CN118757227A - "Ground-tunnel-hole" microseismic-electrical joint monitoring system and method - Google Patents

Abstract

The present invention discloses a "ground-lane-hole" microseismic-electrical joint monitoring system and method, which includes: multiple ground microseismic-electrical joint monitoring substations with the same number of ground survey lines, multiple underground microseismic-electrical joint monitoring substations with the same number of lane survey lines, and multiple underground microseismic-electrical joint monitoring substations with the same number of survey lines in the hole; it also includes an integrated seismic pickup electrode string, a ground solar energy and wireless base station, an underground explosion-proof and intrinsically safe power supply, an underground optical terminal, a ground optical terminal and a ground server; a multi-station collaborative acquisition control module and a microseismic-electrical data comprehensive processing and interpretation module are installed on the ground server; the microseismic-electrical data comprehensive processing and interpretation module is used to read monitoring data from the ground server and process and interpret the monitoring data. The present invention can obtain monitoring data with higher sensitivity, laying a data foundation for high-precision imaging of water hazards.

Description

"Ground-tunnel-hole" microseismic-electrical joint monitoring system and method

Technical Field

The invention relates to a mine water hazard monitoring method, belongs to the field of mine water prevention and control, and specifically relates to a "ground-tunnel-hole" microseismic-electrical method joint monitoring system and method.

Background Art

The formation of coal mine water hazards is the result of the combined effect of a series of factors. The occurrence of water inrush includes changes in the mechanical state of the rock mass and changes in the groundwater seepage field. Both are indispensable. The "Detailed Rules for Coal Mine Water Prevention and Control" stipulates that "for mines with complex and extremely complex hydrogeological types threatened by bottom plate pressure water, scientific and effective monitoring technologies such as microseismic and microseismic-electrical coupling should be used to establish a water inrush monitoring and early warning system, detect water bodies and water channels, evaluate the effects of engineering treatment such as grouting, and monitor the changes in water channels affected by mining." In the detailed rules, microseismic-electrical coupling is used as a scientific and effective technical means for water hazard monitoring and early warning. For working face water hazard monitoring, microseismic monitoring can locate the development position of mining cracks induced by changes in the mechanical state of the rock mass, and electrical monitoring can distinguish changes in the water content of cracks caused by changes in the groundwater seepage field. When the two methods are used together, the question of whether mining cracks are connected to water-rich areas can be answered, and water hazard monitoring and early warning of coal mining working faces can be realized.

Due to the limited space available underground in coal mines, whether it is microseismic monitoring or electrical monitoring, sensors are generally installed in the tunnels on both sides of the working face. All sensors are basically located on the same plane, and the sensitivity to information in the depth direction is poor, resulting in poor resolution of microseismic and electrical monitoring results in the depth direction, making it difficult to accurately locate the true depth of water inrush hazards. However, for water hazard warning, it is necessary to judge the strength of water hazard risks based on depth information. Inaccurate depth information will lead to a significant decrease in the accuracy of warnings, making it difficult to effectively guide water prevention and control work in coal mines. Therefore, there is an urgent need to improve the installation method of existing monitoring sensors and improve the resolution of monitoring results for depth information of water inrush hazards.

With the vigorous development of intelligent mining technology, the joint monitoring and early warning technology of microseismic and electrical methods for water hazards at working faces has ushered in a market explosion period. However, when these two monitoring methods are currently used together in coal mines, both the hardware and software are isolated from each other, which makes the installation and maintenance of the monitoring system difficult. At the same time, the interpretation results of the two monitoring methods are also independent of each other, which further leads to poor resolution and low accuracy of the monitoring results for water inrush hazards, making it difficult to meet the needs of intelligent construction of coal mines and water prevention and control work. Therefore, it is urgent to integrate microseismic and electrical monitoring systems to form an integrated water hazard monitoring system, improve the accuracy of water hazard monitoring and early warning, and meet the corresponding market technology needs.

Summary of the invention

In order to solve the technical problems of poor resolution and low monitoring accuracy of water inrush hazards in the prior art, the present invention provides a "ground-tunnel-hole" microseismic-electrical joint monitoring system and method.

In order to achieve the above object, the present invention adopts the following technical solution:

On the one hand, a "ground-lane-hole" microseismic-electrical method joint monitoring system is provided, including a plurality of ground microseismic-electrical method joint monitoring substations with the same number of ground survey lines, a plurality of underground microseismic-electrical method joint monitoring substations with the same number of lane survey lines, and a plurality of underground microseismic-electrical method joint monitoring substations with the same number of borehole survey lines; it also includes an integrated seismic pickup electrode string, a ground solar energy and wireless base station, an underground flameproof and intrinsically safe power supply, an underground optical terminal, a ground optical terminal and a ground server, wherein each ground microseismic-electrical method joint monitoring substation and each underground microseismic-electrical method joint monitoring substation are connected to the ground. The stations are connected with one or two integrated seismic pickup electrode strings respectively; the ground optical terminal communicates wirelessly with the ground server; the ground optical terminal connects to all underground microseismic-electrical joint monitoring substations corresponding to the tunnel measurement lines and the in-hole measurement lines through the underground optical terminal, and connects to the ground server on the other hand, and communicates wirelessly with the ground microseismic-electrical joint monitoring substation through the ground solar energy and wireless base station equipped with each ground microseismic-electrical joint monitoring substation; each underground microseismic-electrical joint monitoring substation is equipped with an underground flameproof and intrinsically safe power supply, and the underground flameproof and intrinsically safe power supply is connected to the underground power grid;

A multi-station collaborative acquisition control module and a microseismic-electrical data comprehensive processing and interpretation module are installed on the ground server; wherein, the multi-station collaborative acquisition control module is used to control the ground microseismic-electrical joint monitoring substation to transmit electrical signals, collect microseismic and electrical signals and store them on the ground server; at the same time, it is used to control the underground microseismic-electrical joint monitoring substation to transmit electrical signals, collect microseismic signals and store them on the ground server; the microseismic-electrical data comprehensive processing and interpretation module is used to read monitoring data from the ground server and process and interpret the monitoring data.

On the other hand, a "ground-tunnel-hole" microseismic-electrical joint monitoring method is provided. Based on the above-mentioned "ground-tunnel-hole" microseismic-electrical joint monitoring system, the method specifically includes the following steps:

Step 1: Design a monitoring plan, including collecting relevant information on the working face, delineating the monitoring target area, designing a monitoring data collection plan, and designing a monitoring system construction plan;

Step 2: Install the monitoring system, including preparation of monitoring equipment, installation of ground monitoring equipment, installation of tunnel monitoring equipment, installation of in-hole monitoring equipment, and installation of monitoring platform;

Step 3: Debug the monitoring system, including system connection test, vibration pickup electrode coupling state test, background noise test, and electrical signal strength test;

Step 4, calibrating the background parameters of the monitoring area, including calibrating the velocity model of the monitoring area and the background resistivity model of the monitoring area, and obtaining the calibration results;

Step 5, collection parameter configuration, including monitoring substation timing, electrical monitoring signal collection parameter configuration;

Step 6, controlling each monitoring substation to collaboratively collect monitoring signals through a multi-substation collaborative collection control module;

Step 7, evaluating the quality of the monitoring signals collected in step 6 to obtain effective microseismic monitoring signals and high-quality electrical monitoring signals;

Step 8, performing data processing on the effective microseismic monitoring signal obtained in step 7 to obtain a microseismic event location result;

Step 9, correcting the high-quality electrical monitoring signal obtained in step 7 to obtain corrected electrical monitoring data;

Step 10, based on the microseismic event location result of step 8, analyzing the connectivity state of mining fractures to obtain the connectivity relationship of microseismic events;

Step 11, establishing a mining fracture model based on the connectivity relationship of the microseismic events obtained in step 10; establishing a resistivity reference model based on the background resistivity model and the mining fracture model of the monitoring area obtained in step 5; for the electrical monitoring data corrected in step 9, performing microseismic-resistivity constrained inversion based on the resistivity reference model to obtain the inverted resistivity model, i.e., the microseismic-resistivity joint imaging result.

Compared with the prior art, the present invention has the following beneficial effects:

(1) In view of the characteristics of water hazard development in the working face, a "ground-lane-hole" combined three-dimensional monitoring system was established, which can obtain more sensitive monitoring data and lay a data foundation for high-precision imaging of water hazard hazards;

(2) Through the integrated design of seismic pickup electrodes, microseismic-electrical joint monitoring is carried out. The survey line only needs to be installed once to simultaneously collect microseismic monitoring signals and electrical monitoring signals, which greatly reduces the on-site construction workload and improves construction efficiency.

(3) Taking into account the location, density, and intensity of microseismic events, the connectivity of mining fractures was analyzed through the connectivity of microseismic events. A mining fracture model was established based on the connectivity relationship of microseismic events, which achieved a detailed description of mining fractures and laid a foundation for improving the resolution of water hazard imaging.

(4) The microseismic monitoring results are used as prior information for resistivity inversion, and microseismic-resistivity joint imaging is performed, which realizes real-time monitoring and high-precision dynamic imaging of the mining damage process of the top and bottom plates of the working face and the evolution process of water hazard hazards.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a structural diagram of the "ground-tunnel-hole" microseismic-electrical method joint monitoring system;

FIG2 is a schematic diagram of the setup of the “ground-lane-hole” combined three-dimensional monitoring system for monitoring tests;

Figure 3 is a sensitivity distribution diagram of the "ground-lane-hole" combined three-dimensional monitoring system;

Figure 4 is a schematic diagram of a mining fracture model;

Figure 5 shows the resistivity inversion imaging results without microseismic information constraints;

Figure 6 shows the results of microseismic-resistivity joint imaging.

1—ground microseismic-electrical joint monitoring substation; 2—underground microseismic-electrical joint monitoring substation; 3—integrated seismic pickup electrode string; 4—ground solar energy and wireless base station; 5—underground explosion-proof and intrinsically safe power supply; 6—underground optical terminal; 7—ground optical terminal; 8—ground server; 9—multi-station collaborative acquisition control module; 10—microseismic-electrical data comprehensive processing and interpretation module; 11—monitoring results multi-dimensional visualization module; 12—ground survey line; 13—first tunnel survey line; 14—second tunnel survey line; 15—first hole survey line; 16—second hole survey line; 17—ground monitoring substation; 18—first underground monitoring substation; 19—second underground monitoring substation;

DETAILED DESCRIPTION

The specific implementation of the present invention is further described below in conjunction with the accompanying drawings.

