Small-scale gauge function determination method based on micro-seismic monitoring system

Abstract

A small-scale gauge function determination method based on a micro-seismic monitoring system comprises the following steps: installing a plurality of micro-seismic monitoring stations for receiving strong mine seismic events in a mine small-scale range according to a gauge function formula to be fitted and a mining area range; the method comprises the following steps of: completely recording a vibration wave waveform of a strong mine earthquake event generated by a mine excavation activity by utilizing a micro-earthquake monitoring station, and calculating to obtain a maximum displacement amplitude; according to the maximum displacement amplitude and the magnitude and focus position of the strong mine earthquake event monitored by the earthquake monitoring station network, gauge function values corresponding to the micro-earthquake monitoring stations in the small scale range and the distance between the micro-earthquake monitoring stations and a focus are obtained through back calculation; and a gauge function calculation formula in a small-scale range is obtained through numerical fitting of a gauge function value and the distance between the monitoring station and the seismic source. According to the method, a more accurate gauge function is provided for strong mine earthquake magnitude calculation in a specific region or under a specific condition, and the accuracy and reliability of strong mine earthquake magnitude calculation in a small-scale range are improved.

Description

Technical Field

[0001] The present invention relates to a method for determining a small-scale gauge function based on a microseismic monitoring system, and belongs to the technical field of strong mine earthquake magnitude. Background Art

[0002] In the field of seismology, the gauge function is a key tool for converting the observed seismic wave amplitude into the earthquake magnitude. It can accurately correct the influence of the change of seismic wave amplitude with distance, and has an important impact on seismic monitoring and research.

[0003] Traditional gauge functions are usually obtained based on extensive seismic data and geological surveys. Especially for medium- and long-distance seismic observation points, they can better reflect the influence of distance on amplitude. However, in the small-scale range (0 - 5 km), this method is not accurate enough. For example, for strong mine earthquakes induced by coal mining activities, in microseismic monitoring within the small-scale range, the existing gauge functions cannot fully reflect regional geological differences and cannot accurately calculate the magnitude of strong mine earthquakes. This inaccuracy leads to, on the one hand, the inconsistency between the magnitude calculated by microseismic monitoring and the magnitude released by the seismic department; on the other hand, it also results in significant differences in the magnitudes measured at different observation points under the same instrument and foundation conditions, and the equivalent comparison of magnitudes in different regions cannot be achieved. Summary of the Invention

[0004] The present invention provides a method for determining a small-scale gauge function based on a microseismic monitoring system, which can accurately calculate the gauge function value within the small-scale range, thereby improving the accuracy and reliability of calculating the magnitude of strong mine earthquakes in the small-scale range.

[0005] To achieve the above object, the present invention provides a method for determining a small-scale gauge function based on a microseismic monitoring system, including the following steps:

[0006] S1. Within the small-scale range of the mine, install multiple microseismic monitoring stations for receiving strong mine earthquake events according to the gauge function formula to be fitted and the range of the mining area.

[0007] S2. Use the microseismic monitoring stations to completely record the vibration wave waveforms of strong mine earthquake events generated by mine excavation activities, and calculate the maximum displacement amplitude A.

[0008] S3. According to the maximum displacement amplitude obtained in S2 and the magnitude and epicenter location of the strong mine earthquake events monitored by the seismic monitoring network, back-calculate the gauge function values corresponding to each microseismic monitoring station within the small-scale range and the distance between the microseismic monitoring station and the epicenter.

[0009] S4. Through numerical fitting of the gauge function values and the distance between the monitoring station and the epicenter, obtain the gauge function calculation formula within the small-scale range.

[0010] Further, the strong mine tremor event in S1 refers to an event where the propagation distance of its shock wave is not less than 10 km and is recorded by the seismic monitoring network; the small-scale range refers to the spatial distance r between the occurrence location of the strong mine tremor event and the microseismic monitoring station within the range of 0 to 5 km; the formula for the gauge function to be fitted is: R = αln(r) + β, where R is the gauge function value, and α and β are fitting coefficients.

[0011] Further, the multiple microseismic monitoring stations in S1 include velocity type, acceleration type, and displacement type, respectively corresponding to the velocity, acceleration, and displacement values of the strong mine tremor shock wave signal received; the microseismic monitoring stations start from 100 to 300 m from the center point of the excavation area range and are arranged at approximately equal ratio distances towards the distance, The ratio range is q = 1.0 to 3.0, ensuring that there are at least 8 monitoring stations within the range of 0 to 10 km, where r i and r i+1 are respectively the distance between the i-th microseismic monitoring station and the center point of the excavation area range and the distance between the (i + 1)-th microseismic monitoring station and the center point of the excavation area range.

