A method and device for confirming a stress critical value of a deep base point coal body of rock burst

Abstract

The present application relates to the technical field of coal mining, and particularly relates to a rock burst deep base point coal body stress critical value confirmation method and equipment, comprising: obtaining a rock burst coal mine coal body sample, preparing a first sample model, a second sample model and a third sample model, loading the first sample model by using a stress control method, obtaining static mechanical parameters, performing a Hopkinson impact operation on the second sample model, obtaining coal block information of different particle sizes, establishing an impact damage grading index, carrying out numerical simulation or coal rock mass three-dimensional stress measurement based on rock burst mine environment data, obtaining three-dimensional stress values at different depth positions, performing triaxial dynamic and static combination operation on the third sample model by using the static mechanical parameters and the three-dimensional stress values, obtaining the coal body stress critical value based on the impact damage grading index, and taking the coal body stress critical value as a basis for setting a deep base point coal body stress monitoring index critical value, and improving the scientific nature of rock burst monitoring and early warning effect.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, and in particular to a method, apparatus, equipment, and storage medium for confirming the critical value of coal body stress at deep foundation points of rockburst. Background Technology

[0002] Although various measures have been taken in recent years to prevent and control rockbursts, rockburst accidents still occur frequently. For monitoring the static load of coal, production units mostly use borehole stress gauges to monitor the stress in the coal body. However, there is a lack of unified understanding and scientific guidance on determining the critical values ​​of coal stress monitoring indicators. A quantitative solution has not yet been provided from a theoretical perspective. As a result, the setting of critical values ​​of coal stress monitoring indicators can only rely on the experience of technical personnel. In many cases, only the relative change of coal stress during the monitoring process is used as the basis, and the depth of utilization of the absolute value of coal stress data is insufficient. This will also lead to distortion of coal stress monitoring results to a certain extent, affecting the early warning effect of rockbursts and the selection of stress control measures. This brings a certain degree of uncertainty to the safe mining of mines prone to rockbursts.

[0003] Borehole stress gauges typically detect significant stress changes only after substantial borehole deformation. Therefore, if a theoretically sound method can be developed to determine the critical values ​​for stress monitoring indicators, a method for determining the critical values ​​of coal body stress monitoring indicators at deep foundation points can improve the accuracy and reliability of rockburst monitoring and early warning. Rockburst monitoring and early warning are prerequisites for rockburst prevention and control. In my country, rockburst monitoring and early warning has evolved from traditional single-point distributed monitoring to a multi-parameter real-time monitoring and early warning model. Among these, coal body stress monitoring remains the most fundamental and crucial monitoring unit. Currently, the setting of coal body stress thresholds in rockburst monitoring and early warning systems often relies on engineering analogies, the experience of technical personnel, or initial installation and dynamic adjustment in mining roadways. This leads to insufficient scientific rigor in setting coal body stress thresholds, limiting the effectiveness of rockburst monitoring and early warning. Therefore, an accurate and reliable method for confirming the critical values ​​of coal body stress at deep foundation points is needed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for confirming the critical stress value of coal body at deep foundation points in response to rockburst, in order to solve the problems of insufficient scientific basis in the existing setting of stress threshold for coal body at deep foundation points and the limitation of the role of rockburst monitoring and early warning.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for confirming the critical stress value of coal body at deep foundation points of rockburst, comprising:

[0006] Obtain coal samples from the target rockburst mine and prepare a first sample model, a second sample model, and a third sample model;

[0007] The first sample model was loaded using a stress control method to obtain static mechanical parameters;

[0008] The second sample model was subjected to Hopkinson impact operation to obtain coal block state information of different particle sizes;

[0009] Based on the sphericity fractal dimension, the state information of coal blocks of different sizes is classified, and an impact damage classification index is established.

[0010] Numerical simulations or field measurements of triaxial stress in coal and rock masses are conducted based on environmental data of mines prone to rock bursts to obtain triaxial stress values ​​at different depths.

[0011] Using the static mechanical parameters and the triaxial stress values, a triaxial dynamic-static combined loading operation is performed on the third sample model, and the critical stress value of the coal body is obtained based on the impact failure classification index.

