A method and system for continuous automatic and accurate measurement of wave velocity of three-dimensional loaded gas-containing coal

Abstract

The present invention relates to the field of mine disaster prediction and early warning and gas prevention and control, and in particular to a method and system for continuous automatic and precise measurement of the wave velocity of three-dimensionally loaded gas-containing coal. The method comprises: obtaining synchronously acquired acoustic wave data of the coal body under three-dimensional loading conditions of the gas-containing coal; synchronously integrating the synchronously acquired acoustic wave data of the coal body, and automatically intercepting effective waveform data of the synchronously integrated data by the peak interval method; automatically identifying the arrival time of the first arrival wave of the effective waveform data by the short-time window mean mutation method; and calculating the continuous automatic measurement result of the wave velocity of the gas-containing coal based on the arrival time of the first arrival wave of the excitation wave and the arrival time of the first arrival wave of the receiving wave. The present invention has strong compatibility and is applicable to different loading forces and acoustic wave measurement devices, saving the data storage space required for the analysis of experimental results, and significantly improving the test accuracy and efficiency. The measurement results can provide important data support for the quantitative identification of coal rock stress and the prediction and early warning analysis of coal rock dynamic disaster risks.

Description

Technical Field

[0001] The present invention relates to the technical field of mine disaster prediction and early warning and gas prevention and control, and in particular to a method and system for continuous automatic and precise measurement of the wave velocity of three-dimensionally loaded gas-containing coal. Background Art

[0002] Various coal and rock dynamic disasters are the main reasons that restrict the safe and efficient production of coal mines. These disasters are the result of the combined effects of ground stress, mining stress, and mining disturbance. There is a certain relationship between stress and the wave velocity of gas-containing coal. Calculating the wave velocity of gas-containing coal under different loads provides important data support for establishing the coupling relationship between stress and wave velocity, quantitatively analyzing the danger of coal and gas outburst disasters, and avoiding disasters. Summary of the Invention

[0003] To address the technical issues of improving the quantitative characterization of coal and rock mass stress and the prediction and early warning of coal and rock dynamic disaster risks, the present invention provides a method and system for continuous, automatic, and precise measurement of the wave velocity of three-dimensionally loaded gas-containing coal. The technical solution is as follows:

[0004] In one aspect, a method for continuously and automatically accurately measuring the wave velocity of gas-containing coal under three-dimensional loading is provided. The method is implemented by a device for continuously and automatically accurately measuring the wave velocity of gas-containing coal under three-dimensional loading. The method comprises:

[0005] S1. Acquire synchronous acoustic wave data of coal body under three-dimensional loading conditions of gas-containing coal.

[0006] The acoustic wave synchronous acquisition data of the coal body includes: the excitation wave data at the top of the coal body and the receiving wave data at the bottom of the coal body.

[0007] S2. Synchronously integrate the synchronously collected acoustic wave data of the coal body, and automatically intercept effective waveform data from the synchronously integrated data using a peak interval method.

[0008] S3. Automatically identify the arrival time of the first wave of the valid waveform data through the short-time window mean mutation method.

[0009] The first arrival time includes the first arrival time of the excitation wave at the top of the coal body and the first arrival time of the receiving wave at the bottom of the coal body.

[0010] S4. Calculate and obtain the continuous automatic measurement result of the wave velocity of the gas-containing coal based on the arrival time of the first arrival wave of the excitation wave and the arrival time of the first arrival wave of the receiving wave.

[0011] Optionally, obtaining the acoustic synchronous acquisition data of the coal body under the three-dimensional loading condition of the gas-containing coal in S1 includes:

[0012] The acoustic wave synchronous acquisition data of the coal body under the three-dimensional loading conditions of gas-containing coal is obtained through the three-dimensional loading acoustic wave measurement system device.

[0013] Among them, the three-dimensional loaded acoustic wave measurement system for gas-containing coal includes: a gas-solid coupling three-axis coal rock clamping sub-device, a three-axis loading power sub-device connected to the gas-solid coupling three-axis coal rock clamping sub-device, a gas transmission control sub-device and an acoustic wave signal excitation and collection sub-device.

[0014] Optionally, a three-dimensionally loaded acoustic wave measurement system for gas-containing coal is used to obtain synchronously acquired acoustic wave data of the coal body under three-dimensional loading conditions, including:

[0015] By exciting and receiving the signal of preset repetition period through the acoustic signal excitation and collection sub-device in the three-way loaded acoustic wave measuring device for gas-containing coal, the acoustic wave synchronous collection data of the coal body under the three-way loaded condition of gas-containing coal is obtained.

[0016] The number of signals excited each time is 2.

[0017] Optionally, stimulating and receiving a signal of a preset repetition period includes:

[0018] Excite and receive signals with a preset repetition period, with a sampling frequency of not less than 3 MHz, a pulse width range of 2 to 20 us, a pulse period of 500 to 3000 us, and an amplitude of the excited signal of not less than 5 V.

[0019] Optionally, S2 automatically extracts valid waveform data from the synchronously integrated data using a peak interval method, including:

[0020] The amplitude of the synchronously integrated data, in which the maximum amplitude exceeds the preset amplitude threshold twice in a preset first time, is obtained, and the peak moment of the obtained amplitude is marked as the first exceeding-limit moment.

