Analysis Method and System for Rockburst Based on Different Coal-Rock Mass Combination Forms

Abstract

This application relates to the field of coal and rock safety technology, and provides a rock burst analysis method and system based on different coal and rock combination forms. In this method, according to the stress-strain relationship of the combined coal and rock mass under stress, the combination form of the combined coal and rock mass is determined, and a strain softening model of the combined coal and rock mass with different combination forms is constructed for rock burst simulation to determine the elastic energy accumulation distribution of different strata of the combined coal and rock mass with different combination forms under stress, and to determine the combined anti-burst measures of the combined coal and rock mass with different combination forms under stress. Thereby, the characteristics of energy accumulation in each layer of various different coal and rock combination forms, the laws of shear failure and plastic failure of coal and rock masses in each stratum, and the change and accumulation laws of elastic energy are analyzed theoretically, and targeted anti-burst measures are proposed according to the change characteristics of coal and rock masses in each stratum, providing a theoretical basis for decision-making on whether the working face with different combined coal and rock mass forms can be safely mined.

Description

Technical Field

[0001] This application relates to the technical field of coal and rock safety, and particularly to a method and system for analyzing rock burst based on different coal and rock combination forms. Background Art

[0002] With the increase in mining intensity and depth, multiple rock burst accidents have been induced (including coal body impact, roof impact, and floor impact). The instability of the surrounding rock in the working face induces rock burst, large mine tremors, and even underground rock burst accompanied by mine tremors. Such rock bursts often belong to the catastrophic impacts induced by the large energy elastic energy accumulated in the coal and rock mass, causing serious casualties and property losses.

[0003] Currently, a large number of studies have been conducted on the overlying rock spatial structure, the distribution characteristics of abutment pressure, the pre-assessment of impact risk, and the mechanism of rock burst occurrence. Beneficial explorations have been made on the monitoring and early warning of rock burst. However, there is a lack of research on the induction mechanism of rock burst for different coal and rock combination forms and targeted prevention and control measures. Determining the failure law of coal and rock mass, the change law of elastic energy density, the layer where rock burst occurs in coal and rock mass at different horizons, and targeted three-dimensional rock burst prevention measures during the stress loading process of different combined coal and rock masses have become safety issues of concern to coal mines. Summary of the Invention

[0004] The purpose of this application is to provide a method and system for analyzing rock burst based on different coal and rock combination forms to solve or alleviate the problems existing in the above-mentioned prior art.

[0005] To achieve the above purpose, this application provides the following technical solutions:

[0006] This application provides a method for analyzing rock burst based on different coal and rock combination forms, including: Step S101, determining the combination form of the combined coal and rock mass according to the stress-strain relationship of the combined coal and rock mass under stress; Step S102, constructing a strain-softening model of the combined coal and rock mass with different combination forms for rock burst simulation to determine the elastic energy accumulation distribution of different horizons of the combined coal and rock mass with different combination forms under stress; Step S103, determining the combined rock burst prevention measures of the combined coal and rock mass with different combination forms under stress according to the elastic energy accumulation distribution of different horizons of the combined coal and rock mass with different combination forms under stress.

[0007] Preferably, in step S101, in response to ε 11 > ε 10 = ε 12 , then the combined coal and rock mass is in the combination form of hard roof - soft coal seam - hard floor; in response to ε 22 > ε 21 > ε 20, then the combined coal and rock mass is in the combined form of hard roof - hard coal seam - soft floor; in response to ε 30 > ε 31 > ε 32 , then the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor;

[0008] wherein, ε 12 , ε 11 , ε 10 are the strains of the floor, coal seam, and roof in the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of hard roof - soft coal seam - hard floor; ε 22 , ε 21 , ε 20 are respectively the strains of the floor, coal seam, and roof in the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of hard roof - hard coal seam - soft floor; ε 32 , ε 31 , ε 30 are respectively the strains of the roof, coal seam, and floor in the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor.

[0009] Preferably, in response to the combined coal and rock mass being in the combined form of hard roof - soft coal seam - hard floor, the relationship between the elastic energy accumulated in the floor, coal seam, and roof of the combined coal and rock mass is:

[0010]

[0011] In the formula, ε 12 , ε 11 , ε 10 are the strains of the floor, coal seam, and roof in the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of hard roof - soft coal seam - hard floor; E 12 , E 11 , E 10 are respectively the elastic energies accumulated in the floor, coal seam, and roof of the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of hard roof - soft coal seam - hard floor; x is the thickness of each combined layer in the combined coal and rock mass.

[0012] Preferably, in response to the combined coal and rock mass being in the combined form of hard roof - hard coal seam - soft floor, the relationship between the elastic energy accumulated in the floor, coal seam, and roof of the combined coal and rock mass is:

[0013]

[0014] In the formula, ε 22 , ε 21 , ε 20When the combined coal and rock mass is in the combined form of hard roof - hard coal seam - soft floor, the strains of the floor, coal seam, and roof in the combined coal and rock mass under the same stress; E 22 、E 21 、E 20 are the elastic energies accumulated in the floor, coal seam, and roof of the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of hard roof - hard coal seam - soft floor; x is the thickness of each combined layer in the combined coal and rock mass; x1 is the thickness of the roof in the combined coal and rock mass, x2 is the thickness of the coal seam in the combined coal and rock mass, and x3 is the thickness of the floor of the combined coal and rock mass.

