A method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines

Abstract

The present invention discloses a method for determining the in-situ stress critical criterion for inducing strong dynamic disasters in mines, belonging to the technical field of judging the causes of strong dynamic disasters. First, collect the mine geological data and establish a numerical calculation model for the whole mine; obtain the coordinates of variable monitoring points and set variable monitoring points in the model; then simulate the change of the self-weight stress field, and implement step-by-step excavation of the numerical model after initial equilibrium; after that, collect the measured data, modify the model parameters, and realize the assimilation of the simulation results and the measured data; finally, obtain the pattern recognition model of the in-situ stress critical criterion for inducing strong dynamic disasters in mines, and determine the in-situ stress critical criterion for inducing strong dynamic disasters in mines; by continuously correcting the mechanical parameters of the numerical calculation model and assimilating the simulation results and the measured data, the accurate in-situ stress evolution results of the whole mine can be obtained. This method has simple steps, is easy to use, and has wide practicability.

Description

Technical Field

[0001] The present invention relates to a method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines, belonging to the technical field of judging the causes of strong dynamic disasters. Background Technique

[0002] With the continuous increase of coal mining depth and mining intensity, strong dynamic disasters in mines are becoming more and more serious. Once disasters such as rock bursts and outbursts occur, they will cause a large number of casualties and property losses to coal mining enterprises, seriously threatening the safe production underground in coal mines.

[0003] In-situ stress is a key parameter for coal mines to prevent disasters such as rock bursts and outbursts. Determining the magnitude of in-situ stress and then predicting geological disasters is an important basis for preventing the occurrence of rock bursts and coal and gas outbursts. The methods for determining in-situ stress can be roughly divided into: on-site measurement method, laboratory measurement method and numerical simulation method. Among them, on-site measurement methods include stress recovery method, hydraulic fracturing method, etc., which can obtain relatively reliable in-situ stress data, but the cost is high and the test location is limited, and it is difficult to obtain and study the stress field distribution near geological structures such as faults and folds by actual measurement; the laboratory measurement method mostly uses the core experiment method to indirectly obtain the in-situ stress value by conducting mechanical experiments on the core. This method has high requirements for core samples, and the core is separated from the original underground environment, and the results obtained often cannot represent the actual in-situ stress state; the numerical simulation method is a numerical calculation model established according to the actual geological conditions and mining sequence of the mine, and the in-situ stress data at the monitoring location is obtained by simulation. The advantages of the numerical simulation method are low cost, unrestricted test location, and the numerical values and changes of key parameters such as in-situ stress can be directly obtained. Therefore, the present invention will use the numerical simulation method to invert the in-situ stress field of the whole mining area and finally determine the critical criterion of in-situ stress for inducing strong dynamic disasters in mines. Summary of the Invention

[0004] According to the deficiencies of the prior art, a method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines is provided. By analyzing the differences in the changes of in-situ stress at key locations and conventional locations, the critical criterion of in-situ stress for inducing strong dynamic disasters is obtained.

[0005] To achieve the object of the present invention, a method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines is characterized in that: firstly, geological data of the mine are collected to establish a numerical model of the whole mine, and then the left sides of the locations where various accidents have occurred in history are taken as key locations to obtain coordinates, and the coordinates of the key locations are set as variable monitoring point coordinates in the model; thereafter, by simulating the change of the self-weight stress field, after initial equilibrium, step-by-step excavation of the numerical model is carried out, measured data are collected, and model parameters are modified to achieve the assimilation of the simulation results and the measured data; a pattern recognition model for the critical criterion of in-situ stress for inducing strong dynamic disasters in mines is obtained, and the critical criterion of in-situ stress for inducing strong dynamic disasters in mines is determined.

