Experimental Study Of The Influence Of Silt Content On Mechanical Properties Of Unsaturated Soil

Most of the actual engineering soil is unsaturated soil, because the mechanical properties of unsaturated soil is not yet fully understand, and thus brought a lot of engineering problems. It is necessary to further study the mechanical properties of unsaturated soil.In this paper, through the combination of direct shear tests and the soil water characteristic curve tests of soil samples at three different silt contents, the shear strength parameters characteristics of unsaturated remolded soil was explored. As to provide theoretical basis for engineering practice, the variation laws of shear strength with the change of silt content and saturation of unsaturated soil are analyzed, and the influence of matrix suction of it is studied as well. The following are some main conclusions made from the paper:1. In summarizing the development process of unsaturated soil mechanics on the basis of the basic physical properties of silty clay, clayey silt, sandy silt were analyzed.2. Controlling the saturation of the silty clay, clayey silt, sandy silt, adopt unconsolidated quick shear test, analysis of saturation internal friction angle and cohesive force of impact. The cohesive force in the unconsolidated quick shear tests increases initially and then decreases as the saturation increases. While the internal friction angle decreases as the saturation increases.3. Analyzing the dry density of silty clay, clayey silt, sandy silt influence of the internal friction Angle and cohesive force. The study found that: the cohesive force and internal friction angle in the unconsolidated quick direct shear tests increases as the dry density increases.4. Comparing the silt content of silty clay, clayey silt, sandy silt, under the same saturation, the lower the silt content of the soil, the greater the cohesion force,the smaller internal friction angle and the lower the shear strength.5. The cohesive force increases initially and then decrease as the matric suction increases, the matric suction increases as the internal friction angle increases, and meanwhile its influence on the internal friction angle declines. The bigger the dry density is, the lower the residual water content is, and the higher the air entry value and the residual suction are.