Study On The Mechanism Of Part Instability And Control Measures Of The Ancient Landslide On The Right Bank Of The Dongla Bridge

China is a mountainous country, nearly70%of its area is mountain, the special terrain and distinctive geological environment makes the landslide disasters occurred frequently. The losses of casualties and property which caused by landslide far from the ancient are too many to count. With the accelerated pace of China’s economic construction, especially the advance of highway and water resources and hydropower in mountains,we can hardly avoid to meet some landslide. Because of its large scale, complicated mechanism,great harm and the huge cost of treatment,the large " engineering-landslide"had attracted much attention of the people.In this paper, we take the Dongla Bridge landslide in Shuiluo Village, Muli Tibetan Autonomous County, Liangshan Yi Autonomous Prefecture, Sichuan Province as the object of study, analysis its mechanism of instability,and Consider the landslide’s nature to make suggestions of comprehensive control measures for it, reached the following understanding and conclusion:1. According to the geological features of the landslide area, we analysis the mechanism of Dongla landslide and find that the formation and inducement factor of it include geological structure and formation lithology, groundwater, river, rainfall and earthquake etc.. In addition, human engineering activities is also a induced factor of the landslide.2. Dongla landslide is in the creeping deformation stage,if wo don’t take some necessary retaining measures, the landslide is very likely to become instability and slide in the effect of factors such as rainfall,then it will not only damage the road of power station,but also block the Shuiluo River, forming lake, bring greater harm to the local residents’ life and property. Therefore, there is no delay to control it.3. According to the nature of the Dongla landslide, we make the comprehensive control measures for it which Implemented in two steps:first,we take engineering measures for emergency treatment, as to cut down the weight of the slope’s top and press its foot; followed by radical engineering, such as surface drainage and slide-resistant pile construction, in order to control the Dongla landslide thoroughly.