction, the stress increment along the y direction, and the shear stress increment on the bth fault, respectively;

[0053] According to the ground stress increment matrix VΦ of the jth combined fault j , obtain the stress increment curve of the working surface under the influence of the j-th combined fault. According to the stress increment curve of the working surface under the influence of the combined fault, the formula for obtaining the in-situ stress influence range and peak influence range of the j-th combined fault is as follows:

[0054] X1, j =Max(x j1 ,x j2 )

[0055] X, 2j =Max(x j3 ,x j4 )

[0056] Among them, X1, j is the in-situ stress influence range of the jth combined fault, X, 2j is the influence range of the peak ground stress of the jth combined fault, x j1 and x j2 are the influence ranges on both sides of the jth combined fault, which are defined as the two critical distances from the combined fault to the time when the stress increment reaches the original rock stress σ0, x j3 and x j4 They are the peak ranges on both sides of the jth combined fault, which are defined as the two critical distances from the combined fault to the time when the stress increment reaches 10σ0 of the original rock stress.

[0057] Furthermore, according to the drop of each fault and J combined faults, the drop influence range and drop peak influence range of each combined fault structure are obtained. The specific process is as follows:

[0058] Get the effective drop of the jth combined fault, and the calculation formula is as follows:

[0059]

[0060] Among them, LLC j is the effective fall of the jth combined fault, LC i is the drop of the ith fault, L dtc-Min , L dtc-Max are the minimum and maximum distances between faults within the combined fault, respectively;

[0061] According to the effective drop of the jth combined fault, the formula for obtaining the drop influence range and drop peak influence range of the jth combined fault structure is as follows:

[0062]

[0063] Among them, Y 1j is the impact range of the jth combined fault, Y 2j is the peak impact range of the jth combined fault;

[0064] According to the in-situ stress influence range X1 of the jth combined fault, j , the influence range of the peak ground stress X, 2j 、The impact range of the combined fault structure Y 1j And the peak impact range Y 2j , obtain the influence range and peak influence range of the jth combined fault structure, based on the following formula:

[0065] Z 1j =Max(X1, j ,Y 1j )

[0066] Z 2j =Max(X2, j ,Y 2j )

[0067] Among them, Z 1j is the combined fault structure influence range of the jth combined fault, Z 2j is the combined fault structure peak influence range of the jth combined fault.

[0068] Furthermore, in step S6, the specific formula for obtaining the plastic zone range and the elastic zone range is as follows:

[0069]

[0070] Among them, X et is the plastic zone range, X pt is the elastic range, kγH is the X in the plastic region et The stress peak is at the point where H is the depth of coal seam, γ is the average bulk density of coal seam overburden, k is the stress concentration factor, σ r is the residual stress of the surrounding rock, is the internal friction angle of the coal body, f is the friction coefficient of the micro-unit in the plastic zone, p is the thickness of the coal seam, and λ is the lateral pressure coefficient of the coal body.

[0071] Furthermore, in step S7, the specific process of obtaining the regional hazard level of the combined fault advance and executing corresponding measures according to the hazard level is as follows:

[0072] The combined fault advance regionality is divided into two stages: the working face facing stage and the working face departing stage;

[0073] Working surface facing stage:

[0074] The influence range Z of the j-th combined fault structure 1j 、Plastic zone range X et and elastic range X pt Add the plastic zone range X et and the peak influence range Z of the jth combined fault structure 2j Add the sum, and the summed values ​​are equal to D + For comparison:

[0075] When D + >Z 1j +X et +X pt , indicating that the combined fault advance regionality is a general dangerous area, and roof blasting and coal blasting are required;

[0076] When X et +Z 2j <D + ≤Z 1j +X et +X pt , indicating that the combined fault advance regionality is a medium-risk area, which requires roof blasting, coal blasting and large-diameter drilling to relieve pressure;

[0077] When 0≤D + ≤X et +Z 2j , indicating that the combined fault advance area is a dangerous area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure. In addition, roof and large-diameter densification treatment is also required;

[0078] Working face departure stage:

[0079] The influence range Z of the j-th combined fault structure 1j 、Plastic zone range X et and elastic range X pt Add the plastic zone range X et and the peak influence range Z of the jth combined fault structure 2j Add the sum, and the summed values ​​are equal to D - For comparison:

[0080] When D - ≤X et +Z 2j , indicating that the combined fault advance area is a dangerous area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure. In addition, roof and large-diameter densification treatment is also required;

[0081] When X et +Z 2j <D - ≤Z 1j+X et +X pt , indicating that the combined fault advance regionality is a medium-risk area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure;

[0082] D - >Z 1j +X et +X pt , indicating that the combined fault advance regionality is a general dangerous area, and roof blasting and coal blasting are required;

[0083] D + It indicates the distance from the nearest fault in the fault group when the working face is excavated towards the fault group, D - It indicates the distance from the nearest fault in the fault group when the working face is excavated away from the fault group.

