Upper bound seismic limit analysis of shallow landslides with a new kinematically admissible failure mechanism

Many landslides are shallow and earthquake is one of the common triggering factors. This study presents upper bound seismic limit analysis of shallow landslides with a novel kinematically admissible translational failure mechanism. The novel failure mechanism consists of a translational component at the mid-slope and two log-spiral rotational components at the slope crest and toe to capture the boundary effects. The effectiveness of upper bound limit analysis (UBLA) with the new translational failure mechanism and the conventional log-spiral failure mechanism is evaluated with finite element limit analyses. The new translational UBLA agrees well with finite element limit analyses in terms of both critical slip surfaces and stability solutions. On the contrary, the conventional log-spiral UBLA predicts a smaller failure volume and overestimates the pseudo-static factor of safety and yield coefficient by up to 30%. The translational UBLA is further used to generate a database and to develop an analytical shallow landslide model (SLM) through regression analysis. The SLM retains the simplicity of the commonly used infinite slope model (ISM), yet it is more accurate than the ISM by accounting for boundary effects. Hence, the SLM can be used as a more accurate alternative to the ISM for the routine seismic analysis of shallow landslides, e.g. seismic landslide hazard mapping.