Coal rock impact ground pressure prevention and control method based on active structure regulation and control

Abstract

The invention relates to the technical field of rock burst prevention and control, in particular to a coal rock rock burst prevention and control method based on active structure regulation and control, which comprises the following steps: calculating surrounding rock static load energy and impact critical energy based on mining surrounding rock stress distribution, and inversely calculating critical dynamic load energy for inducing impact; based on the impact critical dynamic load energy and the position of the key layer, the critical dynamic load source energy of key layer fracture is inversely calculated according to an energy attenuation rule; inverting the critical fracture length based on the critical dynamic load source energy of the key layer fracture; and active structure regulation and control are carried out based on the critical fracture length of the key layer induced impact, and the fracture length is controlled to be within a safe range. According to the method, the critical fracture length of the key layer inducing the rock burst can be determined, and then structure regulation and control are accurately carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of rock burst prevention and control, and in particular to a method for preventing and controlling coal rock burst based on active structural regulation. Background Art

[0002] Rock burst is one of the most difficult to prevent and control dynamic disasters in mine mining. It is instantaneous and highly destructive, so it is difficult to predict in advance. The occurrence of rock burst is generally related to the evolution of the overlying rock structure. The breaking of the overlying key layer releases high energy, forming a dynamic load source. After being transmitted to the coal body, it is superimposed with the static load energy in the coal body, exceeding the critical energy of impact damage and inducing impact. To this end, the prevention and control of rock burst requires three aspects: first, weakening the energy of the dynamic load source, second, cutting off the transmission path, and finally strengthening the terminal. The most important and critical one is to weaken the energy of the dynamic load source and solve the danger of rock burst from the root. Therefore, it is necessary to weaken the breaking length of the key layer so that it is within a safe range. At present, the weakening of the overlying rock layer is passive, that is, the breaking length of the key layer is reduced by technical means, and the effect is evaluated after implementation. If the effect is poor, it is necessary to re-reinforce and unload the pressure, lacking active structural control ideas and methods.

[0003] In view of this, the present invention proposes a method for preventing and controlling coal rock burst pressure based on active structural regulation, which solves the above-mentioned technical problems. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] A method for preventing and controlling coal rock burst pressure based on active structural regulation comprises the following steps:

[0006] On-site engineering survey, collecting coal and rock samples and determining physical and mechanical parameters;

[0007] On-site measurement of coal body original rock stress and advance support pressure, calculation of the static load energy stored in the coal body;

[0008] Calculate the critical energy of coal body impact and determine the critical dynamic load energy of impact;

[0009] The key layer theory is used to calculate the key layer positions overlying the coal seam;

[0010] According to the energy attenuation theory, the critical dynamic load source energy of the key layer breaking that induces the impact is calculated from the critical dynamic load energy of the coal body.

[0011] According to the dynamic load source energy generated when the key layer breaks, the critical breaking length of the key layer that can induce rock burst is inverted;

[0012] According to the critical breaking length of the key layer that induces impact, the structure of each key layer is actively regulated to control its breaking length within a safe range.

[0013] As a preferred solution of the coal rock burst rock pressure prevention and control method based on active structural regulation provided by the present invention, the stress distribution in the coal seam is measured, the original rock stress and the advance support pressure of the coal seam are determined, and the static load in the coal body is calculated, thereby obtaining the static load energy stored in the coal body;

[0014] The specific steps are as follows:

[0015] The typical characteristic of rock burst is that the coal and rock mass are instantly destroyed and thrown out. Therefore, for rock burst to occur, two conditions must be met. First, the coal mass itself needs to consume energy to break, and second, the broken coal mass needs sufficient kinetic energy to be thrown out.

[0016] The specific steps for determining the critical dynamic load for coal body impact are as follows:

[0017] Determination of coal seam original rock stress: σ o =λγH;

[0018] Measure the coal seam advance support pressure and obtain the peak stress: σ p =KγH, and the λ value and K value are calculated;

[0019] Where, λ is the tectonic stress concentration coefficient; γ is the bulk density of the overlying rock formation; H is the thickness of the overlying rock formation; K is the abutment pressure concentration coefficient;

[0020] In general, the static load of the surrounding rock is composed of the original rock stress and the support pressure, from which the static load of the surrounding rock can be determined: j =σ o +σ p =(K+λ)γH;

[0021] The static load energy stored in the coal rock mass is calculated by static load:

[0022]

[0023] Where Ec is the elastic modulus of the coal body.

