长螺旋扩底压灌混凝土桩的应用研究

长螺旋压浆灌注桩近年来得到广泛的应用，但存在单桩承载力低、容易缩颈和断桩的缺点。针对传统工艺中存在的不足，研究了整套施工工艺和质量控制方法。利用特种材料制作旋叶进行挤土扩削成型，同时在桩的端部用扩孔设备形成扩大头；实践证明，采用该法不但施工简便、排土量少、污染少，且桩的承载力大幅度提高。

Study on Application of Long Auger Bored Concrete Pile with Expanding Bottom

Long auger bored pressure grouting pile has been widely used in recent years, but with the defects of low bearing capacity for single pile, easy to necking and being broken. In relation to the shortcomings existing in the traditional process, a complete set of construction technology and quality control method were studied to the extent that rotary vane made from special material was used for soil compaction and boring; simultaneously, with reaming equipment, the pile end was enlarged. The practice has proved that this method has the advantages of simple construction, less soil discharge, less contamination, and substantially increased bearing capacity of the pile, and may be referred by engineers and technicians.