[0021] The waveform data of a preset second time before and after the first exceeding limit moment is intercepted and saved as the first valid waveform data.

[0022] According to the first exceeding time and the preset time interval, the next exceeding time is obtained, the waveform data of the preset second time before and after the next exceeding time is intercepted and saved as the next valid waveform data, and then all the valid waveform data of the synchronously integrated data are obtained.

[0023] Optionally, the S3 method automatically identifies the arrival time of the first wave of the valid waveform data by using the short-time window mean mutation method, including:

[0024] S31. The short-time window mean mutation method is used to automatically identify the first arrival time of the excitation wave data at the top of the coal body.

[0025] S32. The short-time window mean mutation method is used to automatically identify the first arrival time of the received wave data at the bottom of the coal body.

[0026] Among them, S31 includes:

[0027] The short-time window mean mutation method is used to calculate the waveform amplitude average within the time window with the data of 10 sampling points of the excitation channel as the time window. The time when the absolute value of the average value is greater than 2 and the amplitude is the smallest within the time window is marked as the arrival time of the first arrival wave of the excitation wave data.

[0028] S32, including:

[0029] The waveform amplitude average value in the time window after the first arrival of the excitation wave data is obtained, and the time when the absolute value of the average value is greater than 0.1 is marked as the first arrival of the received wave data.

[0030] Alternatively, the calculation method of the wave velocity of gas-containing coal is as shown in the following formula (1):

[0031] (1)

[0032] Where V pi is the velocity of the i-th effective waveform; h is the length of the coal sample; ε is the deformation of the sample coal body; T ei T is the arrival time of the first wave of the i-th valid waveform receiving wave data; ri are the first arrival time of the i-th effective waveform excitation wave data; V sd is the wave velocity of the axial material; l is the distance between the probe and the coal sample.

[0033] On the other hand, a system for continuously and automatically accurately measuring the wave velocity of gas-containing coal under three-dimensional loading is provided. The system is applied to a method for continuously and automatically accurately measuring the wave velocity of gas-containing coal under three-dimensional loading. The system comprises:

[0034] The data acquisition module is used to obtain synchronous acoustic wave data of the coal body under three-way loading conditions of gas-containing coal.

[0035] The acoustic wave synchronous acquisition data of the coal body includes: the excitation wave data at the top of the coal body and the receiving wave data at the bottom of the coal body.

[0036] The effective waveform interception module is used to synchronously integrate the acoustic wave synchronous acquisition data of the coal body, and automatically intercept the effective waveform data from the synchronously integrated data through the peak interval method.

[0037] The first arrival wave arrival time identification module is used to automatically identify the first arrival wave arrival time of valid waveform data through the short-time window mean mutation method.

[0038] The first arrival time includes the first arrival time of the excitation wave at the top of the coal body and the first arrival time of the receiving wave at the bottom of the coal body.

[0039] The output module is used to calculate the continuous automatic measurement result of the wave velocity of gas-containing coal according to the arrival time of the first arrival wave of the excitation wave and the arrival time of the first arrival wave of the receiving wave.

[0040] Optionally, the data acquisition module is further configured to:

[0041] The acoustic wave synchronous acquisition data of the coal body under the three-dimensional loading condition of gas-containing coal is obtained through the three-dimensional loading acoustic wave measurement system device.

[0042] Among them, the three-dimensional loaded acoustic wave measurement system for gas-containing coal includes: a gas-solid coupling three-axis coal rock clamping sub-device, a three-axis loading power sub-device connected to the gas-solid coupling three-axis coal rock clamping sub-device, a gas transmission control sub-device and an acoustic wave signal excitation and collection sub-device.

[0043] Optionally, the data acquisition module is further configured to:

[0044] By exciting and receiving the signal of preset repetition period through the acoustic signal excitation and acquisition sub-device in the three-way loaded acoustic wave measurement system for gas-containing coal, synchronous acoustic wave acquisition data of the coal body under the three-way loaded condition of gas-containing coal is obtained.

[0045] The number of signals excited each time is 2.

[0046] Optionally, the data acquisition module is further configured to:

[0047] Excite and receive signals with a preset repetition period, with a sampling frequency of not less than 3 MHz, a pulse width range of 2 to 20 us, a pulse period of 500 to 3000 us, and an amplitude of the excited signal of not less than 5 V.

[0048] Optionally, the effective waveform interception module is further configured to:

[0049] The amplitude of the synchronously integrated data, in which the maximum amplitude exceeds the preset amplitude threshold twice in a preset first time, is obtained, and the peak moment of the obtained amplitude is marked as the first exceeding-limit moment.

[0050] The waveform data of a preset second time before and after the first exceeding limit moment is intercepted and saved as the first valid waveform data.

[0051] According to the first exceeding time and the preset time interval, the next exceeding time is obtained, the waveform data of the preset second time before and after the next exceeding time is intercepted and saved as the next valid waveform data, and then all the valid waveform data of the synchronously integrated data are obtained.

[0052] Optionally, the first arrival wave arrival time identification module is further configured to:

[0053] S31. The short-time window mean mutation method is used to automatically identify the first arrival time of the excitation wave data at the top of the coal body.