[0024] As a preferred solution of the coal rock burst pressure prevention and control method based on active structural regulation provided by the present invention, the typical characteristic of the occurrence of burst pressure is that the coal rock mass is instantly destroyed and thrown out. Therefore, the coal mass needs to meet two conditions for the occurrence of burst pressure. One is that the coal mass itself needs to consume energy for crushing, and the other is that the crushed coal mass needs sufficient kinetic energy to be thrown out.

[0025] The specific steps for determining the critical dynamic load for coal body impact are as follows:

[0026] Calculate the energy consumed by the coal body's own crushing: Calculate the kinetic energy required for the broken coal and rock to be thrown out:

[0027]

[0028] In the formula, σ c is the uniaxial compressive strength of coal, U pmin is the minimum kinetic energy required for rock burst per unit coal-rock mass; V0 is the average initial velocity of the crushed coal-rock mass. According to general research, when V0 ≥ 10 m / s, the possibility of rock burst is very high, so 10 m / s is taken as the critical value; ρ is the average density of the crushed coal mass;

[0029] Calculate the critical energy U of coal body for rock burst bmin for:

[0030]

[0031] Calculation of critical dynamic load energy U for rock burst in coal d for:

[0032]

[0033] As a preferred solution of the coal rock burst rock pressure prevention and control method based on active structural regulation provided by the present invention, there are thick and thick rock layers in the overlying rock layers of the coal seam. Such rock layers control the rock layers within a certain range overlying them, and the overlying rock layers within a certain range deform in coordination with them. Such rock layers are called key layers, among which the rock layers that control the overlying rock layers of the mining area and all the activities on the surface are called main key layers, and the rock layers that control the activities of the local overlying rock layers of the mining area are called sub-key layers;

[0034] The specific steps for determining the positions of each key layer are as follows:

[0035] The key layers are determined from the first rock layer overlying the coal seam upwards. Assuming that the first rock layer is the key layer, the m-th rock layer overlying it deforms in coordination with it, has the same bending curvature, and forms a composite beam with the first key layer; the m+1-th rock layer deforms uncoordinatedly with it, and the m+1-th rock layer is the second key layer; thus, the weight of the rock layer loaded on the first key layer can be obtained as:

[0036]

[0037] Where: q1(x) is the load formed by the mth rock layer on the first hard rock layer; hi, Vi, Ei are the thickness, bulk density, and elastic modulus of the i-th rock layer (i = 1, 2, ..., m);

[0038] The load generated by the m+1th rock layer on the first key layer is calculated as:

[0039]

[0040] Since the m+1th layer is the key layer, its deformation deflection is smaller than that of the lower rock layer, and the weight of the overlying rock layer is borne by the m+1th layer, thus:

[0041] q1(x) m+1 <q1(x) m

[0042] It can be further concluded that:

[0043]

[0044] Use the above formula to determine the position of the key layer, starting from the 1st layer and calculating upwards layer by layer. When the above formula is satisfied when calculating to the mth layer, the mth rock layer is the key layer, and continue calculating upwards in this way until it is determined that the nth rock layer is the last key layer.

[0045] As a preferred solution of the coal rock burst rock pressure prevention and control method based on active structural regulation provided by the present invention, the overlying key layer breaks to form a dynamic load, releasing energy, and the energy will be lost and attenuated during the process of propagating to the coal body. Therefore, the dynamic load energy added to the coal body of the working face is the attenuated breaking energy of the key layer;

[0046] The specific steps are as follows:

[0047] The vertical distance between the critical layer fracture position and the coal seam is the sum of the thickness of each rock layer:

[0048]

[0049] Where: H is the vertical distance between the critical layer fracture position and the coal seam, hi is the thickness of each rock layer;

[0050] According to the rock fracture angle, the distance between the key layer fracture position and the coal wall can be obtained:

[0051]

