全风化花岗岩层咬合桩施工关键技术研究

Research on Key Technology of Secant Pile Construction in Completely Weathered Granite Layer

咬合桩是一种常见的基坑围护结构,目前工艺已经较为成熟。全风化花岗岩层是咬合桩施工中常见的地质情况之一,该情况下咬合桩施工成桩质量不易控制。基于深惠城际大鹏站-新大站区间项目,阐述了咬合桩施工工艺,并对钢护筒埋设、钻机钻进、泥浆质量控制等施工关键技术进行了阐述。根据实际施工过程,分析了成孔垂直度控制、水下混凝土初凝时间控制以及孔壁塌方三个问题的成因与解决措施,以期为相关工程施工提供些许借鉴。

The secant pile is a common enclosure structure of foundation pit.At present,the technology has been relatively mature.The completely weathered granite layer is one of the common geologic conditions in the construction of secant piles.Under this condition,the finished pile quality of secant pile construction is not easy to control.Based on the project of Shenzhen-Huizhou Intercity Dapeng Station-Xinda Station,the construction process of the secant pile wall is set forth.And the key construction techniques of steel casing embedment,drilling rig drlling and mud quality control are expounded.Based on the practical construction process,the causes and solutions of three problems of verticality control of forming holes,initial setting time control of underwater concrete and collapse of hole walls are analyzed in order to provide some reference for the related engineering construction.