Discontinuous Deformation Analysis (DDA) and Distinct Element Method (DEM) has been used as analyses methods of the slope disasters. However, these methods cannot handle the mixed body of fluid and solid material appropriately. In the past decades, the meshless MPS method has been developed within the Lagrangian framework. In MPS, the fully Navier-Stoke equation can be solved without using computational grids or meshes, and MPS is suitable for simulating motion and fragmentation of fluid. In this study, NMM-DDA and MPS have been newly combined to simulate landslide behavior in the earthquake. In the coupling method of NMM-DDA and MPS, rock block movement is solved by NMM-DDA and water movement inside the rock mass is solved by MPS method separately. The formulation of the coupling method and the simulation for the large-scale landslide triggered by the earthquake will be presented.
Topographically, the mountainous area in Japan occupies about 70% of the whole country and the earthquake and volcanic activities is very dynamic. The disaster due to earthquake and heavy rain has occurred frequently. The analytic method also has been applied to the estimation of the hazards and damage. However, it is not always successful. One of the reason is considered that continuum method such as FEM is applied to analyze the phenomenon with large movement and a breakdown occurring in slope disasters. On the other hand, discontinuous method such as Discontinuous Deformation Analysis (DDA) (Shi & Goodman 1989) and Distinct Element Method (DEM) (Cundall 1971) has also been used as analyses methods of the slope disasters. However, these methods cannot handle the mixed body of fluid and solid material appropriately. It is known that the water explicitly affect stability of rock slope in earthquake.
Recently, a particle method such as MPS (Moving Particle Semi-implicit) (Koshizuka & Oka 1996) and SPH (Smoothed Particle Hydrodynamics) (Lucy 1977), which is one of mesh free methods, has been used to analyze water movement. The particle method is simple but powerful method to solve the problem of fluid mechanics. The authors introduce the coupling analysis by a discontinuous DDA and a particle MPS method to solve complex solid and fluid interaction problems such as collapse of natural landslide dam and debris flow (Miki et al. 2017). The proposed method shows the potential ability for the application in landslide, debris flow and other related fields.