[0015] Preferably, in response to the combined coal and rock mass being in the combined form of soft roof - hard coal seam - hard floor, the relationship of the elastic energies accumulated in the floor, coal seam, and roof of the combined coal and rock mass is:

[0016]

[0017] In the formula, ε 32 、ε 31 、ε 30 are the strains of the roof, coal seam, and floor in the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor; E 32 、E 31 、E 30 are the elastic energies accumulated in the roof, coal seam, and floor of the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor; x is the thickness of each combined layer in the combined coal and rock mass; x1 is the thickness of the roof in the combined coal and rock mass, x2 is the thickness of the coal seam in the combined coal and rock mass, and x3 is the thickness of the floor of the combined coal and rock mass.

[0018] Preferably, in step S102, a rockburst simulation is performed on the strain - softening model of the combined coal and rock mass with different combined forms to determine the plastic failure zone, shear failure characteristics, elastic energy distribution, and elastic energy density distribution of the combined coal and rock mass with different combined forms under stress.

[0019] Preferably, in step S102, in response to the combined coal and rock mass being in the combined form of hard roof - soft coal seam - hard floor, the plastic failure zone, the area with the largest elastic energy distribution, and the area with the largest elastic energy density distribution of the combined coal and rock mass are all the coal body, and the shear failure characteristic is the instantaneous outburst of the coal body;

[0020] In response to the combined coal and rock mass being in the combined form of hard roof - hard coal seam - soft floor, the plastic failure zone of the combined coal and rock mass is the coal seam and the floor, the shear failure feature is the instantaneous protrusion of the floor, the area with the highest elastic energy density is the coal body, and the degree of elastic energy accumulation in the coal body is the highest and gradually decreases from the core outwards;

[0021] In response to the combined coal and rock mass being in the combined form of soft roof - hard coal seam - hard floor, the plastic failure zone of the combined coal and rock mass is the coal seam and the roof, the shear failure feature is mainly the instantaneous caving of the roof, the area with the highest elastic energy density is the junction area between the roof and the coal body, and the degree of elastic energy accumulation in the coal body is the highest and gradually decreases from the core outwards.

[0022] Preferably, step S103 includes: in response to the combined coal and rock mass being in the combined form of hard roof - soft coal seam - hard floor, performing borehole pressure relief on the coal body of the combined coal and rock mass;

[0023] In response to the combined coal and rock mass being in the combined form of hard roof - hard coal seam - soft floor, performing borehole pressure relief on the coal body of the combined coal and rock mass and performing bottom - cutting pressure relief on the floor of the combined coal and rock mass;

[0024] In response to the combined coal and rock mass being in the combined form of soft roof - hard coal seam - hard floor, performing borehole pressure relief on the coal body of the combined coal and rock mass and performing blasting pressure relief on the roof of the combined coal and rock mass.

[0025] Preferably, the performing blasting pressure relief on the roof of the combined coal and rock mass includes: performing blasting pressure relief on the roof of the combined coal and rock mass in two directions, namely, the direction parallel to the working face and the direction parallel to the strike of the working face;

[0026] The performing bottom - cutting pressure relief on the floor of the combined coal and rock mass includes: performing blasting pressure relief on the bottom coal with a roadway thickness greater than 1 meter, arranging the blasting boreholes along the roadway strike, and drilling vertically to the floor of the combined coal and rock mass until reaching the floor of the combined coal and rock mass.

[0027] The embodiment of the present application also provides a rock - burst analysis system based on different coal - rock combination forms, including: a combination form analysis unit configured to determine the combination form of the combined coal and rock mass according to the stress - strain relationship of the combined coal and rock mass under stress;

[0028] A combination form simulation unit configured to construct a strain - softening model of the combined coal and rock mass with different combination forms for rock - burst simulation to determine the elastic energy accumulation distribution of different layers of the combined coal and rock mass with different combination forms under stress;

[0029] The impact prevention setting unit is configured to determine the combined impact prevention measures of the combined coal-rock mass in different combined forms under stress according to the elastic energy accumulation distribution of different layers of the combined coal-rock mass in different forms under stress.

[0030] Beneficial effects:

[0031] In the rock burst analysis method based on different coal-rock combination forms provided by the embodiments of the present application, first, according to the stress-strain relationship of the combined coal-rock mass under stress, the combined form of the combined coal-rock mass is determined; then, a strain softening model of the combined coal-rock mass in different combined forms is constructed for rock burst simulation to determine the elastic energy accumulation distribution of different layers of the combined coal-rock mass in different combined forms under stress; finally, according to the elastic energy accumulation distribution of different layers of the combined coal-rock mass in different combined forms under stress, the combined impact prevention measures of the combined coal-rock mass in different combined forms under stress are determined. Thereby, the characteristics of energy accumulation in each layer of various different coal-rock combination forms, the laws of shear failure and plastic failure of coal-rock masses in each layer, and the change and accumulation laws of elastic energy are analyzed theoretically, and targeted impact prevention measures are proposed according to the change characteristics of coal-rock masses in each layer, providing a theoretical basis for decision-making on whether the working face with different combined coal-rock mass forms can be safely mined. Description of the drawings

