Abstract Based on the results of rock triaxial test,the creep mechanical properties of the sandstone from the compressive rupture zone in Xiangjiaba Hydropower Station are investigated,and the laws of axial and lateral creep of rock are also analyzed. In the low stress level,the rock only appears decay creep and steady creep. The steady creep strain rate is non-zero constant,and the creep deformation cannot be ignored. The creep of rock is consistent with Burgers model. When the stress reaches a certain level,the accelerated creep damage of rock occurred after the decay creep and steady creep. The characteristics of rock creep failure under different confining pressures are different,especially the starting time of accelerated creep. According to the feature,the startup component of accelerated creep is proposed. By connecting the startup component and Burgers model in series,a new six-component nonlinear viscoelasto-plastic creep model of rock is constructed. The creep property of the nonlinear model is carried out based on the theoretical analysis. The creep constitutive equation in three- dimensional stress state is deduced. The creep parameter identification method is investigated. The comparison between nonlinear creep model and experimental curve shows that the proposed nonlinear viscoelasto-plastic creep model is available and reasonable.
|
Received: 23 July 2010
|
|
|
|