Method and system for monitoring rock burst in ultra-thin coal seams

Abstract

A method for monitoring a rock burst in ultra-thin coal seams, which method belongs to the technical field of fully mechanized coal mining in ultra-thin coal seams. The method comprises: respectively recording the acquired propagation times and propagation velocities of attenuated seismic waves from artificial seismic sources and the acquired propagation time and propagation velocity of a rock burst, and comparing different seismic wave signals and real-time rock burst signals passing through a mining area; converting the different seismic wave signals and the real-time rock burst signals into digital signals, and determining via comparison whether the digital signals have waveforms during the rock burst; when the digital signals have waveforms during the rock burst, identifying the waveforms of micro-seismic events, and determining the energy intensity of the rock burst; locating rock burst sources, and obtaining an intersection area of the rock burst sources, so as to obtain a seismic source position after a delineated range is reduced; and on the basis of acquired real-time pressure data in underground rock or coal seams, obtaining the positions of the maximum pressure and maximum pressure changes of a seismic source, and the numerical values thereof by means of analyzing a real-time pressure value and a real-time strain change rate. By means of the method, potential hazardous areas can be monitored. The present invention further relates to a system for monitoring a rock burst in ultra-thin coal seams.

Description

[0056] S3: Convert the arrival times, amplitudes, and frequencies of different seismic wave signals and real-time rockburst signals into digital signals. Compare the waveforms of these digital signals with those present during rockbursts. When waveforms indicative of rockbursts are detected in the digital signals, identify microseismic event waveforms. Determine the rockburst energy intensity by analyzing the amplification or attenuation of amplitudes within the waveforms.

[0057] S4: Utilize the time difference and propagation velocity of seismic waves to locate the rockburst pressure source. Identify the intersection area of pressure sources to obtain the source location within the narrowed delineation range.

[0058] S5: Based on real-time pressure data from underground rock or coal strata, derive real-time pressure values and strain rate changes. Using these real-time pressure values and strain rate changes, determine the location and numerical values of the maximum pressure point and maximum pressure change point at the source.

[0059] This also includes determining a series of threshold values for relevant indicators at the mining point based on the energy intensity of the rockburst, the location of maximum pressure and maximum pressure variation, and the position of the rockburst source, while referencing historical data.

[0060] By analyzing the location information of the rockburst source and its corresponding energy intensity, the energy intensity value upon propagation to the mining location is calculated. This value is then compared against a preset threshold to determine whether it exceeds the threshold.

[0061] The difference between this energy intensity value and the set threshold is used as the basis for establishing first, second, and third-level warning signals. The hazard level of mining operations is determined according to the warning signal level.

[0062] The warning signal level is determined based on a series of thresholds for relevant indicators at the mining point.

[0063] In step S1, the acquisition of rockburst data includes the following steps:

[0064] Based on the surface area of the mining zone, divide the entire mining zone into multiple rectangular regions by determining the center point of the entire mining zone and then identifying the center points of each rectangular region.

[0065] Based on the center points within each rectangular area, determine the deployment locations for seismic wave transmitters.

[0066] By detecting seismic waves generated by artificial sources on the surface and subsequently attenuated, and when no artificial sources are active on the surface, conduct real-time passive monitoring of rockburst phenomena caused by underground microseismic activity.

[0067] In step S3, the energy intensity of rockburst is determined, including the following steps:

[0068] Based on the amplitude of seismic waves, the energy of the rockburst is determined. Since the amplitude of seismic waves is proportional to seismic energy, the rockburst energy is calculated.

[0069] By comparing the different segments of artificial seismic wave signals and real-time rockburst signals monitored by monitoring devices deployed at various locations within the mining area, the different amplitudes, frequency variations, and energy magnitudes are recorded to obtain the rockburst energy intensity.

[0070] In step S4, locating the source of rockburst pressure involves the following steps:

[0071] By comparing the decayed seismic waves emitted from artificial sources throughout the mining area, utilizing the propagation velocity differences between decayed seismic waves from various artificial sources and the propagation time differences between the decayed seismic waves' transverse and longitudinal waves from the same artificial source, the spatial location of extremely thin coal seams with high stress concentration is preliminarily delineated, thereby preliminarily delineating the spatial location of the seismic source.

[0072] Based on the spatial location of the source, the time of occurrence is determined through spatio-temporal backtracking.