[0054] S32. The short-time window mean mutation method is used to automatically identify the first arrival time of the received wave data at the bottom of the coal body.

[0055] Among them, S31 includes:

[0056] The short-time window mean mutation method is used to calculate the waveform amplitude average within the time window with the data of 10 sampling points of the excitation channel as the time window. The time when the absolute value of the average value is greater than 2 and the amplitude is the smallest within the time window is marked as the arrival time of the first arrival wave of the excitation wave data.

[0057] S32, including:

[0058] The waveform amplitude average value in the time window after the first arrival of the excitation wave data is obtained, and the time when the absolute value of the average value is greater than 0.1 is marked as the first arrival of the received wave data.

[0059] Alternatively, the calculation method of the wave velocity of gas-containing coal is as shown in the following formula (1):

[0060] (1)

[0061] Where V pi is the velocity of the i-th effective waveform; h is the length of the coal sample; ε is the deformation of the sample coal body; T ei T is the arrival time of the first wave of the i-th valid waveform receiving wave data; ri are the first arrival time of the i-th effective waveform excitation wave data; V sd is the wave velocity of the axial material; l is the distance between the probe and the coal sample.

[0062] On the other hand, a device for continuously and automatically accurately measuring the wave velocity of three-dimensional loaded gas-containing coal is provided. The device comprises: a processor; a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, any one of the above-mentioned methods for continuously and automatically measuring the wave velocity of three-dimensional loaded gas-containing coal is implemented.

[0063] On the other hand, a computer-readable storage medium is provided, in which at least one instruction is stored. The at least one instruction is loaded and executed by a processor to implement any one of the above-mentioned methods for continuous automatic and precise measurement of the wave velocity of three-dimensional loaded gas-containing coal.

[0064] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0065] In the embodiment of the present invention, based on the experimentally obtained high-precision acoustic wave synchronous acquisition data of the excitation and reception at the top and bottom of the coal body under three-way loading conditions of gas-containing coal, the acquired data are synchronously integrated, and the effective waveform is automatically and synchronously intercepted using the peak interval method. The intercepted effective waveform is subjected to the short-time window mean mutation method to calculate the arrival time t of the first arrival wave of the excitation and receiving probes. i and t r Automatic calibration enables the compressed storage of massive amounts of data and the automatic measurement and calculation of wave velocity in gassy coal under different operating conditions. This invention is highly compatible with various loading forces and acoustic wave measurement devices, saving data storage space required for experimental result analysis and significantly improving test accuracy and efficiency. The measurement results provide important data support for quantitative identification of coal and rock mass stress and for the prediction and early warning of coal and rock dynamic disaster risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0067] Figure 1 This is a flow chart of a method for continuous automatic and accurate measurement of wave velocity of three-dimensional loaded gas-containing coal provided by an embodiment of the present invention;

[0068] Figure 2 This is a system diagram of a method for continuous automatic determination of three-way carrier speed of gas-containing coal provided by an embodiment of the present invention;

[0069] Figure 3 This is a block diagram of a system for continuous automatic and precise measurement of wave velocity of three-dimensional loaded gas-containing coal provided by an embodiment of the present invention;

[0070] Figure 4 It is a structural schematic diagram of a three-dimensional loaded gas-containing coal wave velocity continuous automatic and precise measurement device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0072] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0073] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, when the distinction is not emphasized, the meanings they convey are the same. The terms "of," "corresponding," and "corresponding" may sometimes be used interchangeably. It should be noted that, when the distinction is not emphasized, the meanings they convey are the same.

[0074] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0075] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0076] The embodiment of the present invention provides a method for continuously and automatically accurately measuring the wave velocity of three-way loaded gas-containing coal. The method can be implemented by a device for continuously and automatically accurately measuring the wave velocity of three-way loaded gas-containing coal. The device can be a terminal or a server. Figure 1 The flowchart of the method for continuous automatic and accurate measurement of wave velocity of three-dimensional loaded gas-containing coal is shown. The processing flow of the method may include the following steps:

[0077] S1. Acquire synchronous acoustic wave data of coal body under three-dimensional loading conditions of gas-containing coal.

[0078] The acoustic wave synchronous acquisition data of the coal body includes: the excitation wave data at the top of the coal body and the receiving wave data at the bottom of the coal body.

[0079] Optionally, the above step S1 may be:

[0080] like Figure 2 As shown, by exciting and receiving signals of a preset repetition period through the acoustic wave signal excitation and collection sub-device in the three-dimensional loaded acoustic wave measuring device for gas-containing coal, high-precision acoustic wave synchronous collection data of the excitation and reception of the top and bottom of the coal body under the three-dimensional loaded conditions of gas-containing coal is obtained; wherein, the number of signals excited each time is 2.

[0081] Among them, the three-dimensional loaded acoustic wave measuring device for gas-containing coal can include: a gas-solid coupling three-axis coal rock clamping sub-device, a three-axis loading power sub-device connected to the gas-solid coupling three-axis coal rock clamping sub-device respectively, a gas transmission control sub-device and an acoustic wave signal excitation and collection sub-device.

[0082] In one feasible implementation, the three-dimensional loading conditions for gas-laden coal require a triaxial airtight device capable of regulating axial pressure, confining pressure, and gas pressure. Confining pressure loading is connected to the supercharger oil pipe via an adapter. This adapter is removable and replaceable to accommodate different models of triaxial loading devices, enhancing the versatility of data acquisition.

