Applying Smoothed Particle Hydrodynamics to Model Landslides Triggered by Impulse Loads: A Validation Study to Determine the Optimum Value of Smoothing Length

Vibrations caused by impulse loads have been one of the major causes of landslides. The damage caused by such instances is immense, both in terms of economy and loss of life. Over the past few years, modeling of such hazards has gained momentum due to various efficient numerical tools coming into the picture. One such advancement is the introduction of a mesh-free, particle-based method, smoothed particle hydrodynamics (SPH), into the field of Geomechanics. Ever since its applicability to such problems has been explored, it has been very efficiently used to model a vast range of problems involving large deformation, including complex phenomena such as landslides and debris flows. In this study the authors have validated the applicability of an SPH-based code, to model the landslides triggered by impact loading. For this purpose, the Daguangbao landslide, triggered by the Wenchuan earthquake of 2008 (Magnitude 7.9) has been chosen. To apply the earthquake impact load, the average peak ground acceleration PGA from the north-south component of ground motion has been used. The slope has been analyzed for various values of smoothing length ‘h’ and for each case, the final deformed profile has been compared to the actual deformed profile at the site. Smaller values of the smoothing length to inter-particle distance ratio (h/dx) i.e. 1.2 and 1.4 were found to increase the computational time, as a smaller time step was required. However, ‘h/dx’ values of 1.6 and 1.8 were found to give results that were closer to the actual deformed profile and in a reasonable time. Although the model slightly overestimated the volume of sliding mass, it can still be deemed fit to carry out further studies of this type.