Experimental Study On The Mechanical Properties Of Typical Unsaturated Sandy Silt In Hangzhou

Through unconsolidated quick direct shear tests and consolidated undrained direct shear tests, the influence of the two single variables water content and dry density on the shear strength parameters of the typical unsaturated sandy silt in Hangzhou was studied in this paper. And by conducting the experiment of soil-water characteristic curve of multiple dry densities, the influence of matric suction on the shear strength parameters of the soil was explored. The following are some main conclusions made from the paper:(1) The cohesive force in both the unconsolidated quick direct shear tests and the consolidated undrained direct shear tests increases initially and then decreases as the water content increases. While the internal friction angle decreases as the water content increases. The influence of water content on internal friction angle in unconsolidated quick direct shear tests is larger than that in consolidated undrained direct shear tests.(2) The cohesive force in both the unconsolidated quick direct shear tests and the consolidated undrained direct shear tests increases as the dry density increases. While the internal friction angle decreases as the water content increases. In unconsolidated quick direct shear tests, the influence of dry density becomes deeper as the water content increases.(3) The cohesive force of three different dry densities increases initially and then decrease as the matric suction increases, and the significant variation mainly occurs at the capillary water effect zone. 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.(4) In summary, both the water content and the dry density have a significant influence on the shear strength parameters of the soil, and the matric suction also plays an important role in the enhancement of the shear strength of the sandy silt in Hangzhou.