[0012] Preferably, the loading of the first sample model using the stress control method to obtain static mechanical parameters includes:

[0013] The first sample model was loaded with stress control. Using a stress-strain monitoring instrument and a non-contact full-field strain measurement system, the stress-strain curve, surface strain and acoustic emission events of the coal sample during the entire uniaxial compression process were analyzed to obtain static mechanical parameters such as uniaxial compressive strength, residual strength, elastic modulus, Poisson's ratio and internal friction angle.

[0014] Preferably, the step of performing a Hopkinson impact operation on the second sample model to obtain coal block state information of different particle sizes includes:

[0015] Hopkinson impact experiments with different incident gas pressures were conducted on the second sample model to obtain the dynamic strength of coal under different strain rates. The morphology of coal fragments after impact under different strain rates was analyzed, and the surface morphology information of coal blocks with different particle sizes was obtained. The obtained three-dimensional surface coordinates were used as the basis for reconstructing the three-dimensional structure to obtain its sphericity. Fractal statistical methods were used to statistically analyze the sphericity characteristics of coal fragments under different strain rates to obtain the state information of coal blocks with different particle sizes.

[0016] Preferably, the step of classifying the state information of coal blocks of different particle sizes based on the sphericity fractal dimension and establishing an impact damage classification index includes:

[0017] Based on the severity of the impact damage that occurred when the coal was subjected to impact during the experiment, the coal was classified according to the obtained sphericity fractal dimension. The classification index of the degree of coal impact damage was established by the sphericity fractal dimension of the broken coal blocks, namely no impact manifestation, weak impact manifestation, and strong impact manifestation.

[0018] Preferably, the step of obtaining triaxial stress values ​​at different depths by performing numerical simulations or conducting field measurements of triaxial stress in coal and rock masses based on environmental data from rockburst mines includes:

[0019] Based on the geological occurrence of the roadway, the measurement of ground stress, the geometric characteristics of the roadway, the support characteristics, and combined with the physical and mechanical parameters of the roof, floor and coal seam, numerical simulation of the roadway and its surrounding rock is carried out to obtain the damage range of the roadway and the stress distribution at the deep part of the roadway, and to obtain the triaxial stress values ​​at different depths of the roadway.

[0020] Preferably, the step of performing a triaxial dynamic-static combined loading operation on the third sample model using the static mechanical parameters and the triaxial stress values, and obtaining the critical stress value of the coal body based on the impact failure classification index, includes:

[0021] A triaxial dynamic-static combined loading experiment was conducted on the third sample model. Based on the static mechanical parameters and the triaxial stress values, the dynamic load incident air pressures of different pressures were set to obtain the surface morphology information of coal blocks of different particle sizes, thereby obtaining their sphericity. By analyzing the sphericity within different particle size ranges, the fractal dimension of the sphericity of the coal under the dynamic-static combined loading conditions was determined. The impact manifestation intensity caused by the combined conditions was determined by referring to the impact damage classification index, and the critical value of coal body stress was obtained.

[0022] Preferably, the first sample model, the second sample model, and the third sample model use the same type of coal sample to maintain consistent physical properties.

[0023] The present invention also provides a device for confirming the critical value of coal body stress at deep foundation points of rockburst, comprising:

[0024] The sample acquisition module acquires coal samples from the target rockburst mine and prepares a first sample model, a second sample model, and a third sample model.

[0025] The static mechanics acquisition module uses a stress control method to load the first sample model and obtain static mechanical parameters;

[0026] The pneumatic impact module performs a pneumatic impact operation on the second sample model to obtain coal block state information of different particle sizes;

[0027] The damage classification index module classifies the state information of coal blocks of different particle sizes based on the sphericity fractal dimension, and establishes an impact damage classification index.

[0028] The triaxial stress value module uses rockburst mine environmental data as a basis to perform numerical simulations or conduct field measurements of triaxial stress in coal and rock masses to obtain triaxial stress values ​​at different depths.

[0029] The stress critical value module uses the static mechanical parameters and the triaxial stress values ​​to perform a triaxial dynamic and static combined loading operation on the third sample model, and obtains the coal body stress critical value based on the impact failure classification index.

[0030] This invention also provides a device for confirming the critical value of coal body stress at deep foundation points of rockburst, comprising:

[0031] Memory, used to store computer programs;

[0032] A processor is used to execute the computer program to implement the steps of the method for confirming the critical value of coal body stress at deep foundation points in rockburst.

