深厚软土超大基坑中双门架式支护结构

传统双排桩单门架式支护结构是软土地区基坑支护设计中常用的一种支护手段，由于其施工简便、不需设置内支撑、投资小并节约场地而被经常采用。但在深厚软土超大型基坑且中等开挖深度时采用，往往会出现基坑侧向位移大、沉降大、结构稳定性差的问题。结合对传统门架式支护结构的改进，在软土大型中等深度开挖基坑工程中提出了不设内支撑的双门架式支护结构形式，进一步提高支护结构整体安全稳定性和控制支护结构侧向位移，通过将该结构设计应用于绍兴县一小区项目地下室基坑支护工程，验证了该改进方法的适用性和可行性，为今后类似工程提供了宝贵的经验。

Improvement and Application of Double Portal Frame Support Structure for Super-large Foundation Pit in Deep Soft Soil

The traditional support structure of double-row piles single portal frame is a frequently used supporting design for foundation pit in soft soil area because of the advantages of simple construction without inner support, small investment and space saving. But for super-large foundation pit of medium excavating depth in soft soil, large lateral displacement and settlement as well as poor structure stability often appear. Combined with the improvement on the traditional support structure of portal frame, double portal frame support structure without inner support was proposed in a large medium-depth excavation project in soft soil to further improve the overall safety and stability and control the lateral displacement of the supporting structure. The applicability and feasibility of this improved design are verified through a basement foundation pit supporting project in Shaoxing County, which provides valuable experience for the similar projects in the future.