Coal mine underground surrounding rock abnormal sound accurate positioning method based on sound wave and microseismic combined monitoring

Abstract

The invention provides a coal mine underground surrounding rock abnormal sound accurate positioning method based on sound wave and microseismic combined monitoring, and belongs to the field of coal mine safety mining. The problem that the existing micro-seismic monitoring system cannot accurately position the abnormal sound of the rock stratum is solved. Comprising the following steps: arranging a micro-seismic monitoring system and a sound wave monitoring system in a coal mine tunnel; setting various parameters of the micro-seismic monitoring system, monitoring the target roadway in a specific time period, and obtaining all micro-seismic events in the time period; basic parameters of a sound wave monitoring system are set, a sound wave frequency band interval is set to be a frequency band which can be received by human ears, and a target roadway is monitored in a specific time period; sound wave data collected by the sound wave monitoring system at the same moment and effective micro-seismic events collected by the micro-seismic monitoring system are subjected to data comparison, the micro-seismic events meeting the rock stratum abnormal sound conditions are screened out, and the accurate rock stratum height emitting abnormal sound waves is positioned through the micro-seismic monitoring system; the method is applied to mine surrounding rock abnormal sound monitoring.

Description

Technical Field

[0001] The invention provides a method for accurately locating abnormal noises in surrounding rocks in underground coal mines based on combined monitoring of acoustic waves and microseismicity, belonging to the technical field of safe mining of coal mines. Background Art

[0002] my country has rich reserves of coal resources, complex and diverse geological structures of coal seams, and differences in lithology among rock strata. During the process of coal resource exploitation, some mines have excessive development of rock strata cracks, resulting in abnormal noises from surrounding rocks, which has a large impact on the safe production of mines. Therefore, it is an important guarantee for the safe and efficient exploitation of coal resources to accurately locate the abnormal noises caused by surrounding rocks in coal mines, eliminate the potential dangers of abnormal noises from surrounding rocks, or provide effective early warnings for the impact areas of surrounding rocks.

[0003] Under the existing technical equipment conditions, the monitoring method for surrounding rock damage in coal mines mainly adopts acoustic emission and microseismic monitoring technology. This method records and analyzes tiny seismic activities through highly sensitive sensors and data processing systems to provide detailed information about underground activities. However, with the advancement of coal mining technology, some deficiencies have also appeared in actual production applications. First, there is a partial difference between its prediction of the degree of fracture and damage of the rock formation and the actual situation. Secondly, it is impossible to realize acoustic wave monitoring and realize the real-time positioning of the source of abnormal noise underground. At the same time, the workload of on-site construction is large, the number of personnel required to participate is large, the data obtained is uneven and has errors, and the cost is relatively high.

[0004] Some scholars have proposed a new rock mass stability monitoring system and application based on acoustic emission and microseismic technology, article number (1671-4172 (2008) 04-0032-04). The stability of the engineering rock mass is monitored by using the waves and microseismic signals emitted by the rock mass after deformation and destruction. The disadvantages of this method are: 1. The monitoring frequency band is relatively wide, and the frequency interval of the specific sound waves of the surrounding rock abnormal sound is not refined enough. 2. The recognition of specific monitoring objects is weak, and the data screening and extraction of abnormal sound waves cannot be accurate and effective. 3. It can only determine the location of the earthquake source and the energy of the microseismic event, and cannot effectively identify which type of rock layer the receiving wave emission source belongs to, and the actual development of rock layer fractures. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a method for accurately locating abnormal noises in surrounding rocks in underground coal mines based on joint monitoring of sound waves and microseismicity, with the purpose of classifying and screening effective events monitored by the microseismic monitoring system, effectively identifying events that meet the abnormal noises in the rock formations, and extracting and saving key data. The location of the "abnormal noise" in the rock formation can be accurately determined, and the location of the abnormal noise source can be obtained, providing a basis for further research on its sound generation mechanism. Through real-time monitoring of sound waves and combining with a microseismic monitoring system, it is possible to prevent the mine roof or surrounding rock from being affected by dynamic pressure and posing a threat to mine safety production. By experimentally calculating the ground pressure and energy release of the broken rock formation, it is possible to further provide a basis for the selection of support strength and the prevention of surrounding rock outburst disasters.

