中文摘要：

击实膨胀土在干湿循环作用下产生的胀缩体变可以分解为一个随含水率或吸力改变而同步变化的可逆性分量和一个主要产生于干湿循环过程初期的不可逆性分量。可逆性干湿体变来源于组成土骨架的黏土微观结构变形的可逆性,主要由当前吸力或含水率的变化确定。不可逆性干湿体变分量与干湿循环引起的土的宏观结构的不可逆变化有关,其大小依赖于当前状态与平衡状态的宏观结构的差异。分别给出了可逆性和不可逆性干湿体变分量的数学描述,结合低塑性非饱和土的BBM模型,提出了一个适用于击实膨胀土的实用本构模型。该模型的参数数量少且易于确定。通过对试验结果的模拟,表明本模型比经典的膨胀土BExM模型的模拟效果更好,更易于实用。

英文摘要：

The volumetric strain of compacted expansive clays induced by cyclic wetting and drying can be decomposed into a reversible component, which changes synchronously with the suction or water content, and an irreversible component with mainly generated at the early stage of wetting-drying process. The reversible component is derived from the reversible deformation behavior of the microstructure of clay aggregates that form the soil skeleton, and depends mainly on the current suction. The irreversible component is derived from the irreversible change of the macrostructure of the soil skeleton, and is associated with the difference of macrostructure between the current and equilibrium states. The mathematical descriptions of the two components are given according to the analysis of the physical mechanism and by fitting the experimental results. A practical constitutive model is proposed for compacted expansive clays by combining the mathematical description with the BBM model proposed by Alonso et al. The proposed model has a small number of material parameters that can be easily determined. Its predictive capabilities are better than that of the BExM model through comparative simulation of comprehensive experimental data set.