Abstract: Since viscous debris flow is comprised of coarse particles and viscous mud, its movement process exhibits discontinuous deformation. Thus the fluid theory, which is based on continuous medium assumption, is difficultly applied to describe the process. Considering the influence of viscous media, a numerical model for viscous debris movement is firstly compiled according to the theory of granular materials and the platform of PFC3D software. Then the model parameters are obtained from the experimental results of indoor tensile tests and rotary shear tests on the viscous mud, which is called Chengdu clay and its density is 1.413 g/cm3.Moreover,numerical simulation of viscous debris movement is performed, which reproduces the movement process and the phenomenon of discontinuous deformation during the process. Meanwhile, the numerical simulations are verified by the experiment with the same size of the physical model. The results show that the PFC3D discrete element method, based on theory of granular materials, is applicable to simulate the movement process and present the phenomenon of discontinuous deformation during the movement process of viscous debris soil. This study provides a new way for further analyzing the viscous debris movement on slope under the impact of viscous media.

Key words: viscous debris flow, numerical model experiments, physical model experiment, PFC3D