Three-dimensional stability analysis of seismically induced landslides using the displacement-based rigorous limit equilibrium method

Previously, the stability analysis of seismically induced landslides was investigated by the factor of safety of the entire sliding body, which provided no information on the displacements of the analyzed seismically induced landslides. The landslides are assessed to be dangerous when the minimum value of the factor of safety (Fs) is less than a critical value. However, unlike the landslides subjected to static loads, the dynamic safety factors of seismically induced landslides vary with time. The minimum value of the dynamic safety factors being less than the critical value does not necessarily imply failure of the seismically induced landslides. In this paper, the three-dimensional displacement-based rigorous limit equilibrium method is proposed to study the displacements of seismically induced landslides. The relationship between the shear stresses acting on the base of the columns and the shear displacements is established based on the hyperbolic soil model. By introducing the strength reduction technique, the relationship between the reduction factor (RF) and the accumulated vertical displacement can be obtained. According to the definition of the strength reduction method, the safety factors of seismically induced landslides are determined, which do not vary with time. Then, the landslides can be assessed to be dangerous when the minimum value of Fs is less than a critical value.