[0032] The specification drawings forming a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. Among them:

[0033] Figure 1 It is a schematic flow chart of a rock burst analysis method based on different coal-rock combination forms provided by some embodiments of the present application;

[0034] Figure 2 It is the stress-strain curve of the combined coal-rock mass with the combined form of hard roof - soft coal seam - hard floor provided by some embodiments of the present application;

[0035] Figure 3 It is the stress-strain curve of the combined coal-rock mass with the combined form of hard roof - hard coal seam - soft floor provided by some embodiments of the present application;

[0036] Figure 4 It is the stress-strain curve of the combined coal-rock mass with the combined form of soft roof - hard coal seam - hard floor provided by some embodiments of the present application;

[0037] Figure 5 It is a schematic diagram of plastic failure of the combined coal-rock mass with the combined form of hard roof - soft coal seam - hard floor provided by some embodiments of the present application;

[0038] Figure 6 Schematic diagram of plastic failure of combined coal and rock mass with the combined form of hard roof - hard coal seam - soft floor provided according to some embodiments of the present application;

[0039] Figure 7 Schematic diagram of plastic failure of combined coal and rock mass with the combined form of soft roof - hard coal seam - hard floor provided according to some embodiments of the present application;

[0040] Figure 8 Schematic diagram of shear failure of combined coal and rock mass with the combined form of hard roof - soft coal seam - hard floor provided according to some embodiments of the present application;

[0041] Figure 9 Schematic diagram of shear failure of combined coal and rock mass with the combined form of hard roof - hard coal seam - soft floor provided according to some embodiments of the present application;

[0042] Figure 10 Schematic diagram of shear failure of combined coal and rock mass with the combined form of soft roof - hard coal seam - hard floor provided according to some embodiments of the present application;

[0043] Figure 11 Schematic diagram of elastic energy density distribution of combined coal and rock mass with the combined form of hard roof - soft coal seam - hard floor provided according to some embodiments of the present application;

[0044] Figure 12 Schematic diagram of elastic energy density distribution of combined coal and rock mass with the combined form of hard roof - hard coal seam - soft floor provided according to some embodiments of the present application;

[0045] Figure 13 Schematic diagram of elastic energy density distribution of combined coal and rock mass with the combined form of soft roof - hard coal seam - hard floor provided according to some embodiments of the present application;

[0046] Figure 14 Schematic diagram of elastic energy distribution of combined coal and rock mass with the combined form of hard roof - soft coal seam - hard floor provided according to some embodiments of the present application;

[0047] Figure 15 Schematic diagram of elastic energy distribution of combined coal and rock mass with the combined form of hard roof - hard coal seam - soft floor provided according to some embodiments of the present application;

[0048] Figure 16 Schematic diagram of elastic energy distribution of combined coal and rock mass with the combined form of soft roof - hard coal seam - hard floor provided according to some embodiments of the present application;

[0049] Figure 17 Schematic diagram of the structure of a rock burst analysis system based on different coal - rock combination forms provided according to some embodiments of the present application. Detailed implementation manners

[0050] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. Each example is provided by way of explanation of the present application rather than a limitation of the present application. In fact, those skilled in the art will clearly understand that modifications and variations can be made to the present application without departing from the scope or spirit of the present application. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the embodiments of the present invention shall fall within the scope protected by the embodiments of the present invention.

[0051] At present, for different "roof - coal seam - floor" coal and rock mass combination forms, there is still a lack of effective theoretical basis for plastic failure, shear failure, elastic energy density and elastic energy accumulation degree, as well as the failure horizons of different combined coal and rock masses during the stress loading process and targeted three - dimensional impact prevention measures. There is still a lack of effective theoretical basis for engineering problems such as which parts of higher - level isolated working faces can be mined, which cannot be mined, and which can be mined after taking impact prevention measures. The resulting rock bursts have caused huge casualties and property losses.

[0052] First of all, it should be noted that the distinction between "hard" and "soft" for the roof, coal seam, and floor in the present application is only the relative hardness relationship between the roof, coal seam, and floor in the combined coal and rock mass under the same conditions. For example, hard roof - soft coal seam - hard floor means that in the same combined coal and rock mass, the hardness of the coal seam is relatively less than that of the roof and the floor; hard roof - hard coal seam - soft floor means that in the same combined coal and rock mass, the hardness of the floor is relatively less than that of the roof and the coal seam; soft roof - hard coal seam - hard floor means that in the same combined coal and rock mass, the hardness of the roof is relatively less than that of the coal seam and the floor. That is to say, "hard" and "soft" are the relative hardness relationships of the roof, coal seam, and floor in the same combined coal and rock mass, rather than absolute values. Here, a rock with a hardness less than 20 MPa in the roof and floor is defined as a soft rock, and a rock with a hardness greater than or equal to 20 MPa is defined as a hard rock; a coal seam with a hardness less than 10 MPa is defined as a soft coal seam, and a coal seam with a hardness greater than or equal to 10 MPa is defined as a hard coal seam.

