Mine dynamic disaster early warning method and device based on ground microseismic monitoring

Abstract

The application discloses a mine dynamic disaster early warning method and device based on ground microseismic monitoring, which comprises the following steps: S1, acquiring microseismic events of a target ground area; S2, setting the ground area as a grid; S3, establishing a spatial plane according to the microseismic events and the grid; S4, calculating the distance between the next microseismic event in a time sequence and the spatial plane; S5, judging whether the mechanical property of the microseismic event is similar to the property of a selected early warning plane according to the distance; and S6, determining whether to early warn and the early warning level according to the frequency of microseismic events with similar mechanical properties in a unit time. The technical scheme of the application realizes the monitoring and early warning of mine dynamic disasters, and the early warning time can be advanced by at least 5 hours to start the indication, thereby effectively guaranteeing the safety of life and property in the mine production process.

Description

Technical Field

[0001] This invention belongs to the field of geological engineering technology, specifically relating to a method and device for early warning of mine dynamic disasters based on ground microseismic monitoring. Background Technology

[0002] Based on the analysis of shear zone intersections and nonlinear dynamic evolution behavior of coal and rock under plane strain conditions, the theory of predicting the spatiotemporal patterns of large earthquakes through numerous small earthquake events is a classic seismological theory. The fundamental premise of this theory is that the spatiotemporal and intensity distribution of seismic activity and the characteristics of seismic waves are responses of the stratum stress field. Therefore, predicting earthquakes involves analyzing past earthquakes to observe the state of the geostress field and searching for premonitory seismic events caused by the concentration and intensification of stress near the epicenter.

[0003] Applying the theory and methods of earthquake-based earthquake prediction to microseismic early warning of rockbursts in coal mines can be summarized as follows: During mining, rapid changes in stress in the coal and rock mass trigger a series of microseismic events. These microseismic events are generally distributed linearly or planarly in space, and consecutively occurring microseismic events often have the same or similar mechanical properties. When the frequency of microseismic events with the same or similar mechanical properties occurring in a certain plane within a unit of time exceeds a certain critical value, it is often a precursor to a destructive earthquake and should be used as an important indicator for rockburst early warning.

[0004] Currently, early warning methods for mine dynamic disasters mainly include the following: First, the seismic monitoring method, which involves setting up seismic monitoring stations near the mine to monitor the propagation of seismic waves in real time and issue timely warnings when seismic anomalies are detected; second, the geostress monitoring method, which involves setting up geostress monitoring stations near the mine to monitor the stress changes of underground rocks in real time and issue timely warnings when geostress anomalies are detected; third, the microseismic monitoring method, which involves setting up multiple microseismic sensors around the mine to monitor weak seismic signals in real time and issue timely warnings when microseismic anomalies are detected; and fourth, the acoustic monitoring method, which involves setting up acoustic wave sensors in the mine to monitor the propagation of acoustic waves inside the mine in real time and issue timely warnings when acoustic anomalies are detected. However, many early warning methods for mine dynamic disasters still have certain errors and cannot completely and accurately predict the occurrence of mine dynamic disasters. In addition, they have high requirements for geological conditions, such as the need for monitoring at a certain depth underground. Therefore, it is necessary to continuously explore and research new early warning methods to improve their accuracy and reliability. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and device for early warning of mine dynamic disasters based on ground microseismic monitoring, which realizes the monitoring and early warning of mine dynamic disasters, and the early warning time can start at least 5 hours in advance, effectively protecting the safety of life and property during mine production.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for early warning of dynamic disasters in mines based on ground microseismic monitoring includes:

[0008] Step S1: Acquire microseismic events in the target ground area;

[0009] Step S2: Set the ground area as a grid;

[0010] Step S3: Establish a spatial plane based on microseismic events and grids;

[0011] Step S4: Calculate the distance between the next microseismic event in the time series and the spatial plane;

[0012] Step S5: Determine whether the mechanical properties of the microseismic event are similar to those of the selected warning plane based on the distance;

[0013] Step S6: Determine whether to issue an early warning and the warning level based on the frequency of microseismic events with similar mechanical properties calculated per unit time.

[0014] Preferably, in step S1, microseismic signal data of the target ground area is collected by high-precision stations, and microseismic events are obtained based on the microseismic signal data.

[0015] Preferably, in step S2, the ground area is set as a square grid.

