This paper proposes an application of the distinct element method on damming up performance of drift wood capturing structures subjected to woody debris. In order to simulate the behavior of drift woods, a column shape element model is developed. In advance to analysis works, the debris flow experiments, with various combinations of the length of drift woods and the intervals of vertical columns of the structure, were carried out. Those results are utilized as a simulation object of the proposed method and a flow velocity modeling in this study. The flow velocity model used herein considered a turbulence of water flow occurred in the experiment. The turbulence model consists of combination of3kinds of turbulence effects, i.e., turbulence of water height by damming up, flow to avoid columns, and turbulence in the water. This paper pointed out that the simulation results by using the flow velocity model without the turbulence effect is not able to express the experimental results adequately. However, the simulation results by using the flow velocity model with the turbulence models show good agreement from the view point of debris capturing mechanism and debris flow capturing probability. Because the turbulences make the posture of the drift wood sway around the structures, which shorten the projection length to the column interval, tear down the temporary linked structure of the drift wood captured by columns, and/or flow to avoid the column.

Key wordsFdrift wood, DEM, cylindrical element, drift wood capturing structure