CN118688716A - A method for improving positioning accuracy of coal mine microseismic monitoring system based on wave velocity zone division - Google Patents

Abstract

The present invention belongs to the field of coal mine safety technology, and specifically relates to a method for improving the positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division, comprising the following steps: step 1: arranging a microseismic monitoring system in a target mine, arranging vibration pickup sensors underground and on the ground, and measuring the coordinates of each sensor; step 2: performing regional division according to the geological and mining technical conditions of the mine and the different wave velocity values of the vibration wave in different regions, and constructing a three-dimensional wave velocity zone division model according to the regional division results; step 3: calculating the wave velocity values of each wave velocity zone by using a blasting source method; step 4: first using the entity zone wave velocity _V1 as the initial wave velocity value of each sensor of the system to locate the source, and calculating the initial position 0 ( _X0 , _Y0 , _Z0 ); according to the initial position of the source and the position of each vibration pickup sensor, according to the distance of the different wave velocity zones passed between the two, the wave velocity of each sensor is calculated; step 5: recalculating the source position by using the new wave velocity value. The source positioning of the present invention is more accurate.

Description

A method for improving positioning accuracy of coal mine microseismic monitoring system based on wave velocity zone division

Technical Field

The invention belongs to the technical field of coal mine safety, and in particular relates to a method for improving the positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division.

Background Art

Rock burst is a serious coal mine disaster. It has become the sixth largest disaster in coal mines after water, fire, gas, coal dust and roof. With the continuous increase in the depth of coal mining, it has the tendency to become the most important disaster in coal mines. In recent years, rock burst disasters have occurred frequently. Rock burst monitoring technology is the primary and key link in preventing and controlling rock burst disasters. Article 46 of the "Detailed Rules for Preventing and Controlling Rock Burst in Coal Mines" stipulates that rock burst mines must establish a regional and local impact hazard monitoring system. Regional monitoring should cover the mining area of the mine. Regional monitoring can adopt microseismic monitoring methods, etc.; when the force reaches a certain level, cracks will be generated in the coal rock mass. During the generation and expansion of the cracks and the movement of the rock blocks, vibration waves will be released. Microseismic monitoring technology is a technology that locates the fracture or movement position of the coal rock mass and calculates the amount of released energy by monitoring vibration waves; microseismic monitoring technology is the most important monitoring technology used in rock burst mines, among which the accuracy of earthquake source positioning plays a key role in monitoring impact hazard; microseismic monitoring technology locates the earthquake source through a certain positioning algorithm, among which the key to affecting the positioning accuracy is the determination of the wave velocity value. Current microseismic monitoring technologies all use a fixed wave velocity, but the strata themselves are heterogeneous, and mining activities will cause significant changes in the stratum's state of occurrence. When the vibration wave passes through solid areas, goaf areas, geological anomaly areas, topsoil layers and other areas, the wave velocity difference is large. If fixed wave velocity positioning is used, the source error will inevitably be large, which will seriously affect the microseismic monitoring technology's monitoring of impact hazards.

For example, the Chinese patent with patent number CN105022031A discloses a layered velocity positioning method for regional rock microseismic sources, and the steps are as follows: ① Divide the rock mass area of the source to be measured into different wave velocity layers, establish a three-dimensional rectangular coordinate system, and calculate the analytical equation of the interface of each wave velocity layer; ② Install sensors in the rock mass area and measure the spatial coordinates of each sensor; ③ Carry out blasting experiments in the rock mass area to calculate the rock mass wave velocity of each wave velocity layer; ④ Calculate the spatial coordinates (x0, y0, z0) of the microseismic source. The method of the present invention has high positioning accuracy for the microseismic source, which can promote the microseismic monitoring technology to better play a predictive and early warning role in engineering practice; However, in the prior art, the rock mass is divided into different wave velocity layers parallel to each other, and the subsequent method is only applicable to the layered wave velocity zone division; The invention requires that sensors must be arranged in the first and last wave velocity layers; The applicability is relatively local; Therefore, it is of great significance to study a scientific and reasonable wave velocity determination and positioning method to improve the accuracy of source positioning and the monitoring capability of impact danger.

