Load Evaluation of Debris Flow Against Steel Open Sabo Dam Using DEM

Toshiyuki HORIGUCHI, Yoshiharu KOMATSU, Satoshi KATSUKI and Nobutaka ISHIKAWA

Although latest statistics indicate a decrease in the number of victims of natural disasters in Japan, numbers of sediment disasters have actually increased. For instance, a torrential downpour hit the mountain areas of northern Kyusyu in July 2017, and this caused loss of live and damage to property. Development of sediment control structures is necessary for countering sediment and debris flow disasters. One of such counter measures is steel open type check dam (hereafter, steel open Sabo dam). By utilizing segregation mechanism of boulders in a debris flow, the steel open dam is expected to capture them. When the debris flow attacks the steel open Sabo dam, huge impact load occurs between boulders and steel pipes. Therefore, it is very significant to evaluate the debris flow load of steel open Sabo dam from the design point of view. This paper presents experimental and computational approaches to impact load of debris flow including boulders hitting the steel open Sabo dam. First, debris flow experiments are carried out by using 1/40 scale channel slope, and the impact load is measured by using a load cell. Second, the distinct element method is used for a simulation analysis of the model test. Herein, the computational results show good reproducibility of experiments. This debris flow load analysis will be very useful for the safety assessment of steel open dam against rock impact in the debris flow.

2018/1 228-235