土石流の流量予測

Abstract

Prediction of maximum discharge of a debris flow is as essential for the design of hard counter-measures as for the planning of soft countermeasures. Although the senior author has presenteda formula predicting the discharge of a debris flow generated from rather uniform sediment bed, the one which predicts the discharge due to failure of a natural dam has not been available yet.This paper presents two discharge predicting forumlae, the one is applicable to the case inwhich overspilled water flow scours the dam-body, and the other is applicable to the case in whichthe collapse of the dam-body occurs by the effect of seepage flow. A method to classify the twocases is also proposed. The discharge of a debris flow which occurred in the basin of the Kizuriver is well explained by the latter discharge predicting formula. This formula would be alsoapplicable to a debris flow which originates from a moving earth block accelerated by a landslide.