A coal body impact danger detection method and system based on while-drilling vibration monitoring

Abstract

This application relates to the field of coal mine rockburst disaster monitoring and early warning technology, and provides a method and system for detecting coal rockburst hazard based on drilling vibration monitoring. This method directly acquires the intrinsic vibration response signal of the coal body under drilling disturbance by coupling sensors to the coal body. It establishes the correlation between the vibration characteristics of the vibration response signal and the physical and mechanical properties, stress state, and energy accumulation characteristics of the coal body, and combines this with abnormal drilling dynamic phenomena to construct a multi-parameter fusion coal rockburst hazard evaluation model, outputting the coal rockburst hazard index and corresponding hazard level. Therefore, this application utilizes the characteristic that the drilling vibration response signal of the coal body can directly reflect changes in the coal body's structural state and stress conditions to construct a coal rockburst hazard evaluation model, applicable to complex underground coal mine conditions, achieving continuous, quantitative monitoring and graded evaluation of coal rockburst hazard without increasing construction procedures.

Description

Technical Field

[0001] This application relates to the field of coal mine rockburst disaster monitoring and early warning technology, and in particular to a method and system for detecting coal rockburst hazard based on drilling vibration monitoring. Background Technology

[0002] Rockburst is a typical dynamic disaster during deep coal mining. Its essence is the sudden release of elastic energy of the coal body under high ground stress and structural constraints. It is characterized by its suddenness, great destructiveness, and difficulty in early warning.

[0003] Existing shock hazard monitoring methods mainly include microseismic monitoring, stress monitoring, electromagnetic radiation monitoring, and drill cuttings monitoring. Among these, electromagnetic radiation, microseismic, and stress monitoring systems are complex to deploy and costly to construct, and have limited ability to distinguish local high-stress concentration areas. Moreover, electromagnetic radiation monitoring is highly susceptible to electromagnetic noise interference from high-power underground electromechanical equipment such as coal mining machines and scraper conveyor frequency converters, resulting in a low signal-to-noise ratio. Drill cuttings monitoring relies on manual operation and experience-based judgment, making it difficult to achieve continuous and quantitative monitoring, and it is not applicable to coal seams with excessively high moisture content or excessively soft coal seams. Summary of the Invention

[0004] The purpose of this application is to provide a method and system for detecting coal impact hazard based on drilling vibration monitoring, so as to solve or alleviate the problems existing in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solution: In its first aspect, this application provides a method for detecting coal impact hazard based on drilling vibration monitoring. The method includes: acquiring drilling vibration response signals generated during drilling using vibration sensors arranged inside the coal body to be drilled, and preprocessing the drilling vibration response signals; inverting the physical and mechanical properties of the coal body based on the vibration characteristic parameters of the drilling vibration response signals to obtain coal body property characterization parameters, wherein the vibration characteristics include vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics, and vibration non-stationarity characteristics; constructing a coal body energy accumulation index and a coal body state level variable based on the temporal evolution characteristics of the drilling vibration response signals; setting abnormal event parameters based on the abrupt change characteristics, spectral anomaly characteristics, and abnormal change characteristics of drilling parameters of the drilling vibration response signals; and constructing a coal body impact hazard evaluation model by combining the coal body property characterization parameters, the coal body energy accumulation index, the coal body state level variable, the abnormal event parameters, and the vibration stability characteristics of the drilling vibration response signals to output a coal body impact hazard index and its corresponding hazard level.

[0006] Preferably, the vibration sensor is installed through drilled holes, pre-embedded holes, or existing monitoring holes, and is coupled to the coal body using an embedded or external installation structure. The embedded installation structure includes anchoring and grouting. The external installation structure includes: the vibration sensor is suspended on an existing anchor rod in the coal body and connected to the anchor rod through a universal connector. The universal connector has a male and a female end, respectively. The male end is fastened to the vibration sensor through a threaded structure and a locking nut, and the female end is fastened to the anchor rod through a threaded structure and a locking nut.

[0007] Preferably, the method further includes: removing invalid signals corresponding to unstable drilling conditions from the drilling vibration response signal, wherein unstable drilling conditions include drilling rig start-up, drilling rig stop-up, and drilling rig idling; filtering the remaining valid drilling vibration response signal to eliminate low-frequency mechanical interference and high-frequency random noise; and using a sliding time window to segment the filtered valid drilling vibration response signal to form multiple vibration signal analysis units.