[0052] Where: ld is the horizontal distance between the critical layer breaking position and the peak value of the coal seam advance support pressure, α is the rock formation breaking angle;

[0053] It can be concluded that the horizontal distance between the critical layer fracture position and the peak value of the coal seam support pressure is:

[0054]

[0055] From this, the straight-line distance between the critical layer fracture position and the peak value of the coal seam advance support pressure can be determined:

[0056]

[0057] Where: l is the straight-line distance from the critical layer breaking position to the peak value of the coal seam advance support pressure;

[0058] According to the energy attenuation theory, the relationship between the dynamic load source energy of the key layer breaking and the dynamic load energy transmitted to the coal body can be obtained as follows:

[0059] U d =U y l -μ

[0060] Where: Uy is the dynamic source energy, μ is the energy propagation attenuation coefficient;

[0061] From this, we can infer that the critical dynamic load source energy formed when the key layer breaks is:

[0062]

[0063] As a preferred solution of the coal rock rock burst pressure prevention and control method based on active structural regulation provided by the present invention, the overlying key layer breaks under the disturbance of coal seam mining. When the key layer is broken with a large block size, the energy released by the breaking is high, and rock burst pressure is easily generated after being transmitted to the coal body; thus, the breaking length of the key layer is inverted by the critical dynamic load source energy that causes rock burst pressure;

[0064] The specific steps are as follows:

[0065] According to the periodic breaking law of the key layer, the dynamic load source energy released by the breaking of the mth key layer is calculated:

[0066]

[0067] Where lm is the breaking length of the key layer, qm is the load borne by the key layer, Em is the elastic modulus of the key layer, hm is the thickness of the key layer, g is the gravitational acceleration, and ρ r is the density of the rock layer above the key layer, hs is the thickness of the rock layer above the key layer, hc is the thickness of the coal seam, H is the vertical distance between the key layer and the coal seam, and s is the expansion coefficient of the rock layer below the key layer;

[0068] The energy of breaking the mth critical layer is the same as the energy of the critical dynamic load source of the impact, then:

[0069] U m =U y

[0070] Where Um is the energy released when the mth critical layer breaks.

[0071] From this we can conclude that:

[0072]

[0073] The right side of the above formula has nothing to do with the critical layer breaking length lm, so it can be simplified to a constant term A:

[0074]

[0075] From this, the key layer breaking length lm can be obtained by inversion calculation:

[0076]

[0077] As a preferred solution of the coal rock burst pressure prevention and control method based on active structural regulation provided by the present invention, the critical breaking length lm of the low and high key layers induced by the burst pressure is calculated according to the above formula, and the length range of the key layer of active structural regulation is determined: l max <l m ; Determine structural control measures and implement active pressure-relieving control.

[0078] Beneficial effects of the present invention:

[0079] 1. This method can determine the critical breaking length of the key layer that induces rock burst, and then accurately control the structure.

[0080] 2. This method is based on the step-by-step inversion of the critical energy of coal body rock burst, and finally obtains the critical breaking length of the key layer.

[0081] 3. This method can be applied to any mine with rock burst and can be used to actively control the structure of any key layer that may induce rock burst. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0083] in:

[0084] Figure 1 This is a schematic diagram of the distribution of coal seam advance support pressure;

[0085] Figure 2 This is a schematic diagram of the key layer positions;

[0086] Figure 3 Schematic diagram of the distance between the critical layer fracture position and the coal body. DETAILED DESCRIPTION

[0087] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0088] Example

[0089] 1. On-site engineering investigation, collection of coal and rock samples and determination of physical and mechanical parameters

[0090] Conduct engineering geological surveys in mines with rock burst hazards and collect basic geological data, including the positions, lithology, thickness, hardness, etc. of each coal and rock layer. Collect coal samples without obvious cracks at the mining face and drill cores of overlying rock layers of different levels.

[0091] According to the national standard GB / T 25217.2-2010 (Measurement, Monitoring and Prevention Methods of Rock Burst Pressure), the material testing machine loads at a rate of 0.5MPa / s to 1.0MPa / s until the specimen is destroyed. The coal and rock specimens are loaded to obtain relevant physical and mechanical parameters, including uniaxial compressive strength, elastic modulus, density, etc.

