TY - JOUR
TI - Variation law of coal permeability under cyclic loading and unloading
AU - Guo Jingna
AU - Liu Jiangfeng
AU - Li Qiang
AU - Chen Xu
AU - Chen Zhanqing
AU - Huang Bingxiang
AU - Chen Shuliang
JN - Thermal Science
PY - 2019
VL - 23
IS - 3
SP - 1487
EP - 1494
PT - Article
AB - In the excavation process, the coal pillar will undergo shear failure due to repeated loading and unloading from mining stress. Meanwhile, plastic flow will occur after shear failure. The permeability change of the coal pillar under plastic flow is closely related to the loading path. Through a permeability test of the coal sample after shear yielding under cyclic loading and unloading conditions, the variation law of permeability of a coal seam under plastic flow was obtained. The results show that the permeability of the coal sample increases as the axial strain decreases during the unloading phase. During the loading phase, as the axial strain increases, the permeability of the coal sample decreases. Scanning electron microscope tests show that the crack opening is larger at lower confining pressures. As the confining pressure increases, the crack opening decreases and moves toward the middle of the sample.