1. “Ground-tunnel-hole” microseismic-electrical joint monitoring system

As shown in FIG1 , the “ground-tunnel-hole” microseismic-electrical method joint monitoring system provided by the present invention comprises:

(1) Hardware

The hardware part includes a plurality of ground microseismic-electrical method joint monitoring substations 1 having the same number as the ground survey lines, a plurality of underground microseismic-electrical method joint monitoring substations 2 having the same number as the tunnel survey lines, and a plurality of underground microseismic-electrical method joint monitoring substations 2 having the same number as the in-hole survey lines; it also includes an integrated seismic pickup electrode string 3, a ground solar energy and wireless base station 4, an underground explosion-proof and intrinsically safe power supply 5, an underground optical terminal 6, a ground optical terminal 7 and a ground server 8; wherein each ground microseismic-electrical method joint monitoring substation 1 and each underground microseismic-electrical method joint monitoring substation 2 are respectively connected with one or two integrated seismic pickup electrode strings. 3; the ground optical terminal 7 communicates wirelessly with the ground server 8; the ground optical terminal 7 is connected to all underground microseismic-electrical joint monitoring substations 2 corresponding to the tunnel measurement lines and the in-hole measurement lines through the underground optical terminal 6 on the one hand, and is connected to the ground server 8 on the other hand, and communicates wirelessly with the ground microseismic-electrical joint monitoring substation 1 through the ground solar energy and wireless base station 4 equipped with each ground microseismic-electrical joint monitoring substation 1; each underground microseismic-electrical joint monitoring substation 2 is equipped with an underground flameproof and intrinsically safe power supply 5, and the underground flameproof and intrinsically safe power supply 5 is connected to the underground power grid; the software part is deployed on the ground server 8.

Ground microseismic-electrical joint monitoring substation 1 has GPS timing, solar power supply and wireless transmission functions, and is compatible with power supply and optical fiber transmission. It is used to transmit high-power electrical signals and collect ground microseismic signals and electrical signals.

The underground microseismic-electrical joint monitoring substation 2 meets the intrinsic safety and explosion-proof requirements, has high-precision well-ground clock synchronization and optical fiber transmission functions, and is used to transmit electrical signals and collect microseismic and electrical signals in tunnels and holes;

The ground solar and wireless base station 4 is used to supply power to the ground microseismic-electrical method joint monitoring substation 1 connected to it, and realize network communication between the ground microseismic-electrical method joint monitoring substation 1 and the ground server 8 through wireless communication with the ground optical terminal 7.

The underground flameproof and intrinsically safe power supply 5 is used to supply power to the underground microseismic-electrical method joint monitoring substation 2 connected thereto;

The underground optical terminal 6 is connected to the underground power grid, and is used to realize network communication between all underground microseismic-electrical method joint monitoring substations 2 and the ground server 8 through the ground optical terminal 7.

The integrated seismic pickup electrode string 3 is composed of a transmission cable and a spindle-shaped seismic pickup electrode, and can pick up microseismic signals and electrical signals with high precision; the integrated seismic pickup electrode string 3 is used to cooperate with the ground microseismic-electrical joint monitoring substation 1 and the underground microseismic-electrical joint monitoring substation 2 to realize the microseismic and electrical signal collection on the ground, in the tunnel and in the hole.

The spindle-shaped seismic pickup electrode can be used as a seismic pickup sensor for collecting microseismic signals, and can also be used as an electrode for transmitting and collecting electrical signals. In order to avoid the interference of electrical transmission signals on microseismic signal collection and electrical signal collection, when a spindle-shaped seismic pickup electrode is used to transmit electrical signals, its microseismic signal collection and electrical signal collection functions are suspended.

The ground optical terminal 7 is connected to the ground server 8 to ensure network communication between the ground server 8 and the ground microseismic-electrical method joint monitoring substation 1 and the underground microseismic-electrical method joint monitoring substation 2.

The ground server 8 includes a local server and a cloud server, which are used for installing the software part.

(2) Software part.

The software part includes a local database and a multi-station collaborative acquisition control module 9 installed on a local server, a cloud database installed on a cloud server, and a microseismic-electrical data comprehensive processing and interpretation module 10 and a monitoring results multi-dimensional visualization module 11 installed on a local server or a cloud server. Among them:

The multi-station collaborative acquisition control module 9 is used to control the ground microseismic-electrical joint monitoring substation 1 to transmit electrical signals and collect microseismic signals and electrical signals; at the same time, it is used to control the underground microseismic-electrical joint monitoring substation 2 to transmit electrical signals and collect microseismic signals;

The local database is used to store and manage local monitoring data (ie, data collected by the multi-substation collaborative collection control module 9).

The cloud database is used to perform cloud backup storage and management of monitoring data extracted regularly from the local server;

The microseismic-electrical method data comprehensive processing and interpretation module 10 is used to read the monitoring data from the local server or the cloud database, and process and interpret the monitoring data, and store the processing and interpretation results in the ground server 8 or the cloud database, which specifically includes: (1) calibrating the velocity model of the monitoring area to obtain the average velocity value of the calibrated velocity model; calibrating the background resistivity model of the monitoring area to obtain the background resistivity model of the monitoring area; (2) managing the local monitoring data, including quality evaluation of the collected monitoring signals, to obtain effective microseismic monitoring signals and high-quality electrical method monitoring signals; (3) (4) Process the effective microseismic monitoring signals to obtain the microseismic event location results; (5) Analyze the connectivity of mining fractures based on the microseismic event location results to obtain the connectivity relationship of microseismic events; (6) Establish a mining fracture model based on the connectivity relationship of microseismic events; Establish a resistivity reference model based on the background resistivity model and mining fracture model of the monitoring area; For the corrected electrical monitoring data, perform microseismic-resistivity constraint inversion based on the resistivity reference model to obtain the inverted resistivity model, i.e., the microseismic-resistivity joint imaging result. The microseismic-electrical data comprehensive processing and interpretation module 10 supports both local deployment and cloud deployment.

The monitoring result multi-dimensional visualization module 11 is used to read the results of the microseismic-electrical data comprehensive processing and interpretation module 10 from the local server or cloud database, and to perform two-dimensional, three-dimensional and four-dimensional multi-dimensional spatiotemporal display and monitoring and early warning on the results of the processing and interpretation. This module supports local deployment and cloud deployment.

The above functions of the software part have corresponding implementation processes in the "ground-tunnel-hole" microseismic-electrical joint monitoring method of the present invention below.

2. “Ground-tunnel-hole” microseismic-electrical joint monitoring method

The "ground-tunnel-hole" microseismic-electrical joint monitoring method provided by the present invention is based on the "ground-tunnel-hole" microseismic-electrical joint monitoring system of the present invention, and specifically includes the following steps:

Step 1: Design a monitoring plan, including collecting relevant information on the working face, delineating the monitoring target area, designing a monitoring data collection plan, and designing a monitoring system construction plan.

(1) Collection of relevant information on the working face.

Collect information such as working face mining maps, working face hydrogeological data, working face preliminary geophysical data, working face drilling data, etc.; conduct ground and underground working condition surveys in coal mines to confirm the access locations of power supply systems and network systems near the working face.

(2) Define the target monitoring area.

Based on the hydrogeological data of the working face, the early geophysical data of the working face and the drilling data of the working face, areas with potential water hazards are identified as monitoring target areas.

(3) Design a monitoring data collection plan.

According to the working face mining map and the results of the underground working condition investigation, select available tunnels and boreholes, design the location of underground survey lines and the distance between adjacent monitoring points, and the distribution range of underground survey lines needs to cover the monitoring target area; according to the results of the ground working condition investigation, design the location of ground survey lines and the distance between adjacent monitoring points, and the distribution range of ground survey lines needs to cover the projection range of the monitoring target area on the ground.

(4) Design a construction plan for the monitoring system.

According to the deployment position of the ground survey line, the installation position of the ground microseismic-electrical joint monitoring substation 1 is designed; according to the ground working condition survey results, it is confirmed whether there is an available power supply system and network system access position on the ground. If yes, the laying position of the ground power line and access fiber is designed; if not, the installation position of the ground solar energy and wireless base station 4 is designed. According to the deployment position of the underground (tunnel and hole) survey line, the installation position of the underground microseismic-electrical joint monitoring substation 2 is designed; according to the access position of the power supply system and network system near the underground working face, the laying position of the underground power line and access fiber is designed.

Step 2, install the monitoring system, including preparation of monitoring equipment, installation of ground monitoring equipment, installation of tunnel monitoring equipment, installation of in-hole monitoring equipment, and installation of monitoring platform.

(1) Preparation of monitoring equipment.

According to the monitoring scheme design, prepare the ground microseismic-electrical joint monitoring substation 1, the underground microseismic-electrical joint monitoring substation 2, the integrated seismic pickup electrode string 3, the ground solar energy and wireless base station 4, the underground explosion-proof and intrinsically safe power supply 5, the underground optical terminal 6, the ground optical terminal 7 and the ground server 8; among them, the ground microseismic-electrical joint monitoring substation 1 and the underground microseismic-electrical joint monitoring substation 2 need to be configured with fixed network IP according to the gateway information; the integrated seismic pickup electrode string 3 needs to be customized according to the survey line length and the distance between adjacent monitoring points designed in the monitoring scheme, the distance between adjacent spindle-shaped seismic pickup electrodes is consistent with the distance between adjacent monitoring points, and the length of the integrated seismic pickup electrode string 3 is generally longer than the survey line length, which is convenient for connecting the ground microseismic-electrical joint monitoring substation 1 and the underground microseismic-electrical joint monitoring substation 2.

(2) Installation of ground monitoring equipment.

The ground monitoring equipment includes a ground microseismic-electrical joint monitoring substation 1, an integrated seismic pickup electrode string 3, and a ground solar and wireless base station 4. According to the design of the monitoring plan, the ground microseismic-electrical joint monitoring substation 1 and the ground solar and wireless base station 4 are placed at appropriate locations; the ground solar and wireless base station 4 is connected to the ground microseismic-electrical joint monitoring substation 1 through a power supply interface to continuously supply power to the ground microseismic-electrical joint monitoring substation 1; the ground solar and wireless base station 4 uses a wireless network to provide network communication for the ground microseismic-electrical joint monitoring substation 1; the integrated seismic pickup electrode string 3 is installed on the ground, and a 30-50 cm deep trench is first dug according to the designed position of the ground survey line, and the trench length is consistent with the length of the integrated seismic pickup electrode string 3, and then the integrated seismic pickup electrode string 3 is buried in the trench and compacted, leaving the cable joint exposed on the surface, and finally the cable joint of the integrated seismic pickup electrode string 3 is connected to the ground microseismic-electrical joint monitoring substation 1 through the cable interface. If the monitoring plan designs multiple ground survey lines, multiple ground microseismic-electrical joint monitoring substations 1 need to be installed according to the above steps, each ground microseismic-electrical joint monitoring substation 1 is connected to a ground solar and wireless base station 4, and each ground microseismic-electrical joint monitoring substation 1 is connected to a maximum of two integrated seismic pickup electrode strings 3. If there is an access point for the power supply system and the network system near the installation location of the ground microseismic-electrical joint monitoring substation 1, it is also possible to directly access the power supply system and the network system without installing the ground solar and wireless base station 4.

