A multi-block sliding approach to calculate the permanent seismic displacement of slopes

The Newmark sliding block method is widely used to assess the seismic performance of earth slopes by calculating the permanent displacement of the simplified sliding mass. The conventional Newmark method models the potential landslide mass as a single rigid block sliding on a well-defined slip surface. In this study, a multi-block approach to calculate the sliding displacement of slopes is presented. The dynamic equation of a series of rigid blocks in different sliding conditions is established and the complex interactions within the slip episodes of rigid block assemblies are explicitly resolved. The results show that the original Newmark single block method may produce unconservative estimates of permanent displacement of the shallow sliding mass when the deep-seated sliding subsequently occurs during the earthquake. The predicted displacement of the upper sliding mass, which is simplified as a summation of the Newmark displacement of each single sliding mass, may either overestimate or underestimate the computed displacement including the coupling of sliding of multiple soil masses. The developed approach extends the well-accepted Newmark sliding block method, and can serve as an alternative to predict the seismic slope displacement in which multiple failure surfaces are expected during earthquakes.