Generation of Complex Slope Geometries by DEM for Modeling Landslides: A Case Study of Tangjiashan Landslide

The generation of complex slope geometries by discrete element method (DEM) for modelling landslides is difficult, among other issues, due to the lack of an efficient technique to manipulate and pack a large number of particles within a predefined slope domain. The existing numerical techniques generally use some regular and simple slope geometries, which can lead to some unreliable results. The current study proposes a flexible and simple technique to generate complex slope samples in DEM by feeding the slope domain with rigid and frictionless spherical particles. The slope profile and failure surface are imported from available site investigation data, which can be used to construct the slide boundary in DEM. Based on the geometry of the slide boundary, a virtual hopper is placed atop of the profile, feeding granular particles continuously into the slide bounding space, until it is fully filled. The layered structure of the slope can be attained in this model by generating each sub-layer separately. The slope mass generated by the proposed technique in this study has been used to simulate the failure and subsequent valley damming of Tangjiashan landslide, from which some mechanisms of slope motion and deformation, as controlled by the complex layering geometries, are clearly illustrated. The model is very flexible and requires only minor corrections to fully describe the slope or other complex geometries with realistic stress-strain state in DEM models.