scholarly journals Coal–rock damage characteristics caused by blasting within a reverse fault and its resultant effects on coal and gas outburst

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kui Gao ◽  
Ping Huang ◽  
Zegong Liu ◽  
Jian Liu ◽  
ChiMin Shu ◽  
...  
Keyword(s):  
Stress Wave ◽  
High Stress ◽  
Elastic Strain Energy ◽  
Coal And Gas Outburst ◽  
Blasting Vibration ◽  
Reverse Fault ◽  
Rock Damage ◽  
Gas Outburst ◽  
Coal Rock ◽  
Tectonic Belt

AbstractIn view of the coal and gas outburst accidents occur frequently caused by blasting in geological structural belt, in order to study the mechanical characteristics of coal rock in tectonic belt disturbance by blasting and blasting vibration effect influenced on the stability of surrounding rock, coal–rock damage and failure characteristics within a reverse fault caused by a blasting stress wave were investigated using numerical analyses and experiments. According to the experimental results, the causes of coal and gas outburst dynamic disasters within a reverse fault during blasting are analyzed. The outcomes indicated that the crushing circle created by the crack propagation near the blasting hole severely damaged the fault plane and floor rocks adjacent to the footwall of the reverse fault. Fractures also extended to the upper and lower coal seams of the reverse fault; this caused the surface of the coal seam to fall off and severe internal damage. According to theoretical analysis, the reflection of the blasting stress wave propagating to the reverse fault intensified the damage to coal and rock. Elastic strain energy accumulation within the reverse fault structural zone was accompanied by high-stress concentration. The reverse fault tectonic region was destroyed by blasting vibration. It increased gas pressure and caused a weak surface, which provided a channel for gas flow and a dynamic basis for the occurrence of coal and gas outburst. The research results have important theoretical value to reveal the mechanism of coal and gas outburst in tectonic belt induced by blasting.

scholarly journals Energy Action Mechanism of Coal and Gas Outburst Induced by Rockburst

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Wenqing Zhang ◽  
Chaomin Mu ◽  
Dengke Xu ◽  
Zhongqing Li
Keyword(s):  
Coal Mine ◽  
Split Hopkinson Pressure Bar ◽  
High Stress ◽  
Coal Mass ◽  
Coal And Gas Outburst ◽  
Energy Conditions ◽  
Hopkinson Pressure Bar ◽  
Action Mechanism ◽  
Gas Outburst ◽  
Study Results

The essence of both rockburst and coal and gas outburst lies in fast energy release. In order to explore the energy action mechanism of coal and gas outburst induced by rockburst in rockburst and coal and gas outburst combined mines, the split Hopkinson pressure bar (SHPB) experimental device was firstly used to conduct uniaxial impact failure test of coal specimens prone to outburst under different strain rates, and their energy dissipation laws under impact loading were obtained. Next, under the engineering background of coal and gas dynamic phenomena induced by rockburst with different intensities in Xinyi Coal Mine and Pingdingshan Coal Group No. 12 Colliery in Henan Province and Dingji Coal Mine of Huainan Mining Group in Anhui Province, experimental study results were combined with numerical simulation analysis to discuss the energy mechanism of coal and gas outburst induced by rockburst. The study results show that the outburst can be divided into two different processes—critical outburst and outburst—according to the evolution law of outburst energy, and the critical energy conditions for coal and gas outburst are proposed. The minimum destructive energy range for the critical outburst of coal mass is obtained as (5–10) × 104 J/m3. Under some low gas, high stress, or strong disturbance conditions, applied loads can become the main energy sources causing critical failure and even crushing and throwing of coal mass. The coal mass will present an interval splitting structure under dynamic loading, which is obviously different from the failure mode of coal mass under static actions.

scholarly journals Numerical Simulation of Mining-Induced Stress Evolution and Fault Slip Behavior in Deep Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhenhua Jiao ◽  
Lei Wang ◽  
Ming Zhang ◽  
Jiong Wang
Keyword(s):  
Rock Burst ◽  
Underground Mining ◽  
High Stress ◽  
Three Dimensional ◽  
Elastic Strain Energy ◽  
Fault Reactivation ◽  
Reverse Fault ◽  
Geological Model ◽  
Stress Evolution ◽  
3D Geological Model

The ground pressure distributes significant variation in underground mining near fault. Fault reactivation is an important factor to induce the rock burst. Therefore, characterizing geological settings in mining areas by the geological information can improve the accuracy of simulation. To investigate the characteristic of mining stress evolution and reactivation of the F16 reverse fault during the retreat Mining-Induced s in Yima coalfield, a three-dimensional digital elevation model based on GIS platform was applied. The 3D geological model includes three working faces, and F16 fault was constructed by AutoCAD software. Then, the 3D geological model was imported into the FLAC3D code to simulate the potential of mining-induced fault reactivation. The simulation results illustrate that the footwall of F16 fault is a high stress concentration area. Affected by F16 fault and the huge thick gravel rock in the roof, the coal seam near the fault accumulates a large amount of elastic strain energy, which increases the potential of rock burst hazards in the process of mining.