[0084] Compared with the prior art, the present invention has the following beneficial effects:

[0085] The present invention constructs a cross-sectional view and a plan view of a combined fault and a working surface, collects basic data of the fault and the working surface, obtains a fault geostress increment matrix and a combined fault according to the cross-sectional view and the plan view of the combined fault and the working surface, the original rock stress in the non-structural area, the vertical geostress and the horizontal geostress around the fault, obtains the influence range and the peak influence range of each combined fault structure according to the combined fault, the geostress increment matrix and the drop of each fault, obtains the plastic zone range and the elastic zone range according to the average bulk density of the coal seam overburden, the coal seam burial depth and thickness, the stress concentration factor, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone, the friction angle of the coal body and the lateral pressure coefficient of the coal body, obtains the advanced regional hazard level of the combined fault according to the influence range of the combined fault structure and the fault structure peak range, the plastic zone range and the elastic zone range, and executes corresponding measures according to the hazard level. Therefore, by constructing cross-sectional and plan views of the combined faults and working faces, and dynamically considering the interaction between faults and the coupling relationship with the advance support stress, a more comprehensive geological structure analysis is provided. This dynamic analysis helps to more accurately assess the potential risk of rock bursts, establish a "fault structure-advance support stress" rock burst hazard prevention and control system, and correctly control the contradiction between the intensity, scope and cost of the advance unloading of the horizontal tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0087] Figure 2 The working face plan view and vertical section view along the working face lane of the present invention;

[0088] Figure 3 It is a plane section comparison diagram of the combined fault and the mining area section of the present invention;

[0089] Figure 4 The stress increment cloud diagram of the fault and the stress increment curve of the working face and lane of the present invention;

[0090] Figure 5 is a schematic diagram of the fault spacing of the present invention;

[0091] Figure 6 It is the stress increment cloud map of the combined fault and the stress increment curve of the working face and lane of the present invention. DETAILED DESCRIPTION

[0092] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0093] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0094] Embodiment 1:

[0095] See also Figure 1 , the present invention provides a technical solution:

[0096] A regional hazard classification and solution under a combined fault, the specific steps include:

[0097] S1. Construct the cross-section and plan view of the combined fault and working face, and collect the basic data of the fault and working face, including the fall of each fault, the original rock stress in the non-structural area, the vertical ground stress around the fault, the horizontal ground stress, the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration factor of the coal rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone of the coal body, the friction angle of the coal body and the lateral pressure coefficient of the coal body;

[0098] S2. According to the cross-sectional view and plan view of the combined fault and the working surface, the vertical geostress, and the horizontal geostress, the calculated dip angle and plane grid matrix of the fault layer in the combined fault are obtained, the plane grid matrix includes a distance matrix and an angle matrix, according to the calculated dip angle and plane grid matrix of the fault layer in the combined fault, the geostress increment matrix of the fault is obtained, according to the geostress increment matrix of the fault, the influence range of each fault is obtained, according to the influence range of each fault, the combination relationship of the fault is judged, and the combined fault is obtained;

[0099] S3. according to the faults and geostress increment matrix included in the combined fault, obtain the geostress increment matrix of the combined fault, and according to the geostress increment matrix of the combined fault, obtain the geostress influence range of the combined fault and the geostress peak influence range of the combined fault;

[0100] S4. according to the drop of each fault and the combined fault, obtain the drop influence range and the drop peak influence range of each combined fault structure; according to the effective drop of the combined fault, obtain the drop influence range and the drop peak influence range of each combined fault structure;

[0101] S5. Obtain the influence range and peak influence range of the combined fault structure according to the combined fault in-situ stress influence range, the in-situ stress peak influence range, the drop influence range of the combined fault structure, and the drop peak influence range;

[0102] S6. Process the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration coefficient of the coal-rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone and the internal friction angle of the coal body to generate the range of the plastic zone, and process the lateral pressure coefficient of the coal body, the coal seam thickness, the stress concentration coefficient and the friction coefficient of the micro-unit in the plastic zone to generate the range of the elastic zone;

[0103] S7. Divide the working face into the facing stage and the diverging stage, and judge the regional danger level of the combined fault advance according to the influence range of the combined fault structure, the peak influence range of the combined fault structure, the plastic zone range and the elastic zone range, and implement corresponding measures according to the danger level.