[0073] Among these, preliminary delineation of spatially concentrated high-stress zones within extremely thin coal seams was conducted, specifically including:

[0074] When seismic waves emitted from surface seismic stations propagate and encounter rockbursts, the transverse waveform of artificial seismic waves undergoes instantaneous disturbance, exhibiting varying degrees of waveform alteration. When propagating through macroscopic disturbances such as fractures, cavities, or faults, the energy of the artificial seismic wave's P-wave component undergoes instantaneous attenuation, manifesting as a sudden reduction in amplitude and waveform gaps.

[0075] When encountering no rockburst, the transmission of artificial seismic waves from the surface to the subsurface involves energy attenuation, manifested as a reduction in waveform amplitude. However, this reduction occurs uniformly without abrupt changes.

[0076] Upon encountering a compressed coal seam, the P-wave form of artificial seismic waves exhibits increased density, sparsity, and amplitude, with the increase in density being more pronounced. P-wave velocity increases, becoming more significant in stress concentration zones.

[0077] To determine the source location after narrowing the search area, the following steps are performed:

[0078] Based on seismic wave propagation time and velocity, locate the source using the time-difference positioning method. Using multiple monitoring devices deployed on the map as reference points, plot time-difference curves for each group of three monitoring devices. These curves are generated from the time differences and propagation velocities of seismic wave signals and rockburst signals after attenuation from different artificial sources. Identify the three intersection points on the reverse time difference curves derived from the same artificial source's attenuated seismic waves and rockburst signals. Enclose these three points to determine one rockburst source location.

[0079] Similarly, all deployed monitoring devices are grouped into sets of three. By analyzing and processing seismic wave signals and rockburst signals from different artificial sources after attenuation, multiple rockburst source locations are identified.

[0080] The intersection of these multiple rockburst source locations defines the refined source location after narrowing the delineation area.

[0081] In step S5, the location and numerical value of the maximum pressure and maximum pressure change at the seismic source are obtained, including the following steps:

[0082] Based on real-time pressure data from underground rock or coal strata, realtime pressure data and real-time strain data are obtained through sensor monitoring. The data is sequentially processed, stored, and analyzed to derive real-time pressure values and stress change rates.

[0083] Using the real-time pressure values and stress change rates obtained through data analysis and processing, the location and numerical value of the maximum pressure point and the maximum pressure change point of the seismic source are determined.

[0084] Based on this monitoring method, the present application further proposes an impact ground pressure monitoring system for extremely thin coal seams, comprising:

[0085] A data acquisition unit, including seismic wave transmission devices, underground seismic wave reception devices, and sensors, wherein:

[0086] Seismic wave transmission devices are uniformly deployed at the center points of each block within the surface coal seam overburden area of the delineated extremely thin coal seam, for transmitting artificial seismic sources from the surface to the subsurface.

[0087] Underground seismic wave receivers, uniformly deployed in the surface coal seam overburden areas or roadways of the subdivided ultra-thin coal seam, detect seismic waves generated by the attenuation of artificially emitted seismic sources from the surface. They also perform real-time passive monitoring of rockburst events caused by underground microseismic activity when no artificial seismic sources are emitted from the surface.

[0088] Sensors, installed on the roof surface of hydraulic supports and in roadways, monitor real-time pressure variation data within underground rock or coal seams.

[0089] Seismic Wave Signal Acquisition Unit: Used to separately record the propagation time and velocity of seismic waves from artificial sources after attenuation and of rockburst waves, and to compare different seismic wave signals and real-time rockburst signals passing through the mining area.

[0090] Rockburst Energy Intensity Acquisition Unit: Used to convert the arrival time, amplitude, and frequency of different seismic wave signals and real-time rockburst signals into digital signals.

[0091] Ground Central Monitoring Station: Analyzes and processes digital signals by comparing seismic waveforms from artificial sources with real-time pressure variation data to identify the presence of rockburst events. When digital signals exhibit rockburst waveforms, it identifies microseismic event waveforms and determines rockburst energy intensity by analyzing amplitude enhancements or reductions within these waveforms. It also locates rockburst pressure sources using seismic wave time differences and propagation velocities. The intersection area of the rockburst pressure sources is identified to narrow down the location of the seismic source. It also analyzes stored pressure data based on real-time pressure changes in underground rock or coal seams to obtain real-time pressure values and real-time strain rate changes. Based on these real-time pressure values and strain rate changes, it determines the location and numerical values of the real-time maximum pressure point and the point of maximum pressure change.