[0006] Specifically, it includes the following steps:

[0007] S1 Collect geological data of the target mine, use Rhino software to establish an equal-proportion numerical calculation model of the mine including all mined-out sections, key roadways, key geological structures, and real strata of the mine, use the Griddle plug-in to divide the grid of the equal-proportion numerical calculation model of the mine, and then import the equal-proportion numerical calculation model of the mine with the divided grid into FLAC3D. Set the parameters of each marked rock layer material in the model in FLAC3D, and set the simulated boundary conditions, and assign the initial in-situ stress of the coal and rock layers.

[0008] S2 According to the coordinates of the locations where coal and gas outbursts, rock bursts, locations with dynamic phenomena of coal and gas outbursts, or locations where the prediction indexes of coal and gas outbursts exceed the limit have occurred in the history of the target mine, set these locations with disaster conditions in the history as variable detection points in the model generated by FLAC3D software; and record the in-situ stress evolution process of these key locations in real time, specifically record the change of in-situ stress values.

[0009] S3 First, simulate the change of the self-weight stress field of the target mine. After initial equilibrium, combine the mining succession order of all sections and key roadways of the target mine, and simulate the mining of the model in FLAC3D software according to the mining steps recorded in the real historical data, simulate the evolution process of all in-situ stresses from the initial production period to the present of the whole mine, obtain the stress field distribution of the entire model area and the stress evolution process of the key locations. In order to provide a more realistic mining stress environment, when excavating the mined-out working face, the footage per advance is 1 - 30m each time, and for the working face set near the key geological structure, the footage per advance is 1 - 100m each time.

[0010] S4 collects the measured data of the movement of coal and rock strata and the ground surface during the actual mining process, and the measured data of in-situ stress under the specific mining and excavation succession state in the mine; by continuously fitting and adjusting the density, bulk modulus, shear modulus, tensile strength, internal friction angle and cohesion parameters of each rock stratum in the model, the simulation results are made more consistent with the measured data, realizing the assimilation of the simulation results and the measured data, so that the in-situ stress evolution results obtained by simulation are closer to the actual in-situ stress evolution process of the target mine;

[0011] S5 intercepts the stress nephograms of key locations in the model generated by FLAC3D software, and analyzes the stress change differences near the key locations; extracts the in-situ stress evolution data of the key locations, analyzes the in-situ stress evolution curves of the key locations, and obtains a pattern recognition model for the critical criterion of in-situ stress for strong dynamic disasters, that is:

[0012] 1) When there is a stress concentration area and a stress relief area at a certain place in the stress nephogram, it is judged that the stress change at that place is abnormal;

[0013] 2) When there is an abnormal sudden increase or decrease in the maximum principal stress or the minimum principal stress at a certain place in the stress nephogram, it is judged that the stress change at that place is abnormal;

[0014] By analyzing the in-situ stress evolution process of the key locations, combining with the mining and excavation succession order of the mine, through statistical analysis, the differences in the in-situ stress changes of the key locations are obtained, and the critical criterion for the in-situ stress inducing strong dynamic disasters in the mine is determined:

[0015] When the ratio of the horizontal stress to the vertical stress at the key location exceeds the safety factor interval (αμ, βμ)), that is , it is considered that strong dynamic disasters occur in the mine; where μ is the lateral pressure coefficient, α and β are the safety change coefficients of μ determined according to the measured data and the simulation data, σ x is the horizontal stress, σ z is the vertical stress, σ H is the maximum principal stress, σ h is the minimum principal stress;

[0016] When the monitoring points in the model simultaneously meet the requirements of the pattern recognition model and the critical criterion, it is considered that strong dynamic disasters will occur. Protective measures should be implemented in advance according to the results predicted by the model to prevent the adverse effects on the safe production of the mine caused by the occurrence of disasters.

[0017] In step S1, the geological data collected includes the actual stratigraphic situation of the target mine, key geological structures, mining and excavation engineering plans, borehole columnar diagrams, coal seam floor contour maps, and mining and excavation succession order of the mine. Key geological structures refer to faults, folds, and collapse columns that have a significant impact on the stress field, gas field, etc. of the mine.

