Stability of Slopes Undergoing Creep Deformation

An analysis of a long slope undergoing creep deformation is presented. The analysis is based on assumptions that the soil flows viscously with no volume change, and that the creep deformation ensues when the shear stress due to gravity exceeds the soil residual shear strength. Expressions to describe the velocity field in the creep zone of the slope are derived. The results are discussed for the cases of with or without surcharge loads and results are presented in dimensionless charts. Because of the assumptions used, the theoretical results appear to be applicable to slopes of over-consolidated clay or clay shales. In order to determine the average coefficient of viscosity of the soil, field displacement versus time records of the slope undergoing creep is necessary. Two published soil creep case histories are utilized to verify the theoretical analysis and the results are reasonable.