关键词: 高温, 围岩, 蠕变, 时效性, 加速蠕变

Abstract: Creep characteristics of deep surrounding rock under the coupling effect of high temperature and confining pressure is studied by conducting triaxial creep tests on sandstone under different temperatures using the rock test system MTS815.02. We consider the influence of temperature, confining pressure, and time on these characteristics, and assume an exponential decay form for the relationship of temperature, confining pressure and time versus damage variables. Then, we develop a new time-dependent creep model that, coupling rock temperature and confining pressure, is equipped with non-constant creep parameters obtained through improving the Nishihara model. The results show the strain-stress curves and time-dependent strain curves at different temperatures are all in good agreement with measurements. This new model not only better describes attenuation creep deformation and stable creep deformation, but better reflects deformation characteristics in the accelerated creep stage. And it verifies the significant influence of temperature, confining pressure and time on rock creep characteristics.

Key words: high temperature, surrounding rock, creep, time-dependent, accelerated creep