[0092] 2. Measure the original rock stress and advance support pressure of the coal body on site, and calculate the static load energy stored in the coal body.

[0093] Determine the stress distribution in the coal seam and determine the original rock stress and advance support pressure of the coal seam, such as Figure 1 The static load in the coal body is calculated, and then the static load energy stored in the coal body is obtained.

[0094] The specific steps are as follows:

[0095] (1) Determination of coal seam original rock stress: σ o =λγH. Measure the coal seam advance support pressure and obtain the peak stress: σ p = KγH. The λ value and K value are calculated.

[0096] Where λ is the tectonic stress concentration coefficient; γ is the bulk density of the overlying rock formation; H is the thickness of the overlying rock formation; and K is the abutment pressure concentration coefficient.

[0097] (2) In general, the static load of the surrounding rock is composed of the original rock stress and the support pressure, from which the static load of the surrounding rock can be determined: j =σ o +σ p =(K+λ)γH.

[0098] (3) The static load energy stored in the coal rock mass is calculated by static load:

[0099]

[0100] Where Ec is the elastic modulus of the coal body.

[0101] 4. Calculate the critical energy of coal body impact and determine the critical dynamic load energy of impact

[0102] The typical characteristic of rock burst is that the coal rock mass is instantly destroyed and thrown out. Therefore, two conditions must be met for the coal mass to experience rock burst. The first is that the coal mass itself consumes energy to break, and the second is that the broken coal mass needs sufficient kinetic energy to be thrown out.

[0103] The specific steps for determining the critical dynamic load for coal body impact are as follows:

[0104] (1) Calculate the energy consumed by coal body crushing: Calculate the kinetic energy required for the broken coal and rock to be thrown out:

[0105]

[0106] In the formula, σ c is the uniaxial compressive strength of coal, U pmin is the minimum kinetic energy required for rock burst per unit coal-rock mass; V0 is the average initial velocity of the crushed coal-rock mass. According to general research, when V0 ≥ 10 m / s, the possibility of rock burst is very high, so 10 m / s is taken as the critical value; ρ is the average density of the crushed coal mass.

[0107] (2) Calculate the critical energy U of coal body that causes rock burst bmin for:

[0108]

[0109] (3) Calculation of the critical dynamic load energy U for coal body rock burst d for:

[0110]

[0111] 5. Use the key layer theory to calculate the position of the key layers overlying the coal seam.

[0112] There are thick and thick rock layers in the overlying strata of coal seams. Such rock layers control the overlying strata within a certain range, and the overlying strata within a certain range deform in coordination with them. Such rock layers are called key layers. Among them, the rock layers that control the overlying strata of the mining area and all surface activities are called main key layers, and the rock layers that control the activities of local overlying strata of the mining area are called sub-key layers. Figure 2 shown.

[0113] The specific steps for determining the positions of each key layer are as follows:

[0114] (1) Determine the key layer from the first rock layer overlying the coal seam upwards. Assume that the first rock layer is the key layer, and the mth rock layer overlying it deforms in coordination with it, with the same bending curvature, and forms a composite beam with the first key layer. The m+1th rock layer does not deform in coordination with it, so the m+1th rock layer is the second key layer. It can be concluded that the weight of the rock layer loaded on the first key layer is:

[0115]

[0116] Where: q1(x) is the load formed by the mth rock layer on the first hard rock layer; hi, Vi, Ei are the thickness, bulk density and elastic modulus of the ith rock layer respectively (i=1, 2,…, m).

[0117] (2) Calculate the load generated by the m+1th rock layer on the first key layer as follows:

[0118]

[0119] (3) Since the m+1th layer is the key layer, its deformation deflection is smaller than that of the lower rock layer, and the weight of the overlying rock layer is borne by the m+1th layer. Therefore, we can get:

[0120] q1(x) m+1 <q1(x) m

[0121] It can be further concluded that:

[0122]

[0123] (4) Use the above formula to determine the position of the key layer, starting from the first layer and calculating upwards layer by layer. When the above formula is satisfied when calculating to the mth layer, the mth layer is the key layer. Continue calculating upwards in this way until the nth layer is determined to be the last key layer.

