Creep strain analysis and an improved creep model of granite based on the ratio of deviatoric stress-peak strength under different confining pressures

Creep refers to the deformation of rock with time under long-term applied stress, which occurs in most underground engineering. The creep behavior granite Shuangjiangkou powerhouse Western Sichuan Province, China, was studied by tests. Based on test results, a new parameter DPR, ratio deviatoric stress peak strength, is proposed. DPR found be key describe parameters such as instantaneous elastic modulus, and viscosity coefficient different confining pressures. tests show that modulus increases increase DPR. when changes from 0.54 0.7004, but decreases 0.7004 0.88, indicating fractures closes first then are generated. = 0.7171, maximum, for reach stability longest By introducing pressure into model, interconnects unified expression, an improved generalized Kelvin model proposed can accurately primary secondary given stresses