Numerical Simulation Study on the Multi-Physical Field Response to Underground Coal and Gas Outburst under High Geo-Stress Conditions

Abstract

Based on thermal–fluid–solid coupling law in coal and gas outburst, a multi-physical field numerical analysis model is built for the whole outburst process. The response laws of stress, gas pressure, temperature, and seepage in different areas and different time nodes around coal and rock mass in the coal and gas outburst under high stress condition are discussed. Research results show: Firstly, the stress response law of the coal and rock mass around the burst hole is initial vibration–sudden attenuation–late stability. Secondly, the gas pressure response law in different areas is that the gas pressure response rate decreases gradually with the increase of the distance from the outburst. Thirdly, the adsorbed gas contained in the broken coal near the outburst port is desorbed rapidly and expands to do work, and the temperature changes dramatically after outburst occurs. In contrast, with the increase of stress, the proportion of elastic potential in total coal and gas outburst energy increases, and the proportion of elastic potential is positively correlated with stress. The critical gas pressure under the energy condition of coal and gas outburst decreases with the increase of stress. It illustrates that the lower gas pressure can also meet the energy condition of coal and gas outburst under high stress.

Research of roadway deformation induced by mining disturbances and the use of subsection control technology

“…Bai and Wu analyzed the impact degree of multiple mining disturbances in tunnel through theoretical analysis and numerical simulations and showed that the superposition of multiple dynamic pressures on the working face made the support of the lower coal roadway invalid 19‐22 . Cheng studied roof movement and evolution of mining stress of excavation roadway in the process of close‐distance coal seam mining and analyzed the macro‐migration impact of close‐distance coal seam superposition mining on the overlying strata 23‐26 . Liu and Xu performed numerical simulation analysis of roof deformation and failure caused by mining in overlapping working faces and obtained the stress distribution characteristics of the overlying strata as well as the characteristics of deformation and failure in the condition of multi‐seam overlapping mining 27‐30 …”

“…[19][20][21][22] Cheng studied roof movement and evolution of mining stress of excavation roadway in the process of close-distance coal seam mining and analyzed the macro-migration impact of close-distance coal seam superposition mining on the overlying strata. [23][24][25][26] Liu and Xu performed numerical simulation analysis of roof deformation and failure caused by mining in overlapping working faces and obtained the stress distribution characteristics of the overlying strata as well as the characteristics of deformation and failure in the condition of multi-seam overlapping mining. [27][28][29][30] In addition, scientists have deeply studied the deformation control of dynamic pressure roadway.…”

Experimental study on ultrasonic irradiation for enhancing coalbed methane recovery

“…The phenomena of gas adsorption–desorption and matrix swelling–shrinkage caused the gas migration in coal to be much more complex than other rock types. A number of studies have previously focused on the permeability evolution influence by water, stress, gas pressure, and other conditions through physical experimentation and theoretical analysis, which is the key parameter of methane well deliverability in low-permeability coal reservoirs 1 – 14 . They found that gas migration in coal seams is accompanied by the behaviours of mechanics and non-mechanics, and there is a larger flow space, i.e., higher permeability can guarantee gas desorption and better continuous directional movement, with the inhibition of stress and coal expansion, as well as the enhancement of matrix shrinkage.…”

A Prediction Method for Floor Water Inrush Based on Chaotic Fruit Fly Optimization Algorithm–Generalized Regression Neural Network

“…With the increasing depletion of shallow coal resources and the increasing intensity of coal mining, more and more coal mines will encounter deep mining issues [1][2][3][4][5]. Compared with shallow coal mining, deep rock mass is in a typical complex mechanical environment of "three highs and one disturbance" (high ground stress, high karst water pressure, high ground temperature, and strong mining disturbance), showing large deformation and uncoordinated deformation and impact deformation [6][7][8][9][10][11][12][13][14][15].…”