[0018] In step S1, the key roadways refer to the sectional return airway, the sectional haulage roadway, and other roadways that have a special influence on the stress distribution characteristics of the mining field.

[0019] In step S4, the measured data of the movement of coal and rock strata and the surface, and the measured data of in-situ stress under specific mining and excavation succession states in the mine are used as the criteria for judging the assimilation of the simulation results with the actual situation of the target mine. The numerical model parameters are continuously modified to make the numerical simulation results consistent with the measured data, realizing the assimilation of the simulation results and the measured data, improving the accuracy of the numerical simulation, and finally obtaining the in-situ stress evolution results of the whole mine;

[0020] Since it is relatively easy to obtain parameters such as density, elastic modulus, Poisson's ratio, tensile strength, internal friction angle, and cohesion in the laboratory, the modification ranges of these parameters are given here:

[0021]

[0022] In step S5, the whole evolution process of the horizontal stress σ x , vertical stress σ z , maximum principal stress σ H , and minimum principal stress σ h at the key locations can be extracted from the monitoring data at the key locations to determine the critical criterion for the in-situ stress that induces strong dynamic disasters in the mine;

[0023] where μ is the coefficient of lateral pressure, Analyze the widely cited distribution law of the coefficient of lateral pressure varying with the burial depth H:

[0024]

[0025] Introducing the parameters (αμ, βμ) in step S5 is to newly determine the safety factor range based on the above formula, combined with the actual situation of the mining area and the numerical inversion results. The value ranges of α and β are respectively:

[0026]

[0027] The result is:

[0028] Since the burial depth H is obtained when the key location is set as the monitoring point, so H is a known quantity. Only the vertical stress σ z , maximum principal stress σ H and minimum principal stress σ h need to be determined, and then the value ranges of α and β can be calculated. Combining the measured data and the simulation data, the appropriate values of α and β can be determined;

[0029] Analyze the horizontal stress σ x and vertical stress σz The ratio, if it is considered that strong dynamic disasters will occur at this key location.

[0030] Beneficial effects: According to the measured data of the movement of coal and rock strata and the surface, and the measured data of in-situ stress under the specific mining succession state in the mine, by continuously modifying the density, bulk modulus, shear modulus, tensile strength, internal friction angle and cohesion parameters of each rock stratum in the model, the assimilation of the simulation results and the measured data is realized, and finally a more accurate in-situ stress evolution result of the whole mine is obtained; by developing a pattern recognition model of in-situ stress critical criterion for complex strong dynamic disasters closer to reality, the location where strong dynamic disasters occur is determined; the critical criterion of in-situ stress inducing strong dynamic disasters is determined, which provides an important basis for preventing mine geological disasters and is beneficial to the safe production of coal mines. Description of the drawings

[0031] Figure 1 It is a flow chart of the method for determining the in-situ stress critical criterion for inducing disasters such as coal and gas outburst and rock burst.

[0032] Figure 2 It is a schematic diagram of the equal-proportion numerical calculation model of the embodiment of the present invention. Specific implementation manners

[0033] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0034] Embodiment 1

[0035] As Figure 1 shown, a method for determining the in-situ stress critical criterion for inducing strong dynamic disasters in a mine includes the following steps:

[0036] S1 Collect mine geological data and establish a numerical calculation model of the whole mine

[0037] 1) Collect the true stratum conditions, key geological structures, mining engineering plans, borehole columnar diagrams, coal seam floor contour maps, and mining succession sequences of the target mine;

[0038] 2) Use Rhino software to establish an equal-proportion numerical calculation model of the mine including all mined-out sections, key roadways, key geological structures, and true strata in the mine. Use the Griddle plug-in that can be perfectly compatible with Rhino software to divide the model grid, and then import the model with the divided grid into FLAC3D. In the FLAC3D software, set the material parameters for each marked rock stratum of the model, set the simulation boundary conditions, and assign the initial in-situ stress of the coal and rock strata, as specifically shown in Figure 2 (a) and (b).