[0092] The seismic wave emitter, including a seismic source generator / vibration vehicle, generates high-frequency seismic waves. These waves propagate through rock strata at speeds of 3-4 km / s for shear waves and 5-7 km / s for compressional waves. The propagation time from the surface to the underground coal seam is instantaneous.

[0093] The underground seismic wave receiving device comprises seismometers and seismometers, serving as the core components of this monitoring system.

[0094] Sensors include pressure sensors and strain sensors, used to detect underground pressure changes caused by earthquakes, underground explosions, or other subterranean activities. They also monitor underground stress conditions and subsurface activity.

[0095] The rockburst energy intensity acquisition unit receives and preliminarily processes signals collected by sensors, generating analog signals. These analog signals are converted into digital signals for initial data filtering and amplification.

[0096] Communication equipment, including 5G, radio, Wi-Fi, or satellite, transmits processed data from the acquisition unit to the surface central monitoring station.

[0097] The surface central monitoring station is equipped with computers and storage devices. It processes and interprets microseismic data using specialized data analysis software to determine locations of high stress concentration and maximum stress variation, as well as the spatial location and occurrence time of seismic sources.

[0098] The monitoring method and system proposed herein enable precise detection of all potential hazardous zones.

[0099] Implementation Example

[0100] An embodiment of the present invention provides a method for monitoring rockbursts in ultra-thin coal seams based on a multi-parameter model, comprising the following steps:

[0101] As shown in Figure 2, deploy ground seismic wave transmission stations according to the ground seismic wave transmission station layout. By defining the ground area of the mining zone, locate the center point of Mining Zone 1. Within Mining Zone 2, identify a small rectangle 1, and find the center point within this rectangle, which is Mining Zone 3. Proceed similarly to locate center points at other positions, such as the points shown in Mining Zone 4. Deploy seismic wave transmission stations at each of these center points.

[0102] Ground seismic wave transmitters intermittently emit seismic waves underground, covering the entire mining area. Underground seismic wave receivers (microseismic monitoring devices) capture the attenuated artificial seismic waves. The subsurface data acquisition unit records the arrival time, amplitude, frequency, and other parameters of the artificial seismic waves. It performs differential amplification, filtering, and other signal processing, converting the waveforms into digital signals. These digital signals are transmitted via 5G communication to the surface central processing station. Specialized software analyzes and processes the digital signals, including digital filtering, waveform analysis, frequency domain analysis, time domain analysis, and more, to understand the characteristics and information contained within the signals.

[0103] As shown in Figures 3 and 4, these diagrams illustrate the changes in artificial seismic waves before and after encountering high stress concentrations. When seismic waves emitted from ground seismic stations encounter rockbursts during propagation, the transverse waveform of the artificial seismic wave undergoes instantaneous disturbance. The waveform may exhibit varying degrees of alteration, including irregularities, sudden amplitude increases, and chaotic signals potentially indicating energy release. If propagation encounters macroscopic disruptions such as fractures, voids, or faults, the energy of the seismic wave's transverse component will instantly decay, manifesting as abrupt amplitude reduction, waveform gaps, and similar phenomena. When encountering coal seams under compression, both the dense and sparse phases of the P-wave amplitude increase, with the dense phase exhibiting a more pronounced rise. P-wave velocity also increases, particularly within stress concentration zones.

[0104] By comparing the attenuation of seismic waves from artificial sources across the entire mining area, we utilize the differences in propagation velocity between these waves and the time difference between the arrival of P-waves and S-waves from the same source. This allows for the preliminary delineation of spatially concentrated high-stress zones within extremely thin coal seams and the initial spatial localization of seismic sources. Subsequently, based on the approximate source location, spatiotemporal backtracking determines the approximate time of source occurrence. That is, the active monitoring system enables the spatial location of the source to be roughly delineated, the time of source occurrence to be preliminarily estimated, and the high-stress concentration zones within extremely thin coal seams to be preliminarily delineated.