[0083] Next, the holder was placed on an operating table and connected to a three-dimensional acoustic wave measurement device for gas-bearing coal. A coal sample was placed in the holder, the holder was evacuated, and the loading system was activated to apply a preload and confining pressure to ensure the device's airtightness. The gas transmission control system was activated, and the pressure reducing valve was adjusted to the set pressure. When the gas pressure at the outlet matched the pressure in the pressure reducing valve, the pressure reducing valve was closed. Simultaneously, the loading system and acoustic wave excitation system were activated to collect acoustic wave propagation experimental data.

[0084] Specifically, the gas-solid coupled triaxial coal rock clamping device consists of a confining pressure clamp, a confining pressure loading adapter, a pressure shaft, a polytetrachloroethylene confining pressure sleeve, an air inlet slot, an air outlet slot, a base, an air inlet valve, an air outlet tee, an air outlet valve and other components.

[0085] The gas transmission control device consists of a high-pressure gas cylinder, a pressure reducing valve, a gas leakage monitor, an explosion-proof gas cylinder cabinet, a vacuum pump, an air inlet pipe, an air outlet pipe, etc.

[0086] The acoustic wave signal excitation and acquisition device includes an acoustic wave transducer, an acoustic emission amplifier, and an acoustic emission signal acquisition instrument.

[0087] The triaxial loading power device and system include a servo rock pressure testing machine, a loading control system, a hydraulic pump, etc.

[0088] The specific implementation of the above step S1 can be:

[0089] The acoustic wave transducers are placed in the top and bottom cavities of the triaxial holder and fixed by pressure rods. After the specimen is placed in the internal cavity of the triaxial holder, the triaxial holder is assembled and placed on the operating table, and connected to the pressure system, acoustic wave acquisition instrument, and gas transmission device.

[0090] Furthermore, a new loading control file is created, the loading mode of the pressure control system is selected, and manual control is selected (manual control can achieve load maintenance under a fixed pressure of the sample, so that gas can be injected under a fixed pressure to achieve coal gas adsorption and desorption equilibrium), the initial axial pressure and confining pressure parameters are input, and loading is started until the stress reaches the initial parameters.

[0091] Furthermore, open the air outlet valve and the air inlet valve, evacuate the air for 10 minutes, then close the air outlet and air inlet valves, open the gas cylinder valve, adjust the pressure reducing valve to the required pressure, open the air inlet valve, and observe the pressure on the air outlet digital display until the value on the digital display reaches the specified pressure value.

[0092] Next, trigger the external excitation button on the acoustic emission signal acquisition instrument to control the excitation sensor until loading is complete. After the experiment is completed, stop the acoustic emission acquisition. Then, close the gas cylinder valve, pressure reducing valve, and gripper inlet valve, open the outlet valve, and wait until the gas pressure in the gripper drops to zero. Then stop the press loading.

[0093] Furthermore, the excitation signal of the acoustic signal excitation acquisition device and system is repeatedly excited with a repetition period c, and two signals are excited simultaneously each time to distinguish between the coal damage signal and the active excitation signal; the sampling frequency of the excitation and receiving waveform data is not less than 3 MHz, the pulse width is 2~20 us, the pulse period is 500~3000 us, and the excitation signal amplitude is not less than 5V to ensure the accuracy of data acquisition.

[0094] Among them, before the clamp is injected with gas pressure, axial pressure and confining pressure must be applied in advance, and the confining pressure must be greater than the gas pressure by more than 2MPa to ensure the airtightness of the device.

[0095] S2. Synchronously integrate the synchronously collected acoustic wave data of the coal body, and automatically intercept effective waveform data from the synchronously integrated data using a peak interval method.

[0096] In a feasible implementation, the automatic interception method system synchronously collects and integrates data, the wave clipping parameters are set in advance, and the peak interval method is used to automatically intercept the effective waveform data in the massive continuous sound wave data, and the data is compressed and stored.

[0097] Optionally, the step of automatically intercepting effective waveform data from the synchronously integrated data using the peak interval method in S2 may include the following steps S21-S23:

[0098] S21 , acquiring amplitudes of the synchronously integrated data, the maximum amplitude of which exceeds a preset amplitude threshold value twice in a preset first time, and marking the peak moment of the acquired amplitude as the first exceeding-limit moment.

[0099] S22: intercepting waveform data of a preset second time before and after the first limit-exceeding moment and saving the data as the first valid waveform data.

[0100] S23. According to the first exceeding time and the preset time interval c, the next exceeding time is obtained, waveform data of a preset second time before and after the next exceeding time is intercepted and saved as the next valid waveform data, thereby obtaining all valid waveform data of the synchronously integrated data.

[0101] In a feasible implementation, the steps for automatically intercepting a valid waveform using the peak interval method are as follows:

[0102] (1) Synchronously read the collected data and integrate the waveform data; the automatic interception system frequency parameter can be set to 3.0 MHz.

[0103] (2) Compare the waveform amplitudes. Once the maximum amplitude exceeds the preset amplitude threshold twice within 3 milliseconds, the moment of the first amplitude peak is marked as the first exceeding time T0; the waveform amplitude threshold can be set to 3.0 mv.