[0039] S2 Obtain the coordinates of variable monitoring points and set variable monitoring points in the model

[0040] 1) Obtain the coordinates of variable monitoring points, that is, the coordinates of the locations where coal and gas outbursts, rock bursts, coal and gas outburst dynamic phenomena, or coal and gas outburst prediction index exceedances have occurred in the target mine's history;

[0041] 2) In the FLAC3D software, set variable monitoring points at the same coordinate positions within the model. During the numerical simulation calculation process, record the in-situ stress evolution process of these key locations in real time.

[0042] Key monitoring points refer to the monitoring points set at the same positions in the model based on the locations where coal and gas outbursts, rock bursts, coal and gas outburst dynamic phenomena, or coal and gas outburst prediction index exceedances have occurred in the target mine's history. During the numerical simulation calculation process, record the stress evolution process of these key monitoring points in real time.

[0043] S3 Simulate the change of self-weight stress field and implement step-by-step excavation of the numerical model after initial equilibrium

[0044] First, simulate the change of self-weight stress field. After initial equilibrium, combined with the mining and excavation succession order of all sections and key roadways in the mine, implement step-by-step excavation of the numerical model. The mining and excavation succession order in the numerical model is the same as the actual mining and excavation succession order, simulate the evolution process of all in-situ stresses from the initial production stage to the present day of the entire mine, and obtain the stress field distribution of the entire model area and the stress evolution process of key locations. In order to provide a more realistic mining stress environment, when excavating the mined-out working face, the advance per cut is 1 - 30 m, and for the working face near key geological structures, the advance per cut is 1 - 100 m.

[0045] S4 Collect measured data, modify model parameters, and achieve the assimilation of simulation results and measured data

[0046] 1) Collect the measured data of the movement of coal and rock strata and the surface, and the measured data of in-situ stress under specific mining and excavation succession states in the mine;

[0047] 2) Continuously modify the parameters of the density, elastic modulus, Poisson's ratio, tensile strength, internal friction angle, and cohesion of each rock stratum in the model to achieve a relatively consistent effect between the simulation results and the measured data, realize the assimilation of the simulation results and the measured data, and obtain the in-situ stress evolution results of this mine.

[0048] The following table shows the modification ranges of density, elastic modulus, Poisson's ratio, tensile strength, internal friction angle, and cohesion.

[0049]

[0050] The pattern recognition model for obtaining the critical criterion of in-situ stress for strong dynamic disasters in S5 is determined to obtain the critical criterion of in-situ stress inducing strong dynamic disasters in mines.

[0051] Intercept the stress nephogram of key locations, analyze the difference in stress changes between key locations and a specific range nearby; extract the stress evolution data of key locations, analyze the stress evolution curve of key locations, and obtain the pattern recognition model for the critical criterion of in-situ stress for strong dynamic disasters, that is:

[0052] 1) The stress change is abnormal, with stress concentration areas and stress relief areas appearing;

[0053] 2) The maximum principal stress or the minimum principal stress suddenly increases or decreases abnormally.

[0054] The horizontal stress σ x , vertical stress σ z , maximum principal stress σ H , and minimum principal stress σ h of the whole process of evolution can be extracted from the monitoring data of key locations. Combining with the mining and excavation succession order of the mine, through statistical analysis, the difference in in-situ stress changes between key locations and conventional locations is obtained.

[0055] In 1978, based on the statistical results of global measured in-situ stress data, Brown and Hoek analyzed the widely cited distribution law of the lateral pressure coefficient μ varying with the burial depth H:

[0056]

[0057] On the basis of the above formula, combined with the actual situation of the mining area and the numerical inversion results, the safety factor interval ((αμ, βμ)) is introduced. α and β are the safety change coefficients of μ determined according to the measured data and simulation data. The value ranges of α and β are respectively:

[0058]

[0059] The result is:

[0060] Since the burial depth H is obtained when the key location is set as the monitoring point, so H is a known quantity. Only the vertical stress σ z , maximum principal stress σ H and minimum principal stress σ h need to be determined, and then the value ranges of α and β can be calculated. Combining with the measured data and simulation data, the appropriate values of α and β can be determined.

