Surface subsidence and rock burst combined monitoring and integrated analysis method

Abstract

The invention relates to a surface subsidence and rock burst combined monitoring and integrated analysis method, which comprises the following steps of: establishing a numerical model, simulating a surface subsidence and overlying strata stress change rule in a mining process, monitoring surface subsidence by adopting a traditional survey line method and a UAV (Unmanned Aerial Vehicle) laser radar, monitoring micro-seismic by adopting a micro-seismic monitoring system, and analyzing the surface subsidence and rock burst combined monitoring and integrated analysis. And through comprehensive analysis of surface subsidence data, overlying strata stress data and micro-seismic data, rock burst risk assessment is carried out. According to the method, a scientific basis is provided for integrated prevention and control of coal mine surface deformation-underground dynamic disasters, a scientific prediction basis and technical support are provided for safe mining of a coal mine, and the risk of mine disasters is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of coal mining safety technology, and specifically to a combined monitoring and integrated analysis method for surface subsidence and rock burst, which is suitable for disaster prediction and prevention in the process of deep near-horizontal coal seam mining. Background Art

[0002] As the depth of coal mining continues to increase, mining disasters are characterized by multiple complexities and linkage between the mine and the ground. Under deep mining conditions, surface subsidence shows different temporal and spatial evolution laws from shallow mining, and is increasingly becoming a research hotspot in the field of rock movement control; the frequency and intensity of underground rock bursts are also increasing.

[0003] In recent years, surface deformation monitoring of rock burst mines has found that the amount of surface subsidence, sinking speed, etc. have a certain linkage effect with mine earthquakes. Since mine earthquake loads are an important source of force and energy for inducing rock bursts, it can be inferred that there is a certain correlation and linkage mechanism between surface subsidence and rock bursts. Although domestic and foreign scholars have conducted in-depth research on the laws of surface subsidence and rock burst mechanisms in deep mining, the research on the correlation and linkage effect between the two is still in its infancy.

[0004] In the existing technology, the monitoring of surface subsidence and rock burst mostly adopts a single means, which is difficult to fully reflect the correlation between the two. For example, numerical simulation can predict surface subsidence and overburden stress changes, but it is difficult to reflect the actual dynamic response of underground rock mass; surface subsidence monitoring can obtain high-precision surface subsidence data, but it is difficult to reflect the stress changes and microseismic activities of underground rock mass; microseismic monitoring can reflect the dynamic response of underground rock mass, but it is difficult to obtain surface subsidence data. Therefore, a joint monitoring and integrated analysis method is urgently needed to improve the prediction and prevention capabilities of mine disasters.

[0005] To this end, the present invention establishes a joint monitoring and integrated analysis method for surface subsidence and rock burst, which provides a scientific basis for the integrated prevention and control of surface deformation and underground dynamic disasters in coal mines, provides a scientific prediction basis and technical support for the safe mining of coal mines, and effectively reduces the risk of mine disasters. Summary of the invention

[0006] The present invention aims to solve the above problems and proposes a joint monitoring and integrated analysis method for surface subsidence and rock burst. This method realizes a comprehensive analysis of the correlation between surface subsidence and rock burst during deep mining by organically combining numerical simulation, surface subsidence monitoring and microseismic monitoring technology, thereby providing a scientific basis for the prediction and prevention of rock burst.

[0007] The technical solution adopted by the present invention is as follows: a method for joint monitoring and integrated analysis of surface subsidence and rock burst, the steps of which are as follows:

[0008] 1) Using finite element software, according to the rock distribution and physical and mechanical parameters of the coal mining area, a numerical model of the coal mining area is established to simulate the surface subsidence and overburden stress changes during coal mining; combined with the actual conditions of the coal seams, roof and floor plates in the mining area and the comprehensive geological columnar diagram, the physical and mechanical parameters of each rock layer, including thickness, bulk density, elastic modulus, Poisson's ratio, cohesion and internal friction angle, are set, and a three-dimensional numerical model is constructed using finite element software to simulate the movement and stress distribution of the rock layer during coal mining. According to the simulation results, a comparison diagram of surface subsidence values ​​and coal body-roof vertical stress under different advancement distances is obtained, and the center line of the roof strike is set as the measurement line to obtain the vertical stress growth rate at different measuring points under different advancement distances.