[0016] Preferably, the time series in step S4 satisfies the following: the moment when the most events occur within a predetermined time period is selected as the start time of the time series, and the time when the most events occur per unit time period is selected is denoted as Tmax; the distance in step S4 satisfies the following: when determining whether microseismic events belong to the same spatial plane, the positioning system error is allowed to be within the distance from the point to the plane.

[0017] This invention also provides a method for early warning of mine dynamic disasters based on ground microseismic monitoring, comprising:

[0018] The acquisition module is used to acquire microseismic events in the target ground area;

[0019] The partitioning module is used to set the ground area as a grid;

[0020] A module is created to establish a spatial plane based on microseismic events and grids;

[0021] The calculation module is used to calculate the distance between the next microseismic event in the time series and the spatial plane;

[0022] The judgment module is used to determine whether the mechanical properties of microseismic events are similar to those of the selected warning plane based on the distance.

[0023] The early warning module is used to determine whether to issue an early warning and the warning level based on the frequency of microseismic events with similar mechanical properties calculated per unit time.

[0024] Preferably, the acquisition module collects microseismic signal data of the target ground area through high-precision stations and obtains microseismic events based on the microseismic signal data.

[0025] Preferably, the division module sets the ground area as a square grid.

[0026] Preferably, the time series satisfies the following: the moment when the most events occur within a predetermined time period is selected as the start time of the time series, and the time when the most events occur per unit time period is selected is denoted as Tmax; the distance satisfies the following: when determining whether microseismic events belong to the same spatial plane, the positioning system error is allowed to be within the distance from the point to the plane.

[0027] The mine dynamic disaster early warning method of this invention is based on the principle that if continuous microseismic events occur in a spatially defined plane, and these events have similar or identical source properties, then high-energy dynamic disaster events will preferentially occur along the line connecting the spatial locations of adjacent microseismic events. This early warning method utilizes monitoring stations deployed around the mine to monitor microseismic events in underground coal mines in real time. Through signal processing and data analysis, abnormal vibration signals are identified, and the potential severity of the disaster and the reliability of the early warning can be predicted. Alarms are issued through changes in sound and color, while simultaneously displaying the expected geological layers where the disaster is expected to occur. This method has the advantages of convenient deployment, accurate early warning, simple operation, and is not limited by coal mine tunnel engineering. In particular, the monitoring system will not be damaged after a coal mine disaster occurs, providing uninterrupted data support for mine rescue and disaster management.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. Timely Early Warning: This method can monitor microseismic signals within the mining area in real time and generate corresponding early warning information based on the results of excavation and analysis. This helps to promptly identify potential dynamic disaster risks, thereby enabling measures to be taken to mitigate their impact.

[0030] 2. Improved Production Efficiency: Because this method can provide timely warnings of dynamic disaster risks within the mine, it can prevent production interruptions and shutdowns caused by disasters. When danger is imminent, measures can be taken in advance to prevent disasters from occurring. This helps improve the mine's production efficiency and economic benefits. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the embodiments will be briefly described below using the accompanying drawings. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of a mine dynamic disaster early warning method based on ground microseismic monitoring, according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the principle of a mine dynamic disaster early warning method based on ground microseismic monitoring, according to an embodiment of the present invention.

[0034] Figure 3 Case study for early warning of large-scale energy events in coal mines;

[0035] Figure 4 Site layout and station distribution map. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the implementation examples of the present invention, and not all of the implementation examples. Based on the implementation examples of the present invention, all other implementation examples obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Example 1:

[0039] like Figure 1 As shown, this embodiment of the invention provides a method for early warning of mine dynamic disasters based on ground microseismic monitoring, including: installing a large number of high-precision stations in the target ground area to form a 3D monitoring network for picking up and analyzing microseismic signal data, monitoring microseismic events to assess the vibration situation of underground mines, specifically including the following steps:

[0040] Step S1: Acquire microseismic events in the target ground area;

[0041] Step S2: Set the ground area as a grid;

[0042] Step S3: Establish a spatial plane based on microseismic events and grids;

[0043] Step S4: Calculate the distance between the next microseismic event in the time series and the spatial plane;

[0044] Step S5: Determine whether the mechanical properties of the microseismic event are similar to those of the selected warning plane based on the distance;

[0045] Step S6: Determine whether to issue an early warning and the warning level based on the frequency of microseismic events with similar mechanical properties calculated per unit time.