[0104] (3) Intercept the waveform data 1.5ms before and after time T0 and save it as P1;

[0105] (4) After the first effective waveform is captured, the reconstructed data automatically captures T0+c i The waveform data of 1.5ms before and after the moment is numbered consecutively as P i , c i The effective waveform is automatically intercepted based on the peak interval method to achieve automatic interception and compressed storage of effective waveform data in massive continuous sound wave data.

[0106] S3. Automatically identify the arrival time of the first wave of the valid waveform data through the short-time window mean mutation method.

[0107] The first arrival time includes the first arrival time of the excitation wave at the top of the coal body and the first arrival time of the receiving wave at the bottom of the coal body.

[0108] Optionally, the above step S3 may include the following steps S31-S32:

[0109] S31. The short-time window mean mutation method is used to automatically identify the first arrival time of the excitation wave data at the top of the coal body.

[0110] Specifically, the short-time window mean mutation method is used, with the data of 10 sampling points of the excitation channel as the time window, and the average amplitude of the waveform in the time window is calculated in sequence. When the absolute value of the average value is greater than 2, the time mark with the minimum amplitude in the time window is the arrival time of the first arrival wave of the excitation wave data.

[0111] S32. The short-time window mean mutation method is used to automatically identify the first arrival time of the received wave data at the bottom of the coal body.

[0112] Specifically, the waveform amplitude average value in the time window after the first arrival of the excitation wave data is obtained, and the time when the absolute value of the average value is greater than 0.1 is marked as the first arrival of the received wave data.

[0113] In a feasible implementation method, the wave velocity automatic analysis method system automatically and accurately identifies the excitation and reception time through the short-time window mean mutation method. Under the control of axial pressure, confining pressure and gas, it continuously extracts the arrival time of the excitation and reception probe waveforms of the loaded gas-containing coal, and dynamically and continuously calculates the wave velocity.

[0114] Specifically, the arrival time of each effective waveform excitation and reception is analyzed using the short-time window mean mutation method automatic identification algorithm. The short-time window mean mutation method uses the 10 sampling points of the excitation channel as the time window W, and sequentially calculates the average waveform amplitude within the time W; when the absolute value of the average value is greater than 2, the time of the sampling point with the smallest amplitude within the time W is recorded. This time is the excitation time, recorded as T ri .

[0115] Furthermore, after the excitation moment, the receiving channel uses 10 sampling points as the time window and calculates the average amplitude of the waveform in the time window in sequence. If the absolute value of the average value is greater than 0.1, the time of the sampling point with the minimum amplitude in the time window is recorded. This time is the receiving moment, recorded as T ei .

[0116] S4. Calculate and obtain the continuous automatic measurement result of the wave velocity of the gas-containing coal based on the arrival time of the first arrival wave of the excitation wave and the arrival time of the first arrival wave of the receiving wave.

[0117] Alternatively, the calculation method of the wave velocity of gas-containing coal is as shown in the following formula (1):

[0118] (1)

[0119] Where V pi is the velocity of the ith effective waveform, m / s; h is the length of the coal sample, m; ε is the deformation of the sample, m; T ei and T ri are the time of reception and excitation of the i-th effective waveform respectively; V sd is the wave velocity of the axial material, and l is the distance between the probe and the coal sample (m).

[0120] In a feasible implementation manner, this embodiment takes 20 sets of excitation data as an example, and the basic parameters of the system and the analysis data of the wave velocity automatic analysis system are shown in Tables 1 and 2 below.

[0121] Table 1. Sample related data

[0122]

[0123] Table 2 Excitation data of 10 groups of samples

[0124]

[0125] In the embodiment of the present invention, based on the experimentally obtained high-precision acoustic wave synchronous acquisition data of the excitation and reception at the top and bottom of the coal body under three-way loading conditions of gas-containing coal, the acquired data are synchronously integrated, and the effective waveform is automatically and synchronously intercepted using the peak interval method. The intercepted effective waveform is subjected to the short-time window mean mutation method to calculate the arrival time t of the first arrival wave of the excitation and receiving probes. i and t r Automatic calibration enables the compressed storage of massive amounts of data and the automatic measurement and calculation of wave velocity in gassy coal under different operating conditions. This invention is highly compatible with various loading forces and acoustic wave measurement devices, saving data storage space required for experimental result analysis and significantly improving test accuracy and efficiency. The measurement results provide important data support for quantitative identification of coal and rock mass stress and for the prediction and early warning of coal and rock dynamic disaster risks.

[0126] Figure 3 This is a block diagram of a system for continuously and automatically accurately measuring the wave velocity of three-way loaded gas-containing coal according to an exemplary embodiment. The system is used for a method for continuously and automatically accurately measuring the wave velocity of three-way loaded gas-containing coal. Figure 3 The system includes a data acquisition module 310, an effective waveform interception module 320, a first arrival time identification module 330, and an output module 340.

[0127] The data acquisition module 310 is used to obtain synchronous acoustic wave data of the coal body under the three-dimensional loading condition of the gas-containing coal.

[0128] The acoustic wave synchronous acquisition data of the coal body includes: the excitation wave data at the top of the coal body and the receiving wave data at the bottom of the coal body.

