Identifiability of rheological models in landslides modeling: a 3D SPH study

Landslides are one of the most destructive geohazards due to their high mobility and long runout. Numerical prediction of their motion and deposit behavior is an effective method for quantitative hazard assessment. The numerical approaches can get more insight into the landslide dynamics such as displacement, momentum, and impact forces. One of the crucial aspects in the application of continuum models is how to choose an appropriate rheology law for the materials. However, this issue remains poorly addressed in the geo-hazards simulations community. In this study, two constitutive models are applied to interpret landslide materials that integrated within Smoothed Particle Hydrodynamics (SPH) scheme. The elastoplastic Drucker-Prager (DP) model from soil mechanics and its counterpart in fluid mechanics, the non-Newtonian rheological Drucker-Prager (RDP) model. The results indicate that both the soil mechanic model and the fluid model can reproduce key dynamic processes (e.g., acceleration, deceleration, rebound stages) and deposition morphology (e.g., deposit area and height), within different values of input parameters given equivalent burst simulations. There is no order of which is better than another, only the more appropriate model that depends on landslide characteristics.