[0061] In summary, the critical criterion for in-situ stress inducing strong dynamic disasters in mines is: when the ratio of the horizontal stress to the vertical stress at the key location exceeds the safety factor interval (αμ, βμ)), that is When it occurs, it is considered that a strong dynamic disaster in the mine has occurred. Protective measures should be implemented in advance according to the results predicted by the model to prevent the adverse effects on the safe production of the mine caused by the occurrence of the disaster.

[0062] The present invention provides a method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines. Taking a certain mining area as an example, the method provided by the present invention will be described in detail below.

[0063] S1 Collect mine geological data and establish a numerical calculation model for the whole mine

[0064] 1) Collect the true strata situation, key geological structures, mining engineering plan, borehole columnar diagram, coal seam floor contour map, and mining replacement sequence of the mine;

[0065] 2) Use Rhino software to establish an equal-proportion numerical calculation model of the mine including all mined-out sections, key roadways, key geological structures, and true strata of the mine. Use the Griddle plug-in to divide the model grid, and then import the model with the divided grid into FLAC3D, as Figure 2 shown. In the FLAC3D software, set the material parameters for each marked rock layer of the model, set the simulated boundary conditions, and assign the initial in-situ stress of the coal and rock layers.

[0066] S2 Set variable monitoring points

[0067] 1) Obtain the coordinates of the variable monitoring points, that is, the coordinates of the locations where coal and gas outbursts, rock bursts, coal and gas outburst dynamic phenomena, or coal and gas outburst prediction index overrun have occurred in the target mine's history

[0068] 2) In the FLAC3D software, set variable monitoring points at the same coordinate positions in the model. During the numerical simulation calculation process, record the in-situ stress evolution process of these key locations in real time.

[0069] S3 Simulate the change of the self-weight stress field and implement step-by-step excavation of the numerical model after initial equilibrium

[0070] First, simulate the change of the self-weight stress field. After initial equilibrium, combined with the mining replacement sequence of all sections and key roadways of the mine, implement step-by-step excavation of the numerical model. The mining replacement sequence in the numerical model is the same as the real mining replacement sequence, simulate the evolution process of all in-situ stresses from the initial production period to the present of the whole mine, and obtain the stress field distribution of the entire model area and the stress evolution process of key locations. In order to provide a more realistic mining stress environment, when excavating the mined-out working face, the advance per cut is 1 - 30m, and for the working face near the key geological structure, the advance per cut is 1 - 100m.

[0071] S4 Collect measured data, modify the model parameters, and achieve the assimilation of the simulation results and the measured data

[0072] 1) Collect the measured data of the movement of coal and rock strata and the surface, and the measured data of in-situ stress under the specific mining succession state underground.

[0073] 2) According to the modification ranges of the parameters of the model in Table 1, continuously modify the density, elastic modulus, Poisson's ratio, tensile strength, internal friction angle and cohesion of each rock stratum in the model to achieve a relatively consistent effect between the simulation results and the measured data, realize the assimilation of the simulation results and the measured data, and obtain the in-situ stress evolution results of this mine.

[0074] Table 1 Modification ranges of the parameters of the model

[0075]

[0076] S5 Obtain the pattern recognition model for the critical criterion of in-situ stress for strong dynamic disasters, and determine the critical criterion of in-situ stress inducing strong dynamic disasters in the mine

[0077] 1) The pattern recognition model for the critical criterion of in-situ stress for strong dynamic disasters is as follows: The stress changes abnormally, with stress concentration areas and stress relief areas appearing; the maximum principal stress or the minimum principal stress suddenly increases or decreases abnormally. Intercept the stress nephogram of the key location, extract the stress evolution data of the key location, and lock the key locations where strong dynamic disasters may occur according to the pattern recognition model for the critical criterion of in-situ stress for strong dynamic disasters.