[0104] On the basis of the above-mentioned embodiments, the equipment and method for collecting the fall of each fault, the original rock stress in the non-structural area, the vertical ground stress around the fault, the horizontal ground stress, the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration factor of the coal rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone of the coal body, the friction angle of the coal body and the lateral pressure coefficient of the coal body are as follows:

[0105] Determine the height difference and drop of the fault using geological survey instruments (such as total station, GPS);

[0106] By using stress measuring instruments (such as in-hole stress gauges), sensors are placed in underground boreholes to directly measure the stress state in the rock. The stress data is monitored and recorded using a data acquisition system. It is usually necessary to perform multiple measurements at different time periods to capture the dynamic process of stress changes. By analyzing the measurement results, the stress state of the original rock can be obtained, including horizontal stress and vertical stress.

[0107] Conduct field tests using strain gauges and seismic measuring instruments, and calculate vertical ground stress around faults using numerical simulations;

[0108] Install strain gauges in the boreholes and use the strain data from the strain gauges to calculate horizontal ground stress;

[0109] Calculate the average bulk density of the overburden of the coal seam using geotechnical testing instruments (such as a densitometer);

[0110] Obtain the depth data of coal seams through drilling equipment and geological radar;

[0111] Obtain coal seam thickness through drilling sampling and geological profile analysis;

[0112] Run finite element calculation to obtain the stress distribution diagram under the external load. Calculate the stress concentration factor for the stress concentration area. The calculation formula of the stress concentration factor is the ratio of the maximum stress at a certain point to the average stress in the surrounding area.

[0113] Use the drilling test method to drill holes in the surrounding rock. The hole diameter and depth are selected according to the actual situation. Perform partial disassembly to observe the stress release and deformation. Use a laser measuring instrument to measure the deformation around the hole to infer the residual stress.

[0114] By applying shear force, the deformation of coal under different shear stresses is measured, and the friction coefficient is calculated based on the relationship between shear stress and normal stress;

[0115] Through direct shear test or triaxial shear test, the shear deformation of coal body under different stress states is measured, and the internal friction angle of coal body is calculated through stress-strain curve;

[0116] Through triaxial tests, corresponding sensors are configured to monitor stress and strain in real time, axial stress is gradually applied, a certain confining pressure is maintained, and deformation data under different stress conditions are recorded. The lateral pressure coefficient is calculated through the test data. The lateral pressure coefficient is equal to the ratio of horizontal stress to vertical stress.

[0117] Based on the above embodiment, the specific process of step S2 is as follows:

[0118] like Figure 2 and Figure 3As shown in the figure, a vertical profile with the upper and lower ranges of the fault length is made along the working face lane. Four inflection points with large slope changes are found in the vertical profile and connected to form the fault profile line. The angle and length are calculated. The calculation formula is:

[0119]

[0120] Among them, L i is the fault length, θ i is the calculated dip angle of the i-th fault, i is the index of the fault, the value range of i is [1,I], I is the number of faults that pass through the working surface, θ i1 ,θ i2 ,θ i3 and θ i4 are the first, second, third and fourth inflection point angles between the fault profile and the horizontal line, h i1 、h i2 、h i3 and h i4 They are the first, second, third and fourth broken line lengths of the fault profile line in the vertical section diagram;

[0121] On the fault profile, a Cartesian coordinate system xoy is established with the horizontal midpoint of the working surface as the center of the circle, the actual relative profile relationship of the I faults, and the advancing direction of the working surface as the positive semi-axis direction of the x-axis, and the moving point M represents any point relative to the fault;

[0122] Establish 6 plane grid matrices of the same size (m×m) corresponding to the Cartesian coordinate system. The plane grid matrix includes l i1 , l i2 , l i3 , α i1 , α i2 , α i3 , the number of rows and columns of the plane grid matrix are both m, and the elements of the 6 plane grid matrices correspond to the Cartesian coordinate system plane;

[0123] Among them, the elements of the 6 plane grid matrices are:

[0124]

[0125] The matrix element position is defined as the two subscripts of the matrix element, for example: matrix element a 11 The position of is (1, 1), the matrix element a mm The position of is (m, m);

[0126] The correspondence between the element positions of the plane grid matrix and the coordinates in the Cartesian coordinate system is:

[0127]

[0128] Where (x,y) M is the coordinate of point M in the Cartesian coordinate system, x and y are the horizontal and vertical coordinates of point M in the Cartesian coordinate system, respectively. is the element position of the plane grid matrix, and are the horizontal and vertical coordinates of point M in the plane grid matrix, m The size of the fault length L i twice the maximum value in L1, L2, ..., L i );

[0129] l i1 , l i2 , l i3 In the Cartesian coordinate system, the moving point M(x, y) is respectively at the fault point D i1 , D i2 , D i3 distance, using l i1 , l i2 , l i3 , get the distance matrix;

