特大型桥梁群桩基础承载特性离心模型试验研究

Centrifuge Modeling on Bearing Behavior of Large Bridge Group Pile Foundation

苏通大桥超大型主桥索塔群桩基础置于第四系土层中，其承载变形特性是设计急待解决的技术问题。通过离心模型试验，研究了5种工况下主桥索塔群桩基础的竖向承载变形特性，分析了承台竣工、裸塔竣工、成桥阶段群桩基础的沉降及桩顶荷载分布规律。结果表明，5种工况下主桥索塔群桩基础的极限承载力大于5000MN，成桥阶段的总沉降为148～186mm，基础整体稳定，桩顶荷载成W形分布，桩底注浆和冲刷形态对群桩基础的承载变形特性有一定影响。

The main bridge tower group pile foundation of Sutong Bridge is in Quaternary deposit soil. The bearing and deformation are a key problem in design. Centrifuge model tests were carried out to study the vertical bearing and deformation behaviuor of main bridge tower group pile foundation under 5 working conditions. The settlement and load distribution on the top of group pile foundation at the states of completion of platform, tower, bridge were analyzed.The result shows that, the ultimate bearing capacity of main bridge tower group pile foundation under 5 working conditions was larger than 5 000 MN; the settlement at the state of completion of bridge is 148 - 186 ram; the foundation was stable; the load on the top of group pile is distributed as W; the bearing and deformation would be influenced by pile tip grouting and scour shape.