Debris Flow Characteristics And Hazard Assessment About Dadu River Changheba Hydropower Station

Changheba Hydropower Station is an under-construction hydropower station in the middle reaches of the Dadu River. With the geological environmental conditions of the dam area being poorer, geological disasters including critical rock, collapse and debris flow have been developing. Xiangshui Gully is a right branch of the Dadu River at the upper river of the dam area, where a debris flow broke out in July,2009 that caused a certain casualties and property loss. As mining and the construction of the hydropower station and its supporting facilities affect the engineering area environment to a certain degree, the risk of geological disaster is showing an increasing trend. In order to ensure that residents and the hydropower station are safe, it is necessary to survey the debris flow development characteristics and assess its hazard in the researched area.This thesis analyzes forming conditions, disasters causes and development characteristics of the four main debris flow gullies in the study area, and calculates movement characteristic parameters of debris flows including the peak flow, based on the field survey and data access. According to the geological environmental conditions and developmental features of debris flow gullies in the study area, the risk assessment factors which are suitable for the actual situation of the area are selected based on meeting the factors independence and data acquisition convenience. For the first time in the risk assessment of debris flow by the analytic hierarchy process, the weights analysis are made until the scheme layer, and it makes evaluation results and analysis process has a certain unity. The evaluation results obtained with grey relational analysis and the computational results of the gully debris flow risk show good agreement, comprehensive evaluation for each debris flow gully is medium risk, and the results show that it is still probable to break out middle and small scale debris flow under rainstorm. The study combining engineering project reality satisfies social production of life needs, at the same time, the further attempt of risk evaluation methods for debris flow, has certain reference significance to the future similar research.