中文摘要：

云南省蒙自地区的膨胀土危害频繁，是我国膨胀土危害最严重的地区之一。在充分认识膨胀土的特点、膨胀土的分布范围及基坑周边环境后，对基坑支护结构设计中力学参数的合理取值，水平膨胀力的影响，基坑变形特点，以及土方开挖、防排水、监测等措施方面进行分析。膨胀土场地的深基坑支护设计采用放坡＋桩锚的基坑支撑体系是可行的。具有稳定性好、变形小、投入少，在多指标考察下综合效益最优的特点，对膨胀土地区深基坑支护的设计及施工能提供一定的参考和指导。

英文摘要：

The hazard of expansive soil in Mengzi areas is one of the most serious regions in our country with higher occurrence frequency. Based on the knowledge and understanding the characteristics of the expansive soil and its distribution as well as the surrounding environment of the foundation pit, all factors including the reasonable value of mechanical parameters, the influence of the horizontal expansion force, deformation characteristics, and earth excavation, waterproof and drainage measures and monitoring measures are discussed during the design process of foundation pit supporting structure; it is approved that using pile and anchor supporting system is feasible in the deep foundation pit supporting design. It is of good stability, small deformation, lower investment and it is convinced to be the optimal solution under the multi-target evaluation; it can provide certain reference and guidance for design and construction of foundation pit supporting in expansive soil area.