[0124] 6. Based on the energy attenuation theory, the critical dynamic load source energy of the key layer breaking that induces the impact is calculated back from the critical dynamic load energy of the coal body.

[0125] The overlying key layer breaks to form dynamic load, releasing energy, which will be lost and attenuated in the process of propagating to the coal body. Therefore, the dynamic load energy added to the coal body at the working face is the attenuated key layer breaking energy.

[0126] The specific steps are as follows:

[0127] (1) The vertical distance between the critical layer fracture position and the coal seam is the sum of the thickness of each rock layer, such as Figure 3 As shown:

[0128]

[0129] Where: H is the vertical distance between the critical layer fracture position and the coal seam, and hi is the thickness of each rock layer.

[0130] (2) According to the rock fracture angle, the distance between the critical layer fracture position and the coal wall can be obtained, such as Figure 3 As shown:

[0131]

[0132] Where: ld is the horizontal distance from the critical layer breaking position to the peak value of the coal seam advance support pressure, and α is the rock formation breaking angle.

[0133] It can be concluded that the horizontal distance between the critical layer fracture position and the peak value of the coal seam support pressure is:

[0134]

[0135] (3) The linear distance between the critical layer fracture position and the peak value of the coal seam advance support pressure can be determined, such as Figure 3 As shown:

[0136]

[0137] Where: l is the straight-line distance from the critical layer breaking position to the peak value of the coal seam advance support pressure.

[0138] (4) According to the energy attenuation theory, the relationship between the dynamic load source energy of the key layer breaking and the dynamic load energy transmitted to the coal body can be obtained as follows:

[0139] U d =U y l -μ

[0140] Where: Uy is the dynamic source energy, μ is the energy propagation attenuation coefficient.

[0141] (5) From this, we can infer that the critical dynamic load source energy generated when the key layer breaks is:

[0142]

[0143] 7. According to the dynamic load source energy generated when the key layer breaks, the critical breaking length of the key layer that can induce rock burst is inverted.

[0144] Under the disturbance of coal mining, the overlying key layer breaks. When the key layer breaks with a large size, the energy released by the break is high, which is easy to cause rock burst after being transmitted to the coal body. Therefore, the breaking length of the key layer is inverted by the critical dynamic load source energy that causes rock burst.

[0145] The specific steps are as follows:

[0146] (1) According to the periodic breaking law of the key layer, the dynamic load source energy released by the breaking of the mth key layer is calculated:

[0147]

[0148] Where lm is the breaking length of the key layer, qm is the load borne by the key layer, Em is the elastic modulus of the key layer, hm is the thickness of the key layer, g is the gravitational acceleration, and ρ r is the density of the rock layer above the key layer, hs is the thickness of the rock layer above the key layer, hc is the thickness of the coal seam, H is the vertical distance between the key layer and the coal seam, and s is the expansion coefficient of the rock layer below the key layer.

[0149] The energy of breaking the mth critical layer is the same as the energy of the critical dynamic load source of the impact, then:

[0150] U m =U y

[0151] Where Um is the energy released when the mth critical layer breaks.

[0152] From this we can conclude that:

[0153]

[0154] (2) The right side of the above formula has nothing to do with the critical layer breaking length lm, so it can be simplified to a constant term A:

[0155]

[0156] From this, the key layer breaking length lm can be obtained by inversion calculation:

[0157]

[0158] 8. Based on the critical breaking length of the key layer that induces the impact, actively control the structure of each key layer to control its breaking length within a safe range.

[0159] The rock layer that induces rock burst during coal mining is not a certain key layer, it may be a high-level key layer or a low-level key layer. The key points of rock burst prevention and control are to weaken the source, cut off the transmission path, and strengthen the terminal. Among them, the source is the most important and the most difficult to control. In the past, the prevention and control of rock burst were all passive. The present invention is based on the critical dynamic load source inversion of the rock burst to determine the structural breaking length, and the key layer is targeted for structural control based on this. The main methods include ground directional long-borehole hydraulic fracturing, underground directional long-borehole hydraulic fracturing, hydraulic top cutting, deep and shallow hole blasting, etc. These means are all aimed at weakening the breaking step of the key rock layer. Therefore, through active control, the breaking step of the key layer is made smaller than the critical breaking step that induces rock burst.