[0105] Microseismic monitoring devices are deployed in roadways or coal seam working faces. These devices are identical to the seismic wave receivers in the active monitoring system. During intermittent ground-based artificial seismic wave generation, microseismic monitors primarily conduct intermittent active monitoring of the propagated signals underground. Collected data is transmitted to the surface central processing station for analysis and processing. When no artificial seismic waves are being emitted from the surface, the underground microseismic monitoring devices perform real-time passive monitoring of rockbursts. The collected data is transmitted to the surface central processing station for analysis and processing.

[0106] Due to the tendency of rockbursts in extremely thin coal seams to fluctuate, and the low elastic energy of thin seams, the microseismic energy they generate is smaller than that of thick seams. However, microseismic signal variations occur more frequently than in thick seams, resulting in a higher microseismic frequency than in ordinary coal seams. Therefore, microseismic monitoring focuses on detecting minute vibrations. This necessitates the use of underground microseismic monitoring devices for real-time passive monitoring of rockbursts, enabling precise spatial localization of the source, timing of occurrence, and vibration energy.

[0107] Microseismic events triggered by rockbursts resemble artificial seismic waves, and the analytical and processing methods employed are largely similar. The key difference lies in timing: artificial seismic waves are not generated in real time but are intermittently produced by seismic sources or vibration vehicles. In contrast, microseismic events triggered by rockbursts occur continuously in real time, with vibrations present at all times—even if extremely subtle. Additionally, duration differs significantly: artificial seismic waves are brief, whereas rockburst seismic waves can generate prolonged microseismic activity due to continuous or repeated rockburst events. Waveform characteristics also differ: artificial seismic waves exhibit controllable, relatively regular waveforms, whereas rockburst-induced seismic waves feature complex waveforms including sudden high-energy spikes and irregular amplitude variations. The artificial seismic wave stations deployed in this application cover the entire mining area, enabling broad-scale monitoring, whereas seismic waves from rockbursts are only detectable in specific locations like working faces and roadways, limiting their monitoring range.

[0108] Real-time monitoring of rockbursts is conducted using underground microseismic monitoring devices, capturing a series of microseismic signals triggered by rockbursts. The underground data acquisition unit collects the following: arrival times of natural seismic waves, recording the arrival times of both P-waves and S-waves at each sensor. The amplitude and frequency of natural seismic wave vibrations. The waveform characteristics of each natural seismic wave segment, including duration, periodicity, etc., to estimate microseismic event energy release and local magnitude. The rockburst energy intensity acquisition unit performs preliminary processing on this data—applying basic filtering, feature extraction, etc.—and converts it into digital signals. These signals are transmitted via 5G communication to the surface central processing station, where specialized software analyzes and processes the data.

[0109] Comparing various microseismic events, analyze and process the data according to the following steps, as shown in the method flowchart for each subsystem in Figure 5.

[0110] Data Preprocessing: Clean and preprocess the collected microseismic data to remove noise and interference signals. Then perform digital filtering, differential amplification, baseline adjustment, etc., to ensure data quality.

[0111] Waveform Analysis: Identify and analyze microseismic event waveforms, including amplitude, frequency, wave velocity, duration, and determine arrival times of different seismic wave types.

[0112] Event Location: Determine the spatial location of the source based on propagation time differences, then derive the event occurrence time.

[0113] Microseismic Characteristic Analysis: Estimate the energy and local magnitude of the microseismic event.

[0114] Using these processing and analysis methods, the seismic source location is spatially re-positioned, and the occurrence time period is recorded.

[0115] Stress sensors measure stress in real-time at deployment locations. Seismic wave signal acquisition units collect stress data—including stress values and corresponding timestamps—which are transmitted via 5G communication to a groundbased central processing station. The data undergoes necessary processing before analysis to identify stress variation patterns and trends.

[0116] Compare stress values and analyze processed data following these steps:

[0117] Process the collected data, including filtering, noise reduction, and calibration. Analyze specific stress values to determine stress distribution across regions. Derive stress change rates based on the time corresponding to each stress value. Through these processing and analysis steps, identify high stress concentration zones beneath extremely thin coal seams, locations with maximum stress variation, and areas exhibiting continuous stress value changes.

[0118] Combine surface monitoring of rockbursts in extremely thin underground coal seams with underground monitoring of rockbursts. Integrate surface monitoring of high-stress concentration locations with underground monitoring of high-stress concentration locations.

