DEFORMATION MECHANISM OF LOESS SLOPE WITH WEAK INTERLAYER AND ITS STABILIZATION MEASURES

In recent years,more and more loess slopes are excavated in Northwestern China.The instability of slopes affects the engineering facilities,so it is important to study the deformation mechanism and design reasonable stabilization countermeasures.This paper examines the deformation mechanism of one counter-tilt slope composed of sandstone and mudstone with loess covering and fault zone passing through.Based on analysis of engineering geological conditions and deformation characters,the slope deformation mechanism is studied.Three-dimension geological model is established to analyze the distribution of stress and strain of slope.Flac-3D software is used to simulate the excavation process of the loess slope.The numerical result indicates that large area tension stress distributes in fault and loess at upper slope.The rock mass in counter-tilt fault moves along the fault.,Shearing deformation generates in the lower slope along interface between bedrock and loess and develops upward.The pull-type deformation occurs in loess at the upper slope under this type of stress state.Therefore,the control of the slope deformation should concentrate on improvement of the stress state with unloading and controlling deformation of interface between bedrock and loess.At last,the control measures include offloading,steel pile,anchor and slope protection.