[0046] As one embodiment of the present invention, in step S1, microseismic signal data of the target ground area is collected by a high-precision station, and microseismic events are obtained based on the microseismic signal data, requiring timely and accurate data transmission.

[0047] In one embodiment of the present invention, step S2 involves setting the target ground area into a corresponding grid. The grid must be square, requiring the target ground area to be divided into sections and the grids to be numbered. Under the same computational load, a denser grid improves real-time calculation accuracy. This optimization of the automatic positioning method achieves more accurate positioning.

[0048] As one embodiment of the present invention, such as Figure 2 As shown, in step S3, the established spatial plane should meet the following requirements: (1) The spatial plane should be established based on three consecutive microseismic events, and the events should be of moderate energy and with a relatively short time interval; (2) The spatial plane should have a dip angle close to 0° or similar to the dip angle of the strata. This is the first indicator for the optimal selection of the rockburst early warning plane, namely: θ≈0∨θ=α, where α is the dip angle of the strata in the study area and θ is the dip angle of the spatial plane of the early warning plane.

[0049] As one embodiment of the present invention, such as Figure 2 As shown, in step S4, the distance between the next microseismic event in the time series and the plane is calculated. The time series and the distance should satisfy:

[0050] (1) Select the moment when the most events occur within a certain period of time as the start time of the time series, and select the time when the most events occur per unit time as Tmax;

[0051] (2) When determining whether microseismic events belong to the same spatial plane, the positioning system error γ should be allowed within the distance from the point to the plane. This is the second criterion for the optimal selection of the rockburst early warning plane, namely: d ≤ k·γ, where k is the error coefficient, generally taken as 2-5. Positioning system error v p P-wave velocity, in m / s; f s This represents the system sampling rate, expressed in times per second. Generally, d ≤ 30m.

[0052] As one embodiment of the present invention, such as Figure 2 As shown, in step S5, it is determined whether the mechanical properties of the microseismic event are similar to those of the selected warning plane. Tension-type and strike-slip types cannot exist in the same warning plane. Based on the mechanical properties, fault Q can be classified into the following three categories, where f1, f2, and f3 are damage coefficients:

[0053]

[0054] In one embodiment of the present invention, in step S6, when determining the warning level, F = f1 + f2 + f3, the following equation is satisfied if and only if f1, f2, and f3 do not exist simultaneously, where P is the weighted level:

[0055]

[0056] Compared to the limitations of downhole monitoring, where the placement of geophone arrays is restricted to a certain line segment, potentially leading to a series of errors, and downhole equipment is expensive and array construction is complex and time-consuming, resulting in high costs, the surface monitoring of this invention, due to its large monitoring azimuth angle, can more accurately determine the direction of microseismic cracks, with higher horizontal positioning accuracy. Furthermore, the large number of geophones allows for a wider monitoring range. Surface monitoring can also achieve all-weather, continuous monitoring, enabling timely detection of the generation and propagation of microseismic cracks, providing more accurate and reliable early warning information for mine safety. Simultaneously, surface monitoring technology can be combined with other seismic monitoring technologies, such as seismic monitoring and geostress monitoring, to further improve the accuracy and reliability of monitoring results.

[0057] The present invention has the following advantages:

[0058] 1. The underground environment of coal mines is complex, making the installation of monitoring equipment difficult and prone to damage. Surface microseismic monitoring effectively overcomes this limitation. Based on surface microseismic detection technology, the accuracy and reliability of early warning systems for mine dynamic disasters can be improved, reducing false alarms and missed alarms.

[0059] 2. The early warning method of this invention can monitor and collect various parameters within the mine in real time, and can transmit the collected data to the ground monitoring center via a network, realizing real-time data sharing. Through real-time monitoring and early warning, rescue time can be effectively shortened, rescue efficiency improved, and the impact of disasters on production reduced.

[0060] 3. The early warning method of this invention has an automatic alarm function. When the monitored parameter exceeds the set value, the system will automatically issue an alarm signal to notify relevant personnel to take corresponding measures.

[0061] 4. The early warning method of this invention is highly targeted and practical, can adapt to different geological environments and coal mine characteristics, and is easy to promote and apply.

[0062] like Figure 3 , 4 As shown in the figure, this embodiment of the invention provides a mine dynamic disaster early warning method, which is applied to a mine in Shanxi Province.

