Abstract: Taking Kala hydropower station on the Yalong River for example, aiming at the problem of quantitative assessment of group landslide risk in hydropower station dam site selection, and taking the analysis of landslide risk and vulnerability into consideration, four index parameters—engineering influence coefficient, importance coefficient, distance modulus and status coefficient of landslides are introduced. A hydropower landslide risk assessment system which considers the landslide status and the influence of human activity on landslide is built based on annual expected loss index. According to a comprehensive assessment method in which the index of dam site safety, the loss index of power output and river dredging caused by river blocking, and the loss index of surge damage are taken as the standard indices, the principle of balance security and economy is used to get the result of the dam site selection with landslide assessment. The improved risk assessment method under the same dimension is adopted; and it is demonstrated that the calculation and analysis are reliable than the traditional method in practice; therefore it can be used as a reference for dam site selection.

Key words: landslide, risk assessment, risk index, dam site selection