Nonlinear rheological characteristics of rock-like material and its mechanical effects on tunnel-surrounding-rock mass and support

In this paper the mechanical model used to study the nonlinear rheological characteristics of tunnel-surrounding-rock mass in plastic zone is put forward and applied to the tunnel-surrounding-rock mass of a hydroelectric power station in Kunming. By the use of the FEM of the initial viscoplastic incremental strain, the nonlinear rheological mechanical effects on tunnel-surrounding-rock mass and support are computed and analysed. The computed results are compared with those got from the traditional linear rheological theory. Through the research it is proven that the viscosity of rock-like materials is the nonlinear function of the values of the loaded stresses and time.