制样方法和干湿循环对粉质黏土土-水特征曲线影响

基于压力板仪实测了粉质黏土击实试样和泥浆固结试样的脱湿土-水特征曲线(SWCC)以及泥浆固结试样在经历不同次数干湿循环后的SWCC,研究了制样方法和干湿循环对SWCC的影响;同时利用扫描电镜观测了泥浆固结试样干湿循环前后的微观结构特征.试验结果表明:泥浆固结三轴试样的SWCC位于三轴击实试样的上部;干湿循环使得试样的SWCC左移,泥浆固结试样的SWCC在经历2~3次干湿循环后趋于稳定.Van Genuchten模型能够很好地拟合不同干湿循环次数下的实测脱湿SWCC,其参数随干湿循环次数的变化规律可用指数函数进行描述.

Effects of specimen preparation method and drying-wetting cycle on soil water characteristic curves of silty clay

The dehumidified soil water characteristic curves (SWCCs) of the silty clay specimens prepared using the moist tamping method and the slurry consolidation method were measured based on the pressure plate extractor. The SWCCs of the slurry consolidated triaxial specimens subjected to different numbers of drying-wetting cycle were also measured. The effects of the specimen preparation method and drying-wetting cycles were analyzed. Additionally, the soil microstructure before and after drying-wetting cycle was investigated using the scanning electron microscopy (SEM). The experimental data shows that the SWCC of the slurry consolidated triaxial specimen is located in the upside of that of the impacted specimen. The SWCC shifts to the left after drying-wetting cycle and reaches an equilibrium state after 2-3 cycles of drying-wetting. The dehumidified SWCCs of the slurry consolidated triaxial specimens subjected to different numbers of drying-wetting cycles can be exactly fitted by the Van Genuchten model. The relationship between the parameters of the Van Genuchten model and the number of drying-wetting cycles can be described by an exponential function.