中文摘要：

干湿交替环境下，膨胀土具有反复湿胀干缩变形的特性，容易引起工程建筑物的变形破坏。以南宁地区的击实膨胀土为研究对象，通过室内试验揭示膨胀土在干湿交替环境中的变形规律，探讨了体积变形参数、初始切线模量与循环次数的关系，并对试样绝对残余体变率与初始切线模量的关系进行了分析。研究结果表明：试样的绝对残余体变率随干湿循环次数的增加而递增，但相对残余体变率却逐渐减小，体积变形量稳定时所需循环次数均随含水率变化幅度的增加而递减。

英文摘要：

Expansive soil presents a repeated swelling-shrinking deformation in the alternation of wet-dry environment , which easily leads to the deformation damages of the engineering constructions .Indoor cyclic wetting-drying tests were conducted on the compacted expansive soil from Nanning area in order to study the deformation of expansive soil in alter-ation of wet-dry environment .Then ,the relationships between the deformation parameters ,initialization tangent modulus and cycle numbers were analyzed .In addition ,the relationship between the absolute residual volume change rate and ini-tial tangent modulus of soil specimen was discussed .The results showed that the absolute residual volume change rate of soil specimen increased along with the increase of the wetting-drying cycles ,but the relative residual volume change rate decreased .The number of the cycles for the variation volume to reach a constant state reduced with the increase of the water content .