[0008] Preferably, based on the average vibration amplitude of the drilling vibration response signal. Total Energy Center of gravity frequency and non-stationarity characteristics Construct a coal body property inversion model: Determine the physical property characterization parameters of coal. In the formula, They are respectively , , and The weighting coefficients.

[0009] Preferably, according to the formula: Extracting the vibration energy of the drilling vibration signal within the time window t With the rate of change of vibrational energy And statistically analyze the proportion of high-frequency energy. In the formula, For time window Total number of time points within, x i For time window Inner The amplitude value corresponding to the time. ε To prevent extremely small positive numbers with a denominator of zero; according to the formula: Constructing coal body energy storage index In the formula, , and They are respectively , and The normalized value, They are respectively , and Weighting coefficients; Based on the coal body energy accumulation index, vibration energy change rate, and high-frequency energy proportion, the stress state of the coal body is identified and its corresponding state level variables are determined. Among them, the stress state of coal includes a stable stress state, a stress accumulation state, and a critical instability state. The stable stress state corresponds to... A value of 0 corresponds to the stress accumulation state. A value of 1 corresponds to the critical instability state. The value is 2.

[0010] Preferably, the setting of abnormal event parameters includes: based on the vibration amplitude mutation index of the drilling vibration response signal. Spectrum anomaly indicators and abnormal indicators of drilling parameters According to the formula: Determine the strength of anomaly event identification In the formula, They are respectively , and Weighting coefficients; based on the intensity of anomaly event identification. Compared with the preset abnormal threshold The relationship, according to the formula: Set exception event trigger variables According to the formula Determine the parameters of the abnormal event. .

[0011] Preferably, the coal rock impact hazard assessment model is a multi-parameter fusion model. The input parameters of the coal rock impact hazard assessment model include coal physical property characterization parameters, energy accumulation index, state level variables, vibration stability characteristics, and abnormal event parameters. The abnormal event parameters are introduced into the coal rock impact hazard assessment model in the form of nonlinear enhancement terms. The output of the coal rock impact hazard assessment model is the coal rock impact hazard index, which is used to characterize the degree of risk of coal rockburst disaster. The hazard level is divided based on a preset level threshold range.

[0012] The preferred coal seam impact hazard assessment model is as follows: In the formula, The coal seam impact hazard index. These are the physical properties of the coal. E s As an indicator of energy accumulation in coal seams, For vibration stability characteristics, For abnormal event parameters, To enhance the coefficient, , , These are the normalized mapping functions for coal body physical properties, coal body energy accumulation, and vibration stability characteristics, respectively. , , coal , E s and The weighting coefficients.

[0013] In the formula, The coal seam impact hazard index. These are the physical properties of the coal. As an indicator of energy accumulation in coal seams, For vibration stability characteristics, For coal body condition level variables, For abnormal event parameters, This represents the amplification factor for abnormal events. , , The normalized mapping functions are respectively. They are respectively , , and The weighting coefficients.

[0014] Preferably, the impact hazard level is divided according to the coal impact hazard index and the preset level threshold range output by the coal impact hazard assessment model; the actual hazard label on site is marked according to the historical monitoring records, pressure relief measure implementation records and historical impact hazard areas of the mine site; by comparing the impact hazard level with the actual hazard label on site, the weight coefficient of the coal impact hazard assessment model and the preset level threshold are corrected according to the comparison results.

[0015] A second aspect of this application provides a coal impact hazard detection system based on drilling vibration monitoring. The system includes: a vibration signal acquisition and processing module for acquiring the drilling vibration response signal generated by the coal body during drilling through vibration sensors arranged inside the coal body to be drilled; a coal body property inversion module for inverting the physical and mechanical properties of the coal body based on the vibration characteristics of the drilling vibration response signal to obtain coal body property characterization parameters, wherein the vibration characteristics include vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics, and vibration non-stationarity characteristics; and a stress state identification module for determining the stress state based on the drilling vibration... The system employs several modules: a time-series evolution characteristic of the response signal to construct a coal body energy accumulation index; an abnormal event identification module to set abnormal event parameters based on the abrupt change characteristics, spectral anomaly characteristics, and abnormal change characteristics of drilling parameters in the drilling vibration response signal; and an impact hazard assessment module to construct a coal body impact hazard assessment model by combining coal body physical property characterization parameters, coal body energy accumulation index, abnormal event parameters, and vibration stability characteristics of the drilling vibration response signal, thereby outputting the coal body impact hazard index and its corresponding hazard level.

