Experimental Study on Shear Characteristics of Silt under Different Temperature-humidity Freeze-thaw Cycles

To explore the influence of freeze-thaw cycles on the shear characteristics of compacted silt under different temperature and humidity conditions, the silt in the Yellow River flooding area of Zhengzhou was taken as the research object. Under the freeze-thaw cycles of -5°C to 5°C and -15°C to 15°C, the soil samples with water content of 6%, 10%, 14%, 18% and saturation moisture content were subjected to freeze-thaw cycles. The results show that during the freeze-thaw cycle, the contact mode, arrangement and pore characteristics of compacted silt particles change, and the shear strength first decreases and then tends to be stable. Due to the phase change of water in the soil and the change of the inter-particle force, the greater the moisture content of the soil sample, the more obvious the attenuation effect of the freeze-thaw temperature amplitude on the shear strength of the soil sample. Under the condition of the same temperature amplitude, due to the comprehensive effect of particle surface cementation and inter-pore water film lubrication, the higher the moisture content of the compacted silt, the smaller the attenuation ratio of shear strength and cohesion, and the greater the attenuation ratio of internal friction angle during the freeze-thaw cycle.