[0009] 2) Use traditional line surveying method and UAV lidar technology to conduct high-precision real-time monitoring of surface subsidence, obtain measured data of surface subsidence, compare the measured maximum subsidence value with the simulated maximum subsidence value, and the error value is less than 5% to meet the accuracy requirements. If the difference does not meet the requirements, adjust the physical and mechanical parameters of the rock formation until the accuracy requirements are met.

[0010] 3) Deploy a microseismic monitoring system, arrange microseismic monitoring stations in the mining area and its surroundings to form a microseismic monitoring network, monitor microseismic events in the mining area in real time, record the total energy of microseismic events on a single day and the maximum energy of microseismic events on a single day at different advancement distances, and obtain the microseismic characteristic curves of the working face at different advancement distances.

[0011] 4) Comprehensively analyze the surface subsidence data, rock formation stress data and microseismic data, evaluate the risk of rock burst through comparison and correlation analysis, and provide early warning for coal mining. Compare the surface subsidence value, coal body vertical stress, roof vertical stress, single-day microseismic total energy, and single-day microseismic maximum energy. If the surface subsidence value increases, the coal body and roof stress, and the roof stress growth rate reach the maximum value, the single-day microseismic total energy and the single microseismic maximum energy peak, and the possibility of impact is high; the surface subsidence value, coal body and roof stress, and roof stress growth rate gradually stabilize, the single-day microseismic total energy and the single microseismic maximum energy generally show a downward trend, and the possibility of impact is medium; the surface subsidence is not obvious, the roof is in a stable state, the single-day microseismic total energy and the single microseismic maximum energy are both lower than 800J, and the possibility of impact is small.

[0012] The beneficial effects of the present invention are:

[0013] 1. Joint monitoring: Through the joint monitoring of surface subsidence and microseismicity, the safety status of coal mines can be more comprehensively understood and the accuracy and reliability of monitoring can be improved.

[0014] 2. Integrated analysis: Through the correlation analysis of surface subsidence and rock burst, an integrated model can be established to predict rock burst and provide a scientific basis for coal mine safety.

[0015] 3. Early warning function: By assessing the risk of rock burst, early warning can be provided for coal mining, thus improving the safety level of coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of the method of the present invention;

[0017] Figure 2 This is the displacement cloud diagram of the 3-1501 working surface model in the Z direction;

[0018] Figure 3 It is a downward trend curve chart;

[0019] Figure 4 It is a graph of the tendency to sink;

[0020] Figure 5 This is the UAV laser radar measurement result diagram;

[0021] Figure 6 The comparison diagram of ground subsidence value and coal body-roof vertical stress at different advancement distances;

[0022] Figure 7 is the vertical stress growth rate at different measuring points under different advancement distances;

[0023] Figure 8 Microseismic characteristic curve of the working face at different advancement distances. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0025] 1) Establishing numerical model

[0026] According to the actual situation of the study area, a numerical model of the deep mining area is established. The model includes the physical and mechanical parameters of the coal seam, roof and floor rock layers, such as thickness, bulk density, elastic modulus, Poisson's ratio, cohesion and internal friction angle. Finite element software (such as ABAQUS) is used for numerical simulation to simulate the surface subsidence process and the stress change process of the overburden rock.

[0027] 2) Surface subsidence monitoring

[0028] The traditional line survey method and UAV lidar technology are used to monitor the surface subsidence in the study area. Actual surface subsidence data are obtained and compared with the numerical simulation results to ensure the accuracy and reliability of the numerical simulation.

[0029] 3) Microseismic monitoring

[0030] Microseismic monitoring equipment is deployed to monitor microseismic events in real time. Key data such as the maximum energy of a single microseismic event and the total energy of microseismic events in a single day are recorded to analyze the possibility of rock burst.

[0031] 4) Rock burst risk assessment

[0032] Comprehensively analyze the surface subsidence data, rock stress data and microseismic data, and evaluate the risk of rock burst through comparison and correlation analysis, and provide early warning for coal mining. Compare the surface subsidence value, coal body vertical stress, roof vertical stress, single-day microseismic total energy, and single-day microseismic maximum energy. If the surface subsidence value increases, the coal body and roof stress, and the roof stress growth rate reach the maximum value, the single-day microseismic total energy and the single microseismic maximum energy peak, and the possibility of impact is high; the surface subsidence value, coal body and roof stress, and roof stress growth rate gradually stabilize, the single-day microseismic total energy and the single microseismic maximum energy generally show a downward trend, and the possibility of impact is medium; the surface subsidence is not obvious, the roof is in a stable state, the single-day microseismic total energy and the single microseismic maximum energy are both lower than 800J, and the possibility of impact is small.