[0016] Beneficial effects: This application provides a method for detecting coal impact hazard based on drilling vibration monitoring. By coupling sensors to the coal seam, it directly acquires the intrinsic vibration response signal generated by the coal under drilling disturbances. By establishing the correlation between the vibration characteristics of the vibration response signal and the physical and mechanical properties, stress state, and energy accumulation characteristics of the coal, and combining this with abnormal drilling dynamic phenomena, a multi-parameter fusion coal impact hazard evaluation model is constructed, outputting the coal impact hazard index and corresponding hazard level. Therefore, this application utilizes the characteristic that the drilling vibration response signal of the coal can directly reflect changes in the coal's structural state and stress conditions to construct a coal impact hazard evaluation model. This model is applicable to complex underground coal mine conditions and enables continuous and quantitative monitoring of coal impact hazard without adding construction procedures. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a flowchart illustrating a method for detecting coal impact hazard based on drilling vibration monitoring, according to some embodiments of this application. Figure 2 This is a schematic diagram illustrating a drilling vibration response signal analysis and parameter extraction method according to some embodiments of this application; Figure 3This is a schematic diagram of a three-level structure of a coal impact hazard detection model provided according to some embodiments of this application; Figure 4 This is a structural block diagram of a coal impact hazard detection system based on drilling vibration monitoring, according to some embodiments of this application. Detailed Implementation

[0018] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will understand that modifications and variations can be made to the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention should fall within the scope of protection of the embodiments of the present invention.

[0019] like Figure 1 As shown in the embodiment of this application, a method for detecting coal impact hazard based on drilling vibration monitoring is proposed, which includes the following steps S101-S104.

[0020] Step S101: The vibration response signal generated by the coal body during drilling is collected by vibration sensors arranged inside the coal body to be drilled.

[0021] In this embodiment, the vibration response signal while drilling is the intrinsic vibration response signal generated by the coal body under the excitation of drilling disturbance, and it also carries the dynamic response information of the coal body under the combined action of drilling disturbance and original in-situ stress. The energy intensity, spectrum composition, temporal evolution and stability characteristics of the vibration response signal while drilling are intrinsically dominated by the structural state of the coal body itself, the degree of fracture development and the in-situ stress and energy accumulation conditions.

[0022] In some embodiments, during underground drilling in coal mines, vibration sensors are pre-positioned inside the coal seam to be drilled. These sensors are installed through boreholes, pre-embedded holes, or existing monitoring holes. The vibration sensors include acceleration and velocity sensors. They are either anchored, grouted, or embedded in the coal seam using a method that creates vibration coupling, or indirectly coupled to the coal seam through an external installation structure suspended from support components within the coal seam.

[0023] In a preferred embodiment, the vibration sensor is suspended from the anchor bolt already installed in the coal seam using an external mounting structure. The external mounting structure includes: the vibration sensor connected to the anchor bolt via a universal joint; both ends of the universal joint are respectively provided with a male and a female end for connecting the vibration sensor and the anchor bolt, and a threaded structure and a locking nut are used to achieve a secure connection, thereby ensuring reliable contact and mechanical coupling between the vibration sensor and the anchor bolt.

[0024] In some embodiments, the method further includes preprocessing the drilling vibration response signal to remove signals from unstable drilling stages, filter out mechanical background noise, and segment the drilling vibration response signal to obtain multiple vibration signal analysis units for stable drilling stages.

[0025] As a preferred implementation, the acquired drilling vibration signals are preprocessed. The preprocessing process includes, but is not limited to: removing invalid signals corresponding to unstable drilling conditions such as drilling rig start-up and shutdown, and idling; using filtering methods to eliminate low-frequency mechanical interference and high-frequency random noise; and using a sliding time window to segment the vibration signals to form multiple vibration signal analysis units.

