竖向应力及干湿循环对黄土土-水特征曲线的影响

土-水特征曲线是描述非饱和土水力特性的重要参数之一。本文利用非饱和土固结仪对2组5个压实非饱和黄土试样进行土-水特征试验,研究了不同的竖向应力和干湿循环对压实非饱和黄土土-水特征曲线的影响。试验表明,随着竖向应力的增大,压实黄土的进气值和脱湿率逐渐增大；在一个干湿循环中,同一基质吸力下脱湿曲线所对应的含水率大于增湿曲线所对应的含水率,脱湿率大于增湿率；第2次干湿循环所产生的滞回圈大小小于第1次干湿循环；滞回圈大小随竖向应力的变化而变化。

Influences of vertical stress and drying-wetting cycles on soil-water characteristic curve of loess

Soil-water characteristic curve is an important parameter for hydro-mechanical behaviour of unsaturated soil. Experimental study on compacted unsaturated loess was carried out by using unsaturated soil oedometers in this study and the effects of vertical stress and drying-wetting cycle on soil-water characteristics were investigated. The test results show that the air-entry value and desorption rate increase with increasing vertical stress for compacted unsaturated loess. In a drying-wetting cycle, the water content along the drying curve is higher than that along the wetting curve at same matric suction. The size of hysteresis loop between drying and wetting curves of the compacted unsaturated loess decreases with the number of drying-wetting cycles. The sizes of hysteresis loop are different under different vertical stresses.