[0129] The effective waveform interception module 320 is used to synchronously integrate the synchronously collected acoustic wave data of the coal body and automatically intercept effective waveform data from the synchronously integrated data using the peak interval method.

[0130] The first arrival time identification module 330 is used to automatically identify the first arrival time of the valid waveform data by using the short-time window mean mutation method.

[0131] The first arrival time includes the first arrival time of the excitation wave at the top of the coal body and the first arrival time of the receiving wave at the bottom of the coal body.

[0132] The output module 340 is used to calculate the continuous automatic measurement result of the wave velocity of the gas-containing coal according to the arrival time of the first arrival wave of the excitation wave and the arrival time of the first arrival wave of the receiving wave.

[0133] Optionally, the data acquisition module 310 is further configured to:

[0134] The acoustic wave synchronous acquisition data of the coal body under the three-dimensional loading conditions of gas-containing coal is obtained through the three-dimensional loading acoustic wave measuring device.

[0135] Among them, the three-dimensional loaded acoustic wave measuring device for gas-containing coal includes: a gas-solid coupling three-axis coal rock clamping sub-device, a three-axis loading power sub-device connected to the gas-solid coupling three-axis coal rock clamping sub-device, a gas transmission control sub-device and an acoustic wave signal excitation and collection sub-device.

[0136] Optionally, the data acquisition module 310 is further configured to:

[0137] By exciting and receiving the signal of preset repetition period through the acoustic signal excitation and collection sub-device in the three-way loaded acoustic wave measuring device for gas-containing coal, the acoustic wave synchronous collection data of the coal body under the three-way loaded condition of gas-containing coal is obtained.

[0138] The number of signals excited each time is 2.

[0139] Optionally, the data acquisition module 310 is further configured to:

[0140] Excite and receive signals with a preset repetition period, with a sampling frequency of not less than 3 MHz, a pulse width range of 2 to 20 us, a pulse period of 500 to 3000 us, and an amplitude of the excited signal of not less than 5 V.

[0141] Optionally, the effective waveform interception module 320 is further configured to:

[0142] The amplitude of the synchronously integrated data, in which the maximum amplitude exceeds the preset amplitude threshold twice in a preset first time, is obtained, and the peak moment of the obtained amplitude is marked as the first exceeding-limit moment.

[0143] The waveform data of a preset second time before and after the first exceeding limit moment is intercepted and saved as the first valid waveform data.

[0144] According to the first exceeding time and the preset time interval, the next exceeding time is obtained, the waveform data of the preset second time before and after the next exceeding time is intercepted and saved as the next valid waveform data, and then all the valid waveform data of the synchronously integrated data are obtained.

[0145] Optionally, the first arrival time identification module 330 is further configured to:

[0146] S31. The short-time window mean mutation method is used to automatically identify the first arrival time of the excitation wave data at the top of the coal body.

[0147] S32. The short-time window mean mutation method is used to automatically identify the first arrival time of the received wave data at the bottom of the coal body.

[0148] Among them, S31 includes:

[0149] The short-time window mean mutation method is used to calculate the waveform amplitude average within the time window with the data of 10 sampling points of the excitation channel as the time window. The time when the absolute value of the average value is greater than 2 and the amplitude is the smallest within the time window is marked as the arrival time of the first arrival wave of the excitation wave data.

[0150] S32, including:

[0151] The waveform amplitude average value in the time window after the first arrival of the excitation wave data is obtained, and the time when the absolute value of the average value is greater than 0.1 is marked as the first arrival of the received wave data.

[0152] Alternatively, the calculation method of the wave velocity of gas-containing coal is as shown in the following formula (1):

[0153] (1)

[0154] Where V pi is the velocity of the i-th effective waveform; h is the length of the coal sample; ε is the deformation of the sample coal body; T ei T is the arrival time of the first wave of the i-th valid waveform receiving wave data; ri are the first arrival time of the i-th effective waveform excitation wave data; V sd is the wave velocity of the axial material; l is the distance between the probe and the coal sample.

[0155] In the embodiment of the present invention, based on the experimentally obtained high-precision acoustic wave synchronous acquisition data of the excitation and reception at the top and bottom of the coal body under three-way loading conditions of gas-containing coal, the acquired data are synchronously integrated, and the effective waveform is automatically and synchronously intercepted using the peak interval method. The intercepted effective waveform is subjected to the short-time window mean mutation method to calculate the arrival time t of the first arrival wave of the excitation and receiving probes. i and t r Automatic calibration enables the compressed storage of massive amounts of data and the automatic measurement and calculation of wave velocity in gassy coal under different operating conditions. This invention is highly compatible with various loading forces and acoustic wave measurement devices, saving data storage space required for experimental result analysis and significantly improving test accuracy and efficiency. The measurement results provide important data support for quantitative identification of coal and rock mass stress and for the prediction and early warning of coal and rock dynamic disaster risks.

[0156] Figure 4 Schematic diagram of a three-way loaded gas-containing coal wave velocity continuous automatic and precise measurement device provided by an embodiment of the present invention, such as Figure 4 As shown, the three-way loaded gas-containing coal wave velocity continuous automatic accurate measurement equipment can include the above Figure 3The system for continuously and automatically measuring the wave velocity of three-dimensional loaded gas-containing coal is shown. Optionally, the device 410 for continuously and automatically measuring the wave velocity of three-dimensional loaded gas-containing coal may include a first processor 2001 .