[0033] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for confirming the critical value of coal body stress at deep base points of rockburst described above.

[0034] This invention provides a method for confirming the critical value of coal body stress at deep foundation points in response to rockburst. Based on the sphericity fractal dimension, the method classifies the state information of coal blocks with different particle sizes, establishes a rockburst damage classification index, and performs impact operations on the coal body model based on triaxial stress values ​​and static mechanical parameters. Through uniaxial compression experiments, Hopkinson impact experiments, and dynamic-static combined loading experiments on the coal, the method scientifically guides the setting of critical values ​​for rockburst stress monitoring indicators at deep foundation points. This improves the scientific validity of rockburst monitoring and early warning, provides a theoretical basis for setting critical values ​​for rockburst stress monitoring indicators at deep foundation points, and enhances the scientific validity and reliability of rockburst monitoring and early warning. Attached Figure Description

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0036] Figure 1 A flowchart of a first specific embodiment of a method for confirming the critical stress value of coal body at deep foundation points in rockburst provided by the present invention;

[0037] Figure 2 This is a structural block diagram of a device for confirming the critical value of coal body stress at deep foundation points in rockburst, provided in an embodiment of the present invention. Detailed Implementation

[0038] The core of this invention is to provide a method, device, equipment, and storage medium for confirming the critical stress value of deep foundation point coal body in rockburst. This invention scientifically and reliably confirms the critical stress value of deep foundation point coal body, clarifies the role of static and dynamic loads in rockburst disasters, and provides a theoretical basis for setting the critical values ​​of stress monitoring indicators for deep foundation point coal body.

[0039] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The following describes a method for confirming the critical stress value of coal body at deep foundation points in rockburst according to an embodiment of the present invention, with reference to the accompanying drawings.

[0041] like Figure 1 As shown, the present invention provides a method for confirming the critical stress value of coal seam at deep foundation points in the event of rockburst, comprising:

[0042] Step S101: Obtain coal body samples from the target rockburst mine and prepare the first sample model, the second sample model, and the third sample model;

[0043] The first sample model, the second sample model, and the third sample model use the same type of coal sample to maintain consistent physical properties.

[0044] Step S102: Load the first sample model using the stress control method to obtain static mechanical parameters;

[0045] The first sample model was loaded with stress control. Using a stress-strain monitoring instrument and a non-contact full-field strain measurement system, the stress-strain curve, surface strain and acoustic emission events of the coal sample during the entire uniaxial compression process were analyzed to obtain static mechanical parameters such as uniaxial compressive strength, residual strength, elastic modulus, Poisson's ratio and internal friction angle.

[0046] Step S103: Perform a Hopkinson impact operation on the second sample model to obtain coal block state information of different particle sizes;

[0047] Hopkinson impact experiments with different incident gas pressures were conducted on the second sample model to obtain the dynamic strength of coal under different strain rates. The morphology of coal fragments after impact under different strain rates was analyzed, and the surface morphology information of coal blocks with different particle sizes was obtained. The obtained three-dimensional surface coordinates were used as the basis for reconstructing the three-dimensional structure to obtain its sphericity. Fractal statistical methods were used to statistically analyze the sphericity characteristics of coal fragments under different strain rates to obtain the state information of coal blocks with different particle sizes.

[0048] Step S104: Classify the state information of coal blocks with different particle sizes based on the sphericity fractal dimension, and establish an impact damage classification index;

[0049] Based on the severity of the impact damage that occurred when the coal was subjected to impact during the experiment, the coal was classified according to the obtained sphericity fractal dimension. The classification index of the degree of coal impact damage was established by the sphericity fractal dimension of the broken coal blocks, namely no impact manifestation, weak impact manifestation, and strong impact manifestation.

[0050] Step S105: Based on the environmental data of rockburst mines, conduct numerical simulation or carry out triaxial stress measurement of coal and rock mass to obtain triaxial stress values ​​at different depths;

[0051] Based on the geological occurrence of the roadway, the measurement of ground stress, the geometric characteristics of the roadway, the support characteristics, and combined with the physical and mechanical parameters of the roof, floor and coal seam, numerical simulation of the roadway and its surrounding rock is carried out to obtain the damage range of the roadway and the stress distribution at the deep part of the roadway, and to obtain the triaxial stress values ​​at different depths of the roadway.

