Stability Analysis Of The Loess Cave In The Consideration Of Joints

The joints in loess are important factors that affect the loess engineering properties. To recognize the strength characteristics and the infiltration law in unsaturated loess field on the consideration of loess joints is one of the basic works of the study in Loess disaster prevention,loess characteristic and geotechnical problems related in loess area. The paper has made some research work about the strength characteristics and the infiltration law in unsaturated loess field on the consideration of loess joints.Through the improved direct shear test,joint friction angle in reshaped and intact loess has been tested.The results show that the curve shape of the relationships between internal friction angle and water content is similar to compaction curve.When the water content reaches the critical water content,joint friction angle is largest.When the water content is less than the critical water content,joint friction angle increases with the water content increases.When the water content is more than the water content,joint friction angle decreases with the water content increases.Loess joint friction angle is related with the water content and density.Further analysis of test results shows that when the water content higher than the critical water content,the present theory on the soil-water characteristic curve is appropriate.Matrix suction and shear strength reduces with the increase of the water content.But when the water content is lower than the critical water content,the present theory on the soil-water characteristic curve is not appropriate.Matrix suction and shear strength increases with the increase of the water content.The experiment for the infiltration law,in unsaturated loess field on the consideration of loess joints analyses the influence of the different joints position qualitatively.When there is no joints exist,current theory for the infiltration law in unsaturated loess field can be applied directly;When joint is in the middle of the water pit,the joint is the preferred infiltration plan;When joint is on the side of the water pit, joint plays the role of anti-water and has certain contribution to the security for structure on the other side when we irrigate less water.With the increase of irrigate water,joint plane has been filled with water,joint will enhance the infiltration.The initial water content also affect greatly.The higher the initial water content,the bigger the wet ratio is.This is inevitable result what the different matrix suction in unsaturated loess does.Based on the study above,the stability analysis of loess cave has been made with ANSYS qualitatively on the consideration of joints in loess.