Coal rock mass damage analysis method and system

Abstract

This application discloses a method and system for analyzing coal and rock mass damage. The method includes: acquiring elastic wave response signals of the coal and rock mass to be tested, thereby obtaining the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave; determining several different target frequency points based on these two types of characteristics, and obtaining the measured propagation velocity and measured attenuation parameters corresponding to each frequency point; obtaining the theoretical propagation velocity and theoretical attenuation parameters corresponding to each frequency point based on the frequency and dissipation information of the coal and rock mass; constructing a transmission path objective function based on the measured propagation velocity, attenuation parameters, and theoretical propagation velocity, attenuation parameters, and analyzing the function to determine the degree of damage to the coal and rock mass. This method fully utilizes the velocity and attenuation information of multi-frequency elastic waves to extract features closely related to the damage evolution of coal and rock mass, and obtains the degree of damage information by establishing a quantitative relationship between these features and damage, thus achieving a precise quantitative assessment of the damage state of the coal and rock mass.

Description

Technical Field

[0001] This disclosure relates to the field of nondestructive testing and safety monitoring technology for coal and rock masses, and in particular to a method and system for analyzing damage in coal and rock masses. Background Technology

[0002] In mining, tunneling, underground cavern construction, and other underground rock engineering projects, the combined effects of geological environment and human disturbance cause internal fissures in coal and rock masses to gradually initiate, expand, and connect, leading to overall structural deterioration and significantly increasing the risk of instability in underground engineering projects. Therefore, accurately identifying and quantitatively assessing the degree of damage to coal and rock masses and taking timely and effective control measures are key technical issues for ensuring the safe and efficient progress of underground engineering projects.

[0003] Existing methods for detecting and assessing damage in coal and rock masses mainly include mechanical testing, acoustic emission monitoring, image recognition, and elastic wave detection. Among these, elastic wave detection has become an important technical means for evaluating coal and rock mass damage due to its advantages such as non-destructive nature, wide applicability, and sensitivity to internal defects. Damage assessment methods based on elastic waves typically characterize the damage state of coal and rock masses using changes in single parameters such as propagation velocity, amplitude, energy, or dominant frequency. However, coal and rock masses exhibit significant heterogeneity, anisotropy, and multi-scale damage characteristics. Single elastic wave evaluation methods have limited ability to characterize the propagation of micro-cracks, local damage accumulation, and multi-scale structural deterioration processes within coal and rock masses. Therefore, damage analysis of coal and rock masses remains at the level of qualitative identification or empirical judgment, leading to incomplete and inaccurate analytical results. Summary of the Invention

[0004] In view of this, the present disclosure provides a method and system for analyzing coal and rock mass damage, which can solve the problems in the prior art where the analysis results of coal and rock mass damage state are incomplete and inaccurate, and cannot achieve accurate quantitative assessment.

[0005] In a first aspect, embodiments of this disclosure provide a method for analyzing coal and rock mass damage, including: The elastic wave response signal of the coal and rock mass to be tested is collected, and the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave are obtained based on the elastic wave response signal. Based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, several different target frequency points are determined, and the measured propagation speed and measured attenuation parameters corresponding to each target frequency point are obtained. Based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested, the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined are obtained for each target frequency point. Based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point, an objective function for a single transmission path of elastic waves is constructed. The objective function of a single transmission path of the elastic wave is analyzed to determine the degree of damage to the coal and rock mass.

[0006] Secondly, this disclosure also provides a method for analyzing coal and rock mass damage, including: The elastic wave response signal of the coal and rock mass to be tested is collected, and the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave are obtained based on the elastic wave response signal. Based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, several different target frequency points are determined, and the measured propagation speed and measured attenuation parameters corresponding to each target frequency point are obtained. Based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested, the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined are obtained for each target frequency point. Based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point, an objective function for a single transmission path of elastic waves is constructed. The objective function of each elastic wave transmission path is analyzed to determine the degree of coal and rock mass damage corresponding to each transmission path; Based on the information on the degree of damage to the coal and rock mass corresponding to all transmission paths, the overall damage degree parameters are determined; Based on the information on the degree of damage to the coal and rock mass and the parameters on the overall degree of damage, the localization information of the damage to the coal and rock mass to be tested is determined. Based on the measured propagation velocity and measured attenuation parameter corresponding to all the target frequency points, the damage complexity information of the coal and rock mass to be tested is determined; The overall damage degree parameter, the damage localization information, and the damage complexity information are fused to determine the coal and rock mass instability risk information.

[0007] The coal and rock mass damage analysis method provided in this disclosure firstly acquires the elastic wave response signal of the coal and rock mass to be tested, and obtains the transmitted wave frequency domain characteristics and received wave frequency domain characteristics based on the elastic wave response signal, which can accurately mine the latent characteristics of wave signals in different frequency bands; secondly, based on the transmitted wave frequency domain characteristics and received wave frequency domain characteristics, several different target frequency points are determined, and the measured propagation velocity and measured attenuation parameters corresponding to each target frequency point are obtained, which can cover the detection range of different wavelengths and different penetration depths, and can capture the microscopic features of micro-cracks and minor damage inside the coal and rock mass, as well as identify the overall features of large-scale fracturing and macroscopic damage; then... Based on the frequency of each target frequency point and the dissipation information of the coal and rock mass to be tested, the theoretical propagation velocity and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined are obtained for each target frequency point. According to the measured propagation velocity, measured attenuation parameter, theoretical propagation velocity, and theoretical attenuation parameter of each target frequency point, an objective function for a single transmission path of elastic waves is constructed to achieve the integration and optimization of multi-source data and precise focusing on damage problems. Finally, the objective function for a single transmission path of elastic waves is analyzed to determine the damage degree information of the coal and rock mass. Through multi-dimensional information analysis, early hidden micro-damage of the coal and rock mass can be accurately captured, and damage can be predicted in advance. Attached Figure Description

[0008] Figure 1 This is a schematic flowchart of the coal and rock mass damage analysis method provided in the embodiments of this disclosure.

[0009] Figure 2 This is a flowchart illustrating the method for obtaining the measured propagation velocity and measured attenuation parameters corresponding to each target frequency point provided in the embodiments of this disclosure.

[0010] Figure 3 This is a flowchart illustrating the method for obtaining the theoretical propagation speed and theoretical attenuation parameters corresponding to each target frequency point provided in the embodiments of this disclosure.

[0011] Figure 4 A flowchart illustrating the method for constructing the objective function of a single transmission path of elastic waves provided in this embodiment of the present disclosure.

[0012] Figure 5 A flowchart illustrating the coal and rock mass damage analysis method provided in the second embodiment.

