隧洞砂岩的温度-围压耦合时效性蠕变模型

为了研究高温和围压耦合作用下深部围岩的蠕变特性,采用MTS815.02岩石试验系统对砂岩进行不同温度作用下三轴蠕变试验.考虑在岩石蠕变过程中温度、围压和时间对岩石蠕变特性的影响,假定温度、围压和时间与损伤变量之间的关系满足负指数形式,进而将改进西原模型中蠕变参数进行非定常化,得到一种新型的岩石温度-围压耦合的时效性蠕变...

Temperature-confining pressure coupled creep model of sandstone in diversion tunnels

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.