中文摘要：

干湿交替环境下，膨胀土强度具有明显的“变动”特性。结合Palmgren-Miner线性疲劳累积损伤理论，进行了室内不同循环幅度组合的干湿循环强度试验，初步探讨了膨胀土在一定干湿循环条件下的累积损伤规律。研究结果表明：（1）高、低幅度干湿循环的施加顺序对膨胀土的累积损伤有较大影响，膨胀土强度衰减主要受高幅度干湿循环的控制；（2）Palmgren-Miner线性疲劳累积损伤准则可基本反映干湿循环下膨胀土的损伤累积过程，稳定时损伤分数D值接近于1。

英文摘要：

The strength of expansive soil has the changing characteristics in the alternation of wetting-drying environ- ment. Based on Palmgrem-Miner linear accumulative fatigue damage theory, indoor experiments on the wetting-dr- ying cyclic strength of expansive soil with different wetting-drying cyclic amplitudes was performed to study the ac- cumulative damage law of the expansive soil in the ahemation of wetting-drying environment. The results show that ： （ 1 ） The applying sequence of wetting-drying circulation of different amplitudes has obvious effects on the accumula- tive fatigue damage of expansive soil. The strength decay of expansive soil is mainly controlled by the high circula- tion amplitude. （2） The Palmgrem-Miner linear accumulative fatigue damage criterion can reflect the accumulative fatigue damage process of expansive soil in the alternation of wetting-drying environment. The value of is close to 1 when the strength of expansive soil is stable. damage score