[0013] Figure 6 This is a schematic diagram of a multi-frequency elastic wave test provided in an embodiment of this disclosure.

[0014] Figure 7 The time-domain diagrams of the transmitted and received waves provided in the embodiments of this disclosure are shown.

[0015] Figure 8A schematic diagram of the frequency amplitude of the transmitted and received waves provided in an embodiment of this disclosure.

[0016] Figure 9 This is a flowchart illustrating a method for determining damage localization information provided in an embodiment of this disclosure.

[0017] Figure 10 A flowchart illustrating the method for determining the damage complexity information of the coal and rock mass to be tested, provided in an embodiment of this disclosure.

[0018] Figure 11 This is a schematic diagram of fitting corresponding to several target frequency points provided in the embodiments of this disclosure. Detailed Implementation

[0019] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0020] It should be understood that the following specific examples illustrate the implementation of this disclosure, and those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The drawings only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0023] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0024] Reference Figure 1 This application discloses a method for analyzing coal and rock mass damage, including: S100 collects the elastic wave response signal of the coal and rock mass to be tested, and obtains the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave based on the elastic wave response signal.

[0025] Specifically, elastic wave detection is performed on the coal and rock mass under test based on the transmitted wave of the active sound source, and the response signal after the elastic wave penetrates the coal and rock mass under test is collected, that is, the received wave is collected. This response information includes multiple frequency components. The transmitted wave and the response signal are both processed by fast Fourier transform to obtain the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave.

[0026] In this embodiment, a broadband elastic wave excitation device is used to transmit elastic waves. There is one signal transmitting end and one receiving end. That is, in this embodiment, there is one propagation path corresponding to the coal and rock mass to be tested.

[0027] In this step, by collecting the elastic wave response signal of the coal and rock mass and extracting the frequency domain features of the transmitted and received waves, relying on the exclusive technical characteristics of frequency domain analysis, unlike conventional time domain detection which can only identify obvious damage signals such as large waveform distortion and sudden amplitude changes, the features extracted in this step include refined features such as spectral amplitude, energy ratio, and phase shift at different frequency bands. The structural anomalies caused by micro-cracks and initial damage inside the coal and rock mass will only cause slight changes in the frequency domain parameters of the elastic wave and will not significantly change the time domain waveform. By extracting frequency domain features, this kind of early damage sensitive information can be accurately captured.

[0028] Meanwhile, retaining the frequency domain characteristics of the transmitted and received waves separately enables a precise comparison before and after signal propagation, directly avoiding the problem that a single signal feature cannot distinguish between equipment errors, environmental interference, and actual rock mass damage signals.

[0029] S200 determines several different target frequency points based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, and obtains the measured propagation speed and measured attenuation parameters corresponding to each target frequency point.

[0030] Simultaneously refer to Figure 2 The methods for obtaining the measured propagation velocity and measured attenuation parameters for each target frequency point specifically include: S210 determines the main frequency range based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave.

[0031] Specifically, the dominant frequency range is the frequency band where the energy distribution is relatively concentrated in the frequency domain diagram. Further, first, determine the range with fluctuations in the frequency domain characteristics of the received wave; then determine the range with fluctuations in the frequency domain characteristics of the transmitted wave; find the intersection of these two ranges as the dominant frequency range.

[0032] S220 selects several different target frequency points within the main frequency range.

[0033] Specifically, no fewer than five target frequency points are selected within the main frequency range, with equal frequency spacing between each pair of target frequency points.

[0034] S230, based on the transmitted wave phase and received wave phase at each target frequency point 、 The transmitted and received wave amplitude values ​​are used to obtain the measured propagation speed and measured attenuation parameters at the corresponding frequency points.

[0035] Wherein, the measured propagation speed at the corresponding frequency point is : ; ; Given the known distance between the transmitted and received waves, This refers to the frequency corresponding to the target frequency point.

[0036] The phase difference between the transmitted wave phase and the received wave phase, specifically for the transmitted wave phase. and received wave phase The phase difference is obtained by removing integer-cycle π jumps through phase unwrapping. Because the phase acquisition module's periodic values ​​are constrained, the instrument's output phase is limited to a single-cycle interval. Integer-cycle phase information from actual propagation is folded and lost, and abrupt jumps near the π amplitude easily appear in the data sequence. A phase unwrapping algorithm is used to correct the acquired phase data, compensating for the truncated integer-cycle phase components and eliminating step jump interference. Finally, the effective phase difference reflecting the actual propagation delay of the wave in the coal and rock medium is restored. .

[0037] The measured attenuation parameters at the corresponding frequency points are as follows: : ; ; This represents the amplitude of the received wave at the corresponding frequency point. This represents the amplitude of the transmitted wave at the corresponding frequency point.

[0038] In this embodiment, This refers to the attenuation coefficient per unit length of the elastic wave within the coal and rock medium. When the elastic wave propagates inside the coal and rock mass, energy dissipation occurs due to internal cracks, pores, and rock damage, resulting in the received amplitude always being lower than the transmitted amplitude. Therefore, R is less than 1. The result is negative. Multiplying it by a coefficient gives the total attenuation decibel value for the entire propagation path. Dividing this value by the fixed distance L between the transmitting and receiving points eliminates the influence of the propagation distance on the length, and converts it into an attenuation index per unit distance. The larger this index is, the higher the degree of coal and rock fragmentation and the more significant the damage development along the corresponding path. It can be directly converted into rock mass damage parameters for a single propagation path.

[0039] Elastic waves of different frequencies have different wavelengths and propagation characteristics. Low-frequency waves have longer wavelengths and can cover a wide range of rock mass structures and identify macroscopic fracture damage. High-frequency waves have shorter wavelengths and are extremely sensitive to micro-cracks and microscopic damage. This step, through multi-point frequency selection, can achieve full coverage detection of micro, fine, and macroscopic damage in coal and rock masses, and completely eliminate the blind spots of single-frequency detection.

[0040] Meanwhile, this step is equipped with two measured parameters, velocity and attenuation, which accurately match the two-dimensional damage characterization mechanism of the scheme. The propagation velocity corresponds to the density and integrity of the coal and rock mass medium skeleton, reflecting the overall damage degree of the structure. The attenuation parameter corresponds to the dissipation effect of cracks and pores on wave energy, accurately characterizing the development density and aperture of cracks. The two parameters are collected synchronously based on the same frequency point, which can effectively avoid the problem that single parameter detection cannot distinguish similar damage and the quantitative accuracy is insufficient.

[0041] S300, based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested, obtains the theoretical propagation speed and theoretical attenuation parameters of the damage variables of the coal and rock mass to be determined for each target frequency point.

