深大基坑钢板桩钢支撑结合混凝土封底防护施工工艺研究

Research on the Protection Construction Technology of Steel Sheet Pile,Steel Support Combined with Concrete Bottom Sealing for Deep and Large Foundation Pits

深基坑混凝土结构尺寸较大,高度一般在3 m以上,若采用多层设计,可能造成钢支撑与混凝土结构冲突;若采用螺旋钢管作为斜撑,后期修补非常困难。文章结合黄黄高铁花桥镇跨沪渝高速特大桥11#、12#深基坑施工实例,分析了深大基坑钢板桩钢支撑结合混凝土封底防护施工工法的基本原理,提出了具体的施工工艺流程和操作要点,包括有限元分析、确定方案,钢板桩围护结构施工,基坑开挖及钢支撑安装,临时支护安装等,提高了功效和质量,缩短了工期,可为今后类似工程施工提供参考。

The size of deep foundation pit concrete structure is large,and its height is generally more than 3 m.If the multilayer design is adopted,it may cause the conflict between steel support and concrete structure.If the spiral steel pipe is used as the inclined support,the later repair will be very difficult.Based on the construction examples of 11#and 12#deep foundation pits of Huaqiao Town Crossing Shanghai-Chongqing Expressway Grand Bridge on Huanggang-Huangmei High-speed Railway,this paper analyzes the basic principles of the protection construction method of steel sheet pile,steel support combined with concrete bottom sealing for deep and large foundation pits,and puts forward specific construction process and operation points,including finite element analysis,scheme determination,steel sheet pile retaining structure construction,foundation pit excavation,steel support installation,temporary support installation,etc.,which improves the efficiency and quality and shortens the construction period.It can provide reference for similar engineering in the future.