[0026] It should be noted that existing vibration analysis while drilling mainly acquires equipment vibration signals through sensors installed on the drilling rig or drill pipe for lithology identification or drilling condition judgment, and the vibration information of the coal body is easily masked. In contrast, the vibration sensor in this application forms an effective coupling with the coal body through an embedded or external installation structure. The mechanical vibration generated by the drilling rig and drill pipe is significantly attenuated during propagation. The acquired vibration signal is mainly the dynamic response of the coal body and is not sensitive to the vibration of the drilling rig itself and external interference. It can be regarded as the intrinsic vibration response signal of the coal body, which can directly reflect the internal structural state, stress level and local damage degree of the coal body, and directly address the detection of coal impact hazard.

[0027] Step S102: Based on the vibration characteristics of the drilling vibration response signal, the physical and mechanical properties of the coal body are inverted to obtain the physical property characterization parameters of the coal body.

[0028] In this application, a physical and mechanical inversion model of coal is constructed based on vibration characteristics to characterize the physical and mechanical properties of coal and obtain coal property characterization parameters. Among them, vibration characteristics include vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics, and vibration non-stationarity or statistical characteristics. The coal property characterization parameters are used to reflect one or more of the following: coal hardness, brittleness, or the degree of influence of water content.

[0029] In some embodiments, within each vibration signal analysis unit (equivalent to a unit time window), characteristic parameters reflecting the physical and mechanical properties of the coal body are extracted from the drilling vibration response signal, including vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics, and vibration non-stationarity characteristics. Based on the vibration amplitude characteristics...A Vibrational energy characteristics E Vibration spectrum structural characteristics F and vibration nonstationary characteristics Construct a physical-mechanical inversion model for coal: (Formula 1) Obtain coal body physical property characterization parameters In the formula, It is a monotonic mapping function or a normalized mapping function.

[0030] In some embodiments, vibration amplitude characteristics include the average vibration amplitude, root mean square (RMS) value, and root square amplitude of the vibration response signal during drilling within a unit time window; vibration energy characteristics include the total energy value and the proportion of energy in the high-frequency band (e.g., above 500 Hz); vibration spectrum characteristics include the dominant frequency distribution, centroid frequency, spectral centroid, and spectral entropy; vibration non-stationarity characteristics include the kurtosis, skewness, and standard deviation of the amplitude within the sliding window.

[0031] As a preferred embodiment, Formula 1 above is applied, based on the average vibration amplitude of the drilling vibration response signal. Total Energy Center of gravity frequency and non-stationarity characteristics Construct a coal body property inversion model: (Formula 2) Determine the physical property characterization parameters of coal. In the formula, They are respectively , , and The weighting coefficients are determined through regression analysis or the analytic hierarchy process (AHP) of the experimental data. Among them, the average vibration amplitude... The primary response used to reflect rock hardness, total energy Used to reflect crushing power consumption, center of gravity frequency Used to reflect the particle size and stiffness of coal and rock, and its non-stationary characteristics. (For example, kurtosis) can effectively reflect the heterogeneous response caused by the development of internal fractures in coal bodies and can be used to correct the degree of fracture development.

[0032] Step S103: Based on the temporal evolution characteristics of the drilling vibration response signal, construct the coal body energy accumulation index and coal body state level variables.

[0033] In this application, the coal body energy accumulation index is constructed based on the variation characteristics of vibration energy per unit time or per unit drilling depth, and is used to characterize the stress concentration and energy accumulation state of the coal body. When the energy accumulation index continues to rise or shows a significant abrupt change, the coal body is determined to be in a state of high stress or energy concentration.

[0034] In this application, considering the significant differences in the response of coal to drilling disturbances under different stress states, especially under high stress or energy accumulation conditions, the vibration signal during drilling exhibits significant changes in energy level, spectral structure, and stability. The temporal evolution characteristics of the vibration signal during drilling are analyzed to extract the vibration energy, vibration energy change rate, and high-frequency energy proportion within a unit time window or unit drilling depth, thus constructing a coal energy accumulation index. This index characterizes the degree of energy response enhancement of the coal under drilling disturbances. When this index continuously increases or undergoes abrupt changes, it is determined that the coal exhibits a trend of stress concentration or enhanced energy accumulation.

[0035] In some embodiments, characteristic parameters of vibration energy variation with time or drilling depth are extracted, including a unit time window. Vibrational energy within Vibration energy change rate and the proportion of high-frequency energy And construct a coal body energy accumulation index : (Formula 3) In the formula, It is a monotonic mapping function or a normalized mapping function.