[0042] Simultaneously refer to Figure 3 The methods for obtaining the theoretical propagation velocity and theoretical attenuation parameters for each target frequency point specifically include: S310, construct the complex dynamic modulus relationship of the damage variables of the coal and rock mass to be determined for each target frequency point.

[0043] The relationship between complex dynamic moduli is: .

[0044] in, ; ; .

[0045] in, For the coal and rock mass damage variable to be determined, i The imaginary unit, The elastic wave angular frequency corresponding to the target frequency point. The frequency corresponding to the target frequency point; The relaxation characteristic time parameter is the characteristic time scale of the hysteresis response and energy dissipation of the coal and rock mass damage medium to elastic wave disturbance. For example, when the dominant frequency of the elastic wave is in the range of 200kHz-600kHz... The preferred range is 0.1 μs to 5 μs; Let be the dynamic dissipation function in the damaged state. For the complete state basic dissipation parameters, The damage-induced dissipation enhancement coefficient is... The density of the coal and rock mass to be tested is... The elastic wave propagation velocity corresponding to the dominant frequency under the undamaged state of the coal and rock mass.

[0046] Among them, the basic dissipation parameters of the complete state The inherent dissipation parameter is the initial state of the coal and rock mass in a state of no damage, integrity, and homogeneity. It is an inherent physical property of the material. At this time, the rock mass has no microcracks or structural defects, and only the basic internal friction and inherent energy loss of the material itself exist. It is the reference constant of the model and does not change with damage.

[0047] Damage-induced dissipation enhancement coefficient χ1 is the gain sensitivity coefficient of coal and rock mass damage to energy dissipation. It is a material test calibration constant used to quantify the increase in dissipation caused by a unit increase in damage, reflecting the sensitivity of coal and rock mass dissipation performance to damage evolution. The larger the value of χ1, the more obvious the energy dissipation of the rock mass is aggravated under the same damage, and the faster the structural deterioration rate.

[0048] The damage-state dynamic dissipation function establishes a linear positive correlation between the degree of rock mass damage and energy dissipation characteristics. The total energy dissipation of coal and rock mass consists of two superimposed parts: one is the inherent dissipation of the intact rock mass itself, and the other is the additional dissipation increment induced by damage behaviors such as internal crack initiation, propagation, and penetration. This function conforms to engineering laws and can truly restore the energy dissipation evolution law of coal and rock mass from integrity to failure.

[0049] S320, based on the density of the coal and rock mass to be tested, the frequency of each target frequency point, and the complex dynamic modulus relationship, determine the complex wave number relationship of elastic wave propagation in the coal and rock mass corresponding to each target frequency point with respect to the damage variables of the coal and rock mass to be determined.

[0050] The complex wavenumber relationship is: .

[0051] S330, based on the complex wave number relationship and the frequency of each target frequency point, construct the elastic wave propagation velocity relationship of each target frequency point with respect to the damage variables of the coal and rock mass to be determined.

[0052] The relationship between the propagation speeds of elastic waves is as follows: ,in, Representative take The real part.

[0053] S340, based on the complex wave number relationship, construct the elastic wave attenuation coefficient relationship for each target frequency point with respect to the damage variables of the coal and rock mass to be determined.

[0054] The relationship between the elastic wave attenuation coefficients is as follows: , representing taking The imaginary part.

[0055] This step abandons the traditional, crude approach of using fixed theoretical parameters in detection. Instead, it strictly relies on the inherent dissipation properties of coal and rock mass and the coupling mechanism of elastic wave frequency propagation, matching specific theoretical parameters for each selected target frequency point. Since the propagation loss, propagation rate, and frequency of elastic waves in coal and rock mass are strongly correlated, and the theoretical propagation laws of non-destructive testing differ significantly at different frequencies, the targeted solution of the corresponding theoretical parameters enables the construction of a non-destructive benchmark model that is fully adapted to the multi-frequency detection system of this scheme. This allows subsequent comparisons between measured and theoretical parameters to accurately correspond to wave propagation distortion caused by actual damage, rather than systematic errors caused by frequency differences or differences in medium properties. This precisely solves the core problem that traditional methods cannot distinguish between inherent differences in the medium and differences in damage.

[0056] S400 constructs the objective function for a single transmission path of elastic waves based on the measured propagation velocity, measured attenuation parameter, theoretical propagation velocity, and theoretical attenuation parameter corresponding to each target frequency point.

[0057] Reference Figure 4 The method for constructing the objective function for a single propagation path of an elastic wave specifically includes: S410, based on the measured propagation velocity and theoretical propagation velocity corresponding to each target frequency point, determine the relative velocity deviation corresponding to each target frequency point.

[0058] The relative speed deviation is: v is the measured propagation speed at the corresponding target frequency point. This represents the theoretical propagation speed at the corresponding target frequency point.

[0059] S420 determines the relative attenuation deviation for each target frequency point based on the measured and theoretical attenuation parameters.

[0060] The relative attenuation deviation is: , These are the measured attenuation parameters corresponding to the target frequency point. This represents the theoretical attenuation parameters for the corresponding target frequency point.

[0061] S430 determines the deviation fusion information corresponding to each target frequency point based on the relative deviation of velocity and the relative deviation of attenuation.

[0062] The deviation fusion information is as follows: .

[0063] S440 constructs the objective function for a single transmission path of elastic waves based on the deviation fusion information of all target frequency points.

[0064] The objective function for a single propagation path of an elastic wave is: .

[0065] Traditional damage analysis relies solely on qualitative judgments based on single-point parameter differences, failing to integrate effective information from multiple frequencies and parameters. This step constructs an objective function based on measured and theoretical dual parameters at multiple frequency points, weighting and coupling velocity deviations and attenuation deviations at different target frequencies. It fully integrates multi-scale and multi-dimensional damage-sensitive information, enabling accurate conversion from discrete detection data to a quantitative damage model and effectively avoiding the random errors of single-parameter and single-frequency data.

[0066] Meanwhile, by using a single elastic wave transmission path as the modeling unit, the damage calculation range can be strictly limited to the rock mass area where the wave actually propagates. This completely avoids the problems caused by large-scale regional average modeling, where local minor damage is masked by the mean and the damage location is blurred. This allows the numerical change of the objective function to accurately correspond to the degree of damage development of the coal and rock mass within a single path.

[0067] S500 analyzes the objective function of a single transmission path of elastic waves to determine the degree of damage to the coal and rock mass.

[0068] Specifically, the objective function of a single elastic wave propagation path is analyzed using the least squares method to obtain the coal and rock mass damage information D corresponding to the minimum value of the objective function of a single elastic wave propagation path. .

[0069] Furthermore, this application also includes: determining the risk level of the coal and rock mass to be tested based on the information on the degree of damage to the coal and rock mass, and implementing corresponding control measures based on the risk level.

