佛开高速公路拓宽工程带帽CFG桩软基加固数值分析

采用非线性有限元法,对带帽CFG桩加固的K29+ 020断面软基上拓宽路堤新老路基相互作用、加固效果和铺设路面时间进行了数值分析.结果表明,拓宽路堤表面最大沉降为8.9 cm,发生在左侧新路肩附近,新路软基沉降主要来自于下卧亚黏土层沉降.下卧亚黏土层中超静孔隙水压力最大,带帽CFG桩复合地基固结速率主要取决于下卧亚黏土层的固结速率.新路软基的固结速率大于老路软基.拓宽路堤表面工后出现负坡率,说明CFG桩加固的新路软基刚度过大,CFG桩复合地基设计可进一步优化.

Numerical Analysis of Fo-Kai Expressway Widening Embankment on Soft Ground Reinforced by CFG Piles with Caps

For the stake of K29+020 in Foshan-Kaiping Widening Expressway on soft ground reinforced by CFG piles with caps,the interaction between old and new embankment,the reinforcement effect and the preloading time are analyzed by nonlinear finite element method.The results show that the largest settlement with 8.9 cm along surface of widening embankment,which is mainly induced by the loam layer under the medium-fine sand layer,occurs under the shoulder of the new embankment.The maximum excessive pore water pressure occurs in the loam layer.The consolidation rate of CFG pile composite ground depends mainly on that of the underlying loam layer.Consolidation rate of soft soil under new embankment is faster than that under old embankment,so that post-construction transverse gradient is negative value,giving the fact that CFG pile composite ground is over rigid for the stake of K29+020.Optimum design for CFG pile composite ground is needed.