长江下游地区巨厚砂层中钻孔灌注桩施工技术

根据张家港、扬州等地砂层中施工钻孔灌注桩的实践，论述了巨厚砂层对施工的影响，指出必须采取配制优质泥浆、建立科学的泥浆循环系统、选择合适的钻具及钻进参数、进行孔径检查、提高灌注效率等技术措施，介绍了在砂层施工中应注意的问题和有效处理埋钻事故的方法。

Technology of Pre-bored Piles Applied in Mega-heavy Sandy Layers in Lower Reaches of Yangtze River

Distributed widely in Lower Yangtze River Reaches,the mega-heavy sandy layers form a poor construction foundation with pre-bored piles and are considered to be frequent accident scenes and slow drilling.According to the operations of pre-bored piles in the sandy layers of Zhangjiagang and Yangzhou regions,the author thinks it is necessary to carry out technical measurement including the formula of high-grade slurry,perfect circulation system of slurry,suitable drilling tools and parameters,inspection of the bore diameter and enhancement of grouting efficiency for an ideal construction process.As an imperfect groundwork,the effect of the mega-heavy is explained. The main operations and effective treatment for the drilling accidents are introduced for the construction in sandy layers.