[0070] Specifically, when the information on the degree of damage to the coal and rock mass is within the first range, preferably [0, 0.25), the risk level of the coal and rock mass to be tested is determined to be low risk, which means that the coal and rock mass structure is intact, the integrity is good, the original structure has not been destroyed, there is no new damage or deformation, the surrounding rock stability is extremely strong, there is no risk of instability, and it belongs to a healthy working condition.

[0071] The corresponding control measures are routine control measures, which may include: conducting daily routine inspections, performing one manual on-site inspection per day, and collecting and analyzing data from automated monitoring equipment once a week, maintaining monitoring records, without the need to install additional special monitoring equipment; maintaining normal mining operations, strictly implementing standardized construction procedures, strictly prohibiting over-excavation, over-mining, and illegal disturbance of the coal and rock mass structure, and preventing human-caused damage to the surrounding rock; no rectification is required if there are no hidden dangers, only daily status records are kept, and if minor damage changes occur, timely tracking and observation are conducted, and the trend of change is recorded; a comprehensive status review is conducted once a month to continuously maintain the healthy and stable state of the coal and rock mass, etc.

[0072] When the information on the degree of damage to the coal and rock mass is in the second range, preferably [0.25, 0.50), the risk level of the coal and rock mass to be tested is determined to be medium risk. This means that the overall structure of the coal and rock mass is basically intact, there is slight damage in some areas, the deformation of the surrounding rock is within a controllable range, the cracks develop slowly, and there is no risk of instability or collapse in the short term. However, routine monitoring and control are required to prevent the damage from continuing to worsen.

[0073] The corresponding control measures are key control measures, which may include: increasing the frequency of monitoring, conducting two manual inspections daily, collecting and analyzing automated monitoring data daily, focusing on tracking the development of fissures and the trend of surrounding rock deformation, and establishing a special monitoring ledger; setting up warning signs and strictly prohibiting personnel from staying for long periods and equipment from remaining stationary for extended periods; optimizing construction techniques, reducing the intensity of mining disturbance, and slowing down the mining progress; taking simple reinforcement and support measures for areas with minor local damage, such as adding individual props, anchor cable reinforcement, and spraying thin layers of concrete to inhibit fissure extension and surrounding rock deformation; investigating the causes of damage, promptly rectifying problems such as illegal construction and stress concentration, forming rectification records, and achieving dynamic zeroing of hidden dangers; and conducting a special review every three days until the damage indicators fall back to the low-risk range, etc.

[0074] When the information on the degree of damage to the coal and rock mass is in the third range, preferably [0.50, 0.75), the risk level of the coal and rock mass to be tested is determined to be high risk. This means that the overall structure of the coal and rock mass is severely damaged, the integrity is greatly reduced, the deformation rate of the surrounding rock is accelerated, the stress imbalance is obvious, and there is a risk of spalling, local roof collapse, and slight instability of the surrounding rock. It is a high-risk damage state and special control measures must be taken immediately.

[0075] The corresponding control measures are special control and time-limited rectification, which may include: enhanced monitoring: initiating 24-hour uninterrupted real-time monitoring, deploying high-density monitoring points, tracking data on surrounding rock deformation, acoustic emission, and stress changes throughout the process, summarizing and analyzing monitoring data every 2 hours, and timely predicting the development trend of risks; immediately restricting the intensity of operations, suspending disturbing construction such as mining and blasting in the area, strictly prohibiting the passage of heavy-load equipment, reducing the number of on-site workers, and retaining only necessary monitoring personnel; implementing comprehensive reinforcement support, adopting a combined support method of anchor bolts, anchor cables, metal mesh, and shotcrete, grouting and reinforcing areas with dense cracks and looseness, sealing cracks, consolidating coal and rock mass, and improving the stress state of surrounding rock; for areas with concentrated stress, taking measures such as pressure relief drilling and shallow hole blasting to release concentrated stress in the surrounding rock and alleviate the trend of coal and rock mass damage deterioration; conducting special acceptance and review twice a day, dynamically tracking the treatment effect until the risk is reduced to medium risk or below, etc.

[0076] When the information on the degree of damage to the coal and rock mass is in the fourth range, preferably [0.75, 1), the risk level of the coal and rock mass to be tested is determined to be critical risk, which means that the coal and rock mass structure is completely destroyed, the integrity is lost, the surrounding rock is in an unstable critical state, and major disasters such as large-scale roof collapse, severe spalling, and rock bursts may occur at any time. It is an emergency dangerous working condition and the emergency response process needs to be initiated immediately.

[0077] The corresponding control measures are emergency control and emergency response, which may include: immediately stopping operations, decisively evacuating all personnel and construction equipment from the area, sealing off the danger zone, setting up hard warning barriers, and strictly prohibiting anyone or any equipment from entering the danger zone; immediately reporting to the mine-level safety management department, activating the emergency plan for coal and rock mass instability disasters, arranging professional technicians to conduct on-site assessment of the disaster risk level, and formulating a special emergency response plan; deploying an emergency monitoring system to monitor the deformation, stress, and acoustic emission data of the surrounding rock at high frequency throughout the process, and predicting the probability of disasters such as collapse and rockburst in real time, providing data support for emergency response; taking emergency treatment measures such as sealing, strong support, deep grouting, and large-scale pressure relief according to the on-site conditions to quickly control the instability trend of the coal and rock mass and prevent further damage; controlling the roadways connected to the danger zone above, below, and before and after, cutting off the operation channels, and preventing the disaster from spreading to the surrounding operation areas; after the emergency treatment is completed, continuous monitoring for 3-7 working days, and only after confirming that the damage indicators have stabilized and fallen back and the risk has been completely eliminated, and after passing a special acceptance inspection, can operations be gradually resumed.

[0078] This step determines the degree of damage to coal and rock mass by analyzing a single-path, multi-frequency coupled objective function, achieving a breakthrough from qualitative assessment to precise multi-scale quantification of damage. Unlike traditional methods that rely on experience and single indicators to classify damage levels, this step constructs an objective function based on the multi-frequency domain characteristics, dual-parameter measurements, and differentiated theoretical benchmarking described earlier. The function's value has a direct mathematical correspondence with the damage variables of the coal and rock mass, allowing for precise quantification of the specific values ​​of these damage variables. Based on this, a complete classification of damage levels, from micro-damage to mild to severe, can be accurately determined.

[0079] Simultaneously, this method can not only determine the overall damage level but also accurately pinpoint the local damage area corresponding to each wave path, precisely identifying non-uniform and localized hidden damage within the rock mass. The entire analysis process relies entirely on the proprietary frequency domain multi-scale detection, dual-parameter coupling, and path refinement modeling technologies of this scheme, without any subjective human interpretation intervention. The detection results are highly repeatable and objective, accurately capturing early irreversible micro-damage in coal and rock masses and dynamically tracking the evolution of damage under load, providing accurate quantitative data for engineering support and disaster early warning.

