CFG桩复合地基加固高速公路软基的现场试验研究

CFG桩复合地基处理高速公路软基的设计参数是否合理,应看其实际发挥的承载能力及承载时变形的性状。通过对CFG桩复合地基桩、土应力和表面沉降的现场观测,研究了路堤荷载下CFG桩复合地基桩顶、桩间土的应力和沉降变化规律,根据实测数据分析了褥垫层厚度、桩间距及桩体强度等设计参数的合理性。结果表明,路堤荷载下,CFG桩、土最终可达到变形协调,桩、土应力比与桩、土沉降差有着密切的关系,疏桩形式时桩间土承担着大部分荷载;同时,CFG桩复合地基作为路堤荷载的地基时,可设计为桩间距较大的疏桩形式,桩体设计强度可以取得低一些,褥垫层厚度也应适当取大。

In-situ Experiments of CFG Pile Composite Foundation for Strengthening Soft Foundations of Highway

Wether the parameters of CFG pile composite foundation in strengthening soft foundation of highway are reasonable or not is determined by it's actual bearing capacity and deforming characteristics under loads.Based on the in-situ earth pressure and surface settlement tests of the CFG pile composite foundation,this paper investigates the variations of the stress and settlement on the top of the pile and soil under the embankment load,and then analysizes the reasonableness of parameters such as the cushion thickness,the distance of piles and the strength of pile.The experiment results show that CFG piles and soils can eventually deform consistently,the pile-soil ratio is closely related to the balance of settlements of pile and soil,and the soils between piles bear the most loadings in the case of sparsely distributed piles.When the CFG pile composite foundation is subjected to the embankment load,large distance of piles could be chosen,the strength of pile may be reduced and the cushion thickness should be designed to larger accordingly.