[0160] The specific steps are as follows:

[0161] (1) According to the above formula, the critical breaking length lm of the low-level and high-level key layers induced rock burst is calculated to determine the length range of the key layer for active structural regulation: l max <l m .

[0162] (2) Determine structural control measures and implement active pressure relief control.

[0163] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0164] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preventing and controlling coal rock burst pressure based on active structural regulation, characterized in that: The following steps are involved: On-site engineering survey, collecting coal and rock samples and determining physical and mechanical parameters; On-site measurement of coal body original rock stress and advance support pressure, calculation of the static load energy stored in the coal body; Calculate the critical energy of coal body impact and determine the critical dynamic load energy of impact; The key layer theory is used to calculate the key layer positions overlying the coal seam; According to the energy attenuation theory, the critical dynamic load source energy of the key layer breaking that induces the impact is calculated from the critical dynamic load energy of the coal body. According to the dynamic load source energy generated when the key layer breaks, the critical breaking length of the key layer that can induce rock burst is inverted; According to the critical breaking length of the key layer that induces impact, the structure of each key layer is actively regulated to control its breaking length within a safe range.

2. The method for preventing and controlling coal rock burst pressure based on active structural regulation as claimed in claim 1, characterized in that: Determine the stress distribution in the coal seam, determine the original rock stress and advance support pressure of the coal seam, calculate the static load in the coal body, and then obtain the static load energy stored in the coal body; The specific steps are as follows: The typical characteristic of rock burst is that the coal and rock mass are instantly destroyed and thrown out. Therefore, for rock burst to occur, two conditions must be met. First, the coal mass itself needs to consume energy to break, and second, the broken coal mass needs sufficient kinetic energy to be thrown out. The specific steps for determining the critical dynamic load for coal body impact are as follows: Determination of coal seam original rock stress: σ o =λγH; Measure the coal seam advance support pressure and obtain the peak stress: σ p =KγH, and the λ value and K value are calculated; Where, λ is the tectonic stress concentration coefficient; γ is the bulk density of the overlying rock formation; H is the thickness of the overlying rock formation; K is the abutment pressure concentration coefficient; In general, the static load of the surrounding rock is composed of the original rock stress and the support pressure, from which the static load of the surrounding rock can be determined: j =σ o +σ p =(K+λ)γH; The static load energy stored in the coal rock mass is calculated by static load: Where Ec is the elastic modulus of the coal body.

3. The method for preventing and controlling coal rock burst pressure based on active structural regulation as claimed in claim 2, characterized in that: The typical characteristic of rock burst is that the coal and rock mass are instantly destroyed and thrown out. Therefore, for rock burst to occur, two conditions must be met. First, the coal mass itself needs to consume energy to break, and second, the broken coal mass needs sufficient kinetic energy to be thrown out. The specific steps for determining the critical dynamic load for coal body impact are as follows: Calculate the energy consumed by the coal body's own crushing: Calculate the kinetic energy required for the broken coal and rock to be thrown out: In the formula, σ c is the uniaxial compressive strength of coal, U pmin is the minimum kinetic energy required for rock burst per unit coal-rock mass; V0 is the average initial velocity of the crushed coal-rock mass. According to general research, when V0 ≥ 10 m / s, the possibility of rock burst is very high, so 10 m / s is taken as the critical value; ρ is the average density of the crushed coal mass; Calculate the critical energy U of coal body for rock burst bmin for: Calculation of critical dynamic load energy U for rock burst in coal d for:

4. The method for preventing and controlling coal rock burst pressure based on active structural regulation as claimed in claim 3, characterized in that: There are thick and thick rock layers in the overlying strata of coal seams. Such rock layers control the overlying strata within a certain range, and the overlying strata within a certain range deform in coordination with them. Such rock layers are called key layers, among which the rock layers that control the overlying strata of the mining area and all the activities on the surface are called main key layers, and the rock layers that control the activities of the local overlying strata of the mining area are called sub-key layers. The specific steps for determining the positions of each key layer are as follows: The key layers are determined from the first rock layer overlying the coal seam upwards. Assuming that the first rock layer is the key layer, the m-th rock layer overlying it deforms in coordination with it, has the same bending curvature, and forms a composite beam with the first key layer; the m+1-th rock layer deforms uncoordinatedly with it, and the m+1-th rock layer is the second key layer; thus, the weight of the rock layer loaded on the first key layer can be obtained as: Where: q1(x) is the load formed by the mth rock layer on the first hard rock layer; hi, Vi, Ei are the thickness, bulk density, and elastic modulus of the i-th rock layer (i = 1, 2, ..., m); The load generated by the m+1th rock layer on the first key layer is calculated as: Since the m+1th layer is the key layer, its deformation deflection is smaller than that of the lower rock layer, and the weight of the overlying rock layer is borne by the m+1th layer, thus: q1(x) m+1 <q1(x) m It can be further concluded that: Use the above formula to determine the position of the key layer, starting from the 1st layer and calculating upwards layer by layer. When the above formula is satisfied when calculating to the mth layer, the mth rock layer is the key layer, and continue calculating upwards in this way until it is determined that the nth rock layer is the last key layer.

5. The method for preventing and controlling coal rock burst pressure based on active structural regulation as claimed in claim 4, characterized in that: The overlying key layer breaks to form dynamic load, releasing energy, which will be lost and attenuated in the process of propagating to the coal body. Therefore, the dynamic load energy added to the coal body of the working face is the attenuated breaking energy of the key layer; The specific steps are as follows: The vertical distance between the critical layer fracture position and the coal seam is the sum of the thickness of each rock layer: Where: H is the vertical distance between the critical layer fracture position and the coal seam, hi is the thickness of each rock layer; According to the rock fracture angle, the distance between the key layer fracture position and the coal wall can be obtained: Where: ld is the horizontal distance between the critical layer breaking position and the peak value of the coal seam advance support pressure, α is the rock formation breaking angle; It can be concluded that the horizontal distance between the critical layer fracture position and the peak value of the coal seam support pressure is: From this, the straight-line distance between the critical layer fracture position and the peak value of the coal seam advance support pressure can be determined: Where: l is the straight-line distance from the critical layer breaking position to the peak value of the coal seam advance support pressure; According to the energy attenuation theory, the relationship between the dynamic load source energy of the key layer breaking and the dynamic load energy transmitted to the coal body can be obtained as follows: And d =U y the -μ Where: Uy is the dynamic source energy, μ is the energy propagation attenuation coefficient; From this, we can infer that the critical dynamic load source energy formed when the key layer breaks is:

6. The method for preventing and controlling coal rock burst pressure based on active structural regulation as claimed in claim 5, characterized in that: Under the disturbance of coal mining, the overlying key layer breaks. When the key layer breaks with a large size, the energy released by the break is high, which is easy to cause rock burst after being transmitted to the coal body. Therefore, the breaking length of the key layer is inverted by the critical dynamic load source energy that causes rock burst. The specific steps are as follows: According to the periodic breaking law of the key layer, the dynamic load source energy released by the breaking of the mth key layer is calculated: Where lm is the breaking length of the key layer, qm is the load borne by the key layer, Em is the elastic modulus of the key layer, hm is the thickness of the key layer, g is the gravitational acceleration, and ρ r is the density of the rock layer above the key layer, hs is the thickness of the rock layer above the key layer, hc is the thickness of the coal seam, H is the vertical distance between the key layer and the coal seam, and s is the expansion coefficient of the rock layer below the key layer; The energy of breaking the mth critical layer is the same as the energy of the critical dynamic load source of the impact, then: IN m =U y Where Um is the energy released by the breaking of the mth key layer; From this we can conclude that: The right side of the above formula has nothing to do with the critical layer breaking length lm, so it can be simplified to a constant term A: From this, the key layer breaking length lm can be obtained by inversion calculation:

7. The method for preventing and controlling coal rock burst pressure based on active structural regulation as claimed in claim 6, characterized in that: According to the above formula, the critical breaking length lm of the low-level and high-level key layers induced rock burst is calculated, and the length range of the key layer for active structural regulation is determined: l max <l m ; Determine structural control measures and implement active pressure-relieving control.

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