Summary of the invention

The purpose of the present invention is to provide a method for improving the positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division. The method first measures the wave velocity values of different areas, and then automatically calculates the wave velocity value of each sensor based on the distance between the sensor and the wave velocity zone passed by the sensor and the source, and then locates the source according to the new wave velocity value and continuously iterates. This can eliminate the errors caused by the current microseismic monitoring system using fixed wave velocity positioning, thereby greatly improving the positioning accuracy of the coal mine microseismic system.

The technical solution adopted by the present invention is as follows:

A method for improving the positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division comprises the following steps:

Step 1: Arrange a microseismic monitoring system in the target mine, and arrange vibration pickup sensors underground and on the ground, where the ground sensors are numbered T ₁ , T ₂ , T ₃ ..T _n , and the underground sensors are numbered S ₁ , S ₂ , S ₃ ..S _n , and the total number of the ground sensors and the underground sensors is greater than or equal to four; and measure the coordinates of each sensor;

Step 2: According to the geological and mining technical conditions of the mine, the region is divided into different wave velocity zones, namely, solid zone _A1 , collapse zone _A2 , fissure zone _A3 , surface soil zone _A4 and geological structure zone _A5 ... _An. In the process of regional division, the division is carried out according to the actual measurement of the mine. If there is no actual measurement, the division is carried out according to the theoretical value of the mine pressure. According to the regional division results, a three-dimensional wave velocity zone division model is constructed;

Step 3: Calculate the wave velocity value of each wave velocity zone by blasting source, place explosives on one side of the wave velocity zone A _n , and place sensors on the other side to test the wave velocity. If there is no roadway close to the wave velocity zone A _n on the other side to arrange the sensor due to the underground tunnel layout, it is necessary to select the roadway closest to this area to arrange the sensor; for example, the distance between the sensor and the blasting point passes through the physical area distance D ₁ and the geological structure area distance D ₅ , and its wave velocity is measured to be V ₁₅ , where the wave velocity in the physical area is known to be V ₁ , then the wave velocity in the geological structure area V ₅ = [V ₁₅ × (D ₁ +D ₂ )-D ₁ ×V ₁ ]/D ₅ ;

Step 4: First, use the entity area wave velocity _V1 as the initial wave velocity value of each sensor in the system to locate the earthquake source and calculate the initial position 0 ( _X0 , _Y0 , _Z0 ); according to the initial position of the earthquake source and the position of each vibration pickup sensor, according to the distance between the two passing through different wave velocity zones, calculate the wave velocity of each sensor. The earthquake source and the ground sensor _Tn pass through _A1 , _A2 , _A3 , ..., _An in turn; then the wave velocity of sensor T1 should be set to Where _Li is the distance that the shock wave passes through the corresponding area, and _Vi is the velocity of the corresponding area;

Step 5: Use the new wave velocity value to recalculate the source position, and continue iterating until the error between the source position and the previous source position is less than 1m. The calculation is terminated.

The technical effects achieved by the present invention are:

Since the wave velocity of microseismic vibration varies greatly when passing through different areas such as collapse zones, fissure zones, topsoil zones, geological structural zones, coal and rock entities, the current microseismic monitoring system uses a fixed wave velocity for positioning, which inevitably results in large errors. The present invention first measures the wave velocity values of different areas, and then automatically calculates the wave velocity value of each sensor based on the distance between the sensor and the wave velocity zone passed through by the sensor and the source, and then locates the source based on the new wave velocity value and continuously iterates, which can eliminate the errors caused by the current microseismic monitoring system using a fixed wave velocity for positioning, thereby greatly improving the positioning accuracy of the coal mine microseismic system.