[0033] A joint monitoring and integrated analysis method for surface subsidence and rock burst can effectively predict and prevent potential mine disasters and improve the safety of coal mining by real-time monitoring and analysis of surface subsidence and rock burst.

[0034] Embodiment 1:

[0035] like Figure 1 As shown, a method for joint monitoring and integrated analysis of surface subsidence and rock burst pressure includes the following steps:

[0036] 1. Establish a numerical model: According to the actual situation of the 501 working face of the 3-1 coal seam, the model size of the numerical simulation is determined to be 4000m×800m×1000m. The model advances mining along the x direction (the direction of the working face), and the starting line is x=250m. The numerical simulation uses the finite element software ABAQUS. Combined with the actual situation of the coal seam, roof and floor in the mining area and the comprehensive geological columnar diagram, the rock layer and its physical and mechanical parameters are determined.

[0037] like Figure 2As shown in the figure, when the mining of the working face is completed, the impact range of the surface subsidence extends to the entire top of the goaf; the maximum surface subsidence is located above the goaf, the maximum subsidence is 60.03cm, and the minimum subsidence is 25.27cm; from the perspective of strike and dip, it is shown that the subsidence gradually decreases from the goaf to both sides.

[0038] like Figure 3 As shown in the figure, with the continuous advancement of the working face, the maximum subsidence value gradually increases to a stable trend. When the working face advances 250m, the maximum subsidence value is 0.94cm<1.00cm, and the surface has not yet begun to move; when the working face advances 500m, the surface shows a basin trend, the subsidence curve begins to show a funnel shape, and the maximum subsidence rate gradually increases; when the working face advances 2750m, the maximum subsidence value and the scope of the subsidence basin gradually increase, the subsidence curve becomes steeper, and it is in a state of insufficient mining. The maximum subsidence rate first increases and then decreases; when the working face advances more than 3000m, the maximum subsidence value tends to be stable, the subsidence basin has a flat bottom, and the subsidence curve is bowl-shaped.

[0039] like Figure 4 As shown in the figure, with the continuous advancement of the working face, the maximum subsidence value gradually increases to a stable trend, and the subsidence curve is symmetrically distributed about the dip centerline. When the working face advances 250m, the surface subsidence basin has not yet extended to the dip centerline, and the subsidence value is close to 0cm; when it advances to 2750m, the surface subsidence value continues to increase to 58.45cm, and the subsidence value does not change much along the dip; when it advances more than 3000m, the maximum surface subsidence value stabilizes to about 59.90cm.

[0040] 2. Surface subsidence monitoring: Due to limitations in site conditions, traditional observation stations are deployed along roads to move the observation points to the center of the basin, and are unable to monitor the maximum subsidence value of the entire surface subsidence basin. However, UAV-LiDAR technology can obtain surface data of the entire survey area, so it can effectively and accurately detect the maximum surface subsidence.

[0041] like Figure 5 As shown in the figure, UAV laser radar is used to monitor the surface subsidence and the actual measurement is carried out on site. The maximum measured subsidence value is 62.98cm, while the simulated maximum subsidence value is 60.03cm, with an error of 4.68% from the measured value, which meets the accuracy requirements.

[0042] 3. Correlation analysis between surface subsidence and rock burst at different advancement distances: Figure 6 , Figure 7As shown in the figure, when the working face advances to 250m, the subsidence value is 0.94cm, and the vertical stresses of the coal body and the roof are 29.86MPa and 26.90MPa respectively. At this time, the surface subsidence value is very small, and there is no obvious surface subsidence. At this time, the roof is still in a stable state, and the possibility of impact at this stage is small; when it advances to 1500m, the subsidence value increases to 50.53cm, and the vertical stresses of the coal body and the roof increase to 33.68MPa and 30.16MPa respectively. The roof stress growth rate is 17.17%, and the surface subsidence at this time When it reaches the active stage, the stress on the roof exceeds the maximum compressive strength, and the stress growth rate is the largest. The possibility of impact at this stage is high. When it advances to 3500m, the surface subsidence value increases to 60.03cm, and the vertical stresses of the coal body and the roof stabilize at 33.47MPa and 29.97MPa respectively, and the stress growth rate stabilizes at about 17.00%. At this time, the surface subsidence value gradually reaches the maximum, the stress between the coal body and the roof, and the roof stress growth rate tend to be stable, and the stress on the roof is slightly lower than the maximum compressive strength. The possibility of impact at this stage is medium.

