为掌握膨胀土的试验性能，合理评价其基坑施工过程中的支护效能，该文以南宁地区膨胀土基坑为研究背景，先通过试验分析掌握膨胀土的抗剪强度及膨胀力规律，再基于基坑现场监测成果，开展其力学监测项目和变形监测项目的现状发展程度评价及发展趋势分析。实例分析表明：膨胀土的抗剪参数随含水率的增加而减小，且随干湿循环次数的增加，也会降低膨胀土的抗剪参数；在试验含水率范围内，膨胀土的膨胀力随含水率的增加而减小。据现场监测成果，力学监测和变形监测的规律性相近，两者均是具有较高的现状发展程度，程度等级为Ⅱ～Ⅲ级，且两者后续均具增加趋势，但力学监测项目的发展趋势等级相对较高。

To grasp the experimental performance of expansive soil and reasonably evaluate its support efficiency during foundation pit construction, taking the expansive soil foundation pit in Nanning area as the research background, the shear strength and expansion law of the expansive soil are first mastered through experimental analysis in this paper. Then, based on the on-site monitoring results of the foundation pit, the current development degree evaluation and development trend analysis of expansive soil mechanical monitoring projects and deformation monitoring projects are carried out. Example analysis shows that the shear parameters of expansive soil decrease with the increase of moisture content, moreover, with the increase of dry-wet cycles, the shear parameters of expansive soil also decrease. Within the range of experimental moisture content, the expansion force of expansive soil decreases with the increase of moisture content. According to on-site monitoring results, the regularity of mechanical monitoring and deformation monitoring is similar, both of them have a high level of current development, ranging from level II to level III, and both have an increasing trend in the future, however, the development trend level of mechanical monitoring projects is relatively higher.