Compared with the prior art, the present invention has a different wave velocity zone division; in the prior art, the rock mass is divided into different wave velocity layers parallel to each other, and the subsequent method is only applicable to layered wave velocity zone division; the present invention can be divided into wave velocity zones of any shape according to the mine geology and mining technical conditions, and the subsequent method is applicable to the division, and the sensor arrangement method is different from the prior art; the prior art requires that sensors must be arranged in the first and last wave velocity layers; while the present invention has no special requirements for the sensor arrangement position, and only needs to arrange a microseismic monitoring system in the target mine, and arrange vibration pickup sensors underground and on the ground, wherein the ground sensors are numbered T ₁ , T ₂ , T ₃ ... T _n , and the underground sensors are numbered S ₁ , S ₂ , S ₃ ... S _n , the sum of the ground sensors and the downhole sensors is greater than or equal to four; and the coordinates of each sensor are measured; compared with the prior art, the positioning method of the present invention is different; the comparative document in the prior art assumes that the earthquake source is located in a certain wave velocity layer, and determines the earthquake source position by solving the minimum value of the objective function; and the present invention first uses the wave velocity of the physical coal to calculate the earthquake source position, and then continuously recalculates the sensor wave velocity value according to the position of the wave velocity zone passed between the earthquake source and the sensor, and then continuously iterates until the error with the last earthquake source position is less than 1m, that is, the real earthquake source position, so that the final real earthquake source position is more accurate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for improving positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division according to the present invention;

2 is a schematic diagram of wave velocity zone division and earthquake source positioning in a method for improving positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division according to the present invention.

In the accompanying drawings, the components represented by the reference numerals are listed as follows:

1. Topsoil area; 2. Ground microseismic sensor T1; 3. Solid area; 4. Initial earthquake source position 0; 5. Fracture area; 6. Final earthquake source position i+1; 7. Collapse area; 8. Downhole sensor _S1 ; 9. Downhole sensor _S2 ; 10. Downhole sensor _S3 ; 11. Geological structure area; 12. Underground tunnel.

DETAILED DESCRIPTION

In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

As shown in FIG1 , a method for improving the positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division includes the following steps:

Step 1: As shown in FIG2 , which is a schematic diagram of wave velocity zone division and earthquake source location of the present invention, a microseismic monitoring system is arranged in the target mine, and vibration pickup sensors are arranged underground and on the ground, wherein the ground sensors are numbered T ₁ , T ₂ , T ₃ ..T _n , and the underground sensors are numbered S ₁ , S ₂ , S ₃ ..S _n , and the total number of the ground sensors and the underground sensors is greater than or equal to four; and the coordinates of each sensor are measured;

Step 2: According to the geological and mining technical conditions of the mine, the region is divided into different wave velocity zones, namely, solid zone _A1 , collapse zone _A2 , fissure zone _A3 , surface soil zone _A4 and geological structure zone _A5. In the process of regional division, the division is carried out according to the actual measurement of the mine. If there is no actual measurement, the division is carried out according to the theoretical value of the mine pressure. According to the regional division results, a three-dimensional wave velocity zone division model is constructed;

Step 3: Calculate the wave velocity value of each wave velocity zone by blasting source, place explosives on one side of the geological structure zone, and place sensors on the other side to test the wave velocity. If there is no tunnel close to the geological structure zone on the other side to arrange the sensor due to the underground tunnel layout, it is necessary to select the tunnel closest to this area to arrange the sensor. The distance between the sensor and the blasting point passes through the physical zone distance _D1 and the geological structure zone distance _D5 . The wave velocity is measured to be _V15 , where the wave velocity of the physical zone is known to be _V1 , then the wave velocity of the geological structure zone _V5 = [ _V15 × ( _D1 + _D2 ) - _D1 × _V1 ] / _D5 ;

Step 4: First, use the entity area wave velocity _V1 as the initial wave velocity value of each sensor in the system to locate the earthquake source and calculate the initial position 0 ( _X0 , _Y0 , _Z0 ); according to the initial position of the earthquake source and the position of each vibration pickup sensor, according to the distance between the two passing through different wave velocity zones, calculate the wave velocity of each sensor. The earthquake source and the ground sensor _Tn pass through _A1 , _A2 , _A3 , ..., _An in turn; then the wave velocity of sensor T1 should be set to Where _Li is the distance that the shock wave passes through the corresponding area, and _Vi is the velocity of the corresponding area;

Step 5: Use the new wave velocity value to recalculate the source position, and continue to iterate until the error between the source position and the previous source position is less than 1m. When , the calculation terminates and the source position is output, (X _i+1 , Yi ₊₁ , Zi ₊₁ ).