[0036] As a preferred embodiment, formula 3 above is expanded and applied according to the formula: (Formula 4) Extracting the vibration energy of the drilling vibration signal within the time window t With the rate of change of vibrational energy And statistically analyze the proportion of high-frequency energy. In the formula, For time window Total number of time points within, x i For time window Inner The amplitude value corresponding to the time. ε To prevent extremely small positive numbers with a denominator of zero.

[0037] Furthermore, according to the formula: (Formula 5) Constructing coal body energy storage index In the formula, , and They are respectively , and The normalized value, They are respectively , and The weighting coefficients.

[0038] Furthermore, based on the coal body energy accumulation index Vibration energy change rate and the proportion of high-frequency energy The coal body state is divided into three categories: stable stress state, stress accumulation state, and critical instability state, and state level variables are assigned accordingly. Among them, when At a low level and When there is no sustained growth, , indicating a stable stress state; when Continue to rise and When continuously positive, This indicates a state of stress accumulation; when Sudden mutations and high-frequency energy percentage When it rises significantly, , indicating a critical instability state.

[0039] Step S104: Based on the abrupt change characteristics, spectral anomaly characteristics, and abnormal change characteristics of drilling parameters of the drilling vibration response signal, set the abnormal event parameters.

[0040] In this application, considering that abnormal drilling dynamic phenomena such as coal blasting, drill bit suction, and stuck drill bit are important external manifestations of rapid local energy release or instability in the coal body, they can serve as important supplementary information for assessing impact hazard. By analyzing the abrupt change characteristics, spectral anomalies, and abnormal changes in drilling parameters of the vibration response signal during drilling, abnormal dynamic phenomena such as coal blasting, drill bit suction, and stuck drill bit during drilling are identified. When an abnormal dynamic event is identified, it is used as an auxiliary criterion for assessing the impact hazard of the coal body, and the corresponding abnormal event parameters are recorded. Compared to existing technologies, abnormal event parameters are no longer assigned values ​​solely through manual recording, but are determined jointly by vibration amplitude mutation indicators, spectrum anomaly indicators, and drilling parameter anomaly indicators.

[0041] In some embodiments, the vibration amplitude change rate, spectral centroid shift, sudden increase in the proportion of high-frequency energy, and abnormal deviation of drilling parameters such as drilling speed, propulsion pressure, or torque within adjacent time windows are first calculated to obtain the vibration amplitude mutation index. Spectrum anomaly indicators and abnormal indicators of drilling parameters Then, the above indicators are normalized and weighted according to preset weights to obtain the anomaly event identification strength. When the strength of abnormal event identification When the preset abnormal threshold is exceeded, an abnormal dynamic event such as coal blasting, drill bit suction, or drill bit jamming is determined, and the abnormal event trigger variable is set. Set to 1; conversely, when the anomaly detection strength does not exceed the preset anomaly threshold, the anomaly trigger variable will be set to 1. Set to 0.

[0042] As a preferred implementation, the abnormal event parameters are expanded from simple Boolean values ​​to a "two-layer structure," which includes both continuous abnormality intensity and trigger judgment: the first layer is the abnormal event identification intensity. Based on the normalized vibration amplitude abrupt change index Spectrum anomaly indicators and abnormal indicators of drilling parameters According to the formula: (Formula 6) Determine the strength of anomaly event identification In the formula, They are respectively , and Weighting coefficients; The second layer consists of variables that trigger abnormal events. Based on the strength of abnormal event identification Compared with the preset abnormal threshold The relationship, according to the formula: (Formula 7) Set exception event trigger variables .

[0043] Furthermore, the abnormal event parameters Defined as: (Formula 8) Therefore, when abnormal dynamic events such as coal blasting, drill bit suction, and drill bit jamming occur, the abnormal event parameters... Take the strength of abnormal event identification When no abnormal dynamic event is detected, the abnormal event parameters are... Take 0.

[0044] Step S105: Combining coal body physical property characterization parameters, coal body energy accumulation index, coal body state level variables, abnormal event parameters, and vibration stability characteristics of drilling vibration response signals, a coal body impact hazard evaluation model is constructed to output the coal body impact hazard index and its corresponding hazard level.

