Experimental Study On Engineering Geological Properties Of Red Clay In Eastern Region Of Liupan Mountain And The Formation Mechanism Of Landslides

Red hilly-gully landform is one of the typical landscapes in eastern region of Liupan Mountain.The investigation of geological disasters in Jingyuan County shows that landslide is a kind of main geological disaster which is closely associated with the red clay.In addition,some scholars have found that many large and medium-sized landslides were controlled by the unconformity interface of loess and red clay in Loess Plateau region of China.Therefore,researching of engineering geological properties of red clay and its relationship with landslides are of great significance.This paper studies on the red clay of Palaeontology and Neogene in Jingyuan,Ningxia.Through experiments the composition,microstructure,physical and mechanical properties are researched.Also the developing rule and formation mechanism are analyzed.The conclusions list as follows.(1)The results of size distribution testing show that the composition of red clay in two ages are mainy clay and silt,sand content in the least;The result of the XRD test show that the main mineral of red clay are quartz,mica,kaolinite,calcite;The SEM result show that red clay is in reunion structure which contains small pores mostly.(2)The expanding and shrinking experiment indicates that two kinds of red clays have properties of swelling,shrinking and water-destructible.Moreover,the red clay in Neogene belongs to expensive soil.(3)Through shearing test,we got conclusion that angle of internal friction and cohesion will increase accompanying the increasing of dry density under the same moisture content level and decrease accompanying the increasing of moisture content under the same dry density level.(4)This paper elaborates the distribution of red clay and landslides in eastern region of Liupan Mountain,also takes the Majiacun landslide for example and calculates stability of landslide with the new-deduced functions.The result shows that the formation of the landslide is not only related to rainfall effect, the expansive force of red clay also plays a very important role.