[0063] The coal seam in the test mine is buried at a depth of about 600m and has a thickness of 4.2-6.3m. The monitoring area is located in the 3208 working face in the northern part of the mine.

[0064] 1. Deploy ground monitoring stations. The locations of the stations are determined according to the geological conditions of the selected area. The stations are divided into corresponding grids. Microseismic events in the selected area are continuously collected and transmitted to the information processing center. The data are processed through noise reduction, filtering, and other methods to facilitate subsequent screening of microseismic events. Real-time monitoring of the mining area helps ensure production safety. With the reference point coordinates set to (0,0), the relative coordinates of the stations are as follows: (1359.19, 591.29), (1042.28, 663.88), (842.6, 176.16), (833.19, 521.07), (817.8, 831.71), (654.68, -246.81), (559.28, -59.41), (596.14, 811.79), (510.03, 1462.41), (372.12, 484.31), (314.53, -163.42), (21 2.26, 98.54), (186.9, 984.88), (229.1, 1307.73)(-44.26, 455.16), (-8.06, -224.16), (-69.84, 115.61), (-112.51, 982.96), (-39.93, 1136.39), (-378.91, 149.23), (-269.92, 463.16), (-283.38, 914.65), (-633.29, 225.39), (-633.29, 636.28).

[0065] 2. The events are sorted according to their chronological order of occurrence, starting as the first event, then the second event, and so on. In this embodiment of the invention, the three events selected occur consecutively, have moderate energy, and a relatively short time interval. Their relative coordinates are: (-260.91778, 294.09316), (-242.30667, 276.05105), and (860.21556, 1427.13737). The first event occurred at 2022-02-12T07:04:47.99637, with a depth of... The first event occurred at a depth of 705.26m, with a magnitude of -1.63, energy of 253.07J, dominant frequency of 38Hz, and a strike-slip focal nature with a focal direction of NE31. The second event occurred at 2022-02-12T12:03:04.226656, with a depth of 522.11m, a magnitude of -1.78, energy of 152.31J, dominant frequency of 25Hz, and a dip-slip focal nature with a focal direction of NE41. The third event occurred at 2022-02-12T14:58:20.882525, with a depth of 423.83m, a magnitude of -1.05, energy of 1802.36J, dominant frequency of 42Hz, and a strike-slip focal nature with a focal direction of NE36.

[0066] 3. If the projections of these three events onto the plane can be connected by a line, and the projection of the next event also falls on this line, then this line should be taken seriously. The observation should focus on whether subsequent microseismic events will affect the plane or even cause disasters. In this embodiment of the invention, the equation expression composed of the first three events is: Y = 1.0268X + 543.58, where XY represents direction, Y represents east, and X represents north.

[0067] 4. The coordinates of the fourth event are (619.76, 1173.82621), the time of occurrence is 2022-02-12T21:56:13.645795, the depth is 387.45m, the magnitude is -1.05, the energy is 1802.36J, the dominant frequency is 29Hz, the focal nature is strike-slip, the focal direction is NW66, and the distance from the fourth event to this line is 4.2722 meters, which is less than 30 meters and within the allowable error range. Therefore, this event is accepted as the fourth event. Events meeting the requirements are selected, and those not meeting the requirements are not accepted. The results after selection are summarized in a table for subsequent data processing.

[0068] The mechanical properties of each microseismic event and its dependence on the selected plane were analyzed one by one. Based on the fault classification, the relative coordinates of the fifth event were (782.04889, 1366.51589), the depth was 417.52, the magnitude was -0.22, the energy was 29918.55 J, the dominant frequency was 20 Hz, the focal nature was strike-slip, and the focal direction was NE49. In terms of energy, this event was relatively high. According to the weighted index, the weighted index for April 3rd in this area was 4.516, and its impact type was classified as moderate. The weighted index for the event on February 12th, 2022 was 3.333, classifying it as weak impact.

[0069] Example 2:

[0070] This invention provides a mine dynamic disaster early warning device based on ground microseismic monitoring, comprising:

[0071] The acquisition module is used to acquire microseismic events in the target ground area;

[0072] The partitioning module is used to set the ground area as a grid;

[0073] A module is created to establish a spatial plane based on microseismic events and grids;

[0074] The calculation module is used to calculate the distance between the next microseismic event in the time series and the spatial plane;

[0075] The judgment module is used to determine whether the mechanical properties of microseismic events are similar to those of the selected warning plane based on the distance.

