中文摘要：

土水特性影响并控制着非饱和膨胀土的工程特性。基于扫描电子显微镜试验和GDS非饱和应力路径系统试验，对合肥新桥机场场地原状非饱和膨胀土在失水和吸水过程中土水特征曲线进行研究，并数值反演相应的土水特征曲线、相对渗透系数和土水扩散系数，研究得出工程区域原状膨胀土微结构易于形成微裂隙，吸湿土水特征曲线较失水过程的土水特征曲线存在明显的滞后性。数值分析结果表明，Fredlund模型与实测结果吻合较好，研究结果为新桥机场膨胀土地基处理方案的制定提供了一定依据。

英文摘要：

Soil-water characteristics play roles in engineering behaviors of undisturbed and unsaturated expansive clays. Based on SEM and other experiments, microstructures and shrinkage-swelling properties were discussed for the unsaturated expansive clays in the area of Xinqiao International Airport in Hefei. Moreover, soil-water characteristic curves （SWCCs） during drying and wetting process were measured by means of GDS triaxial stress path system, and numerical simulations and comparisons were conducted for the corresponding SWCC, relative hydraulic .conductivity and soil-water diffusivity. The results showed that the measured SWCCs during wetting process behaved hysteresis with reference to that during drying process. The simulation SWCC using Fredlund model was in good agreement with the measured curve. These results provided a certain basis for making a rational foundation treatment plan for the Xinqiao International Airport founded on expansive clays.