[0078] 2) Obtain the buried depth H of the key location from the key location coordinates, and extract the horizontal stress σ x 、vertical stress σ z 、maximum principal stress σ H 、minimum principal stress σ h of the whole evolution process of the key location from the key location monitoring data, and conduct statistical analysis.

[0079] 3) Determine the values of the lateral pressure coefficient μ and safety factors α and β. The calculation formulas are as follows:

[0080]

[0081] Taking a key location with H = 800m as an example, for the vertical stress σ z 、maximum principal stress σ H 、minimum principal stress σ h taking 21.60MPa, 36.72MPa, and 15.96MPa respectively, then μ = 1.22, α ≥ 0.35, β ≤ 1.95. Combining the actual situation of the mining area and the numerical inversion results, determine α = 0.5, β = 1.6, then the safety factor interval is (0.61, 1.952).

[0082] 4) Analyze the horizontal stress σ xThe ratio with the vertical stress σ z If it appears That is Then it is considered that strong dynamic disasters in the mine will occur at this key location.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope defined by the claims of the present invention.

Claims

1. A method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines, characterized in that: First, the geological data of the mine is collected, and the numerical model of the whole mine is established. Then, the coordinates of the locations where various accidents occurred in history are taken as key locations to obtain the coordinates, and the coordinates of the key locations are set in the model as the coordinates of the variable monitoring points. After that, by simulating the changes in the self-weight stress field, the numerical model is excavated in steps after the initial balance, the measured data are collected, and the model parameters are modified to achieve the assimilation of the simulation results and the measured data. The pattern recognition model of the critical criterion of the geostress of the strong dynamic disaster is obtained, and the critical criterion of the geostress that induces the strong dynamic disaster in the mine is determined. The specific steps include: S1 Collect geological data of the target mine, use Rhino software to establish a proportional numerical calculation model of the mine that includes all sections that have been mined, key tunnels, key geological structures, and real strata, use the Griddle plug-in to grid the proportional numerical calculation model of the mine, and then import the gridded proportional numerical calculation model of the mine into FLAC3D, set the parameters of each identified rock material in the model in FLAC3D, set the boundary conditions of the simulation, and assign the initial ground stress of the coal and rock strata; S2 According to the coordinates of the locations where coal and gas outbursts have occurred in the target mine in history, the coordinates of the locations where rock bursts have occurred, the coordinates of the locations where coal and gas outburst dynamic phenomena have occurred, or the coordinates of the locations where coal and gas outburst prediction indicators have exceeded the limit, these locations where disasters have occurred in history are set as variable detection points in the FLAC3D software generated model; and the evolution process of the ground stress at these key locations is recorded in real time, and the specific changes in the ground stress values ​​are recorded; S3 first simulates the change of the self-weight stress field of the target mine. After the initial balance, combined with the mining succession order of all sections and key tunnels of the target mine, the model is simulated in FLAC3D software according to the mining steps recorded in the real historical data. The evolution process of all ground stresses in the entire mine from the initial production to today is simulated to obtain the stress field distribution of the entire model area and the stress evolution process of key locations. In order to provide a more realistic mining stress environment, when excavating the recovered working face, the footage is 1 to 30m each time, and the footage of the working face set near the key geological structure is 1 to 100m each time; S4 collects measured data on the movement of coal and rock layers and the ground surface during the actual mining process, and measured data on ground stress under specific mining and excavation succession conditions in the mine; by continuously fitting and adjusting the density, bulk modulus, shear modulus, tensile strength, internal friction angle and cohesion parameters of each rock layer in the model, the simulation results are relatively consistent with the measured data, and the simulation results and measured data are assimilated, so that the simulated ground stress evolution results are closer to the actual ground stress evolution process of the target mine; S5 intercepts the stress cloud map of key locations in the model generated by FLAC3D software, analyzes the differences in stress changes near key locations; extracts stress evolution data of key locations, analyzes stress evolution curves of key locations, and obtains the pattern recognition model of critical criterion of strong dynamic disaster ground stress, namely: 1) When a stress concentration area and a stress relief area appear somewhere in the stress cloud diagram, it is judged that the stress change at that place is abnormal; 2) When there is an abnormal sudden increase or decrease in the maximum principal stress or minimum principal stress at a certain location in the stress nephogram, it is judged that the stress change at that location is abnormal; By analyzing the in-situ stress evolution process at key locations, combining with the mining and excavation succession order of the mine, through statistical analysis, the differences in in-situ stress changes at key locations are obtained, and the critical criterion for in-situ stress inducing strong dynamic disasters in the mine is determined: When the ratio of the horizontal stress to the vertical stress at the key location exceeds the safety factor range (αμ, βμ), that is a strong dynamic disaster in the mine is considered to occur. where μ is the coefficient of lateral pressure, α and β are the safety change coefficients of μ determined according to the measured data and simulation data, σ x is the horizontal stress, σ z is the vertical stress, σ H is the maximum principal stress, σ h is the minimum principal stress; When the monitoring points in the model simultaneously meet the requirements of the pattern recognition model and the critical criterion, it is considered that strong dynamic disasters will occur. Protective measures should be implemented in advance according to the results predicted by the model to prevent the adverse effects on the safe production of the mine caused by the occurrence of disasters.