This method first measures the wave velocity values in different areas, and then automatically calculates the wave velocity value of each sensor based on the distance between the sensor and the wave velocity zone passed by the sensor and the source. Then, the source is located according to the new wave velocity value and it is continuously iterated. This can eliminate the error caused by the current microseismic monitoring system that uses fixed wave velocity positioning, thereby greatly improving the positioning accuracy of the coal mine microseismic system.

The working principle of the present invention is:

Step 1: For example, a mine is a rock burst mine, and a mine-ground integrated microseismic monitoring system is deployed in the mine. There are 4 sensors around a certain working face, including three underground sensors, numbered S ₁ , S ₂ , and S ₃ , and one ground sensor, numbered T ₁ . The three-dimensional coordinates of the sensors are measured, and the specific positions are shown in Figure 2;

Step 2: According to the geological and mining technical conditions of the region, different wave velocity zones were divided, namely solid zone _A1 , collapse zone _A2 , fissure zone _A3 , topsoil zone _A4 , and geological structure zone _A5 ; the range of the wave velocity zone was determined according to the actual measurement of the mine and the geological exploration results, and a three-dimensional wave velocity zone model was further constructed, as shown in Figure 2;

Step 3: The velocity values of each velocity zone were measured by blasting source, _{with V1} in the solid zone being 4130 m/s, _V2 in the collapse zone being 2470 m/s, _V3 in the fissure zone being 3420 m/s, _V4 in the topsoil zone being 2650 m/s, and _V5 in the geological structure zone being 3750 m/s.

Step 4: First, the solid area wave velocity V1 is used as the initial wave velocity value of each sensor in the system to locate the earthquake source, and the initial position 0 ( _X0 , _Y0 , _Z0 ) is calculated. The calculation method for calculating the initial position of the earthquake source based on multiple wave velocities is common knowledge in this field and will not be repeated here. The position is shown in Figure 2; according to the initial position of the earthquake source and the positions of each sensor, the wave velocity of each sensor is calculated according to the distance between the initial position of the earthquake source and the positions of each sensor and the different wave velocity zones passed between them; if the distance between the initial position 0 and the ground sensor _T1 is _L1 = 60m, _L2 = 250m, and _L3 = 50m respectively, then the wave velocity of sensor T1 should be set to _VT1-1 = (60×3420+250×4130+50×2650)/(60+250+50) = 3806.11m/s, and the same applies to other sensors.

Step 5: Use the new wave velocity value to recalculate the source position 1 (X ₁ , Y ₁ , Z ₁ ), recalculate the sensor wave velocity based on the new source position and the sensor position, and then reposition, and continue to iterate until the error between the source position and the previous source position is less than 1m. The calculation is terminated. The process is shown in 2.

In the present invention, the velocity of microseismic vibration waves varies greatly when passing through different areas such as collapse zones, fracture zones, topsoil zones, geological structural zones, coal and rock entities, but the current microseismic monitoring system uses fixed wave velocities for positioning, which inevitably results in large errors. This method first measures the wave velocity values of different areas, and then automatically calculates the wave velocity values of each sensor based on the distance between the sensor and the wave velocity zone passed through by the source, and then locates the source based on the new wave velocity value and continuously iterates, which can eliminate the errors caused by the current microseismic monitoring system using fixed wave velocity positioning, thereby greatly improving the positioning accuracy of the coal mine microseismic system.