[0043] 4. Analysis of the linkage effect of surface subsidence and rock burst based on microseismic monitoring, such as Figure 6 , Figure 7 , Figure 8 As shown in the figure, when the working face advances to 250m, the possibility of impact is small, the surface subsidence phenomenon has not yet occurred, the stress on the coal seam and the roof is small, the total energy of microseismic events per day and the maximum energy of a single microseismic event are low, both below 800J; when it advances to 1500m, the possibility of impact is high, the surface subsidence value increases, the stress of the coal body and the roof, and the growth rate of the roof stress reach peak values, and the total energy of microseismic events per day and the maximum energy of a single microseismic event reach peak values, which are 68486.61J and 9642.23J, respectively; when it advances to 2500m, the possibility of impact is medium, the surface subsidence value, the stress of the coal body and the roof, and the growth rate of the roof stress gradually stabilize, and the total energy of microseismic events per day and the maximum energy of a single microseismic event generally show a decreasing trend.

Claims

1. A method for joint monitoring and integrated analysis of surface subsidence and rock burst, characterized in that: The steps are: 1) Using finite element software, a numerical model of the coal mining area is established based on the rock distribution and physical and mechanical parameters of the coal mining area to simulate the surface subsidence and overburden stress changes during coal mining; 2) Use traditional line surveying method and UAV laser radar technology to conduct high-precision real-time monitoring of surface subsidence, obtain measured data of surface subsidence, compare the measured maximum subsidence value with the numerical simulation maximum subsidence value, and the error value is less than 5% to meet the accuracy requirements. If the difference does not meet the requirements, adjust the physical and mechanical parameters of the rock formation until the accuracy requirements are met; 3) Deploy a microseismic monitoring system, arrange microseismic monitoring stations in and around the mining area to form a microseismic monitoring network, monitor microseismic events in the mining area in real time, record the total energy of microseismic events per day and the maximum energy of microseismic events per day at different advancement distances, and obtain the microseismic characteristic curves of the working face at different advancement distances; 4) Comprehensively analyze surface subsidence data, rock stress data and microseismic data, evaluate the risk of rock burst through comparison and correlation analysis, and provide early warning for coal mining.

2. A combined monitoring and integrated analysis method for surface subsidence and rock burst according to claim 1, characterized in that: The specific method in 1) is: combining the actual conditions of the coal seams, roof and floor plates in the mining area and the comprehensive geological columnar diagram, setting the physical and mechanical parameters of each rock layer, including thickness, bulk density, elastic modulus, Poisson's ratio, cohesion and internal friction angle, using finite element software to construct a three-dimensional numerical model, simulating the movement and stress distribution of the rock layer during coal seam mining, and according to the simulation results, obtaining a comparison diagram of the surface subsidence value and the vertical stress of the coal body-roof plate at different advancing distances, setting the center line of the roof strike as the measuring line, and obtaining the vertical stress growth rate of different measuring points at different advancing distances.

3. A method for joint monitoring and integrated analysis of surface subsidence and rock burst according to claim 1, characterized in that: In the above 4), the specific method is: comparing the ground subsidence value, the vertical stress of the coal body, the vertical stress of the roof, the total energy of microseismic events in a single day, and the maximum energy of microseismic events in a single day; If the surface subsidence value increases, the stress between the coal body and the roof, and the growth rate of the roof stress reach the maximum value, and the total energy of microseismic events in a single day and the maximum energy of a single microseismic event reach a peak value, the possibility of impact is high; The ground subsidence value, coal body and roof stress, and roof stress growth rate are gradually stable, and the total energy of microseismic events per day and the maximum energy of a single microseismic event are generally decreasing. The possibility of impact is medium. The surface subsidence is not obvious, the roof is in a stable state, the total energy of microseismic events in a single day and the maximum energy of a single microseismic event are both less than 800J, and the possibility of an impact is small.

Images