Impact of Size Fractal Distribution on Flow Behavior of Granular Flow System

According to the general constitutive equation of granular flow, impact of size fractal distribution on porosity and internal friction angle was studied experimentally with large-scale indoor relative densitometer and direct shear apparatus. The results show that, under the condition of the same physical density, elastic recovery coefficient and the geometric mean median granular size, porosity increases with fractal dimension increasing, meanwhile, the internal friction angle, particle concentration, shear stress and normal stress coefficients declines. Further more, in term of analysis on impact of size fractal distribution on flow behavior of granular flow system, it is found that, as for the system with smaller fractal dimension, shear stress is large and the fluid is poor and robustness is strong, On the contrary, as for the system with larger fractal dimension, shear stress is small and the fluid is good and sensitivity is strong. The discussion focuses on the mechanism of impact of fractal characteristics on collapse flow behavior of granular material, which offers a new idea for the study of granular flow system.