A numerical simulation of volumetric enlargement for seismic debris flow using integrated DDA and KANAKO 2D

The assessment of the debris-flow hazard potential has to rely on the debris volume, for now seismic condition and relevant influence is not considered in the current estimation method, which causing the calculating volume far less than reality. Current researches indicate that volumetric enlargement for seismic debris flow mostly due to the debris material accumulation along the flowing path induced by earthquake, however only qualitative or semi-quantitative methods are adopted. In this paper, a method integrating with DDA and dilatant flow model based KANAKO 2D is proposed, in which the process of debris material accumulation is simulated by DDA, the processes of debris material entrainment and debris-flow deposition are simulated by KANAKO 2D. To demonstrate this method, Shekeniluo debris flow gully, which located in the high seismic intensity zone of Wenchuan earthquake in Shimian County, Sichuan Province is selected as a case study. Numerical simulation results show that debris volume and influence area would expand to 3 times, and it is also verified to approximate to the investigation result.