[0080] Traditional coal and rock mass damage detection often relies on single-parameter, single-frequency detection in the time domain, which suffers from inherent limitations such as difficulty in identifying micro-damage, inaccurate damage quantification, and missed detection of local damage. This application, however, focuses on fine-grained frequency domain features, covering multi-scale damage through multi-target frequencies, utilizing complementary velocity and attenuation parameters to characterize damage properties, eliminating systematic errors with differentiated theoretical parameters, and achieving precise local damage analysis through a single-path objective function. The entire method is a customized analysis scheme for the non-uniform, multi-fracture, and highly concealed damage characteristics of coal and rock masses. It not only solves the technical challenges of traditional methods in identifying early micro-damage, quantifying damage severity, and accurately locating local damage, but also effectively improves the detection's anti-interference capability through multi-frequency data coupling, achieving a balance between comprehensive damage identification, accurate quantification, and targeted localization.

[0081] The method disclosed in this application is highly applicable, and all damage assessment results are traceable and quantifiable. It can be accurately adapted to dynamic damage monitoring scenarios of coal and rock masses in underground engineering such as mines and tunnels. It can effectively make up for the shortcomings of existing technologies in terms of refinement, quantification, and early warning, and has strong engineering practicality.

[0082] Secondly, this application discloses a coal and rock mass damage analysis system for performing the coal and rock mass damage analysis method disclosed in the first aspect of this application. The system includes: The acquisition unit is used to acquire the elastic wave response signal of the coal and rock mass to be tested, and to obtain the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave based on the elastic wave response signal. The measured parameter acquisition unit is used to determine several different target frequency points based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, and to obtain the measured propagation speed and measured attenuation parameters corresponding to each target frequency point. The theoretical parameter acquisition unit is used to obtain the theoretical propagation velocity and theoretical attenuation parameters of the damage variables of the coal and rock mass to be determined for each target frequency point based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested. The function construction unit is used to construct the objective function for a single transmission path of elastic wave based on the measured propagation velocity, measured attenuation parameter, theoretical propagation velocity, and theoretical attenuation parameter corresponding to each target frequency point. The analysis unit is used to analyze the objective function of a single transmission path of elastic waves to determine the degree of damage to the coal and rock mass.

[0083] Reference Figure 5 Thirdly, this application discloses a method for analyzing coal and rock mass damage, including: S10: Acquire the elastic wave response signal of the coal and rock mass to be tested, and obtain the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave based on the elastic wave response signal.

[0084] Simultaneously refer to Figure 6 and Figure 7 In this embodiment, a broadband elastic wave excitation device is used to transmit elastic waves. There is at least one signal transmitting end and at least two receiving ends, and there are also two corresponding transmission paths. Through this step, time-domain diagrams containing the frequency domain characteristics of the transmitted wave and time-domain diagrams containing the frequency domain characteristics of the received wave can be obtained respectively.

[0085] It should be noted that the specific implementation method for this step is consistent with the method in the coal and rock mass damage analysis method disclosed in the first aspect of this application, so it will not be described in detail here.

[0086] S20, based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, determines several different target frequency points and obtains the measured propagation speed and measured attenuation parameters corresponding to each target frequency point.

[0087] Specific reference Figure 8 First, determine that the range of fluctuations in the frequency domain characteristics of the received wave is 200kHz~600kHz; then determine that the range of fluctuations in the frequency domain characteristics of the transmitted wave is 100kHz~600kHz; find the intersection of these two ranges as the main frequency range, that is, determine the main frequency range as 200kHz~600kHz. Taking 9 target frequency points with an interval of 50kHz as an example within the main frequency range, 9 sets of corresponding measured propagation speed and measured attenuation parameters can be obtained.

[0088] It should be noted that the specific implementation method for this step is consistent with the method in the coal and rock mass damage analysis method disclosed in the first aspect of this application, so it will not be described in detail here.

[0089] S30, based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested, obtain the theoretical propagation speed and theoretical attenuation parameters of the damage variables of the coal and rock mass to be determined for each target frequency point.

[0090] The relationship of the elastic wave propagation speed corresponding to the i-th transmission path is: .

[0091] The relationship of the elastic wave attenuation coefficients corresponding to the i-th transmission path is as follows: .

[0092] S40. Based on the measured propagation velocity, measured attenuation parameter, theoretical propagation velocity, and theoretical attenuation parameter corresponding to each target frequency point, construct the objective function for a single transmission path of elastic wave.

[0093] The objective function for each transmission path is: .

[0094] S50 analyzes the objective function of a single transmission path of elastic waves to determine the degree of damage to the coal and rock mass corresponding to each transmission path.

[0095] The information on the degree of coal and rock mass damage corresponding to the i-th transmission path is: : .

[0096] It should be noted that the specific implementation methods corresponding to S30-S50 are consistent with the specific steps in the coal and rock mass damage analysis method disclosed in the first aspect of this application, so they will not be described in detail here.

[0097] S60, determine the overall damage level parameters based on the coal and rock mass damage information corresponding to all transmission paths.

[0098] Specifically, firstly, the weighted impairments corresponding to all transmission paths are obtained. Then, the sum of all path weights is obtained, and the result is constrained to a weighted average to eliminate the influence of the total weight. Finally, the ratio of the weighted damage sum to the sum of all path weights is obtained as the overall damage parameter; that is, this parameter is the sum of the path weights. The average damage across the entire path is weighted by coefficients.

[0099] The overall damage level parameter is D: , Let M be the weight corresponding to the i-th transmission path, and M be the total number of transmission paths. This represents the damage level information of the coal and rock mass corresponding to the i-th transmission path.

[0100] Furthermore, the weight of each transmission path is preferably determined based on the path length, signal-to-noise ratio, and reliability of the coverage area; specifically, the path parameters of all candidate transmission paths in the current communication scenario are obtained, including the path length, signal-to-noise ratio, and reliability score of the coverage area for each transmission path. For each i-th transmission path, the path length data of all candidate transmission paths are normalized to obtain the path length normalization score of the corresponding transmission path; where the shorter the path length, the higher the corresponding path length normalization score.

[0101] For each i-th transmission path, the signal-to-noise ratio (SNR) data of all candidate transmission paths are normalized to obtain the SNR normalization score of the corresponding transmission path. The higher the SNR value, the higher the corresponding SNR normalization score, and the normalization score of the SNR value below the preset SNR threshold is set to zero.