[0157] Optionally, the three-way loaded gas-containing coal wave velocity continuous automatic and precise measurement device 410 may also include a memory 2002 and a transceiver 2003 .

[0158] The first processor 2001, the memory 2002 and the transceiver 2003 may be connected via a communication bus.

[0159] The following combination Figure 4 The following describes in detail the components of the three-way loaded gas-containing coal wave velocity continuous automatic precision measurement device 410:

[0160] The first processor 2001 is the control center of the three-way loaded gas-containing coal wave velocity continuous automatic precision measurement device 410. It can be a single processor or a collective term for multiple processing elements. For example, the first processor 2001 can be one or more central processing units (CPUs), application-specific integrated circuits (ASICs), or one or more integrated circuits configured to implement embodiments of the present invention, such as one or more microprocessors (digital signal processors, DSPs) or one or more field programmable gate arrays (FPGAs).

[0161] Optionally, the first processor 2001 can execute various functions of the three-dimensional loaded gas-containing coal wave velocity continuous automatic and precise measurement device 410 by running or executing the software program stored in the memory 2002 and calling the data stored in the memory 2002.

[0162] In a specific implementation, as an embodiment, the first processor 2001 may include one or more CPUs, such as Figure 4 CPU0 and CPU1 are shown in FIG.

[0163] In a specific implementation, as an embodiment, the three-way loaded gas-containing coal wave velocity continuous automatic and accurate measurement device 410 may also include multiple processors, such as Figure 41 and 2. The first processor 2001 and the second processor 2004 are shown in FIG. Each of these processors can be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). A processor herein can refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0164] The memory 2002 is used to store the software program for executing the solution of the present invention, and is controlled by the first processor 2001 for execution. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0165] Optionally, the memory 2002 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, a random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and capable of being accessed by a computer, but not limited thereto. The memory 2002 may be integrated with the first processor 2001 or exist independently and access the memory 2002 via the interface circuit ( Figure 4 (not shown) is coupled to the first processor 2001, which is not specifically limited in this embodiment of the present invention.

[0166] The transceiver 2003 is used to communicate with a network device or a terminal device.

[0167] Optionally, the transceiver 2003 may include a receiver and a transmitter ( Figure 4 The receiver is used to implement a receiving function, and the transmitter is used to implement a sending function.

[0168] Optionally, the transceiver 2003 can be integrated with the first processor 2001 or can exist independently and be connected to the first processor 2001 through the interface circuit of the three-way loaded gas-containing coal wave velocity continuous automatic precision measurement device 410 ( Figure 4 (not shown) is coupled to the first processor 2001, which is not specifically limited in this embodiment of the present invention.

[0169] It should be noted that Figure 4 The structure of the three-way loaded gas-containing coal wave velocity continuous automatic precise measurement device 410 does not constitute a limitation on the router. The actual knowledge structure recognition device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0170] In addition, the technical effects of the three-way loaded gas-containing coal wave velocity continuous automatic and precise measurement equipment 410 can refer to the technical effects of the three-way loaded gas-containing coal wave velocity continuous automatic and precise measurement method described in the above method embodiment, and will not be repeated here.

[0171] It should be understood that the first processor 2001 in the embodiment of the present invention may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0172] It should also be understood that the memory in the embodiments of the present invention may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory may be random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0173] The above embodiments can be implemented in whole or in part via software, hardware (e.g., circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions or computer programs. When loaded or executed on a computer, the processes or functions described in accordance with the embodiments of the present invention are fully or partially performed. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired means (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server or data center that contains a collection of one or more available media. The available medium can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media. The semiconductor media can be a solid-state drive.

[0174] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0175] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0176] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0177] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0178] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described equipment, devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0179] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of the device or unit, which can be electrical, mechanical or other forms.

[0180] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0181] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0182] If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media that can store program code, such as USB flash drives, mobile hard drives, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical disks.

[0183] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for continuous automatic and accurate measurement of the wave velocity of gas-containing coal under three-dimensional loading, characterized in that: The method comprises: S1. Acquire synchronous acoustic wave data of coal body under three-dimensional loading conditions of gas-containing coal; The acoustic wave synchronous acquisition data of the coal body includes: the excitation wave data at the top of the coal body and the receiving wave data at the bottom of the coal body; S2. Synchronously integrating the synchronously collected acoustic wave data of the coal body, and automatically intercepting effective waveform data from the synchronously integrated data using a peak interval method; S3, automatically identifying the arrival time of the first wave of the effective waveform data by using a short-time window mean mutation method; Wherein, the first arrival time of the wave includes: the first arrival time of the excitation wave at the top of the coal body and the first arrival time of the receiving wave at the bottom of the coal body; S4. Calculate the continuous automatic measurement result of the wave velocity of the gas-containing coal according to the first arrival time of the excitation wave and the first arrival time of the receiving wave; The step S3 of automatically identifying the first arrival time of the valid waveform data by using the short-time window mean mutation method includes: S31. Automatically identify the first arrival time of the excitation wave data at the top of the coal body by using the short-time window mean mutation method; S32. Automatically identify the arrival time of the first wave of the received wave data at the bottom of the coal body by using the short-time window mean mutation method; Wherein, the S31 includes: By using the short-time window mean mutation method, the data of 10 sampling points of the excitation channel are used as the time window, and the average amplitude of the waveform in the time window is calculated in sequence. When the absolute value of the average value is greater than 2, the time when the amplitude is the smallest in the time window is marked as the arrival time of the first arrival wave of the excitation wave data; The S32 includes: Obtaining the waveform amplitude average value in a time window after the first arrival of the excitation wave data, and marking the time when the absolute value of the average value is greater than 0.1 as the first arrival of the received wave data; The calculation method of the gas-containing coal wave velocity is shown in the following formula (1): Where V pi is the velocity of the i-th effective waveform; h is the length of the coal sample; ε is the deformation of the sample coal body; T ei T is the arrival time of the first wave of the i-th valid waveform receiving wave data; ri are the first arrival time of the i-th effective waveform excitation wave data; V sd is the wave velocity of the axial material; l is the distance between the probe and the coal sample.