[0006] The technical solution adopted by the present invention is: a method for accurately locating abnormal noise in surrounding rocks in underground coal mines based on combined monitoring of acoustic waves and microseismicity, comprising the following steps: S1: Arrange microseismic monitoring system and acoustic wave monitoring system in coal mine tunnels; S2: Set various parameters of the microseismic monitoring system, monitor the target tunnel for a specific period of time, obtain all microseismic events within the period of time, perform preliminary screening on them, sort out effective microseismic events, and collect relevant data; S3: Set the basic parameters of the acoustic wave monitoring system, set the acoustic wave frequency band to a frequency band that can be received by the human ear, monitor the target lane for a specific time period, obtain all valid acoustic wave events within the time period, and collect relevant data; S4: Compare the acoustic wave data collected by the acoustic wave monitoring system at the same time with the effective microseismic events collected by the microseismic monitoring system, screen out the microseismic events that meet the conditions of abnormal rock sound, and locate the exact height of the rock layer that emits the abnormal sound wave through the effective data collected by the microseismic monitoring system.

[0007] Furthermore, the method further comprises the following steps: S5: designing a rock mechanics test for the rock formation determined to emit abnormal sound waves in step S4, preparing a core specimen, and collecting the fracturing and crushing sound of the core specimen using an acoustic wave collector; S6: Perform uniaxial compression on the core specimen and collect relevant important data during the test; S7: The acoustic wave data generated by the fracturing of core specimens collected in laboratory tests are verified with the microseismic events that have been screened out in the microseismic monitoring system and meet the conditions for abnormal sound in rock formations, and the relevant data of the abnormal sound caused by surrounding rock rupture in accurate and effective microseismic events are further screened.

[0008] Furthermore, the microseismic monitoring system in step S1 includes a seismic sensor and a microseismic monitoring substation. The seismic sensor is connected to the microseismic monitoring substation via a mining communication cable. The microseismic monitoring substation is connected to a ring network switch via a network cable to transmit the signal to a ground collection server, which performs data analysis on the ground processing server.

[0009] Furthermore, the sound wave monitoring system in step S1 includes a sound wave receiving device, a sound wave detector and a main control device, and the sound wave receiving device is connected to the sound wave detector, the main control device and a ground acquisition server through a connecting line.

[0010] Furthermore, the tunnel is divided into a plurality of monitoring sections, a seismic sensor and a sound wave receiving device are arranged in each monitoring section, a microseismic monitoring substation is arranged at the exit of the tunnel, and at least one sound wave detector is arranged in the tunnel.

[0011] Furthermore, in step S4, the microseismic events with abnormal rock sounds are screened out by sequentially comparing the time, sound wave waveform, wave frequency, amplitude, and energy data of the effective microseismic events collected by the microseismic monitoring system with the abnormal sound waves collected by the sound wave monitoring system.

[0012] Furthermore, through the method of contradiction, the abnormal sound waves consistent with the surrounding rock fracturing damage are effectively identified in the microseismic monitoring system, and the energy values ​​of such abnormal sound waves are further collected, and energy indicators are used for impact rock pressure warning.

[0013] Furthermore, the sound wave receiving device adopts a contact sensor, and the contact sensor is installed on the top of the tunnel.

[0014] The beneficial effects of the present invention compared with the prior art are as follows: 1. The present invention can accurately screen the effective microseismic events detected by the microseismic monitoring system and quickly collect data related to abnormal sounds of surrounding rocks. This efficient data processing capability provides a solid foundation for subsequent analysis.

[0015] 2. Through the present invention, the rock layer where surrounding rock compression and shear failure occurs can be accurately located, and the fracture characteristics of the top rock layer can be effectively determined by combining on-site monitoring data with experimental results. This process helps to deeply understand the mechanical behavior of the rock layer and the potential risk of instability.

[0016] 3. The present invention can infer the degree of damage of rock fractures and then evaluate their danger level. At the same time, through uniaxial fracturing tests, the degree of ground pressure can be inferred, providing a scientific basis for the selection of tunnel support.

[0017] 4. The whole system is easy and quick to operate, has a high accuracy rate in identifying target events, and requires relatively little drilling at the construction site, thereby improving work efficiency and reducing construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 Flow chart for combined acoustic wave and microseismic monitoring Figure 2 This is a schematic diagram of the installation layout of the underground monitoring system; Figure 3 Equipment diagram for the acoustic wave monitoring system; Figure 4 Schematic diagram of the waveform monitored by the acoustic wave monitoring system: In the figure: 1 is the sound wave receiving device, 2 is the vibration sensor, 3 is the sound wave detector, 4 is the tunnel, 5 is the microseismic monitoring substation, and 6 is the main control instrument. DETAILED DESCRIPTION

