Creep behavior and long-term strength characteristics of pre-peak damaged sandstone under conventional triaxial compression.

A series of creep tests were carried out on sandstone specimens with different pre-peak instantaneous damage characteristics under different confining pressures. The results revealed that the creep stress was the key factor affecting the occurrence of the three stages of creep, and the steady-state creep rate increased exponentially with increasing creep stress. Under the same confining pressure, the larger the instantaneous damage of the rock specimen was, the more quickly creep failure occurred and the lower the creep failure stress was.