[0053] Based on this, this application analyzes the three forms of different coal-rock mass combinations, namely "soft coal seam + hard roof and floor", "hard roof + hard coal seam + soft floor", and "hard floor + hard coal mass + soft roof", and conducts three-dimensional impact prevention and control analysis on the layers of various plastic failures and shear failures, as well as the layers of elastic energy density and elastic energy accumulation during the stress loading process. The characteristics of energy accumulation in each layer of various different coal-rock combination forms, the laws of shear failure and plastic failure of coal-rock mass in each layer, and the laws of elastic energy change and elastic energy accumulation are analyzed theoretically. According to the change characteristics of coal-rock mass in each layer, targeted impact prevention and control measures are proposed to provide a theoretical basis for decision-making on whether the working face of different combined coal-rock mass forms can be safely mined.

[0054] As Figures 1 to 16 shown, the impact ground pressure analysis method based on different coal-rock combination forms includes:

[0055] Step S101: Determine the combination form of the combined coal-rock mass according to the stress-strain relationship of the combined coal-rock mass under stress.

[0056] According to the influencing factors inducing impacts in rock burst mines, rock burst mines can be divided into six different types. The first type is the self-weight impact of thick coal seams with large burial depth, thin bedrock; the second type is the impact of high-intensity mining of thick coal seams with large burial depth and full bedrock; the third type is the impact of coal pillar mining in coal seam groups; the fourth type is the coupled impact of compound disasters in extra-thick coal seams with shallow burial depth; the fifth type is the impact of mining in complex structures and irregular block sections; the sixth type is the impact of key strata with large burial depth.

[0057] With the influence of factors such as mining depth, mining intensity, and insufficient pressure relief, the degree of damage to roadways caused by rock burst accidents increases year by year; moreover, the areas where rock bursts occur and cause damage are also different. In some mines, the coal seam area is severely damaged, in some mines, the roof and coal seam are severely damaged, and in some mines, the coal seam and floor are severely damaged, etc. When rock bursts occur in mines, it causes huge damage to the personnel, roadways, etc. of the mines. In this application, the geological conditions of rock bursts in different regions, and the layers of the roof, coal seam, and floor after rock bursts occur are analyzed. According to the stress-strain relationship of the combined coal-rock mass under stress, the combination form of the combined coal-rock mass is determined to achieve multi-layer three-dimensional joint precise pressure relief under the lithological conditions of the roof, coal seam, and floor of different combinations in space.

[0058] Specifically, the combination form of the combined coal-rock mass is determined according to the stress-strain relationship of different layers of the combined coal-rock mass under stress. Under the same stress, when ε 11 > ε 10 = ε 12When the strain of the coal body in the combined coal-rock mass is the largest and the strains of the roof and floor are the same, that is to say, the hardness of the coal seam in the combined coal-rock mass is relatively small, and the hardnesses of the roof and floor are both greater than that of the coal seam. The combined coal-rock mass is in the form of a hard roof - soft coal seam - hard floor. Among them, ε 12 and ε 11 and ε 10 are the strains of the roof, coal seam, and floor in the combined coal-rock mass with the form of a hard roof - soft coal seam - hard floor under the action of the same stress.

[0059] When the combined coal-rock mass is in the form of a hard roof - soft coal seam - hard floor, the hardness of the coal body is relatively small and the strain is relatively large. Under the action of the same stress, the energy storage relationship among the roof, coal seam, and floor in the combined coal-rock mass is as follows:

[0060]

[0061] Among them, X is the thickness of each combined layer in the combined coal-rock mass, and E 12 and E 11 and E 10 are the elastic energies accumulated in the floor, coal seam, and roof of the combined coal-rock mass under the action of the same stress when the combined coal-rock mass is in the form of a hard roof - soft coal seam - hard floor, respectively. It can be seen that when the combined coal-rock mass is in the form of a hard roof - soft coal seam - hard floor, the elastic strain energy accumulated in the soft coal seam is the largest. Taking the soft coal seam as the pressure-relief layer for targeted pressure relief can make the energy release more thorough and the danger-removing effect better.

[0062] Under the action of the same stress, when ε 22 > ε 21 > ε 20 , that is, the strain of the floor in the combined coal-rock mass is the largest and the strain of the roof is the smallest. That is to say, the hardness of the floor in the combined coal-rock mass is the smallest, and the hardnesses of the roof and coal seam are both greater than that of the floor. Therefore, the combined coal-rock mass is in the form of a hard roof - hard coal seam - soft floor. Among them, ε 22 and ε 21 and ε 20 are the strains of the roof, coal seam, and floor in the combined coal-rock mass with the form of a hard roof - hard coal seam - soft floor under the action of the same stress.

[0063] When the combined coal-rock mass is in the form of a hard roof - hard coal seam - soft floor, the hardness of the floor is relatively soft, the coal seam is the second, and the hardness of the roof is the largest; the strains are in turn the largest for the floor, the second for the coal seam, and the smallest for the roof strain. Under the action of the same stress, the energy storage relationship among the roof, coal seam, and floor in the combined coal-rock mass is as follows:

[0064]

[0065] Among them, E 22 and E21 and E 20 are the elastic energies accumulated in the floor, coal seam, and roof of the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of hard roof - hard coal seam - soft floor. x is the thickness of each combined layer in the combined coal and rock mass; x1 is the thickness of the combined layer - roof in the combined coal and rock mass, x2 is the thickness of the combined layer - coal seam in the combined coal and rock mass, and x3 is the thickness of the combined layer - floor in the combined coal and rock mass.