(3) Installation of tunnel monitoring equipment.

The tunnel monitoring equipment includes an underground microseismic-electrical method combined monitoring substation 2, an integrated seismic pickup electrode string 3, an underground explosion-proof and intrinsically safe power supply 5 and an underground optical terminal 6. According to the design of the monitoring scheme, an underground microseismic-electrical method combined monitoring substation 2, an underground flameproof and intrinsically safe power supply 5 and an underground optical terminal 6 are placed at appropriate locations; the underground flameproof and intrinsically safe power supply 5 is connected to the underground power grid nearby through a power plug, and is connected to the underground microseismic-electrical method combined monitoring substation 2 through a power supply interface to continuously supply power to the underground microseismic-electrical method combined monitoring substation 2; the underground optical terminal 6 is connected to the underground microseismic-electrical method combined monitoring substation 2 through a network interface to provide network communication for the underground microseismic-electrical method combined monitoring substation 2; an integrated seismic pickup electrode string 3 is installed in the tunnel, and a 30-50 cm deep trench is first dug along the boundary line between the tunnel bottom plate and the outer side of the tunnel according to the designed position of the tunnel survey line, and the trench length is consistent with the length of the integrated seismic pickup electrode string 3, and then the integrated seismic pickup electrode string 3 is buried in the trench and compacted, leaving the cable connector exposed outside the trench, and finally the cable connector of the integrated seismic pickup electrode string 3 is connected to the underground microseismic-electrical method combined monitoring substation 2 through the cable interface. If the monitoring plan designs multiple tunnel measurement lines, it is necessary to install multiple underground microseismic-electrical combined monitoring substations 2 according to the above steps. Each underground microseismic-electrical combined monitoring substation 2 is connected to an underground explosion-proof and intrinsically safe power supply 5. Each underground microseismic-electrical combined monitoring substation 2 is connected to a maximum of two integrated seismic pickup electrode strings 3. Multiple underground microseismic-electrical combined monitoring substations 2 can be placed centrally and share one underground optical terminal 6.

(4) Installation of in-hole monitoring equipment.

The borehole monitoring equipment includes an underground microseismic-electrical method combined monitoring substation 2, an integrated seismic pickup electrode string 3, an underground flameproof and intrinsically safe power supply 5, and an underground optical terminal 6. The installation method of the borehole monitoring equipment is similar to that of the tunnel monitoring equipment, and the main difference lies in the installation of the integrated seismic pickup electrode string 3. According to the design of the monitoring scheme, an underground microseismic-electrical method combined monitoring substation 2, an underground flameproof and intrinsically safe power supply 5 and an underground optical terminal 6 are placed at appropriate locations; the underground flameproof and intrinsically safe power supply 5 is connected to the underground power supply system nearby through a power plug, and is connected to the underground microseismic-electrical method combined monitoring substation 2 through a power supply interface, so as to continuously supply power to the underground microseismic-electrical method combined monitoring substation 2; the underground optical terminal 6 is connected to the underground network system nearby through an optical fiber, and is connected to the underground microseismic-electrical method combined monitoring substation 2 through a network interface, so as to provide network communication for the underground microseismic-electrical method combined monitoring substation 2; an integrated seismic pickup electrode string 3 is installed in the hole, and the integrated seismic pickup electrode string 3 is first sent into the hole by hydraulic transportation according to the designed position of the drilling line, and the cable joint is retained to be exposed outside the hole, and then the hole is sealed by grouting to ensure the tight coupling between the integrated seismic pickup electrode string 3 and the hole wall, and finally the cable joint of the integrated seismic pickup electrode string 3 is connected to the underground microseismic-electrical method combined monitoring substation 2 through a cable interface. If the monitoring plan designs multiple in-hole measuring lines, it is necessary to install multiple underground microseismic-electrical combined monitoring substations 2 according to the above steps. Each underground microseismic-electrical combined monitoring substation 2 is connected to an underground flameproof and intrinsically safe power supply 5. Each underground microseismic-electrical combined monitoring substation 2 is connected to a maximum of two integrated seismic pickup electrode strings 3. Multiple underground microseismic-electrical combined monitoring substations 2 can be placed centrally and share one underground optical terminal 6.

(5) Monitoring platform installation.

The ground server 8 is connected to the ground optical terminal 7 to ensure the network communication of the ground server 8.

A local database is established on the ground server 8 for storage and management of local monitoring data. A multi-substation collaborative acquisition control module 9 is installed on the ground server 8, in which local database information, the number and IP address information of each monitoring substation, the number and coordinate information of each monitoring point, etc. are configured; the multi-substation collaborative acquisition control module 9 connects each monitoring substation through the TCP/IP protocol to control the transmission and acquisition status of each monitoring substation.

A cloud database is established on the cloud server to periodically extract the monitoring data of the local server to the cloud for backup storage and management; a microseismic-electrical data comprehensive processing and interpretation module 10 is installed on the cloud server, in which the cloud database information is configured, the module reads the monitoring data from the cloud database, processes and interprets the monitoring data, and stores the processing and interpretation results on the cloud server; a monitoring results multi-dimensional visualization module 11 is installed on the cloud server, in which the cloud database information is configured, the module reads the processing and interpretation results of the monitoring data from the cloud database, and displays the results in two-dimensional, three-dimensional, and four-dimensional multi-dimensional space-time.

The microseismic-electrical data comprehensive processing and interpretation module 10 and the monitoring results multi-dimensional visualization module 11 can also be installed on the local server.

Step 3: Debug the monitoring system, including system connection test, vibration pickup electrode coupling state test, background noise test, and electrical signal strength test.

(1) System connection test.

Through the multi-station collaborative acquisition control module 9, test the network communication status of each monitoring substation to ensure that each monitoring substation can normally receive and return the test command. Test the connection status of the multi-station collaborative acquisition control module 9 and the local database; test the connection status of the cloud database and the local database; test the connection status of the microseismic-electrical data comprehensive processing and interpretation module 1 and the cloud database; test the connection status of the monitoring results multi-dimensional visualization module 11 and the cloud database; ensure that the connection status of each database tested above is in a normal state.

(2) Test of coupling status of vibration pickup electrodes.

In order to achieve high-precision pickup of microseismic signals and electrical signals, the close coupling between the seismic pickup electrodes and the surrounding rock medium must be ensured. The electrical signal transmission function of the monitoring substation can be used to test the coupling state between the seismic pickup electrodes and the surrounding rock.

The ground microseismic-electrical method joint monitoring substation 1 and the underground microseismic-electrical method joint monitoring substation 2 (collectively referred to as monitoring substations) are uniformly numbered (the underground microseismic-electrical method joint monitoring substation 2 includes monitoring substations in monitoring tunnels and monitoring holes), and are numbered in sequence from the ground to the underground. The monitoring substation number is recorded as k _s , k _s =1, 2, ..., N, where N is the total number of the ground microseismic-electrical method joint monitoring substation 1 and the underground microseismic-electrical method joint monitoring substation 2; each measuring point is numbered in the manner of "monitoring substation number-measuring point number", and is recorded as k _s -j _p , where k _s -j _p represents the jth measuring point of the k _s th monitoring substation. There are _p measuring points, for example, the measuring points of monitoring substation No. 1 are numbered 1-1, 1-2, ..., 1-N1, and the measuring points correspond to the spindle-shaped seismic pickup electrodes one by one. N1 is the total number of spindle-shaped seismic pickup electrodes on the integrated seismic pickup electrode string 3 connected to monitoring substation No. 1, and the corresponding measuring point numbers of other monitoring substations are deduced in the same way.

According to the monitoring substation number, the current transmission test is performed one by one starting from monitoring substation No. 1; first, the electrical signal transmission function of monitoring substation No. 1 is turned on, and the current signal is transmitted one by one starting from measuring point No. 1-1, and the measuring point number and the corresponding transmission current value are stored in real time in the local database; after all measuring points of monitoring substation No. 1 have completed the transmission current test, the electrical signal transmission function of monitoring substation No. 1 is turned off, and the electrical signal transmission function of monitoring substation No. 2 is turned on, and the transmission current test is performed on the measuring points of monitoring substation No. 2 one by one, and the measuring point number and the corresponding transmission current value are stored in the local database; the above transmission current test process is repeated until the transmission current test is completed for the corresponding measuring points of all monitoring substations.

The emission current values of each monitoring substation stored in the local database are analyzed. The normal emission current value range of the ground microseismic-electrical joint monitoring substation 1 is generally between 1A and 3A, and the normal emission current value range of the underground microseismic-electrical joint monitoring substation 2 is generally between 20mA and 60mA. The number of the measuring point where the emission current value deviates from the normal range is recorded. If the measuring point is a measuring point on the ground or in a tunnel, it is necessary to conduct on-site investigation and take measures to improve the coupling between the spindle-shaped seismic pickup electrode and the surrounding rock corresponding to the measuring point. If the measuring point is a measuring point in the hole, since the integrated seismic pickup electrode string has been sealed in the hole by grouting, it cannot be further processed and can only be marked as an abnormal measuring point. This type of measuring point does not participate in the monitoring data collection process.

When investigating and processing the ground or tunnel measuring points whose emission current values deviate from the normal range, the spindle-shaped seismic pickup electrode corresponding to the measuring point can be re-compacted, and the coupling degree between the spindle-shaped seismic pickup electrode and the surrounding rock can be increased by means such as pouring salt water, and then the emission current can be tested again. If the emission current value still deviates from the normal range, the measuring point will be marked as an abnormal measuring point and will not participate in the monitoring data collection process subsequently.

For ground or tunnel measuring points, if the number of abnormal measuring points of a certain monitoring substation exceeds 20% of the total number of measuring points, it is necessary to replace the integrated seismic pickup electrode string and reinstall and test it.

(3) Background noise test.

The acquisition process of microseismic signals and electrical signals is easily affected by background noise. Background noise testing can provide a reference for the frequency selection of electrical transmission signals, subsequent microseismic and electrical signal processing, and monitoring data quality evaluation. When conducting background noise testing, the monitoring substation does not need to transmit electrical signals, but only collects microseismic background noise signals and electrical background noise signals, and stores the collected data in the local database according to the measurement point number.

(4) Electrical signal strength test.

