Abstract: The shear stress of homogeneous slope soil with infinite length under plane strain condition is obtainedand a nonlinear strength is incorporated into the overstress creep model. With Cam-clay model, the explicit expres-sions of slope soil’s sliding velocity and displacement are deducted following Mohr-Coulomb failure criterion by establishing the relationship between velocity or displacement and visco-plastic strain rate of the slope soil. Numerical calculation results agree with the field measured data. Parametric study on the nonlinear strength is also performed to investigate their influences on the creep or progressive deformation of soil slope. It is found that the progressive deformation of slope and thickness of shear zone both increase with the decrease of nonlinear parameters c₀ and σ_t and the increase of parameter m.

Key words: soil slope with infinite length, progressive deformation, nonlinear failure criterion, overstress model, analytical solution