2. The method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines according to claim 1, characterized in that: In step S1, the geological data collected includes the true formation conditions of the target mine, key geological structures, mining and excavation engineering plans, borehole columnar diagrams, coal seam floor contour maps, and the mining and excavation succession order of the mine. Key geological structures refer to faults, folds, and collapse columns that have a significant impact on the stress field, gas field, etc. of the mine.

3. The method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines according to claim 1, characterized in that: In step S1, key roadways refer to the sectional return air roadway, sectional transportation roadway, and other roadways that have a special impact on the stress distribution characteristics of the mining face.

4. The method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines according to claim 1, characterized in that: In step S4, the measured data of the movement of coal and rock strata and the surface, and the measured in-situ stress data under specific mining and excavation succession states in the mine are used as the criteria for judging the assimilation of the simulation results with the actual situation of the target mine. The numerical model parameters are continuously modified to make the numerical simulation results consistent with the measured data, realizing the assimilation of the simulation results and the measured data, improving the accuracy of the numerical simulation, and finally obtaining the in-situ stress evolution results of the whole mine; Since it is relatively easy to obtain parameters such as density, elastic modulus, Poisson's ratio, tensile strength, internal friction angle, and cohesion in the laboratory, the modification ranges of these parameters are given here:

5. The method for determining the critical criterion of in-situ stress for inducing strong dynamic disasters in mines according to claim 1, characterized in that: In step S5, the horizontal stress σ of the key location, x , vertical stress σ, z , maximum principal stress σ, H , and minimum principal stress σ h of the key location can be extracted from the monitoring data of the key location to determine the critical criterion of in-situ stress for inducing strong dynamic disasters in mines. where μ is the coefficient of lateral pressure, Analyze the widely cited distribution law of the coefficient of lateral pressure varying with the burial depth H: The introduction of parameters (αμ, βμ) in step S5 is to newly determine the safety factor interval based on the above formula, combined with the actual situation of the mining area and the results of numerical inversion. The value ranges of α and β are respectively: The result is: Since the burial depth H is obtained when the key location is set as the monitoring point, H is a known quantity, and only the vertical stress σ needs to be determined. z , the maximum principal stress σ H , and the minimum principal stress σ h , the value ranges of α and β can be calculated, and then the appropriate values of α and β can be determined by combining the measured data and the simulation data; Analyze the horizontal stress σ x at this key location and its ratio to the vertical stress σ z . If the following situation occurs , it is considered that strong dynamic disasters will occur at this key location in the mine.

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