[0052] Step S106: Using the static mechanical parameters and the triaxial stress values, perform a triaxial dynamic and static combined loading operation on the third sample model, and obtain the critical stress value of the coal body based on the impact failure classification index.

[0053] A triaxial dynamic-static combined loading experiment was conducted on the third sample model. Based on the static mechanical parameters and the triaxial stress values, the dynamic load incident air pressures of different pressures were set to obtain the surface morphology information of coal blocks of different particle sizes, thereby obtaining their sphericity. By analyzing the sphericity within different particle size ranges, the fractal dimension of the sphericity of the coal under the dynamic-static combined loading conditions was determined. The impact manifestation intensity caused by the combined conditions was determined by referring to the impact damage classification index, and the critical value of coal body stress was obtained.

[0054] This embodiment provides a method for confirming the critical value of coal body stress at deep foundation points in rockburst. By conducting uniaxial compression tests, Hopkinson impact tests, and combined static and dynamic loading tests on the coal, it scientifically guides the setting of critical values ​​for stress monitoring indicators in deep foundation point coal bodies. This improves the scientific rigor of rockburst monitoring and early warning, deepens the understanding of the rockburst disaster mechanism, clarifies the effects of static and dynamic loads on rockburst disasters, and identifies the critical static load level or range affecting the intensity of rockburst manifestation, providing a theoretical basis for setting the critical values ​​of stress monitoring indicators in deep foundation point coal bodies.

[0055] Based on the above embodiments, this embodiment describes the method for confirming the critical stress value of coal seam at deep foundation points of rockburst, as follows:

[0056] Sampling was conducted at the target rockburst mine, and the sampling methods and specifications were in accordance with the requirements of the national standard "Methods for Determination of Physical and Mechanical Properties of Coal and Rock Part 1: General Sampling Requirements" (GB / T 23561.1-2009).

[0057] The coal collected on-site was processed into three types of cylindrical specimens: φ50mm×100mm (Specimen A), φ50mm×50mm (Specimen B), and φ35mm×35mm×70mm (Specimen C). The processed coal samples were randomly sampled for size measurement, weight measurement, ultrasonic testing, and CT scanning to ensure that the physical properties of the coal samples used were similar and to reduce the dispersion of experimental results caused by the anisotropy and heterogeneity of coal.

[0058] Uniaxial compression tests were conducted on specimen A, with stress control (0.5 MPa / s-1.0 MPa) applied. During the process, a stress-strain monitoring instrument and a non-contact full-field strain measurement system were used to analyze parameters such as stress-strain curves, surface strain, and acoustic emission events throughout the uniaxial compression process of the coal sample. Static mechanical parameters such as uniaxial compressive strength, residual strength, elastic modulus, Poisson's ratio, and internal friction angle were obtained. Characterization parameters such as uniaxial compressive strength, dynamic failure time, impact energy index, elastic energy index, residual strength, elastic modulus, Poisson's ratio, acoustic emission ring count, amplitude, and surface strain field were obtained in accordance with the standard "Methods for Determination, Monitoring and Prevention of Rockburst Part 2: Classification and Determination of Impact Tendency Index of Coal" (GB / T 25217.2-2010).

[0059] SHPB impact tests were conducted on specimen B under different incident gas pressures to obtain the dynamic strength of coal under different strain rates. The failure process was recorded using a high-speed camera. The morphology of coal fragments after impact under different strain rates was analyzed. The surface morphology information of coal blocks of different sizes was obtained using a 3D scanner. The obtained surface 3D coordinates were used as the basis for reconstructing the 3D structure to obtain its sphericity. Fractal statistical methods were used to statistically analyze the sphericity characteristics of coal fragments under different strain rates.

[0060] Based on the severity of the impact damage to coal during the experiment, the intensity of the impact damage to coal is classified according to the obtained sphericity fractal dimension. In other words, the grading index of the degree of coal impact damage is established by the sphericity fractal dimension of the broken coal block, namely no impact manifestation, weak impact manifestation, and strong impact manifestation. The specific grading index needs to be determined according to the severity of the damage shown by the coal under impact in the field.

[0061] Based on the geological occurrence of the roadway, the measurement of ground stress, the geometric characteristics of the roadway, the support characteristics, and combined with the physical and mechanical parameters of the roof, floor and coal seam, simulation software such as FLAC3D is used to carry out numerical simulation of the roadway and its surrounding rock to obtain the roadway damage range and the stress distribution at the deep part of the roadway. In other words, the triaxial stress values ​​at different depths of the roadway can be obtained.