[0066] Under the same stress, when ε 30 > ε 31 > ε 32 , that is, the strain of the floor in the combined coal and rock mass is the largest and the strain of the roof is the smallest. That is to say, the hardness of the floor in the combined coal and rock mass is the smallest, and the hardness of both the coal seam and the floor is greater than that of the roof. Therefore, the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor. Among them, ε 30 , ε 31 , ε 32 are the strains of the roof, coal seam, and floor in the combined coal and rock mass with the combined form of soft roof - hard coal seam - hard floor under the same stress.

[0067] When the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor, the hardness of the floor is the largest, the coal seam is the second, and the roof is the softest; the strains are in turn the smallest for the floor, the second for the coal seam, and the smallest for the roof strain. Under the same stress, the energy storage relationship of the roof, coal seam, and floor in the combined coal and rock mass is as follows:

[0068]

[0069] Among them, E 32 , E 31 , E 30 are the elastic energies accumulated in the roof, coal seam, and floor of the combined coal and rock mass under the same stress when the combined coal and rock mass is in the combined form of soft roof - hard coal seam - hard floor. x is the thickness of each combined layer in the combined coal and rock mass; x1 is the thickness of the combined layer - roof in the combined coal and rock mass, x2 is the thickness of the combined layer - coal seam in the combined coal and rock mass, and x3 is the thickness of the combined layer - floor in the combined coal and rock mass.

[0070] Step S102: Construct a strain - softening model of the combined coal and rock mass with different combined forms for the rockburst model to determine the elastic energy accumulation distribution of different layers of the combined coal and rock mass with different combined forms under stress.

[0071] After determining the combined form of the combined coal-rock mass through the stress-strain relationship of the combined coal-rock mass, the elastic energy accumulation distribution of the combined coal-rock mass with different combined forms under stress is determined by simulating rock burst pressure on the combined coal-rock mass with different combined forms. Specifically, a strain softening model of the combined coal-rock mass is constructed based on the physical parameters of the combined coal-rock mass. The strain softening model for rock burst pressure simulation is mainly constructed based on the uniaxial compressive strength, elastic modulus, Poisson's ratio, tensile strength, cohesion and internal friction angle of the combined coal-rock mass. Combined coal-rock masses with different combined forms are constructed by setting parameters of different physical properties.

[0072] Here, the combined coal-rock mass with the combination of hard roof-soft coal seam-hard floor, hard roof-hard coal seam-soft floor, and soft roof-hard coal seam-hard floor is constructed mainly through roofs, coal bodies and floors with different hardness. The plastic failure zone, shear failure characteristics, elastic energy distribution and elastic energy density distribution of the combined coal-rock mass with different combination forms are determined through the rock burst model of different strain softening models.

[0073] For the strain softening model with a combination of hard roof-soft coal seam-hard floor, during the stress loading process, due to the softness of the coal seam, the accumulated elastic deformation energy is the largest and reaches the failure limit first, and the plastic deformation zone is mainly distributed in the coal seam; the shear failure zone of the strain softening model occurs in the coal body and is in the shape of two opposing funnels, and the shear failure feature is mainly the instantaneous protrusion of the coal body.

[0074] During the stress loading process, the area with the largest elastic energy density distribution of the strain softening model with a combination of hard roof-soft coal seam-hard floor is the coal body, and it is in the shape of an I. The elastic energy distribution in the coal body is the largest, and the elastic energy accumulation degree of the roof and floor is relatively low. For the coal body with the largest elastic energy distribution, the elastic energy mainly accumulates at the edge of the coal body. When impact ground pressure occurs, the tunnel damage is most serious.

[0075] For the strain softening model with a combination of hard roof-hard coal seam-soft floor, the floor is relatively soft, especially in a large water mine. The strength of the floor will be further reduced after encountering water. During the stress loading process, the plastic failure of the floor will further extend to the coal body, causing the coal body to be linked to plastic failure. Therefore, when the floor is relatively soft, the combined coal-rock mass is in the combination of hard roof-hard coal seam-soft floor. Under high stress, the damage is mainly concentrated in the coal seam and floor, that is, the plastic crushing area is the coal seam and floor. During the stress loading process, the main shear failure of the strain softening model occurs in the floor, and it is in the shape of a funnel with an opening downward. Therefore, when the rock burst occurs, the main feature of the shear failure is the instantaneous protrusion of the floor.

[0076] When the combined form is hard roof - hard coal seam - soft floor, due to the relatively soft floor and the lack of support action of the coal body, during the stress loading process, some energy is released during the floor heave, and the elastic energy is transferred to the coal body part, resulting in the highest elastic energy density in the coal body, and the accumulation of elastic energy gradually decreases from the core outwards, especially in the area connecting the floor corner and the center of the coal body core, showing a funnel shape with the opening downwards. When rock bursts occur, it is not only manifested as the outburst of the coal body, but also accompanied by floor impacts.

