考虑体积变化的非饱和膨胀土土水特征

为探讨吸力作用下膨胀土体变特征对土水特征的影响规律，开展了一系列完整的脱湿阶段试验，获得了5种不同初始孔隙比的荆门压实膨胀土各级吸力下的重力含水率与体积变化。试验结果表明：不同初始孔隙比下的重力含水率－吸力曲线有交叉与聚拢现象；体积含水率－吸力曲线的交叉现象更为显著；而饱和度－吸力曲线未出现交叉，相同吸力下初始孔隙比大的土样具有更低的饱和度，体现出土水特征与体变特征的耦合效应。基于试验成果，从土的基本体积－质量关系出发，以初始孔隙比与吸力为变量，在一个统一的框架内，构建了吸力作用下的体变方程、分别用重力含水率与饱和度表征的SWCC方程，方程能够描述任意初始孔隙比条件下膨胀土干缩过程中重力含水率、孔隙比与饱和度随吸力的变化规律。

Effect of volume changes on soil-water characteristics of unsaturated expansive soil

This paper investigates the effects of deformation on the soil-water characteristics of expansive soils. A series of SWCC tests are carried out on Jingmen compacted expansive soil along the main drying paths. Values of gravimetric water content and volume changes of soil samples at different levels of suction are measured for five different initial void ratio samples. The test results show that the gravimetric water content - suction curves intersect and merge, while the volumetric water content - suction curves display intersections more remarkably. However, the degree of saturation - suction curves do not intersect, indicating that the soil sample of the larger initial void ratio remains the lower degree of saturation under the same suction. These phenomena reflect coupling effects between the soil-water characteristics and the volume change behavior for expansive soils. Based on the test results, three formulas are presented for predicting the gravimetric water content, the void ratio and the degree of saturation along the main drying paths of the expansive soil, respectively. These formulas rely on the volume-mass relationship and are defined in a unified framework as functions of suction and initial void ratio. Finally, the comparison between the measured and reproduced results validates the presented formulas.