Risk Assessment of the Heiniwan Landslide in Hongkou County, Sichuan Province

Based on stability calculations of multistage potential sliding surface of Heiniwan landslide which caused by heavy rain in July 2013, risk assessment, risk zoning, and the evaluation of the social risk were respectively completed under three different conditions in this paper, namely heaviest rainfall in ten years, in fifty years and in a hundred years. After the superposition of single life risk, the risk map was finished. With the connection of the landslide social risk, the social risk of Heiniwan landslide was evaluated. The maximum property risk is 1,116,660 RMB per year, while the maximum population at risk is 0.00223 a person per year. At the same time, division results show that danger zone ①, ②, ③have the greatest single life at risk, which is more than 10^-3 life at risk; compared to international risk tolerance standard (F-N curve), the social risk value cannot be accepted. Therefore, it is necessary for local governments to strengthen such work as monitoring, relocation of local inhabitants and appropriate engineering control to avoid the risk.