[0012] Further, when a strong mine tremor event occurs in S2, the microseismic monitoring station is triggered and completely records the shock wave signal of the strong mine tremor. When the microseismic monitoring station is of the velocity type, the recorded shock wave signal is a velocity signal; when the microseismic monitoring station is of the displacement type, the recorded shock wave signal is a displacement signal; when the microseismic monitoring station is of the acceleration type, the recorded shock wave signal is an acceleration signal; the maximum displacement amplitude A refers to: when the microseismic monitoring station records a velocity signal, the displacement signal is obtained by using the first-order discrete integration method for the sampling time, and then the maximum value A of the absolute value of the displacement signal is directly found; when the recorded signal is a displacement signal, the maximum value A of the absolute value of the displacement signal is directly found; when the recorded signal is an acceleration signal, the displacement signal is obtained by using the second-order discrete integration method for the sampling time, and then the maximum value A of the absolute value of the displacement signal is directly found.

[0013] Further, for the magnitude of the strong mine tremor event monitored by the seismic monitoring network in S3, its calculation formula is: M L = lg(A) + R; the formula for back-calculating the gauge function value corresponding to each microseismic monitoring station within the small-scale range is: R j = M L - lg(A j ), where R j is the gauge function value corresponding to the j-th station within the small-scale range, A j is the maximum displacement amplitude of the j-th station, M L is the magnitude; the formula for back-calculating the distance r j between the microseismic monitoring station and the earthquake source is: where xj , y j , z j are the spatial coordinates of the position of the j-th microseismic monitoring station; x 0 , y 0 , z 0 are the spatial coordinates of the position of the strong mine earthquake source.

[0014] Furthermore, in step S4, α and β are obtained by numerically fitting the gauge function value and the distance between the monitoring station and the earthquake source using the linear least squares method. The specific formula is:

[0015]

[0016] In the formula, m is the total number of installed microseismic monitoring stations; by determining the gauge function calculation formula R = αln(r) + β in the small-scale range, the gauge function R corresponding to the distance between any earthquake source and the monitoring station at small scales is obtained.

[0017] In the present invention, within the small-scale range of the mine, multiple microseismic monitoring stations for receiving strong mine earthquake events are installed according to the gauge function formula to be fitted and the mining area range; the microseismic monitoring stations are used to completely record the vibration wave waveforms of the strong mine earthquake events generated by the mine excavation activities, and the maximum displacement amplitude is calculated; according to the maximum displacement amplitude and the magnitude and source position of the strong mine earthquake events monitored by the seismic monitoring network, the gauge function values corresponding to each microseismic monitoring station within the small-scale range and the distance between the microseismic monitoring station and the earthquake source are inversely calculated; through the numerical fitting of the gauge function value and the distance between the monitoring station and the earthquake source, the gauge function calculation formula in the small-scale range is obtained. The present invention realizes providing a more accurate gauge function for calculating the magnitude of strong mine earthquakes in specific regions or under specific conditions, which is helpful for the risk assessment of strong mine earthquakes and the design of strong mine earthquake early warning systems, and improves the accuracy and reliability of calculating the magnitude of strong mine earthquakes in the small-scale range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the flowchart of the work of the present invention;

[0019] Figure 2 is the schematic diagram of the layout of microseismic monitoring stations in the embodiment of the present invention;

[0020] Figure 3 is the waveform diagram of the strong mine earthquake event in the embodiment of the present invention;

[0021] Figure 4 is the result diagram of the integration of the velocity signal and the maximum displacement amplitude of the No. 2 microseismic monitoring station in the embodiment of the present invention;

[0022] Figure 5 is the schematic diagram of the fitting of the gauge function expression in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, a method for determining a small-scale gauge function based on a microseismic monitoring system comprises the following steps:

[0025] S1. In the small-scale range of the mine, multiple microseismic monitoring stations for receiving strong mine earthquake events are installed according to the gauge function formula to be fitted and the scope of the mining area;

[0026] S2. Use microseismic monitoring stations to completely record the waveform of strong mine earthquake events generated by mining activities, and calculate the maximum displacement amplitude A;

[0027] S3, based on the maximum displacement amplitude obtained in S2 and the magnitude and focal position of the strong mining earthquake event monitored by the seismic monitoring network, the gauge function value corresponding to each microseismic monitoring station within the small scale range and the distance between the microseismic monitoring station and the focal point are calculated in reverse;

[0028] S4. By numerically fitting the gauge function value with the distance between the monitoring station and the earthquake source, the calculation formula of the gauge function in the small scale range is obtained.