[0045] In some embodiments, the coal rock impact hazard assessment model is a multi-parameter fusion model. The model input parameters include coal physical property characterization parameters, energy accumulation index, state level variables, vibration stability characteristics, and abnormal event parameters. The model output is the coal rock impact hazard index and its corresponding hazard level. The hazard level is divided based on a preset hazard threshold range. The coal rock impact hazard index is used to characterize the degree of risk of coal rockburst disaster.

[0046] In some embodiments, exception event parameters A step enhancement or penalty term is introduced into the coal body impact hazard assessment model. When abnormal dynamic events such as coal blasting, drill bit suction, or drill bit jamming are detected, they have a nonlinear amplification effect on the impact hazard index, so as to reflect the dominant role of abnormal dynamic events in the identification of critical instability of coal body.

[0047] As a preferred implementation method, the coal seam impact hazard assessment model is as follows: (Formula 9) in, The coal seam impact hazard index; These are parameters for characterizing the physical properties of coal. As an indicator of energy accumulation in coal seams; Characteristics of vibration stability; For coal body state level variables; For abnormal event parameters; , , This is the normalized mapping function; These are the weighting coefficients; This represents the amplification factor for abnormal events.

[0048] As a preferred embodiment, according to Table 1 below, based on the impact hazard index The size of the coal seam impact hazard is used to classify the coal seam impact risk into different hazard levels. It also outputs the corresponding impact hazard assessment and treatment recommendations.

[0049] Table 1. Evaluation Table of Coal Body Impact Hazard Classification In some embodiments, to verify the accuracy of the coal seam impact hazard assessment model, historical samples from the mine site and synchronous monitoring data are used to calibrate and verify the model output results.

[0050] As a preferred implementation method, the drilling process is divided into several time windows or drilling depth intervals, and the coal seam impact hazard index is calculated for each interval. The model predicts the hazard level based on a preset threshold. Simultaneously, based on historical abnormal drill cuttings volume, coal blasting records, drill bit suction or stuck records, microseismic event energy and frequency, abnormal support pressure, abnormal roadway deformation, pressure relief measures implementation records, and historical impact hazard areas, the actual on-site hazard labels for the corresponding sections were determined. The model will predict the hazard level. Compared with the actual hazard labels on site The model predictions were compared to establish a consistency relationship between the model predictions and the actual hazards observed on-site. The model performance was evaluated using the confusion matrix, accuracy, recall, false positive rate, and false negative rate. Based on the evaluation results, the weight coefficients and hazard level thresholds in the model were adjusted to better adapt the model to specific mine site conditions.

[0051] Among them, the confusion matrix is ​​used to represent the correspondence between the actual hazard level and the hazard level predicted by the model; the accuracy is used to evaluate the overall correctness of the model's identification; the recall rate is used to evaluate the model's ability to identify actual hazard zones; the false alarm rate is used to evaluate the model's over-warning situation; and the false negative rate is used to evaluate the situation where the model fails to identify actual hazard zones.

[0052] In some embodiments, Figure 2 The process of processing the vibration response signal during drilling from its initial acquisition to parameter output is shown. This includes preprocessing the original vibration signal during drilling, extracting features of vibration amplitude, energy and spectrum, and calculating coal body physical parameters and energy accumulation index.

[0053] In some embodiments, Figure 3 The hierarchical structure of the coal impact hazard assessment model constructed in this application is shown. From bottom to top, the model includes a coal physical property inversion layer, a coal stress state identification layer, and an impact hazard assessment layer. Specifically, the coal physical property inversion layer is used to invert the physical and mechanical properties of the coal; the coal stress state identification layer is used to identify the stress state and energy accumulation characteristics of the coal; and the impact hazard assessment layer is used to fuse multi-source parameters to output the coal impact hazard assessment results.

[0054] It should be noted that any equivalent substitutions or modifications made to the arrangement of vibration sensors, signal processing methods, and evaluation model parameter forms without departing from the technical concept of this invention shall fall within the protection scope of this invention.

