Landslide hazard assessment by smoothed particle hydrodynamics with spatially variable soil properties and statistical rainfall distribution

Rainfall-induced landslides have caused significant damage to structures and casualties in the past decades, and it is of great importance to assess the post-failure behavior of slopes. This study proposes a probabilistic framework to evaluate the hazards associated with landslide runout arising from loose-fill slope failures. The failure process is simulated by the smoothed particle hydrodynamics (SPH) method, which is capable of capturing large deformations of landslides. The shear strength parameters of the soils are modeled as random variables, and random field simulations are performed to explore the effects of soil variability on the runout distance. In addition, the uncertainty in rainfall characteristics is represented by the Gumbel distribution, with the ensuing rainfall infiltration simulated in multiple seepage analyses to obtain pore pressure profiles in the slope, which are then adopted as initial conditions for the SPH method. Combining these various sources of uncertainty, the hazard factors indicating the risks for nearby structures are quantified based on the response uncertainty in landslide runout distances. To demonstrate this framework, the hazard levels associated with two typical layouts of loose-fill slopes are evaluated, and the results may serve as risk zoning indicators for adjacent developments.