When the ground microseismic-electrical joint monitoring substation 1 and the underground microseismic-electrical joint monitoring substation 2 perform electrical signal acquisition, the supported acquisition modes include dipole-dipole, monopole-dipole and monopole-monopole, and the interval between the transmitting electrodes and the interval between the receiving electrodes can be adjusted arbitrarily. The dipole-dipole acquisition mode represents the use of dipole emission and dipole reception for signal acquisition, the monopole-dipole acquisition mode represents the use of monopole emission and dipole reception for signal acquisition, and the monopole-monopole acquisition mode represents the use of monopole emission and monopole reception for signal acquisition.

Conducting an electrical signal strength test can provide guidance for configuring the electrical monitoring signal acquisition mode. When conducting an electrical signal strength test, perform ground-to-well signal strength test and downhole signal strength test respectively.

When conducting a ground-to-well signal strength test, select a ground survey line and a downhole survey line respectively. The downhole survey line can be a tunnel survey line or a borehole survey line. Adjust the electrical monitoring signal acquisition mode, test the signal strength when the ground monitoring substation transmits and the downhole monitoring substation collects, and ensure that the electrical signal strength is greater than the background noise signal strength in this case.

When conducting an underground signal strength test, select two measuring lines with the largest spacing between the tunnel measuring lines and the borehole measuring lines, adjust the electrical monitoring signal acquisition mode, and test the signal strength when one monitoring substation transmits and another monitoring substation collects to ensure that the electrical signal strength is greater than the background noise signal strength in this case.

When adjusting the electrical monitoring signal acquisition mode, the signal strength tests are performed on the dipole-dipole acquisition mode, the monopole-dipole acquisition mode and the monopole-monopole acquisition mode in turn.

During the test, the interval between adjacent measuring points on the same measuring line is set to 1 by default. The interval between transmitting electrodes is recorded as _is and the interval between receiving electrodes is recorded as _is . _Is is only used when the dipole is transmitting _and is only used when the dipole is receiving. The dipole-dipole acquisition mode can increase the signal strength by increasing _is and _is ; the monopole-dipole acquisition mode can increase the signal strength by increasing _is ; the monopole-monopole acquisition mode has nothing to do with _is and _is . After selecting the electrical monitoring signal acquisition mode, adjust _is or _is to ensure that the electrical signal strength is greater than the background noise strength. In order to ensure the data acquisition density, _is and _is cannot be increased indefinitely. Generally, _{is is} ≤3 and is _is ≤3.

First test the signal strength of the dipole-dipole acquisition mode, change _is and _ir successively, and determine whether the signal strength is greater than the background noise strength; if so, select the dipole-dipole acquisition mode for electrical monitoring signal acquisition; if not, further test the signal strength of the monopole-dipole acquisition mode.

When testing the signal strength of the monopole-dipole acquisition mode, change i _r successively to determine whether its signal strength is greater than the background noise strength; if so, use the monopole-dipole acquisition mode for electrical monitoring signal acquisition; if not, further test the signal strength of the monopole-monopole acquisition mode.

When testing the signal strength of the monopole-monopole acquisition mode, determine whether its signal strength is greater than the background noise intensity; if so, use the monopole-monopole acquisition mode to collect electrical monitoring signals; if not, it indicates that the electrical background noise of the working face is too large and is not suitable for electrical monitoring.

Generally speaking, the monopole-monopole acquisition mode is equivalent to the spacing between the transmitting electrodes and the receiving electrodes being infinite, and its signal strength is the largest among the three acquisition modes. However, since its imaging accuracy is the lowest among the three acquisition modes, it is only used when the other two acquisition modes are difficult to acquire valid signals.

The best electrical monitoring signal acquisition mode and the best _is and _r can be determined by the electrical signal strength test. When the electrical monitoring signal is subsequently acquired, the electrical monitoring signal acquisition mode that meets both the ground-well signal strength test requirements and the downhole signal strength test requirements is preferred.

Step 4: calibrate the background parameters of the monitoring area, including calibrating the velocity model of the monitoring area and the background resistivity model of the monitoring area to obtain the calibration results.

(1) Calibrate the velocity model of the monitoring area and obtain the average velocity value of the calibrated velocity model.

In order to improve the accuracy of microseismic event positioning, it is necessary to calibrate the velocity model of the monitoring area using calibration guns. Specifically, the microseismic signal acquisition function of the monitoring system is turned on, and several calibration guns are placed within the coverage of the ground and underground survey lines; the detonation position is regarded as a known point source. Since the source position and the receiving point position are both known, the average velocity between the source and the receiving point can be calculated according to the ray hypothesis; the initial velocity model is established based on the average velocity, and the spatial position of the source is inverted using the calibration gun vibration event collected by the monitoring system; the velocity model parameters are repeatedly adjusted to gradually reduce the error between the spatial position obtained by inversion and the actual calibration gun spatial position, and the velocity model of the monitoring area is calibrated, and the average velocity value of the velocity model obtained after calibration is recorded as c. In summary, this step obtains a velocity model that is closer to the actual stratigraphic structure by means of calibration guns, which can improve the positioning accuracy when locating microseismic events in the future.

(2) Calibrate the background resistivity model of the monitoring area.

In order to improve the imaging accuracy of resistivity inversion, it is necessary to calibrate the background resistivity model of the monitoring area. The background resistivity model of the monitoring area is simplified to a layered medium, which is composed of loose layer on the surface, top rock layer, coal layer and bottom rock layer from top to bottom. The resistivity of each layer is calibrated using a symmetrical quadrupole device. Specifically, 10 measuring points are randomly selected on the ground survey line, and the apparent resistivity of these 10 measuring points is measured by a symmetrical quadrupole device, and the average value of the apparent resistivity is used as the resistivity value of the loose layer on the surface; 10 measuring points are randomly selected on the tunnel survey line, and the apparent resistivity of these 10 measuring points is measured by a symmetrical quadrupole device, and the average value of the apparent resistivity is used as the resistivity value of the coal seam; 10 measuring points are randomly selected on the borehole survey line located in the roof rock layer, and the apparent resistivity of these 10 measuring points is measured by a symmetrical quadrupole device, and the average value of the apparent resistivity is used as the resistivity value of the roof rock layer; 10 measuring points are randomly selected on the borehole survey line located in the bottom rock layer, and the apparent resistivity of these 10 measuring points is measured by a symmetrical quadrupole device, and the average value of the apparent resistivity is used as the resistivity value of the bottom rock layer. The resistivity values of the above layers are evenly distributed, forming a background resistivity model of the monitoring area, and the background resistivity model is recorded as m ₀ .

Step 5: configure the acquisition parameters, including the timing of the monitoring substation and the acquisition parameters of the electrical monitoring signal.

(1) Monitoring substation timing.

Since microseismic signal acquisition has high requirements for signal clock synchronization, when collecting ground-lane-hole joint microseismic monitoring signals, it is necessary to synchronize the monitoring substations to ensure high-precision clock synchronization between the ground and underground monitoring substations. The ground microseismic-electrical joint monitoring substation 1 uses GPS signals for clock synchronization; the coal mine cannot receive GPS signals underground, so the underground microseismic-electrical joint monitoring substation 2 uses the IEEE1588 protocol to keep time synchronization with the ground microseismic-electrical joint monitoring substation 1; through the above method, the consistency of the clocks of the monitoring substations on the ground and underground is guaranteed.

(2) Configuration of electrical monitoring signal acquisition parameters.

In the multi-substation collaborative acquisition control module 9, the frequency of the electrical transmission signal is configured according to the electrical background noise test results. The spectrum analysis of the electrical background noise signal is performed to determine its main frequency components; the frequency of the electrical transmission signal is generally selected within the range of 0Hz to 120Hz, and the main frequency of the electrical background noise signal needs to be avoided.

In the multi-substation coordinated acquisition control module 9, the electrical monitoring signal acquisition mode is configured according to the electrical signal strength test result. If the electrical monitoring adopts the dipole-dipole acquisition mode, the transmitting electrode interval i _s and the receiving electrode interval i _r need to be configured; if the monopole-dipole acquisition mode is adopted, the receiving electrode interval i _r needs to be configured; if the monopole-monopole acquisition mode is adopted, there is no need to configure the transmitting electrode interval and the receiving electrode interval.

Step 6: Monitoring signal acquisition.

Microseismic monitoring is a passive source monitoring, and the signal comes from the seismic waves generated by rock fracture, so there is no need to transmit signals; electrical monitoring is an active source monitoring, which requires first transmitting signals underground to establish an artificial electric field and then collecting signals.

The multi-station collaborative acquisition control module 9 controls each monitoring substation to collaboratively acquire monitoring signals; the monitoring substations are marked as ground microseismic-electrical joint monitoring substation 1 and underground microseismic-electrical joint monitoring substation 2, and the monitoring substations transmit electrical signals one by one in the order from the ground to the underground; when each monitoring substation transmits electrical signals, the transmitting current is supplied to the underground one by one through the spindle-shaped seismic pickup electrodes according to their corresponding measuring point numbers; when a spindle-shaped seismic pickup electrode is used for electrical signal transmission, its microseismic signal acquisition function and electrical signal acquisition function will be suspended, and the remaining spindle-shaped seismic pickup electrodes will perform microseismic and electrical signal acquisition according to the acquisition command of the monitoring substation; while any monitoring substation is transmitting electrical signals, The remaining spindle-shaped seismic pickup electrodes except the spindle-shaped seismic pickup electrode currently transmitting the electrical signal are controlled to collect microseismic signals and electrical signals; when the ground microseismic-electrical joint monitoring substation 1 transmits the electrical signal, the ground microseismic-electrical joint monitoring substation 1 and the underground microseismic-electrical joint monitoring substation 2 (including the monitoring substation currently transmitting the electrical signal) synchronously collect microseismic signals and electrical signals; when the underground microseismic-electrical joint monitoring substation 2 transmits the electrical signal, the ground microseismic-electrical joint monitoring substation 1 only collects microseismic signals, and the underground microseismic-electrical joint monitoring substation 2 (including the monitoring substation currently transmitting the electrical signal) synchronously collects microseismic signals and electrical signals. Through the above steps, the coordinated control of each monitoring substation is realized, and the synchronous collection of microseismic monitoring signals and electrical monitoring signals is realized.

Step 7: perform quality evaluation on the monitoring signals collected in step 6 to obtain effective microseismic monitoring signals and high-quality electrical monitoring signals.

(1) Monitoring signal quality evaluation principles.

