中文摘要：

膨胀土由于具有不良的胀缩性质往往需要对其进行改良。膨胀土改良从作用机理的角度可以分为物理改良和化学改良。本文根据向膨胀土加入的材料和施工工艺，对物理改良进行分类，并分析了其特点、加固机理以及效果；阐述了化学加固机理以及加固效果。在此分析的基础上，对膨胀土改良技术的发展趋势及研究方法进行了展望，以供参考。

英文摘要：

Due to the nature of swelling-shrinkage characteristics, expansive soil needs to be modified. According to the function mechanisms of expansive soil improvement technique, there are two main means： physically modified and chemical modified. According to materials added to expansive soil and construction technology, physically modified is classified, moreover its characters and reinforcement mechanism and effect are analyzed; chemical reinforcement mechanism and effects are introduced in detail. Based on the analysis, the directions and methods of development for expansive soil improvement are prospected for reference.