[0130] α i1 , α i2 , α i3 In the Cartesian coordinate system, the moving point M(x, y) is respectively at the fault point D i1 , D i2 , D i3 The angle between the line connecting the two and the positive direction of the x-axis is calculated using α i1 , α i2 , α i3 , get the angle matrix;

[0131] D i1 , D i2 , D i3 are the upper endpoint, midpoint and lower endpoint of the i-th fault in the cross-section diagram respectively;

[0132] Using matrix point operations, the stress increment matrix of the i-th fault is calculated according to the following formula:

[0133] Vσ i =Max(Vσ xi |,|Vσ yi |,|Vσ xyi |)

[0134] Vσ xi =-σ i (A i -B i -1)

[0135] Vσyi =-σ i (1-A i -B i )

[0136] Vσ xyi =-σ i C i

[0137]

[0138] Among them, Vσ i is the incremental matrix of the ground stress of the ith fault, Vσ xi is the stress increment along the x direction on the i-th fault, Vσ yi is the stress increment along the y direction on the i-th fault, Vσ xyi is the increment of shear stress on the i-th fault, σ i is the simulated inclination of the ith fault ignoring shear stress, A i From moving point M to fault point D i3 The distance from the moving point M to the fault point D i1 and D i2 The ratio parameter between the distances, B i From the moving point M to the fault point D i3 The ratio parameter of the distance and the corresponding angle, C i From moving point M to fault point D i2 The proportionality parameter between the distance and the angle, σ hi is the horizontal stress of the i-th fault, σ vi is the vertical stress of the ith fault.

[0139] According to the fault in-situ stress increment matrix, the combination relationship of I faults is determined. The specific steps are as follows:

[0140] like Figure 4 and Figure 5 As shown, according to the in-situ stress increment matrix Vσ1, Vσ2, ..., Vσ of the i-th fault i ,Vσ Z , obtain the stress increment cloud map and fault stress increment curve of the working face under the influence of I fault, Vσ i is the incremental matrix of the ground stress of the i-th fault;

[0141] Among them, the basic logic of drawing the stress increment cloud map is:

[0142] The stress increment matrix Vσ of the i-th fault iThe grid points are laid out on the plane according to the relative positions of the elements in the matrix, and the points with the same value on the grid are connected with an increment of 1 MPa as the interval. This is repeated to obtain the stress increment cloud map of I fault;

[0143] Among them, the basic logic of drawing the stress increment curve of the fault is:

[0144] Referring to the Cartesian coordinate system, the element position of the matrix and the actual position of the fault relative to the working face, the position of the working face lane is found in the stress increment cloud map of the i-th fault, and the stress increment curve of the working face is drawn along this level according to the ground stress increment cloud map;

[0145] According to the stress increment curve of the working surface under the influence of fault I, the basic logic of obtaining the influence range of the i-th fault is:

[0146] x i =(x i1 +x i2 ) / 2

[0147] Among them, x i is the influence range of the i-th fault, x i1 and x i2 are the influence ranges on both sides of the i-th fault, respectively, and are defined as the two critical distances from both sides of the i-th fault to the time when the stress increment reaches the original rock stress σ0, where σ0 refers to the stress borne by the rock itself when no external force is applied;

[0148] According to the influence range x of the i-th fault i The relative position of the faults is used to determine the combination relationship of the faults. The specific process is as follows:

[0149] satisfy:

[0150] L dtc <(x a +x b )

[0151] x a =(x a1 +x a2 ) / 2

[0152] x b =(x b1 +x b2 ) / 2

[0153] L dtc =Min(L dtc1 ,L dtc2 ,L dtc3 ,L dtc4 ,L dtc5 )

[0154] xa is the influence range of fault a, x b is the influence range of fault b, x a1 and x a2 are the two critical distances from the two sides of fault a to the time when the stress increment reaches the original rock stress σ0, x b1 and x b2 are the two critical distances from the two sides of fault b to the time when the stress increment reaches the original rock stress σ0, L dtc1 , L dtc2 , L dtc3 , L dtc4 , L dtc5 L is the length of the segment of the propulsion line sandwiched between the two fault planes, dtc is the minimum value among them;

[0155] If the distance between fault a and fault b is L dtc If it is smaller than the sum of the influence ranges of the two faults, then the fault a and fault b are combined faults;

[0156] By combining and judging all the faults, the combined relationship of the faults can be obtained, and J combined faults can be obtained.

