总结分析了既有建筑增层开挖与新建基坑开挖的差异,针对既有支护结构在增层开挖过程中会出现承载力不足的问题,提出通过补入新增支护结构形成双排桩组合支护体系,并阐述了双排桩支护体系的施工工序、类型与受力特性,指出在增层开挖工程中应当保留既有支护结构,合理利用既有基础结构作为支撑,并根据开挖深度和现场环境选取合适的排桩分布类型。 The differences between excavation of existing building and excavation of new foundation pit are summarized and analyzed. In view of the problem of insufficient bearing capacity of existing supporting structure in the process of incremental excavation, it is proposed that the newly added supporting structure should be formed Double-row piles combined support system, and expounds the construction procedures, types and stress characteristics of the double-row piles support system. It is pointed out that the existing supporting structures should be retained in the incremental excavation and the existing infrastructure should be rationally used Support, and according to the depth of excavation and site environment to select the appropriate type of row piles distribution.