Strength and Microscopic Characteristics of Ili Loess under the Action of Wetting-Drying Cycles
To investigate the strength degradation and microstructure characteristics of Ili loess under wetting-drying cycling,triaxial shear tests and scanning electron microscopy tests were conducted under five wetting-drying cycling paths.The effects of different dry densities,wetting-drying cycling amplitudes,and cycles on the shear strength of Ili loess and the evolution of micro pore distribution were analyzed.The relationship between macro strength and micro pore loss mechanisms was also explored.The results show that the greater the wetting-drying cycle amplitude and the number of cycles,the faster the attenuation rate of the shear strength of Ili loess,the greater the attenuation amplitude,and the triaxial shear strength of undisturbed soil after five wetting-drying cycles is close to remolded loess.The cohesive force of Ili loess with the same dry density decreases with the increase of cycles.When the dry density is 1.55 g/cm3 under the same wetting-drying cycle path,the cohesive force of Ili loess deteriorates most significantly,while the effect of dry wet cycles on internal friction angle is slightly significant.In addition,the deterioration of cohesion is related to changes in pore area ratio and pore characteristic parameters.The greater the increase rate of pore area ratio and pore characteristic parameters after wetting-drying cycling,the more obvious the degradation of cohesion.The change trend of internal friction angle is similar to that of pore fractal dimension,but the change is not significant.
万方数据
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