[0119] The active monitoring system provides a rough spatial delineation of the source location and a preliminary estimate of the occurrence time. The passive monitoring system offers precise spatial positioning of the source location and the recorded time interval of occurrence. Integrating information from both systems yields a more accurate spatial location of the source and the time interval of microseismic events. The active monitoring system initially delineates high-stress concentration zones within the ultra-thin coal seam.

[0120] The stress monitoring system identifies high stress concentration points beneath the ultra-thin coal seam and locations of maximum stress variation. Integrating data from both systems yields more precise high stress concentration points, locations of maximum stress variation, and areas of continuous stress value changes.

[0121] This monitoring method, tailored to the characteristics of ultra-thin coal seams, reduces the need for underground equipment deployment. It enhances overall system sensitivity by integrating surface-to-underground and underground-to-underground monitoring approaches.

[0122] Based on this monitoring method, the present application also provides a rockburst monitoring system for ultra-thin coal seams utilizing a multi-parameter model.

[0123] The layout of the seismic wave transmission device for this system is shown in Figure 2, with all monitoring stations interconnected. Multiple sets of seismic wave reception devices (microseismic monitoring devices) are deployed underground. Multiple sets of high-precision rock pressure sensors are installed on the roof surface of hydraulic supports and along roadways. Data acquisition units are deployed at the coal mining face, transmitting data to the surface via 5G communication cables. A central monitoring station is established on the surface to process the received data, wherein:

[0124] Seismic wave emitters generate artificial seismic sources using seismic generators or vibrating vehicles, producing high-frequency seismic waves transmitted from surface to subsurface. Seismic wave propagation speeds in rock strata reach 3-4 km / s for shear waves and 5-7 km / s for P-waves, enabling near-instantaneous transmission from surface to subsurface coal seams.

[0125] Seismic wave receiving apparatus (microseismic monitoring device), consisting of seismometers and seismometers, forms the core of the system for detecting shock waves generated by both artificial surface emissions and underground microseismic activity. These sensors are typically highly sensitive, capable of capturing minute seismic fluctuations.

[0126] High-precision pressure sensors measure pressure variations within underground rock formations or coal seams. These sensors detect subsurface pressure changes caused by earthquakes, underground explosions, or other subterranean activities, enabling monitoring of underground stress conditions and subsurface activity. They may include pressure sensors, strain sensors, or similar devices.

[0127] The rockburst energy intensity acquisition unit receives and performs preliminary processing of signals collected by sensors. It converts analog signals into digital format and conducts initial data filtering and amplification.

[0128] Communication equipment is used to transmit data processed by the rockburst energy intensity acquisition unit to the central monitoring station via wired (e.g., 5G communication) or wireless (e.g., radio, Wi-Fi, or satellite) communication systems.

[0129] Surface Central Monitoring Station: At the central monitoring station, received data undergoes further analysis and storage via specialized analysis and processing software. Typically equipped with high-performance computers and large-capacity storage devices, it handles and records extensive datasets.

[0130] Analysis and Processing Software: Professional software for data analysis, capable of processing and interpreting microseismic data. This includes determining the location, magnitude, timing, and potential causes of seismic events.

[0131] To further clarify the functions and relationships among the subsystems, this application correlates them as shown in Figure 5, which depicts the method flowcharts for the passive monitoring system, active monitoring system, and stress monitoring system. Specifically:

[0132] The passive monitoring system comprises: Underground seismic wave receivers (microseismic monitoring devices); Data acquisition units- Communication equipment (data transmission devices); - Ground-based central monitoring stations (data storage / analysis equipment and terminal software).

[0133] The active monitoring system comprises seismic wave transmission instruments, underground seismic wave receivers (microseismic monitoring devices), data acquisition units, communication equipment (data transmission devices), and a surface central monitoring station (data storage / analysis equipment and terminal software).

[0134] The stress monitoring system consists of multiple sets of high-precision pressure sensors, data acquisition units, communication equipment (data transmission devices), and a surface central monitoring station (data processing / analysis equipment).

[0135] The active and passive monitoring systems share the same microseismic monitoring device, data acquisition unit, and terminal processing software, but utilize distinct data transmission equipment and data storage units.

[0136] The stress monitoring system operates independently from the active and passive monitoring systems, employing separate equipment for pressure sensors, data acquisition units, data transmission devices, and data processing / analysis equipment.

