Study On Microstructure And Mechanical Properties Of Slip Soil Of Loess-Bedrock Contact Landslide In Yanan Area

Yan’an is located in the hinterland of the Loess Plateau in China.In recent years, the environment had become worse in case of the over-exploitation and severe soil erosion.There were lots of landslides in Yan’an due to the river erosion and human activity, and the loess-rock sliding surface landslide was one of the most widely distributed landslides, which endangered the safety of nearby residents and property of city life.So the research on the loess- rock contact surface landslide has far-reaching significance for the prevention and treatment of this type of landslide.The paper took three typical loess- rock sliding surface landslides as the main object around Yan’an City based on the research literature and the collection of information summarized Regional geological environment condition and landslide disasters.The paper took Laser particle size analyzer, X- diffraction, scanning electron microscopy and various analytical methods to get the soil moisture content, mineral composition, physical and mechanical particle size distribution, mechanical strength of soil and other characteristics such as Abundance, Roundness, Discrete index, The average shape factor, Qualitative frequency and Directional probability and other microstructural feature parameters to study variation and link of them each other.Study results indicated that the clay mineral content within the landslide zone soil generally higher than the sliding body in an amount higher. Slip zone soil strength with increasing dry density increases with increasing water content is reduced, the greater the content of clay minerals in the soil, the greater the cohesion, internal friction angle substantially unchanged.Dry density and pressure change of slip soil have a great impact on the size of microstructure soil pore and orientation, have a little effect on microstructure of particle. The soil particles microstructure has more effect on the strength of slip soil than the pore microstructure. The distribution of particles has the most effect on the strength of slip soil.The main work and research results of this paper had a great reference value to the physical and mechanical properties of sliding soil and microstructure research, and provide some theoretical guidance for the further study of the formation mechanism of the landslide.