Stability Analysis And Treatment Measures Of Guanjiadi Landslide In Ludian Earthquake Area

At 16:00 on August 3,2014,the M6.5 earthquake occurred in Longtoushan Town,Ludian County,Zhaotong City,Yunnan Province.The focal depth was 12km.The energy released by the earthquake was huge and triggered multiple landslides.The Guanjiadi landslide is the typical landslide triggered by the Ludian earthquake,located on the east side of Longtoushan Town,Ludian County,the left bank of Longquan River,west side of Mule Horse.According to the survey,the landslide threatened the safety of 7 households and 25 people,as well as the transportation company's houses and personnel,road,passing vehicles and mobile base stations.The total threat population was about 150 people,threatening assets of about 5 million yuan.Dangerous level is medium.In this paper,the formation mechanism of the landslide is analyzed by the geological survey combined with means of geological exploration technology.The stability of the landslide is analyzed and the economic and reasonable treatment project is designed to control the landslide in order to eliminate the threat to the safety and property of the surrounding residents.The research results of this paper are summarized as follows:(1)The landslide material is mainly composed of Quaternary artificial soil(Q4ml),landslide plot,landslide accumulation(Q4col + dl + del),block stone,detritus mixed silty clay and sandy soil.Lower Paleozoic Ordovician Oiaojia formation(O1q),the sliding bed is mainly strong weathering dolomite,and the lithology facies of the overall landslide area does not change much.(2)Affected by the fault,the rock is broken in the area.The weak structure plane formed by boundary of rock and soil layer,groundwater enrichment and migration and the slope direction formed the weak structure plane controlled the landslide slip.The formation of the landslide is controlled by the internal and external factors.The terrain conditions,lithology and geological structure were the internal factors of the landslide,and the earthquake,rainfall,surface water infiltration and human engineering activity are the external factors.(3)The result of the stability of each landslide block under the conditions of self-weight,self-weight + rainstorm,self-weight + earthquake state that:the HG1-1 slider and the HG1-2 slider are in a basically stable state under the self-weight condition-in a less stable state under the self-weight + earthquake condition and in an unstable state under the self-weight + rainstorm condition.The HG1-1-1 and the HG1-2-1 secondary block are in less-basically stable state under the self-weight condition,in an unstable state under the self-weight condition and self-weight + rainstorm condition.(4)Considering the construction conditions,treatment effect and economic benefit,the overall treatment project of the landslide includes:anti-slide pile engineering,the anchor(cable)frame beam project and drainage engineering.After the implementation of the landslide treatment,the stability coefficient of the landslide under each condition is greater than the stability coefficient required for the control project grade,that is,the design of the anti-slide pile and the anchor(cable)frame beam project can control the overall deformation of the landslide and insure the overall stability of each slider.