[0055] This invention, by fully exploiting the coal body's physical properties and stress state information contained in drilling vibration signals, establishes a method for detecting and evaluating coal body impact hazard in underground coal mines. This provides a new technical means for monitoring and early warning of coal mine rockburst disasters, and compared with existing technologies, it has the following beneficial effects: 1. By utilizing the coupling relationship between the coal body or the anchor bolt and the coal body, the vibration response information of the coal body under drilling disturbance can be directly obtained, which provides the basis for continuous monitoring of the impact risk of the coal body without adding construction procedures; 2. The use of an external anchor bolt vibration sensor installation structure eliminates the need for separate sensor mounting holes, improving project feasibility; 3. To achieve multi-dimensional coupled analysis of coal body properties, stress state and dynamic anomaly characteristics, and to characterize the coal body impact hazard from multiple perspectives of coal body properties, stress state and abnormal dynamic behavior; 4. Construct a coal impact hazard assessment model with a clear calculation structure to improve the stability and repeatability of the results; 5. Unlike drilling vibration analysis methods that aim at lithology identification or drilling condition judgment, this application focuses on the physical and mechanical properties, temporal evolution characteristics and abnormal dynamic response characteristics of the drilling vibration signal before critical instability. The evaluation results directly point to the risk of coal rock bursts, rather than lithology category or drilling parameter optimization. 6. Applicable to complex working conditions in underground coal mines, with good engineering applicability and promotional value.

[0056] This embodiment also provides a coal seam impact hazard detection system based on drilling vibration monitoring, such as... Figure 4 As shown, the system includes: Vibration signal acquisition and processing module 201 is used to acquire the drilling vibration response signal generated by the coal body during drilling through vibration sensors arranged inside the coal body to be drilled, and to preprocess the drilling vibration response signal. The coal body property inversion module 202 is used to invert the physical and mechanical properties of coal based on the vibration characteristic parameters of the vibration response signal while drilling, and obtain the coal body property characterization parameters. Among them, the vibration characteristics include vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics and vibration non-stationarity characteristics. The stress state identification module 203 is used to construct coal energy accumulation index and coal state level variables based on the temporal evolution characteristics of the drilling vibration response signal. The abnormal event identification module 204 is used to set abnormal event parameters based on the abrupt change characteristics, spectral abnormality characteristics, and abnormal change characteristics of drilling parameters of the vibration response signal while drilling. The impact hazard assessment module 205 is used to construct a coal impact hazard assessment model by combining coal physical property characterization parameters, coal energy accumulation index, coal state level variables, abnormal event parameters, and vibration stability characteristics of drilling vibration response signals, so as to output the coal impact hazard index and its corresponding hazard level.

[0057] It should be noted that the coal impact hazard detection system based on drilling vibration monitoring provided in this application can realize the steps and processes of the coal impact hazard detection method based on drilling vibration monitoring in any of the above embodiments, and achieve the same technical effect, which will not be repeated here.

[0058] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0059] 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.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for detecting coal seam impact hazard based on drilling vibration monitoring, characterized in that, The method includes: Vibration sensors are arranged inside the coal body to be drilled to collect the vibration response signals generated by the coal body during the drilling process. Based on the vibration characteristics of the vibration response signal while drilling, the physical and mechanical properties of the coal body are inverted to obtain the physical property characterization parameters of the coal body. Among them, the vibration characteristics include vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics, and vibration non-stationarity characteristics. Based on the temporal evolution characteristics of the vibration response signal during drilling, a coal body energy accumulation index and a coal body state level variable are constructed. Based on the abrupt change characteristics, spectral anomaly characteristics, and abnormal change characteristics of drilling parameters of the vibration response signal while drilling, abnormal event parameters are set. By combining coal body physical property characterization parameters, coal body energy accumulation index, coal body state level variables, abnormal event parameters, and vibration stability characteristics of drilling vibration response signals, a coal body impact hazard assessment model is constructed to output the coal body impact hazard index and its corresponding hazard level.

2. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 1, characterized in that, Vibration sensors are installed through drilled holes, pre-buried holes, or existing monitoring holes, and are coupled to the coal seam using embedded or external installation structures. Embedded installation structures include: anchoring and grouting. The external installation structure includes: a vibration sensor suspended on an existing anchor rod in the coal seam and connected to the anchor rod via a universal connector. The universal connector has a male and a female end, respectively. The male end is fastened to the vibration sensor via a threaded structure and a locking nut, and the female end is fastened to the anchor rod via a threaded structure and a locking nut.

3. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 1, characterized in that, The method further includes: Invalid signals corresponding to unstable drilling conditions are removed from the vibration response signals while drilling. Unstable drilling conditions include drilling rig start-up, drilling rig stop-up, and drilling rig idling. The remaining effective drilling vibration response signal is filtered to eliminate low-frequency mechanical interference and high-frequency random noise. A sliding time window is used to segment the filtered effective drilling vibration response signal to form multiple vibration signal analysis units.

4. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 1, characterized in that, Based on the average vibration amplitude of the drilling vibration response signal Total Energy Center of gravity frequency and nonstationarity characteristics Construct a coal body property inversion model: Determine the physical property characterization parameters of coal. In the formula, They are respectively , , and The weighting coefficients.

5. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 1, characterized in that, According to the formula: Extracting the vibration energy of the drilling vibration signal within the time window t With the rate of change of vibrational energy And statistically analyze the proportion of high-frequency energy. In the formula, For time window Total number of time points within, x i For time window Inner The amplitude value corresponding to the time. ε To prevent extremely small positive numbers with a denominator of zero; According to the formula: Constructing coal body energy storage index In the formula, , and They are respectively , and The normalized value, They are respectively , and Weighting coefficients; Based on the coal body energy accumulation index, vibration energy change rate, and high-frequency energy proportion, the stress state of the coal body is identified and its corresponding state level variables are determined. Among them, the stress state of coal includes a stable stress state, a stress accumulation state, and a critical instability state. The stable stress state corresponds to... A value of 0 corresponds to the stress accumulation state. A value of 1 corresponds to the critical instability state. The value is 2.

6. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 1, characterized in that, The settings for exception event parameters include: Based on the vibration amplitude mutation index of the drilling vibration response signal Spectrum anomaly indicators and abnormal indicators of drilling parameters According to the formula: Determine the strength of anomaly event identification In the formula, They are respectively , and Weighting coefficients; Based on the strength of abnormal event identification Compared with the preset abnormal threshold The relationship, according to the formula: Set exception event trigger variables ; According to the formula Determine the parameters of the abnormal event. .

7. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 1, characterized in that, The coal seam impact hazard assessment model is a multi-parameter fusion model, in which, The input parameters of the coal impact hazard assessment model include coal physical property characterization parameters, energy accumulation index, state level variables, vibration stability characteristics and abnormal event parameters. Among them, the abnormal event parameters are introduced into the coal impact hazard assessment model in the form of nonlinear enhancement terms. The output of the coal impact hazard assessment model is the coal impact hazard index and its corresponding hazard level, where the hazard level is divided based on a preset hazard level threshold range.

8. The method for detecting coal seam impact hazard based on drilling vibration monitoring according to claim 7, characterized in that, The coal seam impact hazard assessment model is as follows: In the formula, The coal seam impact hazard index. These are the physical properties of the coal. As an indicator of energy accumulation in coal seams, For vibration stability characteristics, For coal body condition level variables, For abnormal event parameters, This represents the amplification factor for abnormal events. , , The normalized mapping functions are respectively. They are respectively , , and The weighting coefficients.

9. A coal seam impact hazard detection system based on drilling vibration monitoring, characterized in that, The system includes: The vibration signal acquisition and processing module is used to acquire the drilling vibration response signal generated by the coal body during the drilling process through vibration sensors arranged inside the coal body to be drilled. The coal body property inversion module is used to invert the physical and mechanical properties of the coal body based on the vibration characteristics of the vibration response signal while drilling, and obtain the coal body property characterization parameters. Among them, the vibration characteristics include vibration amplitude characteristics, vibration energy characteristics, vibration spectrum structure characteristics, and vibration non-stationarity characteristics. The stress state identification module is used to construct coal energy accumulation index and coal state level variable based on the temporal evolution characteristics of the drilling vibration response signal. An abnormal event identification module is used to set abnormal event parameters based on the abrupt change characteristics, spectral abnormality characteristics, and abnormal change characteristics of drilling parameters of the vibration response signal while drilling. The impact hazard assessment module is used to construct a coal impact hazard assessment model by combining coal physical property characterization parameters, coal energy accumulation index, coal state level variables, abnormal event parameters, and vibration stability characteristics of drilling vibration response signals, so as to output the coal impact hazard index and its corresponding hazard level.

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