Risk assessment for NianZi rockfall in Qingchuan County,Sichuan province

Sichuan province suffered magnitude 8 earthquake on May 12,2008.The earthquake severely devastated the Qingchuan County,and triggered a large number of secondary geological disasters at the same time.The paper's study and evaluate objects is the rockfall disaster in the No.five village of NianZi.Based on the study of the engineering geological conditions,the distribution of the dangerous rock body,the failure and variabile modes,calculated the dangerous rock's stability and probability of failure.Based on the test of rolling stones,simulated the motion trajectories of falling rocks in using professional software,then obtained the falling rock's speed,jumping height,kinetic energy and the influence scope is delineated also.Vulnerability and risk assessment of the disaster have been developed acaccording to the field investigation and local social economic data.Appropriate measures for the disaster prevention and mitigation have been proposed according to the hazards characteristics and the results of evaluation.