[0157] Based on the above embodiment, the ground stress increment matrix of the j-th combined fault is obtained:

[0158] VΦ j =Max(Vσ xa +Vσ xb |,|Vσ ya +Vσ yb |,|Vσ xya +Vσ xyb |)

[0159] Among them, VΦ j is the geostress increment matrix of the jth combined fault, a∈[1,I]∩b∈[1,I]∩a≠b, Vσ xa , Vσ ya , Vσ xya are the stress increment along the x direction, the stress increment along the y direction, and the shear stress increment on the ath fault, respectively, Vσ xb , Vσ yb , Vσ xyb are the stress increment along the x direction, the stress increment along the y direction, and the shear stress increment on the bth fault, respectively;

[0160] According to the ground stress increment matrix VΦ of the jth combined fault j , obtain the stress increment curve of the working surface level under the influence of the jth combined fault;

[0161] Among them, the basic logic of drawing the stress increment cloud map is:

[0162] like Figure 6 As shown in the figure, the stress increment matrix VΦ of the jth combined fault is j According to the relative positions of the elements in the matrix, grid points are laid out on the plane, and the points with the same value on the grid are connected with an increment of 1 MPa as the interval. This is repeated to obtain a stress increment cloud map.

[0163] Among them, the basic logic of drawing the working surface stress increment curve is:

[0164] With reference to the Cartesian coordinate system, the element position of the matrix and the actual fault relative to the working face, the position of the working face lane is found in the stress increment cloud map, and the working face stress increment curve is drawn along the level according to the ground stress increment cloud map;

[0165] According to the ground stress increment matrix VΦ of the jth combined fault j , the formula for obtaining the in-situ stress influence range and peak influence range of the jth combined fault is as follows:

[0166] X1, j =Max(x j1 ,x j2 )

[0167] X, 2j =Max(x j3 ,x j4 )

[0168] Among them, X1, j is the in-situ stress influence range of the jth combined fault, X, 2j is the influence range of the peak ground stress of the jth combined fault, x j1 and x j2 are the influence ranges on both sides of the jth combined fault, which are defined as the two critical distances from the combined fault to the time when the stress increment reaches the original rock stress σ0, x j3 and x j4 They are the peak ranges on both sides of the jth combined fault, which are defined as the two critical distances from the combined fault to the time when the stress increment reaches 10σ0 of the original rock stress.

[0169] According to the drop of each fault and J combined faults, the effective drop of the jth combined fault is obtained. The specific process is as follows:

[0170]

[0171] Among them, LLC j is the effective fall of the jth combined fault, LC i is the drop of the ith fault, L dtc-Min , L dtc-Maxare the minimum and maximum distances between faults within the combined fault, respectively;

[0172] According to the effective drop of J combined faults, the formula for obtaining the drop influence range and drop peak influence range of the jth combined fault structure is as follows:

[0173]

[0174] Among them, Y 1j is the impact range of the jth combined fault; Y 2j is the peak impact range of the jth combined fault;

[0175] According to the in-situ stress influence range X1 of the jth combined fault, j , the influence range of the peak ground stress X, 2j 、The impact range of the combined fault structure Y 1j And the peak impact range Y 2j , obtain the influence range and peak influence range of the jth combined fault structure, based on the following formula:

[0176] Z 1j =Max(X1, j ,Y 1j )

[0177] Z 2j =Max(X2, j ,Y 2j )

[0178] Among them, Z 1j is the combined fault structure influence range of the jth combined fault, Z 2j is the combined fault structure peak influence range of the jth combined fault.

[0179] Based on the above embodiment, the specific formula for obtaining the plastic zone range and the elastic zone range is as follows:

[0180]

[0181] Among them, X et is the plastic zone range, X pt is the elastic range, kγH is the X in the plastic region et The stress peak is at the point where H is the depth of coal seam, γ is the average bulk density of coal seam overburden, k is the stress concentration factor, σ r is the residual stress of the surrounding rock, is the internal friction angle of the coal body, f is the friction coefficient of the micro-unit in the plastic zone, p is the thickness of the coal seam, and λ is the lateral pressure coefficient of the coal body.

[0182] On the basis of the above embodiment, the specific process of obtaining the regional hazard level of the combined fault advance and executing corresponding measures according to the hazard level is as follows:

[0183] The combined fault advance regionality (working face lane) is divided into two stages: the working face facing stage and the working face departing stage;

[0184] Working surface facing stage:

[0185] The influence range Z of the j-th combined fault structure 1j 、Plastic zone range X et and elastic range X pt Add the plastic zone range X et and the peak influence range Z of the jth combined fault structure 2j Add the sum, and the summed values ​​are equal to D + For comparison:

[0186] When D + >Z 1j +X et +X pt , indicating that the combined fault advance regionality is a general dangerous area, and roof blasting and coal blasting are required;

[0187] When X et +Z 2j <D + ≤Z 1j +X et +X pt , indicating that the combined fault advance regionality is a medium-risk area, which requires roof blasting, coal blasting and large-diameter drilling to relieve pressure;

[0188] When 0≤D + ≤X et +Z 2j , indicating that the combined fault advance area is a dangerous area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure. In addition, roof and large-diameter densification treatment is also required;

