Experimental Study on Damage and Gas Migration Characteristics of Gas-Bearing Coal with Different Pore Structures under Sorption-Sudden Unloading of Methane

Gang Wang,Zhiyuan Liu,Lulu Sun,Yue Wang,Chang’Ang Du,Yangyang Guo,Jianjun Cao

doi:10.1155/2019/7287438

Abstract

Coal and gas outburst is one of the most serious hazards in underground mine operations. In this paper, we explored the damage and gas seepage characteristics of gas-bearing coal samples with different pore structures under methane sorption-sudden unloading conditions using a self-developed experimental apparatus. The results show that (1) the deformation of coal samples can be divided into three stages, namely, pressure-increase-induced compression, sorption-induced expansion, and sudden-unloading-induced deformation or failure stage; (2) with the increase of the number of diffusion pores in the coal sample, the amount of gas sorption gradually increases and the expansion and failure of coal samples become more obvious; (3) in the experiment, the damage of coal samples is mainly along the axial direction and rarely along the radial direction; (4) the radial strain is always greater than the axial strain.

Highlights

Coal is an important energy source for human activities and engineering applications
The external conditions of this experiment are basically the same, so the difference of the data can be attributed to the change of the basic characteristics of the coal samples themselves
The relationship between the strain of the coal sample and the time is characteristic of the evolution of gas sorption-sudden unloading process, which is directly reflected in the axial strain and the radial strain

Summary

Introduction

Coal is an important energy source for human activities and engineering applications. Many factors could cause disaster during coal mining including coal mine gas, water, and dust. Due to complexity of mining disaster-causing mechanisms, situation for safe mining production is extremely severe [1,2,3]. Coal and gas outburst is an extremely complex phenomenon of dynamic instability occurring in coal mines. Due to the complexity of coal and gas outburst mechanisms, more and more researches accepted the hypothesis that coal and gas outburst is the result of the combined effects of geological structure, gas migration, and the nature of coal samples [8,9,10,11,12,13]

Methods

Results

Conclusion