[0076] The early warning module is used to determine whether to issue an early warning and the warning level based on the frequency of microseismic events with similar mechanical properties calculated per unit time.

[0077] As one embodiment of the present invention, the acquisition module collects microseismic signal data of the target ground area through high-precision stations, and obtains microseismic events based on the microseismic signal data.

[0078] As one embodiment of the present invention, the division module sets the ground area as a square grid.

[0079] As one embodiment of the present invention, the time series satisfies the following: the moment when the most events occur within a predetermined time period is selected as the start time of the time series, and the time when the most events occur per unit time period is selected is denoted as Tmax; the distance satisfies the following: when determining whether microseismic events belong to the same spatial plane, the positioning system error is allowed to be within the distance from the point to the plane.

[0080] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A method for early warning of dynamic disasters in mines based on ground microseismic monitoring, characterized in that, include: Step S1: Acquire microseismic events in the target ground area; Step S2: Set the ground area as a grid; Step S3: Establish a spatial plane based on microseismic events and grids; Step S4: Calculate the distance between the next microseismic event in the time series and the spatial plane; Step S5: Determine whether the mechanical properties of the microseismic event are similar to those of the selected warning plane based on the distance; Step S6: Determine whether to issue an early warning and the warning level based on the frequency of microseismic events with similar mechanical properties calculated per unit time; In step S3, the established spatial plane should meet the following requirements: (1) The spatial plane is established based on three consecutive microseismic events, and the events should have moderate energy and a short time interval; (2) The spatial plane should have a dip angle close to 0° or similar to the dip angle of the strata. In step S5, tension-type and strike-slip faults cannot exist in the same warning plane. Based on their mechanical properties, fault Q can be classified into the following three categories, where f1, f2, and f3 are failure coefficients: The time series in step S4 satisfies the following: the moment when the most events occur within a predetermined time period is selected as the start time of the time series, and the time when the most events occur per unit time period is selected is denoted as Tmax; the distance in step S4 satisfies the following: when determining whether microseismic events belong to the same spatial plane, the positioning system error is allowed to be within the distance from the microseismic event occurrence point to the plane. In step S6, when determining the warning level, F = f1 + f2 + f3, the following equation is satisfied if and only if f1, f2, and f3 do not exist simultaneously, where P is the weighted level: P=Tmax*F= 。 2. The mine dynamic disaster early warning method based on ground microseismic monitoring as described in claim 1, characterized in that, In step S1, microseismic signal data of the target ground area are collected through high-precision stations, and microseismic events are obtained based on the microseismic signal data.

3. The mine dynamic disaster early warning method based on ground microseismic monitoring as described in claim 2, characterized in that, In step S2, the ground area is set as a square grid.

4. A mine dynamic disaster early warning device based on ground microseismic monitoring, which implements the mine dynamic disaster early warning method based on ground microseismic monitoring as described in claim 1, characterized in that, include: The acquisition module is used to acquire microseismic events in the target ground area; The partitioning module is used to set the ground area as a grid; A module is created to establish a spatial plane based on microseismic events and grids; The calculation module is used to calculate the distance between the next microseismic event in the time series and the spatial plane; The judgment module is used to determine whether the mechanical properties of microseismic events are similar to those of the selected warning plane based on the distance. The early warning module is used to determine whether to issue an early warning and the warning level based on the frequency of microseismic events with similar mechanical properties calculated per unit time.

5. The mine dynamic disaster early warning device based on ground microseismic monitoring as described in claim 4, characterized in that, The acquisition module collects microseismic signal data of the target ground area through high-precision stations and obtains microseismic events based on the microseismic signal data.

6. The mine dynamic disaster early warning device based on ground microseismic monitoring as described in claim 5, characterized in that, The partitioning module sets the ground area as a square grid.

7. The mine dynamic disaster early warning device based on ground microseismic monitoring as described in claim 6, characterized in that, The time series satisfies the following: the moment when the most events occur within a predetermined time period is selected as the start time of the time series, and the time when the most events occur per unit time period is selected is denoted as Tmax; the distance satisfies the following: when determining whether microseismic events belong to the same spatial plane, the positioning system error is allowed to be within the distance from the microseismic event occurrence point to the plane.

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