[0102] For each i-th transmission path, the coverage area reliability scores of all candidate transmission paths are normalized to obtain the corresponding regional reliability normalized score; where the higher the coverage area reliability, the higher the corresponding regional reliability normalized score.

[0103] Fixed weighting coefficients are preset for path length, signal-to-noise ratio (SNR), and coverage area reliability, with the sum of these three coefficients being 1. The normalized scores for path length, SNR, and coverage area reliability are fused using a weighted summation formula to obtain the final weight for the i-th transmission path. .

[0104] The final weight pi ranges from 0 to 1. The value is used to characterize the transmission quality of the corresponding transmission path. The larger the weight value, the better the transmission performance of the corresponding transmission path.

[0105] S70, based on the damage degree information of the coal and rock mass and the overall damage degree parameters, determines the localized damage information of the coal and rock mass to be tested.

[0106] Simultaneously refer to Figure 9 Methods for determining damage localization information specifically include: S71. Based on the overall damage degree parameters and the coal and rock mass damage degree information corresponding to each elastic wave propagation path, determine the local differences corresponding to each elastic wave propagation path.

[0107] The local difference corresponding to the i-th elastic wave propagation path is: .

[0108] S72, based on the weights and local differences corresponding to each transmission path, determine the weighted impairment standard deviation corresponding to the transmission path.

[0109] The weighted impairment standard deviation corresponding to the transmission path is: , Let be the weight corresponding to the i-th transmission path, and M be the total number of transmission paths.

[0110] S73. Determine the damage non-uniformity coefficient based on the weighted damage standard deviation and the overall damage degree parameter.

[0111] Damage non-uniformity coefficient is : This value is used to eliminate the influence of the average damage value and to compare the dispersion of rock mass damage across different mining areas and measuring points. S74, based on the damage non-uniformity coefficient, determines the damage localization information corresponding to all propagation paths of the coal and rock mass to be tested.

[0112] Damage localization information corresponding to all propagation paths of the coal and rock mass under test is as follows: : .

[0113] Specifically, through The value can be limited to Within the range, and the obtained damage localization information is in Within this range, corresponding to a disaster probability of 0 to 100%, no additional normalization trimming is required. In this step, the larger the damage non-uniformity coefficient, the greater the damage localization information, that is, the more discrete the damage and the more concentrated the local fragmentation, the higher the risk of instability will inevitably be. This is consistent with monotonicity and engineering logic.

[0114] If the damage is uniform, then A value of 0 indicates that the scattered micro-cracks are not interconnected, with almost no risk of collapse or impact, and the corresponding damage localization information is also 0; if the damage is uneven and gradually increases, it indicates that local damage is enriched, and cracks preferentially initiate, expand, and connect in high-damage areas, with the risk increasing exponentially; if it is extremely uneven, it indicates that the fractured areas are connected, the whole is on the verge of instability, and the risk approaches 1 infinitely.

[0115] S80 determines the damage complexity information of the coal and rock mass to be tested based on the measured propagation velocity and measured attenuation parameters corresponding to all target frequency points.

[0116] Simultaneously refer to Figure 10 The method for determining the damage complexity information of the coal and rock mass to be tested specifically includes: S81, perform linear fitting on the measured propagation velocity corresponding to all target frequency points to obtain the first slope.

[0117] The more numerous and chaotically distributed the internal fissures and pores in the coal and rock, the greater the difference in propagation speed between high-frequency and low-frequency sound waves, the steeper the dispersion curve, and the larger the absolute value of the first slope. In this embodiment, this parameter reflects the degree of geometric distortion in wave propagation caused by macroscopic fissures and structural inhomogeneities within the coal and rock, based on the variation law of wave velocity with frequency.

[0118] S82, linearly fits the measured attenuation parameters corresponding to all target frequency points to obtain the second slope.

[0119] In this study, micro-damage, pores, and fissures in coal and rock absorb incident sound waves. The more complex and disordered the damage, the faster the sound waves attenuate and accelerate with increasing frequency, and the greater the second slope. In this embodiment, the difference in sound wave energy dissipation caused by the filling medium of micro-pores and fissures in coal and rock is characterized by the attenuation variation with frequency.

[0120] Simultaneously refer to Figure 11 Taking the nine selected target frequency points as an example, the measured propagation velocities corresponding to the nine target frequency points are curve-fitted to determine the velocity dispersion curve, and then the slope of the curve is obtained, which is denoted as the first slope.

[0121] Linear fitting is performed on the measured attenuation parameters corresponding to the nine target frequency points to determine the attenuation curve, and then the slope of the curve is obtained, which is denoted as the second slope.

[0122] S83, based on the first slope and the second slope, determines the damage complexity non-uniformity coefficient.

[0123] Damage complexity non-uniformity coefficient is : , The first slope, This is the second slope.

[0124] In this step, the two physical quantities are linearly summed, which can fuse the two types of acoustic characteristic parameters that respectively characterize macroscopic structural inhomogeneity and microscopic energy loss. This not only makes up for the deficiency that a single slope can only reflect a single damage form, but also realizes the integration of full-scale damage information by relying on the dimensionless property of the two types of parameters.

[0125] S84. Based on the damage complexity non-uniformity coefficient, determine the damage complexity information of the coal and rock mass to be tested.

[0126] Damage complexity information of the coal and rock mass to be tested is as follows : This step yields a normalized damage evaluation index ranging from 0 to 1. The closer the value is to 1, the more complex and unevenly distributed the internal damage within the coal and rock. This transformation method physically aligns with the evolutionary characteristics of coal and rock damage, particularly in the low-damage stage. Even a small increase can drive The sensitivity of micro-damage identification is significantly improved, and the indicators in the high-damage stage gradually approach 1 to achieve damage saturation constraint. It can not only rely on the fixed value range of 0 to 1 to divide the damage classification standard and facilitate the classification and judgment on the engineering site, but also weaken the problem of indicator distortion caused by abnormal disturbance of measured data, and realize a complete closed loop from acoustic dispersion measurement to quantitative evaluation of coal and rock damage.

[0127] S90 integrates overall damage degree parameters, damage localization information, and damage complexity information to determine the risk information of coal and rock mass instability.

[0128] Specifically, from a qualitative perspective, if the overall damage degree parameter D is high, and the damage localization information... Low damage complexity information The low value indicates that the overall deterioration of the coal and rock mass is relatively obvious, but the damage is relatively uniform and has not yet shown strong local concentration.

[0129] If the overall damage level parameter D is moderate, and the damage is localized... High, damage complexity information Medium or high indicates that although the average damage may not be particularly high, the damage is concentrated in local areas, suggesting that a main rupture zone or local weak surface may have formed.

