中文摘要：

为掌握大气长期作用下公路膨胀土路堤湿度平衡规律，为膨胀土路堤处治提供依据，以广西包盖膨胀土路堤为例，考虑膨胀土填料受力状态，开展应力相关土水特征曲线试验，揭示了不同应力状态下压实膨胀土平衡湿度随吸力的变化规律。通过现场监测，分析了包盖膨胀土路堤1．5a内的湿度变化和变形特征，利用土与大气相互作用计算方法，对广西气候条件下包盖膨胀土路堤运营10a内的湿度变化过程进行了数值模拟。研究结果表明：0—3MPa吸力范围内应力对膨胀土的平衡湿度有显著影响；1a内膨胀土路堤内部含水率有缓慢增加的趋势，越靠近边部含水率波动越剧烈，路堤总体表现为不均匀沉降；6a后路堤内部湿度逐渐趋于稳定，达到湿度平衡状态；膨胀土的湿法重型击实最佳含水率接近路堤平衡含水率，南方湿热地区膨胀土路堤宜采用湿法重型击实标准控制压卖。

英文摘要：

In order to investigate moisture equilibrium of highway expansive soil embankment and provide reference for corresponding engineering treatment, taking the covered expansive soil embankment in Guangxi for example, considering stress condition of fill in the embankment, a series of stress-dependent SWCC tests are conducted to reveal the variation of equilibrium moisture of recompacted expansive soil with matric suction under different stress conditions. The variation of water content and deformation of a covered expansive soil embankment through one-year and a half field monitoring is analysed. Based on the computation method of interaction between soil and atmosphere, the process of moisture variation of the covered expansive soil embankment under ten-year Guangxi climate effect is numerically simulated. The study results show that （ 1 ） the effect of stress state on equilibrium moisture of expansive soil is obvious in the suction range of 0 - 3 MPa ; （2） in the first year of service, the moisture content of the core of expansive soil embankment increases gradually, the closer to slope side, the greater water content fluctuates, and differential settlement of the embankment is observed ; （3） the moisture content of the core tends to stable after the sixth year of service, and reaches the moisture equilibrium state; （4） the optimum moisture content of expansive soil compacted according to heavy compaction standard is closed to the equilibrium moisture content, it is better to use this standard to control field compaction of expansive soil embankment in moist and heat areas in the southern China.