A simplified approach to analyzing the safety of earthquake-triggered landslides

The sliding of slopes caused by earthquakes is a critical issue, resulting in significant losses and casualties worldwide. This paper presents a simplified analytical formulation for evaluating the safety factor; the approach is essentially coupled, as it incorporates the flexibility of the sliding block. Several issues are considered: soil slope, ground motion direction (horizontal and parallel to the slope), and presence of underground water; however, the transient response and damping are neglected. A Factor of Safety is defined, and closed-form expressions are derived; as well, expressions for the yield accelerations are presented and compared with the Newmark one. Numerical results obtained with the proposed approach provide conclusions that explain some differences between coupled analysis and the traditional uncoupled Newmark method. Finally, validation with experiments, numerical analyses, and actual sliding of slopes demonstrates that the proposed methodology is reliable. • An analytical approach is proposed to assess the seismic stability of soil slopes. • Soil stiffness and input motion frequency are considered. • Expressions for a factor of safety and yield acceleration are presented. • The approach is validated on numerical analyses, tests, and actual landslides.