[0130] If the overall damage level parameter D is moderate, and the damage is localized... Low damage complexity information The high level indicates that the overall damage and local concentration are not prominent at the moment, but the internal crack structure is complex and the multi-frequency response is abnormal, which may indicate the rapid expansion of microcracks or the development of a multi-scale crack network.

[0131] If the overall damage degree parameter D and the damage localization information Damage complexity information The high values ​​indicate that the coal and rock mass is in a critical stage of damage and fracturing.

[0132] Furthermore, it is also possible to analyze the overall damage degree parameter D and damage localization information. Damage complexity information Quantitative analysis was conducted, specifically based on the overall damage severity parameter D and damage localization information. Damage complexity information Construct parameters for the instability risk of coal and rock mass, and determine the instability risk information of coal and rock mass based on these parameters.

[0133] The risk parameter for coal and rock mass instability is R: .

[0134] in, , , , The corresponding weights.

[0135] Furthermore, if the instability risk parameter of the coal and rock mass is within the first range, preferably [0, 0.25), the risk level of the coal and rock mass to be tested is determined to be low risk; if the instability risk parameter of the coal and rock mass is within the second range, preferably [0.25, 0.50), the risk level of the coal and rock mass to be tested is determined to be medium risk; if the instability risk parameter of the coal and rock mass is within the third range, preferably [0.50, 0.75), the risk level of the coal and rock mass to be tested is determined to be high risk; if the instability risk parameter of the coal and rock mass is within the fourth range, preferably [0.75, 1), the risk level of the coal and rock mass to be tested is determined to be critical risk.

[0136] Furthermore, this application also includes: determining the risk level of the coal and rock mass to be tested based on the coal and rock mass instability risk information, and implementing corresponding control measures based on the risk level. The specific control measures are consistent with the control measures in the coal and rock mass damage analysis method disclosed in the first aspect of this application, so they will not be described in detail here.

[0137] The coal and rock mass damage analysis method disclosed in this application, by integrating overall damage degree parameters, damage localization information, and damage complexity information, jointly determines the instability risk of coal and rock mass. This overcomes the limitations of single-indicator assessments and matches the actual mechanical evolution mechanism of coal and rock mass instability, achieving a breakthrough from single-dimensional assessment to multi-dimensional, three-dimensional, and precise judgment of instability risk. Specifically, the overall damage degree parameter primarily characterizes the average damage deterioration level of the overall coal and rock mass structure, mainly used to judge the overall integrity of the rock mass; damage localization information focuses on the concentration of fractures and the enrichment of damage in local areas of the rock mass, enabling the identification of local weak zones; and damage complexity information can characterize the disorder of fracture development, the superposition of multi-scale damage, and the degree of disorder in damage evolution. Through the integrated analysis of these three parameters, a complementary and mutually verifying risk assessment logic can be formed, accurately reconstructing the true damage state and instability mechanism of the coal and rock mass.

[0138] The overall damage level provides a baseline threshold for instability risk, defining whether the rock mass as a whole is in a deteriorated state; damage localization information pinpoints the core risk area, locating the most dangerous points most prone to fracture penetration and structural failure; damage complexity information determines the evolutionary activity and expansion potential of the damage, judging whether the current damage has the conditions for continuous development, chain penetration, and induction of overall instability. The integration of these three factors enables precise differentiation of different instability triggers, effectively addressing the core pain point of traditional methods that know the damage but not the risk, and effectively avoiding the technical deficiency of traditional damage detection which can only determine the damage size but cannot predict the instability trend.

[0139] Meanwhile, relying on the high-precision damage data obtained through multi-frequency domain analysis, dual-parameter modeling, and single-path precise quantification mentioned above, this fusion method can achieve a closed-loop upgrade from quantitative damage analysis to precise early warning of instability risks. It can identify the systemic instability risks caused by overall severe damage, as well as capture the sudden and hidden instability risks caused by the development of highly damaged local areas and complex micro-cracks. This significantly improves the accuracy and comprehensiveness of coal and rock mass instability prediction, providing comprehensive and multi-dimensional quantitative basis for early warning and risk classification management of coal and rock mass disasters in underground engineering.

[0140] Fourthly, this application discloses a coal and rock mass damage analysis system for performing the coal and rock mass damage analysis method disclosed in the third aspect of this application. The system includes: The acquisition unit is used to acquire the elastic wave response signal of the coal and rock mass to be tested, and to obtain the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave based on the elastic wave response signal. The measured parameter acquisition unit is used to determine several different target frequency points based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, and to obtain the measured propagation speed and measured attenuation parameters corresponding to each target frequency point. The theoretical parameter acquisition unit is used to obtain the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined for each target frequency point based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested. The function construction unit is used to construct the target function of a single transmission path of elastic wave based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point. The coal and rock mass damage degree information acquisition unit is used to analyze the objective function of the single transmission path of the elastic wave and determine the coal and rock mass damage degree information corresponding to each transmission path. The overall damage degree parameter acquisition unit is used to determine the overall damage degree parameter based on the coal and rock mass damage degree information corresponding to all transmission paths. The damage localization information acquisition unit is used to determine the damage localization information of the coal and rock mass to be tested based on the damage degree information of the coal and rock mass and the overall damage degree parameters. The damage complexity information acquisition unit is used to determine the damage complexity information of the coal and rock mass to be tested based on the measured propagation velocity and the measured attenuation parameter corresponding to all the target frequency points. The analysis unit is used to fuse the overall damage degree parameters, the damage localization information, and the damage complexity information to determine the coal and rock mass instability risk information.

[0141] It should be noted that the control measures corresponding to different risk levels in this application can be flexibly configured according to actual needs, and all are within the scope of protection of this application.

[0142] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A coal rock mass damage analysis method, characterized by, include: The elastic wave response signal of the coal and rock mass to be tested is collected, and the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave are obtained based on the elastic wave response signal. Based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, several different target frequency points are determined, and the measured propagation speed and measured attenuation parameters corresponding to each target frequency point are obtained. Based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested, the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined are obtained for each target frequency point. Based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point, an objective function for a single transmission path of elastic waves is constructed. The objective function of a single transmission path of the elastic wave is analyzed to determine the degree of damage to the coal and rock mass.

2. The coal rock mass damage analysis method according to claim 1, characterized by, The step of determining several different target frequency points based on the transmitted wave frequency domain characteristics and the received wave frequency domain characteristics, and obtaining the measured propagation velocity and measured attenuation parameters corresponding to each target frequency point, includes: The dominant frequency range is determined based on the transmitted wave frequency domain characteristics and the received wave frequency domain characteristics. Select several different target frequency points within the main frequency range; Based on the transmitted wave phase and received wave phase at each target frequency point 、 The transmitted and received wave amplitude values ​​are used to obtain the measured propagation speed and measured attenuation parameters at the corresponding frequency points.