[0062] Triaxial dynamic and static combined loading experiments were conducted on specimen C. First, the static mechanical parameters were set as follows: the static load was 20% of the uniaxial compressive strength, and the confining pressure was determined based on the horizontal stress value at the deep stress measurement location obtained in FLAC3D. The incident gas pressure of the dynamic load was 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, and 0.8MPa. Five dynamic and static combined loading experiments were conducted for each combination mode. During the experiment, a high-speed camera was used to record the coal impact damage process, and a 3D scanner was used to obtain the surface morphology information of coal blocks of different sizes to obtain their sphericity. By analyzing the sphericity within different particle size ranges, the sphericity fractal dimension value of the coal under the dynamic and static load combination conditions was determined. The impact manifestation intensity caused by the combination conditions was determined by referring to the previously obtained grading index characterizing the degree of coal impact damage.

[0063] During the experiment, if the confining pressure at the measured location is greater than 20% of the uniaxial compressive strength of the coal, a load is applied at a certain rate (e.g., 0.5 MPa / min) at the initial loading stage until 20% of the uniaxial compressive strength of the coal is reached. This is then maintained for 3-5 minutes to stabilize. The loading is then continued at the previous rate until the expected confining pressure is reached, followed by the subsequent SHPB experiment. If the confining pressure at the measured location is less than 20% of the uniaxial compressive strength of the coal, a load is applied at a certain rate (e.g., 0.5 MPa / min) at the initial loading stage until the minimum confining pressure is reached. This is then maintained for 3-5 minutes to stabilize. The loading is then continued at the previous rate until 20% of the uniaxial compressive strength of the coal is reached, followed by the subsequent SHPB experiment.

[0064] Repeat the above-mentioned triaxial static-dynamic load test on coal. The static mechanical parameters were 30%, 40%, 50%, 60%, 70%, and 80% of the uniaxial compressive strength. The dynamic load corresponding to each static load level was set to 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, and 0.8 MPa. Five loading tests were carried out for each dynamic-static load combination mode. The sphericity fractal dimension of coal after load failure under different dynamic-static load combination modes was analyzed. The impact intensity caused by the combination conditions was determined by referring to the previously obtained grading index characterizing the degree of coal impact failure.

[0065] Therefore, a total of 56 dynamic and static load combination modes are formed by 7 static load levels and 8 dynamic load levels, thereby finding the critical level or range (SW, SS) of static load that causes weak impact and strong impact to appear in coal. That is to say, when the static load reaches the critical level (SW) or range, coal will show significant dynamic damage when subjected to a small dynamic load; when the static load reaches the critical level (SS) or range, coal will induce strong dynamic damage when subjected to a small dynamic load.

[0066] Therefore, the critical level of static load obtained from the above experiment can be used as the basis for setting the critical value of the deep foundation point coal body stress monitoring index.

[0067] Different criteria are used for different impact hazard zones. That is, when in a strong impact hazard zone, the SW criterion is used for rockburst early warning; when in a weak impact hazard zone, the SS criterion is used for rockburst early warning.

[0068] This invention provides a method for confirming the critical value of stress in deep-base coal seams during rockburst. It utilizes stress control methods to obtain static mechanical parameters, acquires triaxial stress values ​​through environmental simulation, and, based on these static mechanical parameters and triaxial stress values, conducts triaxial dynamic-static combined loading experiments by applying dynamic loads of different incident air pressures to a coal seam model. The resulting critical level of static load serves as the basis for setting the critical value of stress monitoring indicators for deep-base coal seams. This scientifically guides the setting of critical values ​​for stress monitoring indicators in deep-base coal seams, thereby improving the scientific validity of rockburst monitoring and early warning effects. It identifies the critical static load level or range that affects the intensity of rockburst manifestation, providing a theoretical basis for setting the critical value of stress monitoring indicators for deep-base coal seams.

[0069] Please refer to Figure 2 , Figure 2 This is a structural block diagram of a device for confirming the critical value of coal body stress at deep foundation points in rockburst, provided in an embodiment of the present invention; the specific device may include:

[0070] The sample acquisition module 100 acquires coal samples from the target rockburst mine and prepares a first sample model, a second sample model, and a third sample model.