[0077] For the strain - softening model with the combined form of soft roof - hard coal seam - hard floor, the roof is relatively soft. During the stress loading process, during the plastic failure of the roof, the plastic failure will further extend to the coal body, causing the coal body to have associated plastic failure. Therefore, when the roof is relatively soft, under the action of stress, the damage is mainly concentrated in the coal seam and the roof, that is, the plastic failure area is mainly the coal seam and the roof; the shear failure area mainly occurs in the roof and shows a funnel shape with the opening upwards. When rock bursts occur, the shear failure characteristics are mainly manifested as the instantaneous caving of the roof.

[0078] When the combined form is soft roof - hard coal seam - hard floor, during the stress loading process, the area with the maximum elastic energy density is the interface area between the roof and the coal body, followed by the coal body, and the elastic energy density of the floor is the smallest. And the accumulation degree of elastic energy in the coal body is the highest and gradually decreases from the core outwards; the area with relatively large elastic energy accumulation in the floor is in the area connecting the floor corner and the center of the coal body core, showing a funnel shape with the opening upwards. Therefore, when rock bursts occur, it is not only manifested as the outburst of the coal body, but also accompanied by the caving of the roof.

[0079] Step S103: According to the elastic energy accumulation distribution of different layers of the combined coal - rock mass with different combined forms under the action of stress, determine the combined rock - burst prevention measures for the combined coal - rock mass with different combined forms under the action of stress.

[0080] Through the strain - softening model to simulate the rock bursts of the combined coal - rock mass with different combined forms, the elastic energy accumulation of the combined coal - rock mass with different combined forms at different layers is obtained. It can be seen that when stress is loaded, whether it is the combined form of hard roof - soft coal seam - hard floor, hard roof - hard coal seam - soft floor, or soft roof - hard coal seam - hard floor, plastic and shear failures will occur in the coal body, and the elastic energy density and elastic energy are very high. Therefore, it is necessary to carry out borehole pressure relief on the coal body in all combined forms of the combined coal - rock mass.

[0081] When the combined coal - rock mass is in the combined form of hard roof - hard coal seam - soft floor, during the stress loading process, plastic and shear failures occur in the roof, with high elastic energy density and high elastic energy. The roof has the risk of rock bursts. To prevent rock bursts from occurring in the roof during the coal face mining, blasting pressure relief should be carried out on the roof.

[0082] The reason for the impact of the bottom coal in the roadway or the soft floor rock stratum of a thin coal seam is that the stress concentration degree on both sides of the roadway is too large, resulting in plastic shear failure of the floor, and the bottom coal has impact proneness and can store the bending elastic energy formed by the action of horizontal stress. Since there is no support for the roadway floor, the floor after plastic failure is not restricted, and the stored bending elastic energy and the compressive elastic energy transmitted from the coal rib are released instantly, causing the bottom coal to rush into the roadway. Although the bottom coal cannot provide the force source for the occurrence of rock burst, it becomes the disaster-causing body for the manifestation of rock burst. Therefore, effective measures should be taken to cut off the energy and stress transmission paths between the force source and the bottom coal or the disaster body of the soft floor rock stratum of a thin coal seam. That is to say, it is necessary to carry out blasting pressure relief on the bottom coal with a thickness of more than 1 meter in the roadway (the coal seam is below the roadway floor and the rock pillar is less than 1 meter), that is, bottom cutting pressure relief.

[0083] Therefore, when the combined coal-rock mass is in the combined form of hard roof - soft coal seam - hard floor, during stress loading, the coal body undergoes plastic and shear failure, and both the elastic energy density and the elastic energy are very high. The impact risk is mainly concentrated in the coal body. At this time, it is necessary to carry out borehole pressure relief on the coal body of the combined coal-rock mass.

[0084] When the combined coal-rock mass is in the combined form of hard roof - hard coal seam - soft floor, the coal body undergoes plastic failure, and both the elastic energy density and the elastic energy are very high. The floor undergoes plastic and shear failure, and both the elastic energy density and the elastic energy are very high. The impact risk is mainly concentrated in the coal body and the floor area. At this time, it is necessary to carry out borehole pressure relief on the coal body in the combined coal-rock mass and carry out bottom cutting pressure relief on the floor in the combined coal-rock mass.

[0085] When the combined coal-rock mass is in the combined form of soft roof - hard coal seam - hard floor, the coal body undergoes plastic failure, the elastic energy density is relatively high, and the degree of elastic energy accumulation is relatively high. The roof undergoes plastic and shear failure, the elastic energy density is high, and the degree of elastic energy accumulation is relatively high. The impact risk is mainly concentrated in the coal body and the roof area. At this time, it is necessary to carry out borehole pressure relief on the coal body in the combined coal-rock mass and carry out blasting pressure relief on the roof in the combined coal-rock mass.

[0086] In a specific example, when carrying out blasting pressure relief on the roof in the combined coal-rock mass, the roof pressure relief is divided into two directions. One is the direction parallel to the working face, that is, the inclination direction of the borehole is parallel to the working face, so as to carry out advance determination, reduce the breaking length of the roof, and reduce the dynamic load disturbance intensity during the working face mining; the other is the strike parallel to the working face, so as to reduce the action of horizontal stress, reduce the elastic energy accumulation, and reduce the damage degree of the dynamic load disturbance during the working face mining to the roadway support.