In the present invention, the velocity zone division is different from that in the prior art; in the prior art, the rock mass is divided into different velocity layers parallel to each other, and the subsequent method is only applicable to the layered velocity zone division; the present invention can be divided into velocity zones of any shape according to the mine geology and mining technical conditions, and the subsequent method is applicable to the division, and the sensor arrangement method is different from that in the prior art; the prior art requires that sensors must be arranged in the first and last velocity layers; while the present invention has no special requirements for the sensor arrangement position, and only needs to arrange a microseismic monitoring system in the target mine, and arrange vibration pickup sensors underground and on the ground, wherein the ground sensors are numbered T ₁ , T ₂ , T ₃ ... T _n , and the underground sensors are numbered S ₁ , S ₂ , S ₃ ... S _n , the sum of the ground sensors and the downhole sensors is greater than or equal to four; and the coordinates of each sensor are measured; compared with the prior art, the positioning method of the present invention is different; the comparative document in the prior art assumes that the earthquake source is located in a certain wave velocity layer, and determines the earthquake source position by solving the minimum value of the objective function; and the present invention first uses the wave velocity of the physical coal to calculate the earthquake source position, and then continuously recalculates the sensor wave velocity value according to the position of the wave velocity zone passed between the earthquake source and the sensor, and then continuously iterates until the error with the last earthquake source position is less than 1m, that is, the real earthquake source position, so that the final real earthquake source position is more accurate.

The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims (8)

1. A method for improving the positioning accuracy of a coal mine microseismic monitoring system based on wave velocity zone division is characterized by comprising the following steps: the method comprises the following steps:

Step 1: arranging a microseismic monitoring system in a target mine, arranging vibration pickup sensors underground and on the ground, and measuring the coordinates of each sensor;

Step 2: dividing areas according to mine geology and mining technical conditions, and constructing a three-dimensional wave velocity division model according to area division results;

step 3: calculating the wave speed value of each wave speed region by adopting a blasting source mode;

Step 4: firstly, using a wave velocity V ₁ of an entity area as an initial wave velocity value of each sensor of a system to position a seismic source, and calculating an initial position 0 (X ₀、Y₀、Z₀); according to the initial position of the seismic source and the positions of all vibration pickup sensors, calculating the wave speed of each sensor according to the distance between different wave speed areas penetrated by the two vibration pickup sensors;

Step 5: and (5) recalculating the position of the seismic source by adopting the new wave velocity value, and continuously iterating until the error between the position of the seismic source and the position of the seismic source at the last time is smaller than 1m, and ending calculation.

2. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 1, which is characterized by comprising the following steps of: in the step 1, the surface sensor number T ₁、T₂、T₃…T_n and the downhole sensor number S ₁、S₂、S₃…S_n are used.

3. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 2, which is characterized by comprising the following steps of: and the sum of the surface sensor and the underground sensor is more than or equal to four.

4. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 3, which is characterized by comprising the following steps of: in the region division process in the step 2, the region is divided into a solid region a ₁, a collapse region a ₂, a fracture region a ₃, a surface soil region a ₄ and a geological structure region a ₅...A_n with different wave velocities.

5. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 4, which is characterized by comprising the following steps: in the step 2, in the area dividing process, dividing is performed according to actual measurement of the mine, and if no actual measurement is performed, dividing is performed according to the value of the mine pressure theory.

6. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 5, which is characterized by comprising the following steps: in the step 3, an explosive is placed on one side of the wave velocity zone A _n, and a sensor is placed on the other side to test the wave velocity.

7. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 6, which is characterized by comprising the following steps: in the step 3, if the underground roadway is arranged and the roadway with the other side not being close to the wave velocity zone a _n is used for arranging the sensor, the roadway arrangement sensor closest to the area needs to be selected, the sensor and the blasting point pass through the physical zone distance D ₁ and the geological structure zone distance D ₅, the wave velocity is measured to be V ₁₅, wherein the wave velocity of the physical zone is known as V ₁, and the wave velocity of the geological structure zone is V ₅＝[V₁₅×(D₁+D₂)-D₁×V₁]/D₅.

8. The method for improving the positioning accuracy of the coal mine microseismic monitoring system based on wave velocity zone division according to claim 7, which is characterized by comprising the following steps: in the step 4, the seismic source and the ground sensor T _n sequentially pass through A ₁、A₂、A₃、…、A_n; then

The wave speed of the sensor T _n is set toWhere L _i is the distance that the shock wave passes through the corresponding region and V _i is the velocity of the corresponding region.