Numerical Study on Debris Flow Under Different Rainfall Intensities at Gangou in Hongse Village， Dujiangyan

Abstract:

The movement of debris flow occurred at Gangou in Hongse Village of Dujiangyan City of Sichuan Province was analyzed with field measurements. A two dimension numerical model of the debris flow was set up with DEBRIS 2D software to simulate the debris flow in the region. It is shown that computational results and on site observations are in good agreement. Different scenarios of the debris flow spreading caused by different rainfall intensities were also simulated. The results quantitatively reveal that with abundant debris source, the reduction of rainfall intensity leads to a slower movement and a higher stop position of debris flow. Taking the rainfall intensity of 150 mm·h-1 as a reference, if the rainfall intensity reduces to 100 mm·h-1 and 50 mm·h-1, the increase on final front position will be 25 m and 75 m respectively and the reduction on average deposit thickness will be 0.06 m and 0.14 m respectively.