[0087] In another specific example, when performing floor pressure relief by bottom cutting on the floor of the combined coal and rock mass, boreholes are drilled into the floor of the roadway in the roadway, charged and blasted to damage the floor structure, release the energy, reduce the stress level of the floor, and transfer the high stress deep into the floor, thereby eliminating the impact hazard of the floor. Specifically, the bottom coal with a roadway thickness greater than 1 meter is subjected to blasting pressure relief. The blasting boreholes are arranged along the roadway heading and are drilled vertically into the floor of the combined coal and rock mass until reaching the floor of the combined coal and rock mass.

[0088] Among them, the depth of the borehole is determined according to the thickness of the bottom coal and must be drilled to the coal seam floor; at least 3 boreholes are arranged along the roadway heading, with 1 in the middle of the roadway, drilled vertically to the floor; 1 is arranged at each of the two side bottom corners. The distance between the two side boreholes and the bottom corners of the roadway is 0.3 to 0.5 meters, and they are arranged at 75 degrees to the roadway center line. The row spacing of the boreholes is 3 meters; positive charging is adopted. During connection, parallel connection is used inside the hole and series connection is used outside the hole; 2 - 6 cartridges are charged in each borehole, and the charge amount is adjusted according to the borehole depth and blasting effect. When less than 3 cartridges of ammonium nitrate explosive are used, 1 electric detonator is used for initiation. When more than 3 cartridges of emulsion explosive are used, at least 2 electric detonators are used for initiation.

[0089] Thereby, according to the stress and strain of different combined coal and rock masses, a model of the relationship between the energy storage field - stress field - strain field is established, the energy storage capacity of the rock strata at each layer of the combined coal and rock mass is analyzed theoretically, and the disaster-causing mechanism of different combined coal and rock masses is analyzed from the perspective of the energy field.

[0090] By analyzing the stress concentration area, energy accumulation area, layer failure area of the combined coal and rock mass with different combined forms, and the transfer laws of the stress field and energy storage field after the combined coal and rock mass is damaged, the mutual feedback relationship between the stress field - energy field - failure area, as well as the internal connection between the stress field - energy field - failure area - transferred stress field - transferred energy field are revealed, and the plastic failure and shear failure layers during the stress loading process, as well as the layers where the elastic energy density and elastic energy accumulate, are corresponded to the rock burst failure, and multi-layer three-dimensional combined pressure relief measures for different combined forms in different spaces are formulated.

[0091] As Figure 17 shown, the embodiment of the present application also provides a rock burst analysis system based on different coal and rock combined forms, including:

[0092] A combined form analysis unit 1701, configured to determine the combined form of the combined coal and rock mass according to the stress and strain relationship of the combined coal and rock mass under stress;

[0093] A combined form simulation unit 1702, configured to construct a strain softening model of the combined coal and rock mass with different combined forms for a rock burst model to determine the elastic energy accumulation distribution of different layers of the combined coal and rock mass with different combined forms under stress;

[0094] The impact prevention setting unit 1703 is configured to determine the combined impact prevention measures for the combined coal-rock mass in different combined forms under stress according to the elastic energy accumulation distribution of different horizons of the combined coal-rock mass in different forms under stress.

[0095] The rock burst analysis system based on different coal-rock combined forms provided by the embodiments of the present application can implement the steps and processes of the rock burst analysis method based on different coal-rock combined forms in any of the above embodiments and achieve the same technical effects, which will not be elaborated here one by one.

[0096] In the description of the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The foregoing are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A rock burst analysis method based on different coal-rock combination forms, characterized in that: include: Step S101, determining the combined form of the combined coal-rock mass according to the stress-strain relationship of the combined coal-rock mass under stress; wherein, in response to ε 11 >ε 10 =ε 12 , then the combined coal-rock mass is a combination of hard roof-soft coal seam-hard floor; and ε 12 , ε 11 , ε 10 is the strain of the bottom plate, coal seam and roof in the combined coal rock mass under the same stress when the combined coal rock mass is in the combined form of hard roof plate-soft coal seam-hard bottom plate; In response to ε 22 >ε 21 >ε 20 , then the combined coal-rock mass is a combination of hard roof-hard coal seam-soft floor; and ε 22 , ε 21 , ε 20 are respectively the strains of the bottom plate, coal seam and roof plate in the combined coal rock mass under the same stress when the combined coal rock mass is in the combined form of hard roof plate-hard coal seam-soft bottom plate; In response to ε 30 >ε 31 >ε 32 , then the combined coal-rock mass is a combination of soft roof-hard coal seam-hard floor; and ε 32 , ε 31 , ε 30 are respectively the strains of the roof, coal seam and floor in the combined coal rock mass under the same stress when the combined coal rock mass is in the combined form of soft roof-hard coal seam-hard floor; Step S102: construct a strain softening model of the combined coal-rock mass with different combination forms to perform rock burst simulation to determine the elastic energy accumulation distribution of different layers of the combined coal-rock mass with different combination forms under stress; wherein, in response to the combined coal-rock mass being a combination form of hard roof-soft coal seam-hard floor, the elastic energy relationship of the floor, coal seam and roof in the combined coal-rock mass is: In response to the combined coal-rock mass being a combination of hard roof-hard coal seam-soft floor, the relationship of the elastic energy accumulated among the floor, coal seam and roof in the combined coal-rock mass is: In response to the combined coal-rock mass being a combination of soft roof-hard coal seam-hard floor, the relationship of the elastic energy accumulated among the floor, coal seam and roof in the combined coal-rock mass is: In the formula, E 12 、E 11 、E 10 are respectively the elastic energies accumulated in the bottom plate, coal seam and roof of the combined coal-rock mass under the same stress when the combined coal-rock mass is in the combined form of hard roof plate-soft coal seam-hard bottom plate; E 22 、E 21 、E 20 are respectively the elastic energies accumulated in the bottom plate, coal seam and roof of the combined coal-rock mass under the same stress when the combined coal-rock mass is in the combined form of hard roof plate-hard coal seam-soft bottom plate; E 32 、E 31 、E 30 are respectively the elastic energies accumulated in the roof, coal seam and floor of the combined coal rock mass under the same stress when the combined coal rock mass is in the combined form of soft roof-hard coal seam-hard floor; x is the thickness of each combined layer in the combined coal-rock mass; x1 is the thickness of the roof in the combined coal-rock mass, x2 is the thickness of the coal seam in the combined coal-rock mass, and x3 is the thickness of the bottom plate of the combined coal-rock mass; Step S103, determining the combined anti-collision measures of the combined coal-rock mass with different combined forms under stress according to the elastic energy accumulation distribution of different layers of the combined coal-rock mass with different combined forms under stress.