[0019] like Figures 1 to 4 As shown, the present invention provides a method for accurately locating abnormal noise in surrounding rocks in underground coal mines based on combined monitoring of acoustic waves and microseismicity, comprising the following steps: S1: Arrange a microseismic monitoring system and an acoustic wave monitoring system in the coal mine tunnel 4; The microseismic monitoring system includes a seismic sensor 2 and a microseismic monitoring substation 5. The seismic sensor 2 is connected to the microseismic monitoring substation 5 via a mine communication cable. The microseismic monitoring substation 5 is connected to the ring network switch via a network cable. The signal is transmitted to the ground acquisition server with the help of the underground ring network. The ground processing server performs data analysis and compiles a corresponding achievement report.

[0020] The acoustic wave monitoring system includes an acoustic wave receiving device 1, an acoustic wave detector 3 and a main control device 6. The acoustic wave receiving device 1 is connected to the acoustic wave detector 3, the main control device 6 and the ground acquisition server through a connecting line, thereby completing the arrangement of the monitoring system. The main control device 6 can process the detected acoustic waves and display the waveform, acoustic wave energy, etc.

[0021] Specifically, a plurality of monitoring sections are divided in the tunnel 4, a seismic sensor 2 and an acoustic wave receiving device 1 are arranged in each monitoring section, and a microseismic monitoring substation 5 is arranged at the exit of the tunnel 4, such as Figure 2 As shown, the acoustic wave receiving device 1 may be a contact sensor, and the contact sensor is arranged at the top of the tunnel 4. A plurality of acoustic wave detectors 3 may be arranged in each tunnel 4 according to the number of monitoring sections.

[0022] S2: Set various parameters of the microseismic monitoring system, monitor the target tunnel 4 for a specific period of time, obtain all microseismic events within the period of time, perform preliminary screening on them, organize effective microseismic events, and collect relevant data.

[0023] S3: Set the basic parameters of the sound wave detector 3, and set the sound wave frequency band interval to a frequency band that can be received by the human ear, mainly including the abnormal sound in the tunnel 4. Monitor the target tunnel 4 for a specific time period, obtain all valid sound wave events in the time period, and collect relevant data.

[0024] S4: Compare the time, waveform, frequency, amplitude and other data of the sound waves collected by the sound wave detector 3 with the effective microseismic events collected by the microseismic monitoring system, screen out the microseismic events that meet the conditions of abnormal sound in the rock formation, and locate the exact height of the rock formation that emits the abnormal sound wave through the effective data collected by the microseismic monitoring system.

[0025] The data comparison study of the sound wave and microseismic time in this step can start with the acquisition time to accurately match the approximate time period of abnormal rock sounds, and then compare the sound wave waveform and the waveform of the microseismic event within this time period to find out which microseismic events have abnormal sounds, and then make further comparisons and judgments based on conditions such as sound wave energy and sound wave amplitude, so as to accurately screen out microseismic events with abnormal rock sounds.

[0026] S5: Design rock mechanics tests for rock formations of corresponding heights. On-site construction personnel screen and extract rock blocks of a predetermined height. Since the rock blocks obtained by on-site sampling are irregular in shape and do not meet the test requirements, the rock block samples need to be further processed. Drill, cut and finely process the samples to be tested to meet the requirements of the uniaxial fracturing test. At the same time, prepare sound wave receiving equipment to collect the sound of the specimens being fractured and crushed.

[0027] S6: The core specimens that have met the requirements are subjected to uniaxial compression. The core specimens show obvious failure characteristics and acoustic phenomena. During the uniaxial compression failure process, there are occasional sounds of cracks. The core specimens eventually fail and make violent noises. Important data related to the test process are collected, including stress during the uniaxial compression failure process, acoustic waveform and amplitude when cracks are generated.

[0028] S7: The acoustic wave data generated by rock fracturing and crushing collected in the laboratory test are verified with the microseismic events that meet the conditions of abnormal rock sound in the microseismic monitoring system, and the relevant data of abnormal sound caused by surrounding rock rupture in accurate and effective microseismic events are further screened. This method can also prove that the source of abnormal sound caused by rock stratum compression and shear failure is the rock mass at the sampling height of the construction site.

