Effect of Soil Water Content and Dry Density on Soil Shearing Strength for Calcareous Purple Soil and Neutral Purple Soil

Based on the triaxial shearing test in laboratory,effect of soil water content and dry density on soil shearing strength was determined for calcareous purple soil and neutral purple soil.Experimental data indicated that the soil cohesive force firstly increased and then decreased with the increasing of soil water content under the same soil dry density,and it increased with the increasing of soil dry density under the same soil water content.The internal frictional angle of two types soil fleetly decreased with the increasing of soil water content.There was close relation between the interaction of soil water content and dry density and soil cohesive force,and the soil cohesive force reached to the maximum under the interaction of soil water content and dry density that each soil dry density matched the specifically soil water content.The maximum of soil cohesive force for calcareous purple soil was 154.59 kPa under soil dry density 1.7 g/cm3 and water content 11%,for neutral purple soil was 126.38 kPa when soil dry density was 1.6 g/cm3 and water content was 8%.The interaction of soil water content and dry density was small relatively on the internal frictional angle,and the internal frictional angle tardily increased with the increasing of soil dry density.The internal frictional angle of calcareous purple soil nonlinearly decreased with the increasing of soil water content and there was the transitory increasing and then fleetly decreasing for the internal frictional angle of neutral purple soil.