2. The rock burst analysis method based on different coal-rock combination forms according to claim 1 is characterized in that: In step S102, The rock burst simulation is carried out on the strain softening model of the combined coal-rock mass in different combination forms to determine the plastic failure zone, shear failure characteristics, elastic energy distribution and elastic energy density distribution of the combined coal-rock mass in different combination forms under stress.

3. The rock burst analysis method based on different coal-rock combination forms according to claim 2 is characterized in that: In step S102, In response to the combined coal-rock mass being a combined form of hard roof-soft coal seam-hard floor, the plastic failure zone, the maximum elastic energy distribution zone, and the maximum elastic energy density distribution zone of the combined coal-rock mass are all coal bodies, and the shear failure feature is instantaneous protrusion of the coal bodies; In response to the combined coal-rock mass being a combined form of hard roof-hard coal seam-soft floor, the plastic failure zone of the combined coal-rock mass is the coal seam and the floor, the shear failure feature is the instantaneous protrusion of the floor, the area with the highest elastic energy density is the coal body, and the elastic energy has the highest accumulation degree in the coal body and gradually decreases from the core to the outside; In response to the fact that the combined coal-rock mass is a combination of soft roof-hard coal seam-hard floor, the plastic failure zone of the combined coal-rock mass is the coal seam and the roof, the shear failure feature is mainly the instantaneous collapse of the roof, the area with the highest elastic energy density is the boundary area between the roof and the coal body, and the elastic energy accumulates to the highest degree in the coal body and gradually decreases from the core to the outside.

4. The rock burst analysis method based on different coal-rock combination forms according to claim 1, characterized in that: Step S103 includes: In response to the combined coal-rock mass being a combination of hard roof-soft coal seam-hard floor, drilling to relieve pressure on the coal body of the combined coal-rock mass; In response to the combined coal-rock mass being a combination of hard roof-hard coal seam-soft floor, drilling to relieve pressure on the coal body of the combined coal-rock mass and breaking to relieve pressure on the floor of the combined coal-rock mass; In response to the combined coal-rock mass being a combination of soft roof-hard coal seam-hard floor, the coal body of the combined coal-rock mass is decompressed by drilling, and the roof of the combined coal-rock mass is decompressed by blasting.

5. The rock burst analysis method based on different coal-rock combination forms according to claim 4 is characterized in that: The blasting and decompression of the roof of the combined coal-rock mass comprises: Depressurizing the roof of the combined coal and rock mass by blasting in two directions parallel to the working face and parallel to the working face; The bottom breaking and pressure relief of the bottom plate of the combined coal-rock mass comprises: The bottom coal of the tunnel with a thickness greater than 1 meter is blasted to relieve pressure, and the blasting drill holes are arranged along the direction of the tunnel and are injected vertically to the bottom plate of the combined coal and rock mass.

6. A rock burst analysis system based on different coal-rock combination forms, characterized in that: The rock burst analysis is performed using the rock burst analysis method based on different coal-rock combination forms as described in any one of claims 1 to 5, the system comprising: A combined morphology analysis unit configured to determine the combined morphology of the combined coal-rock mass according to a stress-strain relationship of the combined coal-rock mass under stress; A combined morphology simulation unit is configured to construct a strain softening model of the combined coal-rock mass with different combined morphologies to perform rock burst simulation, so as to determine the elastic energy accumulation distribution of different layers of the combined coal-rock mass with different combined morphologies under stress; The anti-bumping setting unit is configured to determine the combined anti-bumping measures of the combined coal rock mass with different combined forms under stress according to the elastic energy accumulation distribution of different layers of the combined coal rock mass with different forms under stress.

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