2009-08-06四川省汉源县顺河乡猴子岩发生大型崩塌,90余万m3崩塌体直接冲进大渡河,形成40m高的堰塞坝,阻断大渡河,形成库容达6000×104m3堰塞湖,导致2人死亡,29人失踪和重大财产损失。以现场调查与观测为基础,分析灾害发育条件和成灾过程,认为高陡边坡次级断裂造成的岩体破裂是崩塌发育的基础条件,"5.12"汶川大地震、强降雨及道路工程建设造成的边坡失稳是灾害发生的重要原因。针对崩塌堵河灾害的成灾特点,提出加强山区重大工程区地质灾害评价、预防、预警,科学设计、施工减少陡坡开挖,采取果断措施处置施工过程中出现的险情、灾情,及时在灾害点设置警示标志减少灾害损失等减灾对策。

August 6th,2009,a large-scale rock fall occurred at Houziyan in Hanyuan county.900×103 m3 rock directly rushed into Dadu river and created a dam with the height of 40m,which blocked Dadu river and engendered a dammed lake with the length over 10 km and the capacity of 60 ×106 m3.This hazard resulted in 2 persons in dead,29 person lost and quantity of property loss.This paper mainly discussed the causes and characteristics of this disaster on basis of field investigation and observation.It was found that the rock breach induced by high-steep slope sub-rupture provided the favorable condition for this rock fall,and the interaction of S306 highway reconstruction,5.12 Wenchuan Earthquake and intensive rainfall triggered this hazard.For mitigating this kind of hazard,it was recommended that strengthened the assessment,prevention and alarm of geo-hazards at mountain engineering construction areas,reduced steep slope dug and failure by rational design and construction,treated and controlled the hazards in the process of engineering construction as well as decreased the hazard losses by disposing alarm sign at hazard site in time.