[0137] This monitoring method and system overcomes the technical limitations imposed by extremely thin coal seams, which previously prevented comprehensive and high-frequency monitoring, ensuring coverage of all potential hazard zones. By analyzing the amplification or attenuation of waveform amplitudes and comparing recorded seismic signals passing through the mining area with real-time rockburst signals, the system identifies the locations of maximum pressure and maximum pressure change in seismic waveforms generated by both artificially damped seismic waves and underground microseismic activity. This compensates for monitoring deficiencies when no artificial seismic waves are emitted at the surface, enabling more comprehensive localization of the spatial position, occurrence time, and vibrational energy of the seismic source. Based on real-time pressure variation data from underground rock or coal strata, the system identifies the point of maximum real-time pressure change and the location of maximum pressure variation. Furthermore, by intersecting the waveform's maximum pressure position and maximum pressure variation point with the real-time maximum pressure change point and maximum pressure variation location, it determines the maximum pressure position and maximum pressure variation point of the consolidated hazard zone. This narrows the monitoring scope for the hazard zone, thereby enhancing monitoring accuracy.

[0138] The foregoing description pertains only to preferred embodiments of the present invention. However, the scope of protection of the invention is not limited thereto. Any technical personnel familiar with the art field should understand that any equivalent substitution or modification made within the technical scope disclosed herein, based on the technical solutions and inventive concepts of the present invention, should be encompassed within the scope of protection of the invention.

[0139] Furthermore, unless otherwise stated, all technical and scientific terms used herein shall have the same meanings as commonly understood by those skilled in the art to which the invention pertains. All references cited herein are incorporated by reference to disclose and describe the methods related to said references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

Claims

1. A method for monitoring a rockburst of an ultra-thin coal seam, comprising the following steps:acquiring seismic waves attenuated by artificial seismic sources, a rockburst, and real-time pressure data in an underground rock or coal seam;recording propagation time and propagation speeds of the seismic waves attenuated by the artificial seismic sources and propagation time and a propagation speed of the rockburst, and comparing different seismic wave signals and different realtime rockburst signals in a mining area;converting time of arrival, amplitudes, and frequencies of the different seismic wave signals and the different real-time rockburst signals into a digital signal, and comparing waveforms of the digital signal in presence of the rockburst and in absence of the rockburst; and in the presence of the rockburst, identifying a waveform of a microseismic event, and determining an energy intensity of the rockburst by analyzing enhancement or weakening of an amplitude in the waveform of the microseismic event;locating rockburst sources with time differences and the propagation speeds of the seismic waves, and taking an intersection area for the rockburst sources to obtain a position of a seismic source with a narrowed delineated range;obtaining real-time pressure values and real-time strain rates according to the realtime pressure data in the underground rock or coal seam; and according to the real-time pressure values and the real-time strain rates, obtaining a maximum pressure position and a maximum pressure change position of the seismic source as well as a value at the maximum pressure position and a value at the maximum pressure change position;according to the energy intensity of the rockburst, the maximum pressure position, the maximum pressure change position, and positional information of the rockburst sources, and with reference to historical data, obtaining a series of thresholds for indicators related to a mining point;calculating, by analyzing the positional information of the rockburst sources and the energy intensity of the rockburst, an energy intensity value after the rockburst is