Statistical Risk Estimating Method for Rainfall on Surface Collapse of a Cut Slope

Abstract

ABSTRACT Slope collapse for embankments and cut slopes on railways generally occur during heavy rainfall from typhoons etc. and have a strong influence on running safety of trains. Risky locations along the railway right of way must be identified to control railway operations based on the conditions and characteristics for each railway line. For this purpose, a practical damage estimation method, which accurately predicts the hazard of slope collapse and can be used simply by railway workers, has been developed. This paper deals with this method of risk estimation for a surface collapse of a cut slope during times of heavy rainfall using a multivariate analysis. The critical rainfall is obtained using a combination of an accumulated rainfall and an hourly rainfall, which have the powers 0.2 and 0.9 respectively. The critical rainfall is then determined from external variables such as geometrical and structural configuration of the cut slope, subsurface soil and rock conditions, catchment condition and experiential rainfall condition. It was determined that the hourly rainfall has more influence than the accumulated rainfall on the surface collapse of cut slopes. Since it was confirmed that this risk estimation standard agreed with some values observed for the surface collapses, it is suggested that the method can be used not only for planning the disaster prevention along railway right-of-way but also for predicting of the cut slope collapse due to heavy rainfall.