[0189] Working face departure stage:

[0190] The influence range Z of the j-th combined fault structure 1j 、Plastic zone range X et and elastic range X pt Add the plastic zone range X et and the peak influence range Z of the jth combined fault structure 2j Add the sum, and the summed values ​​are equal to D - For comparison:

[0191] When D - ≤Xet +Z 2j , indicating that the combined fault advance area is a dangerous area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure. In addition, roof and large-diameter densification treatment is also required;

[0192] When X et +Z 2j <D - ≤Z 1j +X et +X pt , indicating that the combined fault advance regionality is a medium-risk area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure;

[0193] D - >Z 1j +X et +X pt , indicating that the combined fault advance regionality is a general dangerous area, and roof blasting and coal blasting are required;

[0194] D + It indicates the distance from the nearest fault in the fault group when the working face is excavated towards the fault group, D - It indicates the distance from the nearest fault in the fault group when the working face is excavated away from the fault group.

[0195] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0196] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by computer software, electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution.

[0197] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0198] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

[0199] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0200] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A regional hazard classification and solution under a combined fault, characterized in that: The specific steps include: S1. Construct the cross-section and plan view of the combined fault and working face, and collect the basic data of the fault and working face, including the fall of each fault, the original rock stress in the non-structural area, the vertical ground stress around the fault, the horizontal ground stress, the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration factor of the coal rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone of the coal body, the friction angle of the coal body and the lateral pressure coefficient of the coal body; S2. According to the cross-sectional view and plan view of the combined fault and the working surface, the vertical geostress, and the horizontal geostress, the calculated dip angle and plane grid matrix of the fault layer of the combined fault are obtained; according to the calculated dip angle and plane grid matrix of the fault layer of the combined fault, the geostress increment matrix of the fault is obtained; according to the geostress increment matrix of the fault, the influence range of each fault is obtained; according to the influence range of each fault, the combination relationship of the fault is determined, and the combined fault is obtained; S3. according to the faults and geostress increment matrix included in the combined fault, obtain the geostress increment matrix of the combined fault, and according to the geostress increment matrix of the combined fault, obtain the geostress influence range of the combined fault and the geostress peak influence range of the combined fault; S4. according to the drop of each fault and the combined fault, obtain the drop influence range and the drop peak influence range of each combined fault structure; according to the effective drop of the combined fault, obtain the drop influence range and the drop peak influence range of each combined fault structure; S5. Obtain the influence range and peak influence range of the combined fault structure according to the combined fault in-situ stress influence range, the in-situ stress peak influence range, the drop influence range of the combined fault structure, and the drop peak influence range; S6. Process the average bulk density of the coal seam overburden, the coal seam burial depth, the coal seam thickness, the stress concentration coefficient of the coal-rock layer, the residual stress of the surrounding rock, the friction coefficient of the micro-unit in the plastic zone and the internal friction angle of the coal body to generate the range of the plastic zone, and process the lateral pressure coefficient of the coal body, the coal seam thickness, the stress concentration coefficient and the friction coefficient of the micro-unit in the plastic zone to generate the range of the elastic zone; S7. Divide the working face into the facing stage and the diverging stage, and judge the regional danger level of the combined fault advance according to the influence range of the combined fault structure, the peak influence range of the combined fault structure, the plastic zone range and the elastic zone range, and implement corresponding measures according to the danger level.

2. The regional hazard classification and solution under the combined fault according to claim 1 is characterized by: A vertical profile with the upper and lower ranges of the fault length is made along the working face lane to obtain the fault profile line. Four inflection points with large slope changes are found in the fault profile line, and the angle and length are counted. The calculation formula is: Among them, L i is the fault length, θ i is the calculated dip angle of the i-th fault, i is the index of the fault, the value range of i is [1,I], I is the number of faults that pass through the working surface, θ i1 ,θ i2 ,θ i3 and θ i4 are the first, second, third and fourth inflection point angles between the fault profile and the horizontal line, h i1 、h i2 、h i3 and h i4 They are the first, second, third and fourth broken line lengths of the fault profile line in the vertical section diagram; On the fault profile, a Cartesian coordinate system xoy is established with the horizontal midpoint of the working surface as the center of the circle, the actual relative profile relationship of the I faults, and the advancing direction of the working surface as the positive semi-axis direction of the x-axis, and the moving point M represents any point relative to the fault; Establish 6 plane grid matrices of the same size and corresponding to the Cartesian coordinate system, the number of rows and columns of the plane grid matrix are both m, the plane grid matrix includes a distance matrix and an angle matrix, and the elements of the 6 plane grid matrices correspond to the planes of the Cartesian coordinate system; Among them, the elements of the 6 plane grid matrices are: Among them, the matrix element a mm The position of is (m, m); The correspondence between the element positions of the plane grid matrix and the coordinates in the Cartesian coordinate system is: Where (x,y) M is the coordinate of point M in the Cartesian coordinate system, x and y are the horizontal and vertical coordinates of point M in the Cartesian coordinate system, respectively. is the element position of the plane grid matrix, and are the horizontal and vertical coordinates of point M in the plane grid matrix, m The size of the fault length L i twice the maximum value in L1, L2, ..., L i ); l i1 , l i2 , l i3 In the Cartesian coordinate system, the moving point M(x, y) is respectively at the fault point D i1 , D i2 , D i3 distance, using l i1 , l i2 , l i3 , get the distance matrix; α i1 , α i2 , α i3 In the Cartesian coordinate system, the moving point M(x, y) is respectively at the fault point D i1 , D i2 , D i3 The angle between the line connecting the two and the positive direction of the x-axis is calculated using α i1 , α i2 , α i3 , get the angle matrix; D i1 , D i2 , D i3 They are respectively the upper endpoint, midpoint and lower endpoint of the i-th fault in the profile.

