This paper presents a numerical simulation of debris flow model by using modified Moving Particle Semi�]implicit (MPS) method with solid and liquid particles. The modified MPS method is the Lagrangian model of solid�]liquid flow phase and is proposed by combining the MPS method which was proposed by Koshizuka to simulate fluid dynamics with the Distinct Element Method (DEM). Herein, the contact between solid particles and the friction between solid particles and floor are taken into account. First, outline of the modified MPS method is described. Then, flow water simulation is compared with test result by using the original MPS method. After that, the effects of parameters in the modified MPS method are examined by comparing with the MPS method. Finally, the modified MPS method is applied to simulate the test result of debris flow model with pumice stone. The proposed method could reproduce the surge formation of debris flow model and load time history.


Key words�Fmodified MPS method, debris flow model, Distinct Element Method