京沪高速铁路CFG桩-筏复合地基现场试验研究

结合京沪高速铁路凤阳试验段工程,开展CFG桩+垫层+筏板处理地基试验。实测桩-筏复合地基沉降变形、桩顶应力、桩间土应力、筏板顶面土应力、钢筋应力及桩身应变;分析路基沉降变形、桩土应力比随填筑高度和固结时间的变化规律;获得地基面桩土应力分布、筏板顶面土应力分布、钢筋应力分布、桩身轴力和侧摩阻力分布;研究路堤荷载作用下CFG桩-筏复合地基的工作性状。研究成果有助于高速铁路桩-筏复合地基沉降控制、承载特性和应力传递机理的研究,并为京沪高速铁路及其它相关工程的桩-筏复合地基设计方法提供数据支持。

Experimental Study on CFG Pile-raft Composite Foundation of Beijing-Shanghai High-speed Railway

Combining with the engineering project of the Fengyang Test Section of the Beijing-Shanghai High-speed Railway,field tests of the composite foundation of CFG piles,cushion and raft were carried out.Settlements of the pile-raft composite foundation,stresses of the pile top,inter-pile soil,raft-top soil and steel reinforcements,and strains of the pile shaft were measured on site.The variation law of the pile and soil settlements of the subgrade and the pile-soil stress ratio with the changes of both the filling height of the embankment and the consolidation time was analyzed.Distributions of foundation-top pile-soil stresses,raft-top soil stresses,steel reinforcement stresses,and axial forces & lateral friction resistance forces of the pile shaft were obtained.The operating conditions of the CFG pile-raft composite foundation under load were studied.The research results are helpful to further study settlement control,bearing behavior and stress transmission of the pile-raft composite foundation of high-speed railways and provide reliable data support for design of the pile-raft composite foundation of the Beijing-Shanghai High-speed Railway and other related engineering projects.