propagated to a mining position; and comparing the energy intensity value with a presetthreshold to determine whether the energy intensity value exceeds the preset threshold;based on a difference between the energy intensity value and the preset threshold, setting a first-level warning signal, a second-level warning signal, and a third-level warning signal; and according to a level of a warning signal, determining a degree of danger in mining, whereinthe level of the warning signal is determined according to the series of thresholds for the indicators related to the mining point;the acquiring a rockburst comprises:determining a center point of the mining area according to a ground range of the mining area, equally dividing the mining area into multiple rectangular areas, and determining center points of the multiple rectangular areas;determining arrangement positions of seismic wave emitting devices according to the center points of the multiple rectangular areas; anddetecting the seismic waves attenuated by the artificial seismic sources that are artificially emitted on the ground, and when the artificial seismic sources are not emitted on the ground, performing real-time passive monitoring on the rockburst generated by an underground microseismic activity;the locating rockburst sources comprises:comparing the seismic waves attenuated by the artificial seismic sources emitted in the mining area, and with a difference between the propagation speeds of the seismic waves attenuated by the artificial seismic sources, and a difference between propagation time of a transverse wave and a longitudinal wave in each of seismic waves attenuated by a same one of the artificial seismic sources, preliminarily delineating a highly stress-concentrated spatial position of an ultra-thin coal seam, and preliminarily delineating a spatial position of the seismic source; anddetermining occurrence time of the seismic source through spatiotemporal retrospection according to the spatial position of the seismic source;the preliminarily delineating a highly stress-concentrated spatial position of an ultrathin coal seam specifically comprises:when each of the seismic waves emitted by the seismic wave emitting devices on the ground encounters the rockburst during propagation, determining that a waveform of a transverse wave of the seismic wave is disturbed instantaneously and changes in different degrees, wherein in case of macroscopic damage comprising a crack, a cavity and a fault, energy of the transverse wave of the seismic wave is attenuated instantaneously, specifically, an amplitude decreases instantaneously, and a gap appears in the waveform;when the seismic wave does not encounter the rockburst, determining that the seismic wave experiences energy attenuation during the propagation from the ground to the underground, specifically, an amplitude of a waveform decreases uniformly without an abrupt change;when the seismic wave encounters a squeezed coal seam, determining that a compression, a rarefaction, and an amplitude of a waveform of a longitudinal wave of the seismic wave increase, the compression increases more evidently, and a speed of the longitudinal wave increases and increases more evidently in a stress concentration area; andthe obtaining a position of a seismic source with a narrowed delineated range comprises:according to the propagation time and the propagation speeds of the seismic waves, performing locating through a time difference of arrival (TDOA) method; based on multiple monitoring devices on a map, according to seismic wave signals attenuated by different artificial seismic sources and rockburst signals, drawing a TDOA curve with time differences and the propagation speeds of the seismic waves; and dividing three monitoring devices in the multiple monitoring devices into one group, finding three intersections on a TDOA curve drawn for seismic wave signals attenuated by a same artificial seismic source and rockburst signals, and delineating the three intersections to obtain a position of one rockburst source;similarly, grouping the multiple monitoring devices, and analyzing the seismic wave signals attenuated by the different artificial seismic sources and the seismic wave signals to obtain positions of multiple rockburst sources; andtaking the intersection area between the positions of the multiple rockburst sources as the position of the seismic source with the narrowed delineated range.

