The Journal of Engineering Geology ISSN:1226-5268(Print) 2287-7169(Online) 지질공학

The characteristic of recent rainfall pattern in Korea is concentrated in summer season and it is very different compare with former characteristic. In 2011, there was heavy rainfall in Chuncheon city of northern part of Korea. Because of rainfall in short time, many landslides were occurred in narrow area and many people were killed by these landslides at that time. The purpose of this study is to calculate run-out distance of debris flow and analyze the movement properties of debris flow according to the elapsed time using numerical analysis method at that time. The debris 2D program, which is developed by prof. Liu in National Taiwan University, was used in this study. Run-out distance of debris flow was calculated under different yield strength conditions which were controlled by rainfall amount. The results reveal that absolute maximum velocity of the debris flow is about 8.1 m/s and maximum depth of debris flow is about 7 m when debris flow was occurred. The run-out distance after 500 sec is about 300 m from end of the valley. It is very well similar with actual debris flow run-out distance. From these results, we can presume the maximum velocity and depth of debris flow at that time.