Since both ground and underground signal acquisition may face strong electromagnetic noise interference, especially the underground integrated seismic electrode string 3 will also be affected by mining damage, resulting in the integrated seismic electrode string 3 itself being damaged or difficult to couple closely with the surrounding rock, further resulting in a decrease in the quality of the monitoring signal, and even the acquisition of invalid monitoring signals, it is necessary to evaluate the quality of the monitoring signal to avoid low-quality or invalid monitoring signals from interfering with the subsequent interpretation of the results. When evaluating the quality of monitoring signals, the signal strength, stability and consistency of the signal in time and space are mainly considered, and poor-quality monitoring signals are marked by means of data cleaning, inter-channel consistency analysis, etc.

(2) Microseismic monitoring signal quality evaluation.

Since microseismic events are sporadic, the seismic wave signals collected when no microseismic events occur are mainly background noise. Therefore, the inter-channel consistency analysis is mainly carried out when evaluating the quality of microseismic monitoring signals. When conducting inter-channel consistency analysis, the monitoring signals collected at the measuring points where microseismic events are monitored in the same period are marked as valid microseismic monitoring signals, and the monitoring signals collected at the remaining measuring points are marked as invalid microseismic monitoring signals. Only valid microseismic monitoring signals are subsequently processed.

(3) Evaluation of electrical monitoring signal quality.

Electrical monitoring first transmits signals underground to establish an artificial electric field, and then collects signals. The electrical signals collected during the entire monitoring process contain both background noise signals and emission source signals. When evaluating the quality of electrical monitoring signals, the stability of the emission current is generally evaluated first, and monitoring signals with too small or unstable emission currents are marked; at the same time, the measurement points with unstable emission currents are marked, and the signals collected when these measurement points are used as receiving points are also marked; then the strength of the received voltage is evaluated, and signals with a received voltage close to the background noise are marked. Through the above method, signals with low credibility in the electrical monitoring signals are marked, and the marked low-quality electrical monitoring signals are eliminated in the subsequent signal processing process, and only high-quality electrical monitoring signals are processed and analyzed.

Step 8: Process the effective microseismic monitoring signal obtained in step 7.

The specific steps are as follows:

(1) Noise suppression.

Some random noise will be mixed in the signal acquisition process, and the sliding average filter is used to eliminate the random noise interference. Since the high-frequency part of the seismic signal is basically absorbed by the formation, its frequency is mainly concentrated in the low-frequency part. A low-pass filter is used to filter the high-frequency noise of the effective microseismic monitoring signal obtained in step 8.

(2) Pick up on first arrival.

The first arrival of the microseismic monitoring signal after noise suppression is picked up to determine the time when the seismic wave arrives at the current measuring point; since the microseismic waveforms have good similarity, the cross-correlation method is used to realize the first arrival picking of the microseismic event, that is, the starting time of the microseismic event.

(3) Polarization analysis

After the first arrival is picked, the type of microseismic signal source is determined through polarization analysis to screen effective microseismic events. Microseismic signals contain three components: P wave, SH wave and SV wave. Since P wave propagates fastest in rock mass and the first arrival time is easy to identify, P wave is generally used for source location. Polarization analysis is used to decompose microseismic signals into three components: P wave, SH wave and SV wave. The signal source is analyzed to determine whether it is mainly P wave source, SH wave source or SV wave source. Microseismic signals mainly based on P wave source are marked as effective microseismic events.

(4) Based on the velocity model calibration results of the monitoring area obtained in step 4, microseismic events are located to obtain the coordinates of the microseismic sources.

In the present invention, P waves are used to construct the objective function to locate the source of effective microseismic events. Specifically, the spatial coordinates of the microseismic source are set to x, y, and z, and the starting time of the microseismic event is set to t. According to the calibration results of the velocity model of the monitoring area, it is assumed that the average velocity of the P wave propagating in the rock mass is c, and the first arrival time of the P wave of the a-th spindle-shaped seismic pickup electrode is _ta . Then, the travel time equation between the a-th spindle-shaped seismic pickup electrode and the microseismic source is:

[(x _a -x) ² +(y _a -y) ² +(z _a -z) ² ] ¹² =c(t _a -t)

(a＝1,2,3,…, _na )

Where: _xa , _ya , and _za are the spatial coordinates of the ath spindle-shaped seismic pickup electrode; _na is the number of spindle-shaped seismic pickup electrodes that receive effective microseismic events.

In the above travel time equation, there are 4 unknowns, namely x, y, z and t. Take 4 of the n _a spindle-shaped seismic pickup electrodes and form the following equation group with the microseismic source:

Substitute the known spindle-shaped seismic pickup electrode coordinates _xa , _ya , _za and first arrival time _ta into the above formula and iterate the calculation, the result is the primary positioning coordinates of the microseismic source; then take 4 of the remaining spindle-shaped seismic pickup electrodes and perform positioning calculation according to the above equations to obtain the secondary positioning coordinates of the microseismic source; and so on, until all the spindle-shaped seismic pickup electrodes that have received effective microseismic events are involved in the positioning calculation, take the average of multiple positioning coordinates to obtain more accurate microseismic source coordinates.

Step 9, correcting the high-quality electrical monitoring signal obtained in step 7, including correction of infinity effect, correction of positive and negative properties of observed voltage, correction of consistency of grounding conditions of spindle-shaped seismic pickup electrode, normalization of monitoring data, and correction of correlation analysis of monitoring data, to obtain corrected electrical monitoring data.

The specific steps are as follows:

(1) Infinity effect correction.

The correction of infinite effect is mainly aimed at the monitoring signals obtained in the monopole-dipole acquisition mode and the monopole-monopole acquisition mode. For the monopole-dipole acquisition mode and the monopole-monopole acquisition mode, it is necessary to arrange infinite electrodes to form an approximate monopole transmission or monopole reception. In order to approximate the infinite condition, it is generally required that the distance of the infinite electrodes is not less than 3 times the transmission and reception distance. However, due to the limited observation space available underground in coal mines, the distance of the infinite electrodes is often difficult to meet the above requirements, resulting in the electric field distribution not being a strictly monopole mode. Therefore, it needs to be corrected to ensure that the electrical monitoring signal can correctly reflect the real changes in the earth's electric field.

When performing infinite distance effect correction, it is assumed that the resistivity of the underground medium is uniformly distributed. The infinite distance electrodes and the corresponding transmitting and receiving spindle-shaped seismic pickup electrodes participating in the current voltage value observation are first regarded as a dipole-dipole acquisition mode. The apparent resistivity value corresponding to the voltage value is calculated according to the apparent resistivity calculation formula of the dipole-dipole acquisition mode. The apparent resistivity value is then converted into a voltage value according to the actual electrical monitoring signal acquisition mode, and is used as the corrected voltage value to achieve infinite distance effect correction.

(2) Correction of the positive and negative properties of the observed voltage.

The positive and negative properties of the observed voltage are mainly corrected for the monitoring data obtained in the dipole-dipole acquisition mode and the monopole-dipole acquisition mode. Since only the absolute value of the received voltage is returned when the electrical monitoring signal is collected, the observed voltage value is difficult to correctly reflect the positive and negative properties of the real voltage value. It is necessary to correct the positive and negative properties of the observed voltage to ensure that the electrical monitoring data can correctly reflect the real changes in the geoelectric field.

After completing the correction for the infinite distance effect, the positive and negative properties of the observed voltage are corrected: the distribution intervals of the positive and negative voltages are determined according to the theoretical calculation formula for the received voltage. For the observed voltage values in the negative voltage distribution interval, their absolute values are guaranteed to remain unchanged and corrected to negative numbers; the observed voltage values in the positive voltage distribution interval do not need to be corrected.

(3) Correction of the consistency of the grounding conditions of the spindle-shaped seismic pickup electrode.

During the electrical monitoring signal collection process, mining damage causes the grounding conditions of the spindle-shaped seismic pickup electrode to be inconsistent inside and outside the goaf and before and after entering the goaf, which will lead to false anomalies in the monitoring results. They need to be corrected to avoid interference with the identification of real electrical anomalies.

After completing the correction of the positive and negative properties of the observed voltage, the consistency correction of the grounding conditions of the spindle-shaped seismic pickup electrode is performed: the monitoring data is first sorted according to the order of common emission points and the data is smoothed once, and then sorted according to the order of common receiving points and the data is smoothed twice. The above method can eliminate the false anomalies caused by the inconsistency of the grounding conditions of the spindle-shaped seismic pickup electrode.

(4) Normalization of monitoring data.

Mining damage causes changes in the resistivity of coal-bearing strata, which can be regarded as background resistivity. The initial scale of water inrush channels is small, and they generally develop in the impermeable layer outside the rock damage layer. The large-scale electrical abnormal changes caused by overburden damage and floor damage greatly interfere with the dynamic identification of the development process of water inrush hazards.

After completing the consistency correction of the grounding conditions of the spindle-shaped seismic pickup electrode, the monitoring data is normalized: a new set of data is constructed by multiplying the ratio of the current monitoring data to the initial monitoring data by the simulated monitoring data of any uniform medium. This new set of data will be inverted and fitted in the subsequent resistivity inversion, which can eliminate the influence of the background resistivity and highlight the weak resistivity changes under the background of strong electrical inhomogeneity.

(5)Correlation analysis and correction of monitoring data.

During the electrical monitoring signal acquisition process, there is electromagnetic noise interference from large electromechanical equipment. This type of noise interference is random and time-varying, resulting in a decrease in the quality of monitoring data during certain periods of time.

After completing the normalization processing of the monitoring data, the monitoring data is subjected to correlation analysis and correction according to the characteristics of the electrical monitoring data with time series correlation: by calculating the correlation coefficient of the monitoring data in adjacent time periods, the monitoring data with poor correlation is identified, and then the monitoring data is corrected by interpolating the time series of adjacent time periods to improve the quality of the monitoring data.

Step 10: According to the microseismic event location result of step 8, the connectivity state of mining fractures is analyzed to obtain the connectivity relationship of microseismic events.

The specific steps are as follows:

(1) Calculate the impact radius of microseismic events.

The energy of microseismic events generated by rock fracture spreads spherically in all directions. The energy density of microseismic events can reflect the expansion path and intensity of cracks. The energy impact range of microseismic events is regarded as a sphere, and the calculation formula of its impact radius R is as follows:

Where M is the magnitude of the microseismic event; π is the circumference of a circle; σ ₀ is the apparent stress. The larger the impact radius R, the stronger the energy of the microseismic event.

(2) Calculate the connectivity of the microseismic event based on the microseismic event location result obtained in step 8 and the influence radius of the microseismic event obtained in step (1) above.

The ratio of the impact radius of two microseismic events to their spatial distance is defined as connectivity. The calculation formula of connectivity is as follows:

where R _i and R _j are the influence radii of any two microseismic events i and j, respectively; (xi _{, yi} , z _i ) and ( _xj , _yj , _zj ) are the spatial coordinates of any two microseismic events i and j, respectively; and λ _ij is the connectivity between the two microseismic events.