3. The regional hazard classification and solution under the combined fault according to claim 2 is characterized by: The formula for calculating the incremental matrix of the fault stress of the i-th fault is as follows: Vs i =Max(Vσ xi |,|Vσ yi |,|Vσ xyi |) Vs xi =-s i (A i -B i -1) Vs yi =-s i (1-A i -B i ) Vs xyi =-s i C i Among them, Vσ i is the incremental matrix of the ground stress of the ith fault, Vσ xi is the stress increment along the x direction on the i-th fault, Vσ yi is the stress increment along the y direction on the i-th fault, Vσ xyi is the increment of shear stress on the i-th fault, σ i is the simulated inclination of the ith fault ignoring shear stress, A i From moving point M to fault point D i3 The distance from the moving point M to the fault point D i1 and D i2 The ratio parameter between the distances, B i From the moving point M to the fault point D i3 The ratio parameter of the distance and the corresponding angle, C i From moving point M to fault point D i2 The proportionality parameter between the distance and the angle, σ hi is the horizontal stress of the i-th fault, σ vi is the vertical stress of the ith fault.

4. The regional hazard classification and solution under the combined fault according to claim 3 is characterized by: According to the i-th fault in-situ stress increment matrix, the influence range of each fault is obtained. The specific steps are as follows: According to the i-th fault ground stress increment matrix Vσ i , obtain the stress increment curve of the working surface under the influence of I faults, and obtain the influence range of each fault according to the stress increment curve, according to the following formula: x i =(x i1 +x i2 ) / 2 Among them, x i is the influence range of the i-th fault, x i1 and x i2 are the influence ranges on both sides of the i-th fault, respectively, and are defined as the two critical distances from both sides of the i-th fault to the time when the stress increment reaches the original rock stress σ0, where σ0 refers to the stress borne by the rock itself when no external force is applied; According to the influence range x of the i-th fault i The relative position of the faults is used to determine the combination relationship of the faults. The specific process is as follows: satisfy: L dtc <(x a +x b ) x a =(x a1 +x a2 ) / 2 x b =(x b1 +x b2 ) / 2 L dtc =Min(L dtc1 ,L dtc2 ,L dtc3 ,L dtc4 ,L dtc5 ) x a is the influence range of fault a, x b is the influence range of fault b, x a1 and x a2 are the two critical distances from the two sides of fault a to the time when the stress increment reaches the original rock stress σ0, x b1 and x b2 are the two critical distances from the two sides of fault b to the time when the stress increment reaches the original rock stress σ0, L dtc1 , L dtc2 , L dtc3 , L dtc4 , L dtc5 L is the length of the segment of the propulsion line sandwiched between the two fault planes, dtc is the minimum value among them; The distance L between fault a and fault b dtc If it is smaller than the sum of the influence ranges of the two faults, then the fault a and fault b are combined faults; By combining and judging all the faults, the combined relationship of the faults can be obtained, and J combined faults can be obtained.