3. The method for coal and rock mass damage analysis according to claim 1, characterized in that, The method of obtaining the theoretical propagation velocity and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined for each target frequency point based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested includes: Construct the complex dynamic modulus relationship of the damage variables of the coal and rock mass to be determined for each target frequency point; Based on the density of the coal and rock mass to be tested, the frequency of each target frequency point, and the complex dynamic modulus relationship, the complex wave number relationship of elastic wave propagation in the coal and rock mass corresponding to each target frequency point with respect to the damage variable of the coal and rock mass to be determined is determined. Based on the complex wave number relationship and the frequency of each target frequency point, construct the elastic wave propagation velocity relationship for each target frequency point with respect to the coal and rock mass damage variable to be determined; Based on the complex wave number relationship, the elastic wave attenuation coefficient relationship for each target frequency point with respect to the damage variable of the coal and rock mass to be determined is constructed.

4. The method for coal and rock mass damage analysis according to claim 1, characterized in that, The step of constructing the objective function for a single transmission path of the elastic wave based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point includes: Based on the measured propagation velocity and the theoretical propagation velocity corresponding to each target frequency point, determine the relative velocity deviation corresponding to each target frequency point; Based on the measured attenuation parameter and the theoretical attenuation parameter corresponding to each target frequency point, determine the relative attenuation deviation corresponding to each target frequency point; Based on the relative velocity deviation and the relative attenuation deviation, the deviation fusion information corresponding to each target frequency point is determined; Based on the deviation fusion information of all the target frequency points, an objective function for a single transmission path of elastic waves is constructed.

5. The method for coal and rock mass damage analysis according to claim 1, characterized in that, Also includes: The risk level of the coal and rock mass to be tested is determined based on the information on the degree of damage to the coal and rock mass, and corresponding control measures are implemented based on the risk level.

6. A method for analyzing damage in coal and rock masses, characterized in that, include: The elastic wave response signal of the coal and rock mass to be tested is collected, and the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave are obtained based on the elastic wave response signal. Based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, several different target frequency points are determined, and the measured propagation speed and measured attenuation parameters corresponding to each target frequency point are obtained. Based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested, the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined are obtained for each target frequency point. Based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point, an objective function for a single transmission path of elastic waves is constructed. The objective function of each elastic wave transmission path is analyzed to determine the degree of coal and rock mass damage corresponding to each transmission path; Based on the information on the degree of damage to the coal and rock mass corresponding to all transmission paths, the overall damage degree parameters are determined; Based on the information on the degree of damage to the coal and rock mass and the parameters on the overall degree of damage, the localization information of the damage to the coal and rock mass to be tested is determined. Based on the measured propagation velocity and measured attenuation parameter corresponding to all the target frequency points, the damage complexity information of the coal and rock mass to be tested is determined; The overall damage degree parameter, the damage localization information, and the damage complexity information are fused to determine the coal and rock mass instability risk information.

7. The method for coal and rock mass damage analysis according to claim 6, characterized in that, The determination of damage localization information of the coal and rock mass to be tested based on the damage degree information of the coal and rock mass and the overall damage degree parameters includes: Based on the overall damage degree parameters and the coal and rock mass damage degree information corresponding to each elastic wave propagation path, the local differences corresponding to each elastic wave propagation path are determined. Based on the weights corresponding to each transmission path and the local differences, the weighted impairment standard deviation corresponding to the transmission path is determined; The damage non-uniformity coefficient is determined based on the weighted damage standard deviation and the overall damage degree parameter. Based on the damage non-uniformity coefficient, damage localization information corresponding to all propagation paths of the coal and rock mass under test is determined.

8. The method for coal and rock mass damage analysis according to claim 6, characterized in that, The step of determining the damage complexity information of the coal and rock mass to be tested based on the measured propagation velocity and the measured attenuation parameter corresponding to all the target frequency points includes: A first slope is obtained by linearly fitting the measured propagation velocity corresponding to all the target frequency points. A second slope is obtained by linearly fitting the measured attenuation parameters corresponding to all the target frequency points. Based on the first slope and the second slope, the damage complexity non-uniformity coefficient is determined; The damage complexity information of the coal and rock mass to be tested is determined based on the damage complexity non-uniformity coefficient.

9. A coal and rock mass damage analysis system, characterized in that, include: The acquisition unit is used to acquire the elastic wave response signal of the coal and rock mass to be tested, and to obtain the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave based on the elastic wave response signal. The measured parameter acquisition unit is used to determine several different target frequency points based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, and to obtain the measured propagation speed and measured attenuation parameters corresponding to each target frequency point. The theoretical parameter acquisition unit is used to obtain the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined for each target frequency point based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested. The function construction unit is used to construct the target function of a single transmission path of elastic wave based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point. The analysis unit is used to analyze the objective function of a single transmission path of the elastic wave to determine the degree of damage to the coal and rock mass.

10. A coal and rock mass damage analysis system, characterized in that, include: The acquisition unit is used to acquire the elastic wave response signal of the coal and rock mass to be tested, and to obtain the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave based on the elastic wave response signal. The measured parameter acquisition unit is used to determine several different target frequency points based on the frequency domain characteristics of the transmitted wave and the frequency domain characteristics of the received wave, and to obtain the measured propagation speed and measured attenuation parameters corresponding to each target frequency point. The theoretical parameter acquisition unit is used to obtain the theoretical propagation speed and theoretical attenuation parameter of the damage variable of the coal and rock mass to be determined for each target frequency point based on the frequency of each target frequency point and the dissipation information corresponding to the coal and rock mass to be tested. The function construction unit is used to construct the target function of a single transmission path of elastic wave based on the measured propagation velocity, the measured attenuation parameter, the theoretical propagation velocity, and the theoretical attenuation parameter corresponding to each target frequency point. The coal and rock mass damage degree information acquisition unit is used to analyze the objective function of the single transmission path of the elastic wave and determine the coal and rock mass damage degree information corresponding to each transmission path; The overall damage degree parameter acquisition unit is used to determine the overall damage degree parameter based on the coal and rock mass damage degree information corresponding to all transmission paths. The damage localization information acquisition unit is used to determine the damage localization information of the coal and rock mass to be tested based on the damage degree information of the coal and rock mass and the overall damage degree parameters. The damage complexity information acquisition unit is used to determine the damage complexity information of the coal and rock mass to be tested based on the measured propagation velocity and the measured attenuation parameter corresponding to all the target frequency points. The analysis unit is used to fuse the overall damage degree parameters, the damage localization information, and the damage complexity information to determine the coal and rock mass instability risk information.

Images