(3) Analyze the connectivity of the mining fractures based on the connectivity of the microseismic events obtained in step (2) above to obtain the connectivity relationship of the microseismic events.

In _{order to characterize the connectivity relationship of microseismic events, the data record format of the connectivity relationship of microseismic events is defined as: (xi, yi, z, xj, yj , zj , λij ) .} The connectivity state of mining fissures is analyzed according to the connectivity of microseismic events. When the connectivity _λij of two microseismic events is greater than 1, it is considered that the cracks formed by the two microfractures (i.e., mining fissures) are interconnected; when the connectivity _λij is less than 1, it is considered that the cracks formed by the two microfractures are independent of each other; the larger the value of the connectivity _λij , the greater the probability that the cracks formed by the microfractures are interconnected to form a water channel.

Step 11, establishing a mining fracture model based on the connectivity relationship of the microseismic events obtained in step 10; establishing a resistivity reference model based on the background resistivity model and the mining fracture model of the monitoring area obtained in step 4; for the electrical monitoring data corrected in step 9, performing microseismic-resistivity constrained inversion based on the resistivity reference model to obtain the inverted resistivity model, i.e., the microseismic-resistivity joint imaging result.

(1) Establish a mining-induced fracture model based on the connectivity relationship of the microseismic events obtained in step 10.

Specifically, the monitoring area is divided into three-dimensional grids, and the coordinates of the center point of any grid are marked as (x _l , y _m , z _n ); a crack weight w(l, m, n) is assigned to each grid, and the initial value of the crack weight w(l, m, n) is 1; according to the coordinate relationship, the microseismic events are mapped one by one to the three-dimensional grid; according to the data record of the connectivity relationship of the microseismic events obtained in step 10, two microseismic events with a connectivity greater than 1 are connected by rays, and for the grids through which the rays pass, the value of the crack weight w(l, m, n) is updated to the connectivity λ _ij of the two microseismic events connecting the rays; when a grid is connected by multiple rays of microseismic events, the sum of the connectivity corresponding to each ray is taken as the crack weight of the grid. The grid model composed of w(l, m, n) is recorded as the mining crack model m _frc , which contains information such as the development location, density and intensity of microseismic events, and can indirectly reflect the development of mining cracks.

(2) Establish a resistivity reference model based on the background resistivity model of the monitoring area obtained in step 4 and the mining fracture model obtained in step (1) above.

The background resistivity model _m0 of the monitoring area obtained in step 4 is mapped to the three-dimensional grid. The background resistivity value of each grid is recorded as _ρ0 (l, m, n). The background resistivity value represents the resistivity of the formation when it is not affected by mining damage. The resistivity value of the formation after being affected by mining damage is defined as follows:

Wherein, w(l, m, n) is the fracture weight of the current grid; ρ ₀ (l, m, n) is the background resistivity value of the grid; ρ _ref (l, m, n) is the reference resistivity value of the grid after being affected by mining damage. The grid model composed of ρ _ref (l, m, n) is recorded as the resistivity reference model m _ref . When the stratum is not filled with water, its resistivity value will increase after being affected by mining damage; when the stratum is filled with water, its resistivity value will decrease after being affected by mining damage.

(3) For the electrical monitoring data after correction processing in step 9, microseismic-resistivity constrained inversion is performed according to the resistivity reference model obtained in the above step (2) to obtain the resistivity model after inversion, that is, the microseismic-resistivity joint imaging result.

The inversion model update formula is as follows:

In the formula, is the resistivity model obtained after the kth inversion iteration, is the resistivity model obtained after the k+1th inversion iteration, α is the model correction coefficient, is the model correction, β is the regularization parameter, _Wd is the data weight, _Wm is the model weight, ^Δdk is the residual between the electrical monitoring data corrected in step 9 and the simulated observation data ^dk , is the Jacobian matrix, and m _ref is the resistivity reference model. In the formula, α is generally determined according to the following rules:

In the formula, c ₁ is a very small constant (~10 ^-4 ), and β is generally a constant between 1 and 10. and is the inversion data residual.

During the inversion process, prior condition constraints are imposed through the resistivity reference model m _ref of the monitored area. Since the resistivity reference model m _ref contains prior information related to mining fractures, such as the development location, density and intensity of microseismic events, this prior information is obtained by analyzing the microseismic monitoring results, which indirectly reflects the development of mining fractures. By introducing the resistivity reference model in the inversion process and using microseismic information to constrain the resistivity inversion imaging process, the purpose of microseismic-resistivity joint imaging is achieved, and the imaging resolution of the mining damage process and the evolution process of water hazards on the top and bottom plates of the working face is improved.

Step 12: Dynamic display of monitoring results and monitoring early warning.

(1) Dynamic display of monitoring results.

The microseismic positioning results obtained in step 8, the mining fracture model obtained in step 11, and the microseismic-resistivity joint imaging results are visualized in three dimensions, refreshed in real time, and dynamically displayed to achieve real-time monitoring and high-precision dynamic imaging of the mining damage process of the top and bottom plates of the working face and the evolution process of water hazard hazards.

(2) Flood risk warning.

By analyzing the resistivity change characteristics during the development of water inrush hazards, a resistivity anomaly graded warning mechanism was established. According to the microseismic-resistivity joint imaging results, the change characteristics of the low-resistance anomaly area were analyzed; when the low-resistance anomaly persisted at the same location, a third-level warning was issued; when the low-resistance anomaly continued to strengthen, a second-level warning was issued; when the speed of the low-resistance anomaly strengthening continued to accelerate, a first-level warning was issued. When the third-level and second-level warnings appeared, it is necessary to pay more attention to the abnormal area; when the first-level warning appeared, it is necessary to investigate and treat the abnormal area in a timely manner.

The beneficial effects of the present invention are as follows: in view of the characteristics of water hazard development in the working face, a "ground-tunnel-hole" joint three-dimensional monitoring system is established, which can obtain monitoring data with higher sensitivity and lay a data foundation for high-precision imaging of water hazard hazards; through the integrated design of seismic pickup electrodes for microseismic-electrical joint monitoring, the survey line only needs to be installed once to synchronously collect microseismic monitoring signals and electrical monitoring signals, which greatly reduces the on-site construction workload and improves construction efficiency; taking into account the development location, density and intensity of microseismic events, the connectivity state of mining fractures is analyzed through the connectivity of microseismic events, and a mining fracture model is established based on the connectivity relationship of microseismic events, which realizes the fine characterization of mining fractures and lays the foundation for improving the imaging resolution of water hazard hazards; the microseismic monitoring results are used as prior information for resistivity inversion, and microseismic-resistivity joint imaging is performed, which realizes real-time monitoring and high-precision dynamic imaging of the mining destruction process of the top and bottom plates of the working face and the evolution process of water hazard hazards.

In order to verify the feasibility and effectiveness of the present invention, the present invention designs the following experiments for verification:

As shown in Figure 2, a joint microseismic-electrical monitoring test of roof water damage "ground-lane-hole" was carried out in a certain working face. According to the working face working environment and hydrogeological data, one ground survey line, two lane survey lines, and two hole survey lines were designed, including ground survey line 12, first lane survey line 13, second lane survey line 14, first hole survey line 15, and second hole survey line 16, a total of 5 survey lines, forming a "ground-lane-hole" joint three-dimensional monitoring array; each monitoring substation is connected to a maximum of two survey lines, a total of 5 survey lines are required Three monitoring substations are required, including one ground monitoring substation and two underground monitoring substations; the ground monitoring substation 17 is connected to the ground measuring line 12, the first underground monitoring substation 18 is connected to the first tunnel measuring line 13 and the second tunnel measuring line 14, and the second underground monitoring substation 19 is connected to the first hole measuring line 15 and the second hole measuring line 16; the ground monitoring substation 17 adopts solar energy power supply and wireless transmission, and the first underground monitoring substation 18 and the second underground monitoring substation 19 are both connected to the underground power supply system and network system.

Figure 3 is a sensitivity distribution diagram of the "ground-tunnel-hole" joint three-dimensional monitoring system. Through the "ground-tunnel-hole" joint three-dimensional monitoring, more sensitive monitoring data can be obtained, laying a data foundation for high-precision imaging of water hazards. Figure 4 is a mining fracture model established based on the connectivity relationship of the monitored microseismic events, which realizes the fine characterization of mining fractures and lays a foundation for further improving the imaging resolution of water hazards. Figure 5 shows the imaging results obtained by directly performing resistivity inversion on the electrical monitoring data without microseismic information constraints. The low-resistance anomaly areas in the figure are independent of each other and cannot reflect whether the mining fractures are connected to each other. Based on the imaging results, it is difficult to determine whether the low-resistance area is connected to the aquifer. Figure 6 is the microseismic-resistivity joint imaging result obtained by using the microseismic monitoring results as the prior information of resistivity inversion. The imaging results show that the resistivity anomaly changes more significantly in the area with dense microseismic events, and the low-resistance anomaly areas are connected into one piece, indicating that the mining fractures are connected to each other and there is a risk of conduction with the aquifer. The comparison results of Figure 5 and Figure 6 show that the combined microseismic-resistivity imaging has a higher imaging accuracy for water hazards. This embodiment realizes the real-time monitoring and high-precision dynamic imaging of the mining damage process of the working face roof and the evolution process of water hazards through the combined microseismic-electrical method monitoring of "ground-lane-hole".

Claims (28)

1. The ground-roadway-hole microseismic-electric method combined monitoring system is characterized by comprising a plurality of ground microseismic-electric method combined monitoring substations (1) with the same number as ground survey lines, a plurality of underground microseismic-electric method combined monitoring substations (2) with the same number as roadway survey lines, and a plurality of underground microseismic-electric method combined monitoring substations (2) with the same number as hole survey lines; the system also comprises an integrated vibration-picking electrode string (3), a ground solar and wireless base station (4), an underground explosion-proof and intrinsic safety power supply (5), an underground optical terminal machine (6), a ground optical terminal machine (7) and a ground server (8), wherein each ground micro-vibration-electric method combined monitoring substation (1) and each underground micro-vibration-electric method combined monitoring substation (2) are respectively connected with one or two integrated vibration-picking electrode strings (3); the ground optical transceiver (7) is in wireless communication with the ground server (8); the ground optical terminal machine (7) is connected with all underground microseism-electric method joint monitoring substations (2) corresponding to roadway survey lines and hole survey lines through the underground optical terminal machine (6), is connected with the ground server (8), and is in wireless communication with the ground solar energy and wireless base station (4) equipped with each ground microseism-electric method joint monitoring substation (1) through each ground microseism-electric method joint monitoring substation (1); each underground micro-vibration-electric method combined monitoring substation (2) is provided with an underground explosion-proof and intrinsic safety power supply (5), and the underground explosion-proof and intrinsic safety power supply (5) is connected with an underground power grid;

The ground server (8) is provided with a multi-substation cooperative acquisition control module (9) and a microseism-electric method data comprehensive processing interpretation module (10); the multi-substation cooperative acquisition control module (9) is used for controlling the ground microseism-electric method combined monitoring substation (1) to transmit electric method signals, acquiring microseism and electric method signals and storing the microseism and electric method signals on the ground server (8); meanwhile, the system is used for controlling the underground microseism-electric method combined monitoring substation (2) to emit electric method signals, collecting microseism signals and storing the microseism signals on a ground server (8); the microseism-electrical method data comprehensive processing interpretation module (10) is used for reading monitoring data from the ground server (8) and processing and interpreting the monitoring data.