[0029] Through an example analysis of the use of a microseismic monitoring system and strong mine earthquake signals to determine the small-scale gauge function in the 6306 working face of a mine, the analysis and implementation steps of the method of the present invention are as follows:

[0030] (1) Figure 2 As shown in Figure 1, a microseismic monitoring station is deployed near the 6306 working face of a mine. The station is velocity type, and the total number of stations is 16. Starting from 150m away from the center point of the 6306 working face, according to the gauge function formula R = αln (r) + β, The ratio q is in the range of [1 2.5] and is arranged far away. The spatial coordinates of the measuring stations are shown in Table 1:

[0031] Table 1 Spatial coordinates of microseismic monitoring stations

[0032] Sequence number j <![CDATA[x j > <![CDATA[y j > <![CDATA[z j > 1 39489749 3921194 -652.097 2 39489898 3921495 -650.04 3 39488884 3921842 -645.7 4 39490241 3921283 -659.6 5 39490587 3921620 -657.83 6 39489486 3922456 -453.4 7 39488514 3921940 -446.8 8 39490566 3922241 -739.15 9 39490410 3922141 -447.407 10 39490079 3923066 -555.9 11 39490665 3923302 -449.6 12 39486865 3924466 -549.2 13 39486295 3925638 -506.1 14 39486582 3926050 -477.25 15 39486906 3926367 -476.1 16 39492074 3928063 -622.6

[0033] (2) A strong mine earthquake occurred during the production process at the 6306 working face, which was recorded by the National Earthquake Monitoring Network;

[0034] (3) Figure 3 As shown, the microseismic monitoring station completely records the seismic wave waveform of the strong mining earthquake event, and the recorded seismic wave signal is a velocity signal;

[0035] (4) Figure 4As shown in the figure, the displacement signal is obtained by integrating the velocity signal using the first-order discrete integration method for the sampling time. The maximum value A of the absolute value of the displacement signal of each station is determined in turn for all microseismic monitoring stations, as shown in Table 2:

[0036] Table 2 Maximum value of the absolute value of the displacement signal

[0037] Sequence number j <![CDATA[A j / um]]> Sequence number j <![CDATA[A j / um]]> 1 96.2 9 85.1 2 132.6 10 48.7 3 85.7 11 30.6 4 91.1 12 17.0 5 89.2 13 13.9 6 48.1 14 13.5 7 97.1 15 12.0 8 94.5 16 5.2

[0038] (5) Magnitude M of this strong mine earthquake event released by the China Earthquake Administration L = 2.2 magnitude;

[0039] (6) According to the back-calculation formula R j = M L -lg(A j ), the gauge function values corresponding to each monitoring station within a small scale range are back-calculated using the magnitude M L = 2.2, as shown in Table 3:

[0040] Table 3 Gauge function values corresponding to each microseismic monitoring station

[0041]

[0042]

[0043] (7) The epicenter location of this strong mine earthquake event released by the China Earthquake Administration is x 0 = 39489521.38, y 0 = 3921310.51, z 0 = -420.71. According to the formula The distance from the epicenter to the station is calculated, as shown in Table 4:

[0044] Table 4 Distances from each microseismic monitoring station to the epicenter of the strong mine earthquake event

[0045] Sequence number j <![CDATA[r j / km]]> Sequence number j <![CDATA[r j / km]]> 1 3.45E-01 9 1.22E+00 2 4.78E-01 10 1.85E+00 3 8.59E-01 11 2.30E+00 4 7.59E-01 12 4.13E+00 5 1.13E+00 13 5.40E+00 6 1.15E+00 14 5.58E+00 7 1.19E+00 15 5.69E+00 8 1.43E+00 16 7.22E+00

[0046] (8) Fitted by the linear least squares formula:

[0047]

[0048] Back-calculated to get R = αln(r) + β = 0.4319ln(r) + 0.339, and its fitting curve is as Figure 5 shown.