[0071] The static mechanics acquisition module 200 uses a stress control method to load the first sample model and obtain static mechanical parameters.

[0072] The pneumatic impact module 300 performs a Hopkinson impact operation on the second sample model to obtain coal block state information of different particle sizes;

[0073] The damage classification index module 400 classifies the state information of coal blocks of different particle sizes based on the sphericity fractal dimension and establishes an impact damage classification index.

[0074] The Triaxial Stress Value Module 500 uses rockburst mine environmental data as a basis to perform numerical simulations or conduct field measurements of triaxial stress in coal and rock masses to obtain triaxial stress values ​​at different depths.

[0075] The stress critical value module 600 uses the static mechanical parameters and the triaxial stress values ​​to perform a triaxial dynamic and static combined loading operation on the third sample model, and obtains the coal body stress critical value based on the impact failure classification index.

[0076] This embodiment of the device for confirming the critical stress value of coal seam at a deep base point of rockburst is used to implement the aforementioned method for confirming the critical stress value of coal seam at a deep base point of rockburst. Therefore, the specific implementation of the device for confirming the critical stress value of coal seam at a deep base point of rockburst can be found in the embodiment section of the aforementioned method for confirming the critical stress value of coal seam at a deep base point of rockburst. For example, the sample acquisition module 100, the static mechanics acquisition module 200, the air pressure impact module 300, the damage classification index module 400, the triaxial stress value module 500, and the stress critical value module 600 are respectively used to implement steps S101, S102, S103, S104, S105, and S106 in the aforementioned method for confirming the critical stress value of coal seam at a deep base point of rockburst. Therefore, its specific implementation can be referred to the description of the corresponding embodiments, and will not be repeated here.

[0077] A specific embodiment of the present invention also provides a device for confirming the critical value of coal body stress at deep foundation points of rockburst, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the above-mentioned method for confirming the critical value of coal body stress at deep foundation points of rockburst.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0080] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0081] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0082] The above provides a detailed description of the method, apparatus, equipment, and storage medium for confirming the critical stress value of coal seam at deep foundation points in rockburst, as provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

[0083] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0084] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0085] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

Claims

1. A method for confirming the critical stress value of coal seam at deep foundation points in the event of rockburst, characterized in that, include: Obtain coal samples from the target rockburst mine and prepare a first sample model, a second sample model, and a third sample model. The first sample model, the second sample model, and the third sample model are made from the same type of coal sample and have consistent physical properties. The first sample model was loaded using a stress control method to obtain static mechanical parameters; The second sample model was subjected to a Hopkinson impact test to obtain coal block state information of different particle sizes, including: Hopkinson impact tests with different incident gas pressures were conducted on the second sample model to obtain the dynamic strength of coal under different strain rates. The morphology of coal fragments after impact under different strain rates was analyzed to obtain the surface morphology information of coal blocks with different particle sizes. The obtained surface three-dimensional coordinates were used as the basis for reconstructing the three-dimensional structure to obtain its sphericity. Fractal statistical methods were used to statistically analyze the sphericity characteristics of coal fragments under different strain rates to obtain the state information of coal blocks with different particle sizes. Based on the sphericity fractal dimension, the state information of coal blocks of different sizes is classified, and an impact damage classification index is established. Numerical simulations or field measurements of triaxial stress in coal and rock masses are conducted based on environmental data of mines prone to rock bursts to obtain triaxial stress values ​​at different depths. Using the static mechanical parameters and the triaxial stress values, a triaxial dynamic-static combined loading operation is performed on the third sample model. Based on the impact failure classification index, the critical stress value of the coal body is obtained, including: A triaxial dynamic-static combined loading experiment was conducted on the third sample model. Based on the uniaxial compressive strength obtained from the static mechanical parameters, different static loads were set, triaxial stress values ​​were set, and dynamic load incident air pressures of different pressures were set to obtain the surface morphology information of coal blocks of different particle sizes, thereby obtaining their sphericity. By analyzing the sphericity within different particle size ranges, the fractal dimension of the sphericity of the coal under the dynamic-static combined loading condition was determined. The impact manifestation intensity caused by the combined conditions was determined by referring to the impact failure classification index, and the critical value of coal stress was obtained.