2. The ground-roadway-hole microseismic-electric method joint monitoring system according to claim 1, further comprising a monitoring result multi-dimensional visualization module (11) installed on the ground server (8), wherein the monitoring result multi-dimensional visualization module (11) is used for reading the microseismic-electric method data comprehensive processing interpretation module (10) from the ground server (8) to process the interpreted result and perform two-dimensional, three-dimensional, four-dimensional and other multi-dimensional space-time display or monitoring early warning on the result.

3. The ground-roadway-hole microseismic-electric method joint monitoring system according to claim 1, characterized in that the integrated vibration pickup electrode string (3) is formed by integrating a transmission cable and a spindle-shaped vibration pickup electrode.

4. A combined monitoring system of ground-roadway-hole microseismic-electric method according to claim 3, characterized in that the integrated processing and interpretation module (10) of microseismic-electric method data processes and interprets the monitored data specifically comprises the following steps:

Step1, calibrating a speed model of a monitoring area to obtain an average speed value of the calibrated speed model; calibrating a background resistivity model of the monitoring area to obtain the background resistivity model of the monitoring area;

step2, managing local monitoring data, which specifically comprises the steps of evaluating the quality of the collected monitoring signals to obtain effective microseismic monitoring signals and high-quality electrical monitoring signals;

step3, carrying out data processing on the effective microseism monitoring signals to obtain a microseism event positioning result;

Step4, correcting the high-quality electrical monitoring signal to obtain corrected monitoring data;

step5, carrying out mining fracture communication state analysis according to the positioning result of the microseism event to obtain the communication relation of the microseism event;

Step6, establishing a mining fracture model according to the communication relation of the microseismic events; establishing a resistivity reference model according to a background resistivity model and a mining fracture model of the monitoring area; and carrying out microseism-resistivity constraint inversion on the electrical monitoring data after correction processing according to the resistivity reference model to obtain an inverted resistivity model, namely a microseism-resistivity combined imaging result.

5. The combined monitoring system of ground-roadway-hole microseismic-electric method according to claim 4, wherein in Step1, a speed model of a monitored area is calibrated by a calibration gun, and an average speed value of the speed model obtained after calibration is marked as c.

6. The combined ground-roadway-hole microseismic-electric method monitoring system according to claim 5, wherein in Step1, a background resistivity model of a monitored area is simplified into a layered medium, and the layered medium is a surface loose layer, a roof layer, a coal layer and a floor layer in sequence from top to bottom; optionally selecting 10 measuring points on a ground measuring line, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of a ground surface loose layer; optionally selecting 10 measuring points on a roadway measuring line, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of the coal bed; optionally selecting 10 measuring points on a measuring line in a hole of the roof stratum, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of the roof stratum; optionally selecting 10 measuring points on a measuring line in a hole of the bottom plate rock stratum, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of the bottom plate rock stratum; the resistivity values of the layers together form a background resistivity model m ₀ of the monitored region.

7. The combined ground-roadway-hole microseismic-electric method monitoring system of claim 6, wherein Step3 is specifically implemented as follows:

Step31, filtering high-frequency noise of the effective microseism monitoring signal by adopting a low-pass filter;

Step32, picking up the first arrival of the microseismic monitoring signals after noise suppression, and determining the time when the seismic waves reach the current measuring point, namely the starting time of a microseismic event;

step33, determining the type of the microseismic monitoring signal source through polarization analysis, and realizing screening of effective microseismic events;

step34, positioning the microseism event according to the speed model calibration result of the monitoring area, namely the average speed value of the calibrated speed model, and obtaining the microseism source coordinate.

8. The combined ground-roadway-hole microseismic-electric monitoring system of claim 7, wherein Step34 comprises the following steps:

Setting the coordinates of a microseismic source as x, y and z, setting the starting time of a microseismic event as t, and according to the calibration result of a speed model of a monitoring area, assuming that the average speed of P waves transmitted in a rock mass is equal to the average speed value c of the calibrated speed model, and setting the P wave first arrival time of an a-th spindle-shaped vibration pickup electrode as t _a, then setting a travel time equation between the a-th spindle-shaped vibration pickup electrode and the microseismic source as follows:

[(x_a-x)²+(y_a-y)²+(z_a-z)²]¹²＝c(t_a-t)

(a＝1,2,3,…,n_a)

Wherein x _a、y_a、z_a is the space coordinate of the a-th spindle-shaped vibration pickup electrode respectively; n _a is the number of spindle-shaped vibration pickup electrodes which receive the effective microseism event;

In the travel time equation, the unknown numbers are 4, namely x, y, z and t, 4 of n _a spindle-shaped vibration pickup electrodes are taken, and an equation set is formed by the unknown numbers and a microseismic source as follows:

Substituting the known spindle-shaped vibration pickup electrode coordinate x _a、y_a、z_a and the first arrival time t _a into an equation set, and performing iterative calculation, wherein the calculation result is the primary positioning coordinate of the micro-seismic source; then 4 of the rest spindle-shaped vibration pickup electrodes are taken to carry out the same processing to obtain the secondary positioning coordinates of the micro-vibration source; and analogizing until all spindle-shaped vibration pickup electrodes receiving effective microseism events participate in positioning calculation, and taking an average value of a plurality of positioning coordinates to obtain microseism source coordinates.

9. The combined ground-roadway-hole microseismic-electric method monitoring system according to claim 8, wherein in Step4, the correction processing comprises infinity influence correction, observed voltage positive and negative attribute correction, spindle-shaped vibration pickup electrode grounding condition consistency correction, monitoring data normalization processing and monitoring data correlation analysis correction, and electric method monitoring data after correction processing is obtained.

10. The combined ground-roadway-hole microseismic-electric monitoring system of claim 9 wherein Step5 comprises the following specific sub-steps:

step51, calculating the influence radius of the microseismic event;

Step52, calculating connectivity of the microseismic event according to the microseismic event positioning result and the influence radius of the microseismic event;

step53, analyzing the communication state of the mining fracture according to the communication degree of the microseismic events to obtain the communication relation of the microseismic events.

11. The combined ground-roadway-hole microseismic-electric monitoring system of claim 10 wherein the radius of influence R of said microseismic event is calculated in Step51 as follows:

wherein M is the magnitude of a microseismic event; pi is the circumference ratio; σ ₀ is the apparent stress.

12. The combined ground-roadway-hole microseismic-electric monitoring system of claim 11, wherein, in Step52, the connectivity of the microseismic events is the ratio of the influence radius of the two microseismic events to the space distance of the two microseismic events, and the calculation formula is as follows:

Wherein R _i and R _j are the influence radii of any two microseismic events i and j respectively; (x _i,y_i,z_i) and (x _j,y_j,z_j) are the spatial coordinates of any two microseismic events i and j, respectively; lambda _ij is the connectivity of the two microseismic events.

13. The combined ground-roadway-hole microseismic-electric monitoring system of claim 12, wherein Step53 defines a data record format of: (x _i,y_i,z_i,x_j,y_j,z_j,λ_ij); when the connectivity lambda _ij of the two micro-seismic events is greater than 1, the cracks formed by the two micro-cracks are considered to be mutually communicated; when the connectivity lambda _ij is less than 1, the two micro-cracks are considered to form cracks independent of each other.

14. The ground-roadway-aperture microseismic-electric joint monitoring system of claim 13 wherein Step6 comprises the sub-steps of:

Step61, establishing a mining fracture model according to the communication relation of microseismic events, specifically:

Performing three-dimensional meshing on the monitoring area, wherein the central point of any meshing is marked as (x _l,y_m,z_n); assigning a fracture weight w (l, m, n) to each grid, wherein the initial value of the fracture weight w (l, m, n) is 1; mapping microseismic events into the three-dimensional grid one by one according to the coordinate relation; according to the data record of the communication relation of the microseismic events obtained in Step5, connecting two microseismic events with the communication degree larger than 1 by rays, and updating the value of the fracture weight w (l, m, n) of the grid through which the rays pass into the communication degree lambda _ij of the two microseismic events connected with the rays; when a certain grid is provided with a plurality of rays connected with microseismic events, taking the sum of the connectivity corresponding to each ray as the fracture weight of the grid; the grid model formed by w (l, m, n) is recorded as a mining-induced fracture model m _frc, and the model comprises the development position, the intensity and the intensity of the microseismic events;

Step62, establishing a resistivity reference model according to a background resistivity model and a mining fracture model of the monitored area, wherein the resistivity reference model specifically comprises:

Mapping a background resistivity model of the monitored area into three-dimensional grids, wherein the background resistivity value of each grid is marked as rho ₀ (l, m, n), and the background resistivity value represents the resistivity of the stratum when the stratum is not affected by mining damage; the resistivity values of the formation after being affected by the mining damage are defined as follows:

wherein w (l, m, n) is the fracture weight of the current grid; ρ ₀ (l, m, n) is the background resistivity value of the grid; ρ _ref (l, m, n) is the reference resistivity value of the grid after the mining damage; the grid model consisting of ρ _ref (l, m, n) is denoted as resistivity reference model m _ref;

Step63, for the corrected electrical monitoring data, performing microseism-resistivity constraint inversion according to the resistivity reference model to obtain an inverted resistivity model, namely a microseism-resistivity joint imaging result, wherein:

the inverted model update formula is as follows:

In the method, in the process of the invention, For the resistivity model obtained after the kth inversion iteration,The resistivity model obtained after the k+1st inversion iteration is used, alpha is a model correction coefficient,For model correction, β is regularization parameter, W _d is model weight, W _m is model weight, Δd ^k is residual error of electrical monitoring data and simulated observation data d ^k after correction processing,In the jacobian matrix, m _ref is a resistivity reference model.

