TY - JOUR
TI - Crack closure and initiation stresses of coal subjected to thermo-gas-mechanical coupling
AU - Gao Yanan
AU - Yan Weicheng
AU - Yang Xiaojun
JN - Thermal Science
PY - 2017
VL - 21
IS - 11
SP - 301
EP - 308
PT - Article
AB - In this paper, the orthogonal experiment method is employed to design  physical tests of coal under different temperatures, confining pressures,  and gas pressures. The crack closure stress and crack initiation stress are  calculated using four known methods, i. e. axial strain method, axial  stiffness method, crack volume method, and strain response method. The  obtained results are compared, and the advantages and drawbacks for the used  methods are also discussed. The influences of the three factors on the crack  closure and crack initiation stresses are analyzed.