Study of thermal-mechanical coupling numerical simulation of rock under uniaxial heating

In order to study the evolution laws of overburden temperature,stress and plastic zone distribution under thermal-mechanical coupling condition during underground coal gasification,the thermosetting coupling numerical simulation in the condition of uniaxial heating and axial constraint was carried out by COMSOL software,and the temperature field,stress field,displacement field,volume strain and plastic zone distribution law were obtained.The results show that the temperature increases nonlinearly with time at different axial positions;the temperature gradient is larger along the rock height direction and decreases with time;the main stress is mainly distributed in the lower end and the circle area of the rock axial direction;the plastic zone is mainly distributed at the lower end of sandstone accounting for 1/6 ratio,and existing flats islanding plastic zone;the stress of circumference lower end is tensile,and the radial strain has the maximum value.The simulation results are helpful to guide the thermal damage fracture characteristic of rock from the perspective of thermosetting coupling.