15. The combined ground-roadway-aperture microseismic-electric monitoring system of claim 14 wherein, in Step63, said model correction factor α is determined according to the following rules:

Wherein c ₁ is a constant, beta is a constant between 1 and 10, AndTo invert the data residual.

16. A combined monitoring method of ground-roadway-hole microseismic-electric method, which is characterized by comprising the following steps based on the combined monitoring system of ground-roadway-hole microseismic-electric method as set forth in any one of claims 1 to 15:

Step 1, designing a monitoring scheme, including collecting relevant data of a working face, delineating a monitoring target area, designing a monitoring data acquisition scheme and designing a monitoring system construction scheme;

Step 2, installing a monitoring system, which comprises monitoring equipment preparation, ground monitoring equipment installation, roadway monitoring equipment installation, in-hole monitoring equipment installation and monitoring platform installation;

Step 3, debugging the monitoring system, including a system connection test, a vibration pickup electrode coupling state test, a background noise test and an electrical signal strength test;

step 4, calibrating background parameters of the monitoring area, which comprises calibrating a speed model of the monitoring area and calibrating a background resistivity model of the monitoring area to obtain a calibration result;

Step 5, collecting parameter configuration, including monitoring substation time service and electrical method monitoring signal collecting parameter configuration;

Step 6, controlling each monitoring substation to cooperatively acquire monitoring signals through a multi-substation cooperative acquisition control module (9);

step 7, performing quality evaluation on the monitoring signals acquired in the step6 to obtain effective microseismic monitoring signals and high-quality electrical monitoring signals;

Step 8, carrying out data processing on the effective microseismic monitoring signals obtained in the step 7 to obtain a microseismic event positioning result;

Step 9, correcting the high-quality electrical monitoring signal obtained in the step 7 to obtain corrected electrical monitoring data;

step 10, analyzing the communication state of the mining fracture according to the positioning result of the microseismic event in the step 8 to obtain the communication relation of the microseismic event;

Step 11, establishing a mining fracture model according to the communication relation of the microseismic events obtained in the step 10; establishing a resistivity reference model according to the background resistivity model and the mining fracture model of the monitoring area obtained in the step 5; and (3) carrying out microseism-resistivity constraint inversion on the electrical monitoring data subjected to correction processing in the step (9) according to the resistivity reference model to obtain an inverted resistivity model, namely a microseism-resistivity combined imaging result.

17. The combined monitoring method of ground-roadway-hole microseismic-electric method according to claim 16, wherein in the step 4, a speed model of a monitored area is calibrated by a calibration gun, and an average speed value of the speed model obtained after calibration is marked as c.

18. The combined ground-roadway-hole microseismic-electric method monitoring method according to claim 17, wherein in the step 4, a background resistivity model of a monitored area is simplified into a layered medium, and the layered medium is a surface loose layer, a roof layer, a coal layer and a floor layer in sequence from top to bottom; optionally selecting 10 measuring points on a ground measuring line, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of a ground surface loose layer; optionally selecting 10 measuring points on a roadway measuring line, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of the coal bed; optionally selecting 10 measuring points on a measuring line in a hole of the roof stratum, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of the roof stratum; optionally selecting 10 measuring points on a measuring line in a hole of the bottom plate rock stratum, measuring apparent resistivity of the 10 measuring points by using a symmetrical quadrupole device, and taking an average value of the apparent resistivity as a resistivity value of the bottom plate rock stratum; the resistivity values of the layers together form a background resistivity model m ₀ of the monitored region.

19. The combined monitoring method of ground-roadway-hole microseismic-electric method as set forth in claim 18, wherein the specific implementation procedure of the step 8 is as follows:

Step 81, filtering high-frequency noise of the effective microseismic monitoring signal by adopting a low-pass filter;

Step 82, picking up the first arrival of the microseismic monitoring signals after noise suppression, and determining the time when the seismic waves reach the current measuring point, namely the starting time of a microseismic event;

step 83, determining the type of the microseismic monitoring signal source through polarization analysis, and realizing screening of effective microseismic events;

And step 84, positioning the microseism event according to the calibration result of the speed model of the monitoring area, namely the average speed value of the calibrated speed model, and obtaining the microseism source coordinate.

20. The combined ground-roadway-hole microseismic-electric method monitoring method of claim 19, wherein the implementation procedure of step 84 is as follows:

Setting the coordinates of a microseismic source as x, y and z, setting the starting time of a microseismic event as t, and according to the calibration result of a speed model of a monitoring area, assuming that the average speed of P waves transmitted in a rock mass is equal to the average speed value c of the calibrated speed model, and setting the P wave first arrival time of an a-th spindle-shaped vibration pickup electrode as t _a, then setting a travel time equation between the a-th spindle-shaped vibration pickup electrode and the microseismic source as follows:

[(x_a-x)²+(y_a-y)²+(z_a-z)²]¹²＝c(t_a-t)

(a＝1,2,3,…,n_a)

Wherein x _a、y_a、z_a is the space coordinate of the a-th spindle-shaped vibration pickup electrode respectively; n _a is the number of spindle-shaped vibration pickup electrodes which receive the effective microseism event;

In the travel time equation, the unknown numbers are 4, namely x, y, z and t, 4 of n _a spindle-shaped vibration pickup electrodes are taken, and an equation set is formed by the unknown numbers and a microseismic source as follows:

Substituting the known spindle-shaped vibration pickup electrode coordinate x _a、y_a、z_a and the first arrival time t _a into an equation set, and performing iterative calculation, wherein the calculation result is the primary positioning coordinate of the micro-seismic source; then 4 of the rest spindle-shaped vibration pickup electrodes are taken to carry out the same processing to obtain the secondary positioning coordinates of the micro-vibration source; and analogizing until all spindle-shaped vibration pickup electrodes receiving effective microseism events participate in positioning calculation, and taking an average value of a plurality of positioning coordinates to obtain microseism source coordinates.

21. The method for combined monitoring of ground-roadway-hole microseismic-electric method according to claim 20, wherein in the step 9, the correction process comprises infinity influence correction, observed voltage positive and negative attribute correction, spindle-shaped vibration pickup electrode grounding condition consistency correction, monitoring data normalization process and monitoring data correlation analysis correction, and electric method monitoring data after correction process is obtained.

22. The combined ground-roadway-hole microseismic-electric method monitoring method of claim 21, wherein the specific steps of step 10 are as follows:

Step 101, calculating the influence radius of a microseismic event;

102, calculating the connectivity of the microseismic event according to the microseismic event positioning result and the influence radius of the microseismic event;

And 103, analyzing the communication state of the mining fracture according to the communication degree of the microseismic event to obtain the communication relation of the microseismic event.

23. The method for combined monitoring of ground-roadway-hole microseismic-electric method of claim 22 wherein in step 101, the radius of influence R of the microseismic event is calculated as follows:

wherein M is the magnitude of a microseismic event; pi is the circumference ratio; σ ₀ is the apparent stress.

24. The method for combined monitoring of "ground-roadway-hole" microseismic-electric method of claim 23, wherein in step 102, the connectivity of the microseismic events is the ratio of the radius of influence of two microseismic events to the spatial distance thereof, and the calculation formula is as follows:

Wherein R _i and R _j are the influence radii of any two microseismic events i and j respectively; (x _i,y_i,z_i) and (x _j,y_j,z_j) are the spatial coordinates of any two microseismic events i and j, respectively; lambda _ij is the connectivity of the two microseismic events.

25. The method of claim 24, wherein in step 103, the data record format is defined as: (x _i,y_i,z_i,x_j,y_j,z_j,λ_ij); when the connectivity lambda _ij of the two micro-seismic events is greater than 1, the cracks formed by the two micro-cracks are considered to be mutually communicated; when the connectivity lambda _ij is less than 1, the two micro-cracks are considered to form cracks independent of each other.

26. The ground-roadway-aperture microseismic-electric joint monitoring system of claim 25 wherein step 11 comprises the sub-steps of:

step 111, establishing a mining fracture model according to the communication relation of the microseismic events, specifically:

Performing three-dimensional meshing on the monitoring area, wherein the central point of any meshing is marked as (x _l,y_m,z_n); assigning a fracture weight w (l, m, n) to each grid, wherein the initial value of the fracture weight w (l, m, n) is 1; mapping microseismic events into the three-dimensional grid one by one according to the coordinate relation; according to the data record of the communication relation of the microseismic events obtained in the step 10, connecting two microseismic events with the communication degree larger than 1 by rays, and updating the value of the fracture weight w (l, m, n) of the grid through which the rays pass into the communication degree lambda _ij of the two microseismic events connected with the rays; when a certain grid is provided with a plurality of rays connected with microseismic events, taking the sum of the connectivity corresponding to each ray as the fracture weight of the grid; the grid model formed by w (l, m, n) is recorded as a mining-induced fracture model m _frc, and the model comprises the development position, the intensity and the intensity of the microseismic events;

step 112, establishing a resistivity reference model according to a background resistivity model and a mining fracture model of the monitored area, wherein the resistivity reference model specifically comprises the following steps:

Mapping a background resistivity model of the monitored area into three-dimensional grids, wherein the background resistivity value of each grid is marked as rho ₀ (l, m, n), and the background resistivity value represents the resistivity of the stratum when the stratum is not affected by mining damage; the resistivity values of the formation after being affected by the mining damage are defined as follows:

wherein w (l, m, n) is the fracture weight of the current grid; ρ ₀ (l, m, n) is the background resistivity value of the grid; ρ _ref (l, m, n) is the reference resistivity value of the grid after the mining damage; the grid model consisting of ρ _ref (l, m, n) is denoted as resistivity reference model m _ref;

Step 113, for the corrected electrical monitoring data, performing microseism-resistivity constraint inversion according to the resistivity reference model to obtain an inverted resistivity model, namely a microseism-resistivity joint imaging result, wherein:

the inverted model update formula is as follows:

In the method, in the process of the invention, For the resistivity model obtained after the kth inversion iteration,The resistivity model obtained after the k+1st inversion iteration is used, alpha is a model correction coefficient,For model correction, β is regularization parameter, W _d is model weight, W _m is model weight, Δd ^k is residual error of electrical monitoring data and simulated observation data d ^k after correction processing,In the jacobian matrix, m _ref is a resistivity reference model.

27. The combined ground-roadway-aperture microseismic-electric monitoring system of claim 26, wherein in step 113, said model correction factor α is determined according to the following rule:

Wherein c ₁ is a constant, beta is a constant between 1 and 10, AndTo invert the data residual.

28. The combined ground-roadway-hole microseismic-electric method monitoring method of claim 16, further comprising step 12: and (3) carrying out three-dimensional visualization on the microseism event positioning result obtained in the step (8), the mining fracture model obtained in the step (11) and the microseism-resistivity combined imaging result.