钻孔咬合桩在软土基坑围护中的应用

摘要

钻孔咬合桩通过在混凝土中添加缓凝剂,使先施工的钻孔灌注桩与后继施工的钻孔灌注桩很好的搭接来挡土并止水,该方法已成为地下支挡工程中的重要手段之一,被广泛地应用于天津、杭州、南京、广州及深圳等软土地区,但在上海地区仍处于探索阶段,较少使用。本文结合上海某钻孔咬合桩基坑围护工程,对套管钻孔灌注咬合桩基坑围护结构的基本原理、施工工艺、施工技术要点进行了简要的探讨。%By adding super-slow setting concrete,the secant boring pile makes it perfect to overlap the previous cast-in-place pile and the later one.This method is one of the most important means to retain earth and stop water in the excavation.Thought it is widely used in soft soil aera such as Tianjin,Hangzhou,Nanjing,Guangzhou and Shenzhen,etc,it is still on the stage of exploring in Shanghai where it is rarely used.This paper presents the project of retaining and protecting for foundation excavation with the secant boring pile in Shanghai.It alse briefly discuss the basic principle,construction craft,and the main points of construction technology of the secant boring pile in excavation.