咬合桩撑结构在深大基坑工程中的应用分析

Analysis of the Application of the Secant Pile SupportingStructure in Large Deep Excavation Projects

作为基坑支护的一种围护结构,咬合桩是利用相邻桩桩身相互切割咬合,使之形成具有良好止水防渗作用的整体连续排桩式挡土支护结构;内支撑是指为外围护结构的强度、变形及稳定性提供支撑和约束的系统,由水平支撑(角撑、对撑、桁架、圆环形等)或斜抛撑、立柱等结构组成的体系。以深圳市某建设项目的深基坑工程为例,结合项目自身特点,充分分析咬合桩支护结构在城市有限空间下地下工程的应用,不仅保证了基坑围护结构的安全性,而且可严格控制因基坑开挖引起的周围土体的变形,以保证周边建(构)筑物的安全和正常使用,对于沿海地区具有软弱地层的深基坑工程具有一定的借鉴作用。

As a supporting structure for deep excavations,the secant pile is formed by cutting the adjacent piles,which constructs a continuous piled retaining structure with a good water-proof and seepage-proof function.The internal bracing is a system that provides the support and the restraint for the strength,deformation and stability of exterior envelope.It is composed of horizontal bracing(corner bracing,opposite bracing,trusses and circular supports,etc.)or slanting bracing,column,etc.This paper presents a case history of a deep excavation support system in Shenzhen.Combined with the characteristics of this project,the application of secant pile bracing structure in the deep excavation under limited urban space is fully analyzed,in which not only ensures the safety of excavation bracing structure,but also ensures the deformation of the adjacent structures are within the allowable limits.The safety and the normal use of surrounding buildings are satisfactory.