EXAMINATION FOR A DYNAMIC DEBRIS FLOW LOAD MODEL FOR AN OVERTURN STABILITY OF OPEN SABO DAM

Abstract

In recent years, open Sabo dam has been damaged due to a large-scale boulder debris flow. A new design concept of structural safety against a large load level is discussed. The new design load is largrer than the conventional design one. This study proposes a dynamic debris flow load model subjected to open Sabo dam as a new concept. First, debris flow load is measured from a view point of dynamic load distribution. The load is focused on the overturn stability limit state of Sabo structure by using the device that overturn in exceedance condition of the limit state. The resistance moment at the overturn limit was good agreement with the measured action moment. It was considered a dynamic load model that combines the deposited gravel load acting on the lower part of the structure and the debris flow load acting on the upper part. The proposed load model was examined in comparison with experimental results and the overturn stability obtained from FEM analysis. Furthermore, it was clarified that the maximum uplift of the dam model depends on the time integrated value of excess moment with respect to the resistance moment.