2. The method for continuous automatic and precise measurement of wave velocity of three-dimensional loaded gas-containing coal according to claim 1, characterized in that: The step S1 of obtaining synchronous acoustic wave data of the coal body under three-dimensional loading conditions of the gas-containing coal includes: Acoustic wave synchronous acquisition data of coal body under three-dimensional loading conditions of gas-containing coal is obtained through the three-dimensional loading acoustic wave measuring device of gas-containing coal; Among them, the three-dimensional loaded acoustic wave measuring device for gas-containing coal includes: a gas-solid coupling three-axis coal rock clamping sub-device, a three-axis loading power sub-device connected to the gas-solid coupling three-axis coal rock clamping sub-device respectively, a gas transmission control sub-device and an acoustic wave signal excitation and collection sub-device.

3. The method for continuous automatic and precise measurement of wave velocity of three-dimensional loaded gas-containing coal according to claim 2, characterized in that: The method of obtaining synchronously collected acoustic wave data of a coal body under three-dimensional loading conditions of gas-containing coal by using a three-dimensional loaded acoustic wave measuring device for gas-containing coal includes: The acoustic wave signal excitation and acquisition sub-device in the three-dimensional loaded acoustic wave measuring device for gas-containing coal is used to excite and receive signals with a preset repetition period, thereby obtaining synchronous acoustic wave acquisition data of the coal body under the three-dimensional loaded conditions of gas-containing coal; The number of signals excited each time is 2.

4. The method for continuous automatic and precise measurement of wave velocity of three-dimensional loaded gas-containing coal according to claim 3 is characterized in that: The exciting and receiving of a signal with a preset repetition period includes: The device excites and receives signals with a preset repetition period, with a sampling frequency of not less than 3 MHz, a pulse width range of 2 to 20 us, a pulse period of 500 to 3000 us, and an amplitude of the excited signal of not less than 5 V.

5. The method for continuous automatic and precise measurement of wave velocity of three-dimensional loaded gas-containing coal according to claim 1, characterized in that: The step S2 of automatically intercepting effective waveform data from the synchronously integrated data using a peak interval method includes: Obtaining the amplitude of the synchronously integrated data, in which the maximum amplitude exceeds the preset amplitude threshold twice in a preset first time, and marking the peak moment of the obtained amplitude as the first exceeding-limit moment; intercepting waveform data of a preset second time before and after the first exceeding-limit moment and saving the data as the first valid waveform data; According to the first exceeding time and the preset time interval, the next exceeding time is obtained, the waveform data of the preset second time before and after the next exceeding time is intercepted and saved as the next valid waveform data, thereby obtaining all the valid waveform data of the synchronously integrated data.

6. A system for continuously and automatically accurately measuring the wave velocity of gas-laden coal under three-dimensional loading, the system being used to implement the method for continuously and automatically measuring the wave velocity of gas-laden coal under three-dimensional loading as claimed in any one of claims 1 to 5, characterized in that: The system comprises: The data acquisition module is used to obtain the synchronous acoustic wave data of the coal body under the three-dimensional loading condition of the gas-containing coal; The acoustic wave synchronous acquisition data of the coal body includes: the excitation wave data at the top of the coal body and the receiving wave data at the bottom of the coal body; An effective waveform interception module is used to synchronously integrate the synchronously collected acoustic wave data of the coal body and automatically intercept effective waveform data from the synchronously integrated data using a peak interval method; A first arrival wave arrival time identification module is used to automatically identify the first arrival wave arrival time of the effective waveform data by using a short-time window mean mutation method; Wherein, the first arrival time of the wave includes: the first arrival time of the excitation wave at the top of the coal body and the first arrival time of the receiving wave at the bottom of the coal body; The output module is used to calculate the continuous automatic measurement result of the wave velocity of gas-containing coal according to the arrival time of the first arrival wave of the excitation wave and the arrival time of the first arrival wave of the receiving wave.

7. A three-dimensional loaded gas-containing coal wave velocity continuous automatic precision measurement device, characterized in that: The three-way loaded gas-containing coal wave velocity continuous automatic and precise measurement equipment includes: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the method according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program code, which can be called by a processor to execute the method according to any one of claims 1 to 5.

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