复合地基加固法中的CFG桩的设计与应用

Design and Application of CFG Pile in Composite Foundation Reinforcement Method

从复合地基的基本概念、分类、加固机理出发,着重阐述复合地基加固法中的CFG桩的加固机理、适应范围、设计原则及计算方法、施工工艺选择和质量检验。提出在公路工程软土地基处治中可采用CFG桩,并得出CFG桩施工工艺简单、适应范围广,所用材料是在碎石桩的基础上加入少量的水泥和粉煤灰,受力特性与水泥搅拌桩类似。它可用于杂填土、饱和及非饱和粘性土、粉土、砂性土及湿陷性黄土地基中,以提高地基承载力和减少地基变形。只是当原地基承载力标准值fk≤50kPa时其适用性值得考虑。若以挤密或消除液化为目的时,采用CFG桩是不经济的。

This paper started from the basic concept of composite foundation,classification and reinforcement mechanism.Then the reinforcing mechanism of CFG pile in composite foundation reinforcement as well as its adapting scope,design principles,calculation methods,construction process selection and quality inspection was mainly expounded.It was proposed in this paper that CFG pile could be applied to the soft ground treatment in highway engineering due to its simple construction process and wide applicability.As its material is gravel pile with addition of a small amount of cement and fly ash,it has similar mechanical properties as cement mixing pile.It can be applied to miscellaneous fill,saturated and unsaturated clay,silt,sandy soil and collapsible loess foundation to improve the bearing capacity of foundation and to reduce its deformation.However,its applicability is worth considering only when the standard value of original foundation bearing capacity fk≤50kPa.And it is uneconomic in terms of compaction or eliminating liquefaction.