Claims

1. A method for determining a small-scale gauge function based on a microseismic monitoring system, characterized in that: The steps include: S1. In the small-scale range of the mine, multiple microseismic monitoring stations for receiving strong mine earthquake events are installed according to the gauge function formula to be fitted and the scope of the mining area; S2. Use microseismic monitoring stations to completely record the waveform of strong mine earthquake events generated by mining activities, and calculate the maximum displacement amplitude A; S3, based on the maximum displacement amplitude obtained in S2 and the magnitude and focal position of the strong mining earthquake event monitored by the seismic monitoring network, the gauge function value corresponding to each microseismic monitoring station within the small scale range and the distance between the microseismic monitoring station and the focal point are calculated in reverse; S4. By numerically fitting the gauge function value with the distance between the monitoring station and the earthquake source, the calculation formula of the gauge function in the small scale range is obtained.

2. The method for determining a small-scale gauge function based on a microseismic monitoring system according to claim 1, characterized in that: The S1 medium-strong mining earthquake event refers to an event whose shock wave propagation distance is not less than 10 km and is recorded by the seismic monitoring network; the small-scale range refers to the spatial distance r between the location of the strong mining earthquake event and the microseismic monitoring station is between 0 and 5 km; the gauge function formula to be fitted is: R=αln(r)+β, where R is the gauge function value, and α and β are fitting coefficients.

3. The method for determining a small-scale gauge function based on a microseismic monitoring system according to claim 1 or 2, characterized in that: The multiple microseismic monitoring stations in S1 include velocity type, acceleration type and displacement type, which correspond to the velocity, acceleration and displacement values ​​of the strong mining earthquake vibration wave signal received respectively; the microseismic monitoring stations are arranged from 100 to 300 meters away from the center point of the mining area, and are arranged in approximately equal proportions. The ratio range is q = 1.0 to 3.0, ensuring that there are at least 8 monitoring stations within the range of 0 to 10 km, where r i and r i+1 They are respectively the distance between the i-th microseismic monitoring station and the center point of the mining area and the distance between the i+1-th microseismic monitoring station and the center point of the mining area.

4. The method for determining a small-scale gauge function based on a microseismic monitoring system according to claim 3 is characterized in that: When the strong mining earthquake event in S2 occurs, the microseismic monitoring station is triggered and completely records the shock wave signal of the strong mining earthquake. When the microseismic monitoring station is of velocity type, the shock wave signal recorded by it is a velocity signal; when the microseismic monitoring station is of displacement type, the shock wave signal recorded by it is a displacement signal; when the microseismic monitoring station is of acceleration type, the shock wave signal recorded by it is an acceleration signal; the maximum displacement amplitude A means: when the signal recorded by the microseismic monitoring station is a velocity signal, the displacement signal is obtained by a single discrete integration method for the sampling time, and then the maximum value A of the absolute value of the displacement signal is directly sought; when the recorded signal is a displacement signal, the maximum value A of the absolute value of the displacement signal is directly sought; when the recorded signal is an acceleration signal, the displacement signal is obtained by a quadratic discrete integration method for the sampling time, and then the maximum value A of the absolute value of the displacement signal is directly sought.

5. The method for determining a small-scale gauge function based on a microseismic monitoring system according to claim 2, characterized in that: The magnitude of the strong mining earthquake event monitored by the seismic monitoring network in S3 is calculated as follows: L =lg(A)+R; the formula for back-calculating the gauge function value corresponding to each microseismic monitoring station within the small scale range is: R j =M L -lg(A j ), where R j is the gauge function value corresponding to the jth station in the small scale range, A j is the maximum displacement amplitude of the jth station, M L is the magnitude; the distance r between the microseismic monitoring station and the earthquake source is obtained by reverse calculation j The formula is: In the formula, x j ,y j 、z j is the spatial coordinate of the jth microseismic monitoring station; x0, y0, z0 are the spatial coordinates of the strong mining earthquake source.

6. The method for determining a small-scale gauge function based on a microseismic monitoring system according to claim 5, characterized in that: The numerical fitting of the gauge function value in S4 and the distance between the monitoring station and the earthquake source uses the linear least squares method to obtain α and β. The specific formula is: Where m is the total number of installed microseismic monitoring stations. By determining the small-scale range gauge function calculation formula R = αln(r) + β, the gauge function R corresponding to the distance between any earthquake source and the monitoring station at a small scale is obtained.

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