Study On Formation Mechanism And Prevention Countermeasure Of Sandstone Landslide In Hongjiang - Pu'er Red Layer Area, Yunnan Province

At present, with the rapid development of economic, the transportation, bridges, water conservancy, mine and so on are rapid progress in every field. With the engineering construction and in the operation of the late inevitably lead to the occurrence of a large number of landslides.Thus a series of problems appear.The western development with an emphasis on infrastructure construction.On the one hand, the construction of roads and bridges promote the development of the economy. On the other hand, destroy the native environment,topographic features destruction of the vegetation,exploitation of underground resources and lead to soil and water loss. At the same time,all sorts of the excavation of the slope in the construction process,embankment and in addition to the causative factor will lead to geological disasters occurred frequently.Yunnan red layer is mainly distributed West and middle of Yunnan Province,formation is mainly for the jurassic and cretaceous and red bed area accounted for 30% of the whole province.Dali, Pu’er, Xishuangbanna belongs to western red beds area in Yunnan province and Kunming, Chuxiong, Yuxi are belongs to red layer in central area of in Yunnan province.This paper mainly studies and analysis formation mechanism and control measures of red sandstone landslide of Yuanjiang-Puer area of Yunnan province.To research from the geological environment factors, physical and mechanical properties, stability evaluation, landslide formation mechanism and so on.There are 82 landslides in the study area. According to the position of the sliding surface,mechanical properties, the rock mass structure, the scale of landslide and joints and fissures to classification of landslide,lay the foundation for discusses landslide formation mechanism. A total of 63 sliding surface of landslide development in fully weathered layer and strongly weathered layer interface,accounted for 76.83%.A total of 17 sliding surface of landslide development in strongly weathered layer and medium weathering interface,accounted for 20.74%.Due to weathering strongly of fully weathered sandstone,the void ratio is greater than strongly weathered of sandstone.fully weathered weathering of sandstone time is long, high speed, loose structure make the rainwater more easily into the rock mass.Due to the strongly weathered of sandstone permeability is smaller.When rainwater into fully weathered sandstone formation,the rainwater infiltration into the strongly weathered of sandstone is relatively difficult.Rainwater flow along fully weathered layer and strongly weathered layer interface and soften the contact surface of rock mass and shear strength decreased and formation of weak structure plane. When increase in rainfall and its weight will increase and easy cause potential unstable slope sliding.The typical landslides in the studied area calculating the landslide stability evaluation,using qualitative analysis and quantitative analysis to analyze the landsli-de stability evaluation.Quantitative evaluation including to use ANSYS modeling and FLAC-3D calculation and Lizheng soil for checking.According to the result of calculating to design different Treatment methods.