2. The method for confirming the critical stress value of coal seam at deep foundation points of rockburst as described in claim 1, characterized in that, The static mechanical parameters obtained by loading the first sample model using the stress control method include: The first sample model was loaded with stress control. Using a stress-strain monitoring instrument and a non-contact full-field strain measurement system, the stress-strain curve, surface strain and acoustic emission event parameters of the coal sample during the entire uniaxial compression process were analyzed to obtain the static mechanical parameters of uniaxial compressive strength, residual strength, elastic modulus, Poisson's ratio and internal friction angle.

3. The method for confirming the critical stress value of coal seam at deep foundation points of rockburst as described in claim 1, characterized in that, The method of classifying the state information of coal blocks of different particle sizes based on the sphericity fractal dimension and establishing an impact damage classification index includes: Based on the severity of the impact damage that occurred when the coal was subjected to impact during the experiment, the coal was classified according to the obtained sphericity fractal dimension. The classification index of the degree of coal impact damage was established by the sphericity fractal dimension of the broken coal blocks, namely no impact manifestation, weak impact manifestation, and strong impact manifestation.

4. The method for confirming the critical stress value of coal seam at deep foundation points of rockburst as described in claim 1, characterized in that, The method of obtaining triaxial stress values ​​at different depths by conducting numerical simulations or field measurements of triaxial stress in coal and rock masses based on environmental data from rockburst mines includes: Based on the geological occurrence of the roadway, the measurement of ground stress, the geometric characteristics and support characteristics of the roadway, and combined with the physical and mechanical parameters of the roof, floor and coal seam, numerical simulation of the roadway and its surrounding rock is carried out to obtain the damage range of the roadway and the stress distribution at the deep part of the roadway, and to obtain the triaxial stress values ​​at different depths of the roadway.

5. A device for confirming the critical stress value of coal seam at deep foundation points in the event of rockburst, characterized in that, include: The sample acquisition module acquires coal samples from the target rockburst mine and prepares a first sample model, a second sample model, and a third sample model. The first sample model, the second sample model, and the third sample model are made from the same type of coal sample and have consistent physical properties. The static mechanics acquisition module uses a stress control method to load the first sample model and obtain static mechanical parameters; The pneumatic impact module performs a Hopkinson impact operation on the second sample model to obtain coal block state information of different particle sizes, including: Hopkinson impact tests with different incident gas pressures were conducted on the second sample model to obtain the dynamic strength of coal under different strain rates. The morphology of coal fragments after impact under different strain rates was analyzed to obtain the surface morphology information of coal blocks with different particle sizes. The obtained surface three-dimensional coordinates were used as the basis for reconstructing the three-dimensional structure to obtain its sphericity. Fractal statistical methods were used to statistically analyze the sphericity characteristics of coal fragments under different strain rates to obtain the state information of coal blocks with different particle sizes. The damage classification index module classifies the state information of coal blocks of different particle sizes based on the sphericity fractal dimension, and establishes an impact damage classification index. The triaxial stress value module uses rockburst mine environmental data as a basis to perform numerical simulations or conduct field measurements of triaxial stress in coal and rock masses to obtain triaxial stress values ​​at different depths. The stress critical value module, using the static mechanical parameters and the triaxial stress values, performs a triaxial dynamic-static combined loading operation on the third sample model, and obtains the coal body stress critical value based on the impact failure classification index, including: A triaxial dynamic-static combined loading experiment was conducted on the third sample model, and the uniaxial compressive strength was set based on the static mechanical parameters. different Static load is applied, triaxial stress values ​​are set, dynamic load incident air pressures are set at different pressures, surface morphology information of coal blocks of different particle sizes is obtained, and their sphericity is obtained. By analyzing the sphericity within different particle size ranges, the fractal dimension of sphericity of coal under the combined dynamic and static load conditions is determined. The impact manifestation intensity caused by the combined conditions is determined by referring to the impact damage classification index, and the critical value of coal stress is obtained.

6. A device for confirming the critical value of coal body stress at deep foundation points in rockburst, characterized in that, include: Memory, used to store computer programs; A processor, used to execute the computer program to implement the steps of the method for confirming the critical value of coal body stress at deep foundation points of rockburst as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the method for confirming the critical value of coal body stress at deep benchmark points of rockburst as described in any one of claims 1 to 4.

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