5. The regional hazard classification and solution under the combined fault according to claim 4 is characterized by: Get the incremental ground stress matrix of the jth combined fault: VF j =Max(Vσ xa +Vσ xb |,|Vσ ya +Vσ yb |,Vσ xya +Vσ xyb |) Among them, VΦ j is the geostress increment matrix of the jth combined fault, a∈[1,I]∩b∈[1,I]∩a≠b, Vσ xa , Vσ ya , Vσ xya are the stress increment along the x direction, the stress increment along the y direction, and the shear stress increment on the ath fault, respectively, Vσ xb , Vσ yb , Vσ xyb are the stress increment along the x direction, the stress increment along the y direction, and the shear stress increment on the bth fault, respectively; According to the ground stress increment matrix VΦ of the jth combined fault j , obtain the stress increment curve of the working surface under the influence of the j-th combined fault. According to the stress increment curve of the working surface under the influence of the combined fault, the formula for obtaining the in-situ stress influence range and peak influence range of the j-th combined fault is as follows: X1, j =Max(x j1 ,x j2 ) X, 2j =Max(x j3 ,x j4 ) Among them, X1, j is the in-situ stress influence range of the jth combined fault, X, 2j is the influence range of the peak ground stress of the jth combined fault, x j1 and x j2 are the influence ranges on both sides of the jth combined fault, which are defined as the two critical distances from the combined fault to the time when the stress increment reaches the original rock stress σ0, x j3 and x j4 They are the peak ranges on both sides of the jth combined fault, which are defined as the two critical distances from the combined fault to the time when the stress increment reaches 10σ0 of the original rock stress.

6. The regional hazard classification and solution under the combined fault according to claim 5 is characterized by: According to the drop of each fault and J combined faults, the drop influence range and drop peak influence range of each combined fault structure are obtained. The specific process is as follows: Get the effective drop of the jth combined fault, and the calculation formula is as follows: Among them, LLC j is the effective fall of the jth combined fault, LC i is the drop of the ith fault, L dtc-Min , L dtc-Max are the minimum and maximum distances between faults within the combined fault, respectively; According to the effective drop of the jth combined fault, the formula for obtaining the drop influence range and drop peak influence range of the jth combined fault structure is as follows: Among them, Y 1j is the impact range of the jth combined fault, Y 2j is the peak impact range of the jth combined fault; According to the in-situ stress influence range X1 of the jth combined fault, j , the influence range of the peak ground stress X, 2j 、The impact range of the combined fault structure Y 1j And the peak impact range Y 2j , obtain the influence range and peak influence range of the jth combined fault structure, based on the following formula: Z 1j =Max(X1, j ,Y 1j ) Z 2j =Max(X2, j ,Y 2j ) Among them, Z 1j is the combined fault structure influence range of the jth combined fault, Z 2j is the combined fault structure peak influence range of the jth combined fault.

7. The regional hazard classification and solution under the combined fault according to claim 6 is characterized by: In step S6, the specific formula for obtaining the plastic zone range and the elastic zone range is as follows: Among them, X et is the plastic zone range, X pt is the elastic range, kγH is the X in the plastic region et The stress peak is at the point where H is the depth of coal seam, γ is the average bulk density of coal seam overburden, k is the stress concentration factor, σ r is the residual stress of the surrounding rock, is the internal friction angle of the coal body, f is the friction coefficient of the micro-unit in the plastic zone, p is the thickness of the coal seam, and λ is the lateral pressure coefficient of the coal body.

8. The regional hazard classification and solution under the combined fault according to claim 7 is characterized by: In step S7, the specific process of obtaining the regional hazard level of the combined fault advance and executing corresponding measures according to the hazard level is as follows: The combined fault advance regionality is divided into two stages: the working face facing stage and the working face departing stage; Working surface facing stage: The influence range Z of the j-th combined fault structure 1j 、Plastic zone range X et and elastic range X pt Add the plastic zone range X et and the peak influence range Z of the jth combined fault structure 2j Add the sum, and the summed values ​​are equal to D + For comparison: When D + >Z 1j +X et +X pt , indicating that the combined fault advance regionality is a general dangerous area, and roof blasting and coal blasting are required; When X et +Z 2j <D + ≤Z 1j +X et +X pt , indicating that the combined fault advance regionality is a medium-risk area, which requires roof blasting, coal blasting and large-diameter drilling to relieve pressure; When 0≤D + ≤X et +Z 2j , indicating that the combined fault advance area is a dangerous area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure. In addition, roof and large-diameter densification treatment is also required; Working face departure stage: The influence range Z of the j-th combined fault structure 1j 、Plastic zone range X et and elastic range X pt Add the plastic zone range X et and the peak influence range Z of the jth combined fault structure 2j Add the sum, and the summed values ​​are equal to D - For comparison: When D - ≤X et +Z 2j , indicating that the combined fault advance area is a dangerous area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure. In addition, roof and large-diameter densification treatment is also required; When X et +Z 2j <D - ≤Z 1j +X et +X pt , indicating that the combined fault advance regionality is a medium-risk area, which requires roof blasting, coal blasting, and large-diameter drilling to relieve pressure; D - >Z 1j +X et +X pt , indicating that the combined fault advance regionality is a general dangerous area, and roof blasting and coal blasting are required; D + It indicates the distance from the nearest fault in the fault group when the working face is excavated towards the fault group, D - It indicates the distance from the nearest fault in the fault group when the working face is excavated away from the fault group.

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