2. The method for monitoring a rockburst of an ultra-thin coal seam according to claim 1, wherein the determining an energy intensity of the rockburst comprises:determining energy of the rockburst according to amplitudes of the seismic waves, wherein the amplitudes of the seismic waves are directly proportional to the energy of the rockburst, thereby calculating the energy of the rockburst; andcomparing different intermittent artificial seismic wave signals and different real-time rockburst signals monitored by the multiple monitoring devices arranged at different positions in the mining area, and recording different amplitudes, different change frequencies, and different energy to obtain the energy intensity of the rockburst.

3. The method for monitoring a rockburst of an ultra-thin coal seam according to claim 2, wherein the obtaining a maximum pressure position and a maximum pressure change position of the seismic source as well as a value at the maximum pressure position and a value at the maximum pressure change position comprises:obtaining real-time pressure data and real-time strain data through sensor monitoring according to the real-time pressure data in the underground rock or coal seam, and sequentially performing processing, storage, and analysis on the real-time pressure data and the real-time strain data to obtain the real-time pressure values and the real-time strain rates; andaccording to the real-time pressure values and the real-time strain rates, obtaining the maximum pressure position and the maximum pressure change position of the seismic source as well as the value at the maximum pressure position and the value at the maximum pressure change position.

4. A system for monitoring a rockburst of an ultra-thin coal seam, comprising:a data acquisition unit configured to acquire seismic waves attenuated by artificial seismic sources, a rockburst, and real-time pressure data in an underground rock or coal seam;a seismic wave signal acquisition unit configured to record propagation time and propagation speeds of the seismic waves attenuated by the artificial seismic sources and propagation time and a propagation speed of the rockburst, and compare different seismic wave signals and different real-time rockburst signals in a mining area;a rockburst energy intensity acquisition unit configured to convert time of arrival, amplitudes, and frequencies of the different seismic wave signals and the different realtime rockburst signals into a digital signal, and compare waveforms of the digital signal in presence of the rockburst and in absence of the rockburst; and in the presence of the rockburst, identify a waveform of a microseismic event, and determine an energy intensity of the rockburst by analyzing enhancement or weakening of an amplitude in the waveform;a seismic source position determination unit configured to locate rockburst sources with time differences and the propagation speeds of the seismic waves, and take an intersection area for the rockburst sources to obtain a position of a seismic source with a narrowed delineated range;a stress-concentrated position acquisition unit configured to obtain real-time pressure values and real-time strain rates according to the real-time pressure data in the underground rock or coal seam; and obtain, according to the real-time pressure values and the real-time strain rates, a maximum pressure position and a maximum pressure change position of the seismic source as well as a value at the maximum pressure position and a value at the maximum pressure change position; anda signal warning unit configured to obtain, according to the energy intensity of the rockburst, the maximum pressure position, the maximum pressure change position, and positional information of the rockburst sources, and with reference to historical data, a series of thresholds for indicators related to a mining point; calculate, by analyzing the positional information of the rockburst sources and the energy intensity of the rockburst, an energy intensity value after the rockburst is propagated to a mining position; and compare the energy intensity value with a preset threshold to determine whether the energy intensity value exceeds the preset threshold; set, based on a difference between the energy intensity value and the preset threshold, a first-level warning signal, a second-level warning signal, and a third-level warning signal; and determine, according to a level of a warning signal, a degree of danger in mining, wherein the level of the warning signal is determined according to the series of thresholds for the indicatorsrelated to the mining point;the data acquisition unit is configured to acquire the rockburst by: determining a center point of the mining area according to a ground range of the mining area, equally dividing the mining area into multiple rectangular areas, and determining center points of the multiple rectangular areas; determining arrangement positions of seismic wave emitting devices according to the center points of the multiple rectangular areas; and detecting the seismic waves attenuated by the artificial seismic sources that are artificially emitted on the ground, and when the artificial seismic sources are not emitted on the ground, performing real-time passive monitoring on the rockburst generated by an underground microseismic activity;the seismic source position determination unit is configured to locate the rockburst sources by: comparing the seismic waves attenuated by the artificial seismic sources emitted in the mining area, and with a difference between the propagation speeds of the seismic waves attenuated by the artificial seismic sources, and a difference between propagation time of a transverse wave and a longitudinal wave in each of seismic waves attenuated by a same one of the artificial seismic sources, preliminarily delineating a highly stress-concentrated spatial position of an ultra-thin coal seam, and preliminarily delineating a spatial position of the seismic source; and determining occurrence time of the seismic source through spatiotemporal retrospection according to the spatial position of the seismic source, whereinthe preliminarily delineating a highly stress-concentrated spatial position of an ultrathin coal seam specifically comprises: when each of the seismic waves emitted by the seismic wave emitting devices on the ground encounters the rockburst during propagation, a waveform of a transverse wave of the seismic wave is disturbed instantaneously and changes in different degrees, wherein in case of macroscopic damage comprising a crack, a cavity and a fault, energy of the transverse wave of the seismic wave is attenuated instantaneously, specifically, an amplitude decreases instantaneously, and a gap appears in the waveform; when the seismic wave does not encounter the rockburst, the seismic wave experiences energy attenuation during the propagation from the ground to the underground, specifically, an amplitude of a waveform decreases uniformly without an abrupt change; and when the seismic wave encounters a squeezed coal seam, a compression, a rarefaction, and an amplitude of a waveform of a longitudinal wave of the seismic wave increase, the compressionincreases more evidently, and a speed of the longitudinal wave increases and increases more evidently in a stress concentration area; andthe seismic source position determination unit is configured to obtain the position of the seismic source with the narrowed delineated range by: according to the propagation time and the propagation speeds of the seismic waves, performing locating through a time difference of arrival (TDOA) method; based on multiple monitoring devices on a map, according to seismic wave signals attenuated by different artificial seismic sources and rockburst signals, drawing a TDOA curve with time differences and the propagation speeds of the seismic waves; dividing three monitoring devices in the multiple monitoring devices into one group, finding three intersections on a TDOA curve drawn for seismic wave signals attenuated by a same artificial seismic source and rockburst signals, and delineating the three intersections to obtain a position of one rockburst source; similarly, grouping the multiple monitoring devices, and analyzing the seismic wave signals attenuated by the different artificial seismic sources and the seismic wave signals to obtain positions of multiple rockburst sources; and taking the intersection area between the positions of the multiple rockburst sources as the position of the seismic source with the narrowed delineated range.

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