[0029] Through the proof by contradiction, the abnormal sound waves that are consistent with the surrounding rock fracturing damage can be effectively identified in the microseismic monitoring system later. At the same time, the energy value of this type of sound wave can be further collected. The energy index can better reflect the stability of the rock structure than other indicators. Therefore, it is more effective to use energy indicators for impact ground pressure warning. The yellow warning threshold and red warning threshold of the energy index are determined based on the analysis of on-site monitoring data. In addition, the rock mechanics test on the specimen in the laboratory collects the ultimate stress applied when the rock block is damaged by fracturing, which can also provide a certain reference value for the selection of tunnel 4 support during actual construction.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for accurately locating abnormal noise in surrounding rock in underground coal mines based on joint monitoring of acoustic waves and microseismicity, characterized in that: The following steps are involved: S1: Arrange microseismic monitoring system and acoustic wave monitoring system in coal mine tunnels; S2: Set various parameters of the microseismic monitoring system, monitor the target tunnel for a specific period of time, obtain all microseismic events within the period of time, perform preliminary screening on them, sort out effective microseismic events, and collect relevant data; S3: Set the basic parameters of the acoustic wave monitoring system, set the acoustic wave frequency band to a frequency band that can be received by the human ear, monitor the target lane for a specific time period, obtain all valid acoustic wave events within the time period, and collect relevant data; S4: Compare the acoustic wave data collected by the acoustic wave monitoring system at the same time with the effective microseismic events collected by the microseismic monitoring system, screen out the microseismic events that meet the conditions of abnormal rock sound, and locate the exact height of the rock layer that emits the abnormal sound wave through the effective data collected by the microseismic monitoring system.

2. According to claim 1, a method for accurately locating abnormal noise in surrounding rock in underground coal mines based on combined monitoring of acoustic waves and microseismicity, characterized in that: The following steps are also included: S5: designing a rock mechanics test for the rock formation determined to emit abnormal sound waves in step S4, preparing a core specimen, and collecting the fracturing and crushing sound of the core specimen using an acoustic wave collector; S6: Perform uniaxial compression on the core specimen and collect relevant important data during the test; S7: The acoustic wave data generated by the fracturing of core specimens collected in laboratory tests are verified with the microseismic events that have been screened out in the microseismic monitoring system and meet the conditions for abnormal sound in rock formations, and the relevant data of the abnormal sound caused by surrounding rock rupture in accurate and effective microseismic events are further screened.

3. A method for accurately locating abnormal noise in surrounding rocks in underground coal mines based on combined monitoring of acoustic waves and microseismicity according to claim 1 or 2, characterized in that: The microseismic monitoring system in step S1 includes a seismic sensor and a microseismic monitoring substation. The seismic sensor is connected to the microseismic monitoring substation via a mine communication cable. The microseismic monitoring substation is connected to a ring network switch via a network cable to transmit the signal to a ground collection server, which performs data analysis on the ground processing server.

4. According to claim 3, a method for accurately locating abnormal noise in surrounding rock in underground coal mines based on combined monitoring of acoustic waves and microseismicity, characterized in that: The acoustic wave monitoring system in step S1 includes an acoustic wave receiving device, an acoustic wave detector and a main control device. The acoustic wave receiving device is connected to the acoustic wave detector, the main control device and a ground acquisition server via a connecting line.

5. According to claim 4, a method for accurately locating abnormal noise in surrounding rock in underground coal mines based on combined monitoring of acoustic waves and microseismicity, characterized in that: The tunnel is divided into multiple monitoring sections, a seismic sensor and a sound wave receiving device are arranged in each monitoring section, a microseismic monitoring substation is arranged at the exit of the tunnel, and at least one sound wave detector is arranged in the tunnel.

6. The method for accurately locating abnormal noise in surrounding rock in underground coal mines based on combined monitoring of acoustic waves and microseismicity according to claim 3 is characterized by: In step S4, the microseismic events with abnormal rock formation sounds are screened out by sequentially comparing the time, sound wave waveform, wave frequency, amplitude, and energy data of the effective microseismic events collected by the microseismic monitoring system with the abnormal sound waves collected by the sound wave monitoring system.

7. The method for accurately locating abnormal noise in surrounding rock in underground coal mines based on combined monitoring of acoustic waves and microseismicity according to claim 2 is characterized by: Through the method of contradiction, the abnormal sound waves consistent with the surrounding rock fracturing damage are effectively identified in the microseismic monitoring system. At the same time, the energy values ​​of such abnormal sound waves are further collected, and energy indicators are used for impact rock pressure warning.

8. The method for accurately locating abnormal noise in surrounding rock of underground coal mine based on combined monitoring of acoustic waves and microseismicity according to claim 4 is characterized by: The sound wave receiving device adopts a contact sensor, and the contact sensor is installed on the top of the tunnel.

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