Research and Design of Pre-Warning System for Coal and Gas Outburst Based on Data Mining

2013 ◽  
Vol 336-338 ◽  
pp. 1204-1207
Author(s):  
Ming Deng ◽  
De Fang Liu ◽  
He Liu ◽  
Ning Ning Chen
Keyword(s):  
Data Mining ◽  
Time Series ◽  
Coal Mine ◽  
Moving Average ◽  
Warning System ◽  
Poor Performance ◽  
Coal And Gas Outburst ◽  
Gas Outburst ◽  
Production Safety ◽  
Coal Rock

Coal and gas outburst is one of the most important natural disasters in our country. Thus pre-warning has the great significance to production safety for coal mine. In view of the facts of current pre-warning technologies, such as single pre-warning indicators, poor performance under interference and low real-time capability, some new pre-warning models are presented. The models include G line, moving average line and so on. Based on data mining theory, the pre-warning system works on the time series of gas emission concentration (which is called G series), and the pre-warning system for outburst is designed as well. 4.19 coal and gas outburst in Dashu Village Coal Mine of Hebei Fengfeng Coal Mining Group is studied based on pre-warning system. And the result is in accord with accident investigation. The analysis shows that the pre-warning system can mine the outburst developing process information of coal-rock dynamical system from the time series of gas concentration and realize outburst accidents pre-warning.

Deformation Analysis for Coal and Gas Outburst Cavity

2011 ◽  
Vol 121-126 ◽  
pp. 2607-2613
Author(s):  
Qian Ting Hu ◽  
Wen Bin Wu ◽  
Guo Qiang Cheng
Keyword(s):  
Damage Zone ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Combination Method ◽  
Deformation Analysis ◽  
Failure Zone ◽  
Finite Element Code ◽  
Cavity Volume ◽  
Gas Emission ◽  
Gas Outburst

Outburst cavity formed during coal and gas outburst can be pear shaped, elliptical, or just like an irregularly elongated ellipsoid, its capacity is always smaller than the volume of ejected coal. And the gas emission quantity is almost 4 to 10 times as gas content in ejected coal. These are two different expressions of the same problem. To find the reasons for the decrease of outburst cavity volume and the increase of gas emission quantity per ton, by using the finite element code ANSYS, the damage zone and the failure zone of the outburst cavity were determined based on the static and dynamic combination method. In this paper, the reason for the decrease of the outburst volume was explained.

scholarly journals Mechanical criterion for coal and gas outburst: a perspective from multiphysics coupling

2021 ◽  
Author(s):  
Ting Liu ◽  
Baiquan Lin ◽  
Xuehai Fu ◽  
Ang Liu
Keyword(s):  
Control Method ◽  
Risk Identification ◽  
Controlling Factors ◽  
Gas Pressure ◽  
Critical Values ◽  
Coal And Gas Outburst ◽  
Strong Interactions ◽  
Gas Outburst ◽  
Multiphysics Coupling ◽  
Coal Strength

AbstractAlthough a series of hypotheses have been proposed, the mechanism underlying coal and gas outburst remains unclear. Given the low-index outbursts encountered in mining practice, we attempt to explore this mechanism using a multiphysics coupling model considering the effects of coal strength and gas mass transfer on failure. Based on force analysis of coal ahead of the heading face, a risk identification index Cm and a critical criterion (Cm ≥ 1) of coal instability are proposed. According to this criterion, the driving force of an outburst consists of stress and gas pressure gradients along the heading direction of the roadway, whereas resistance depends on the shear and tensile strengths of the coal. The results show that outburst risk decreases slightly, followed by a rapid increase, with increasing vertical stress, whereas it decreases with increasing coal strength and increases with gas pressure monotonically. Using the response surface method, a coupled multi-factor model for the risk identification index is developed. The results indicate strong interactions among the controlling factors. Moreover, the critical values of the factors corresponding to outburst change depending on the environment of the coal seams, rather than being constants. As the buried depth of a coal seam increases, the critical values of gas pressure and coal strength decrease slightly, followed by a rapid increase. According to its controlling factors, outburst can be divided into stress-dominated, coal-strength-dominated, gas-pressure-dominated, and multi-factor compound types. Based on this classification, a classified control method is proposed to enable more targeted outburst prevention.

The Impact Analysis of Coal’s Elastic Energy on the Coal and Gas Outburst Shock Wave

2012 ◽  
Vol 616-618 ◽  
pp. 390-395
Author(s):  
Cheng Wu Li ◽  
Tian Bao Gao ◽  
Shan Yang Wei ◽  
Teng Li
Keyword(s):  
Shock Wave ◽  
Elastic Energy ◽  
Impact Analysis ◽  
Dynamic Theory ◽  
Coal And Gas Outburst ◽  
Calculation Formula ◽  
Theory Analysis ◽  
Gas Outburst ◽  
Quantitative Calculation ◽  
The Impact

According to the gas dynamic theory, this paper deduces the approximate calculation formula on elastic energy of a tons of coal through theory analysis, and then gets the quantitative calculation method between incident overpressure and reflected overpressure of the coal and gas outburst shock wave. The calculation formula in this paper is in line with the measured values, and so its validity has been verified. The analysis result shows that the effect of the elastic energy during the process of coal and gas outburst should be considered when the depth of the coal seam is great and the coal’s modulus of elasticity is small.

Sign in / Sign up

Export Citation Format

Share Document