铁路软弱地基CFG桩加固效果和变形特性研究

针对CFG桩加固铁路软弱地基的效果和变形特性，运用Midas数值分析软件建立二维全断面双线路基模型，分别对施工期地基加固前和加固后6种工况下的竖向位移进行计算。以地基沉降值、路堤沉降值和工后沉降值作为分析指标，说明了CFG桩加固软弱地基的优越性。由于梯形路基附加应力分布不同，沿路基宽度方向地基表面沉降呈“中心大两边小”的不均匀现象。地基压缩层和路堤填料层是地基加固前路基结构的变形关键区，路堤填料层是地基加固后路基结构的变形关键区。桩土之间由于力的分配不平衡存在差异沉降，桩-砂石垫层之间存在最大剪切应变。

Study on Reinforcement Effect and Deformation Characteristics of CFG Pile on Soft Foundation of Railway

In view of the effect and deformation characteristics of railway soft foundation reinforced by CFG pile, Midas numerical analysis software is used to establish a two-dimensional full section double-track subgrade model and calculate the vertical displacement under six working conditions before and after foundation reinforcement during construction period. Taking foundation settlement value, embankment settlement value and post-construction settlement value as analysis indexes, the superiority of soft foundation reinforced by CFG pile is illustrated. Due to the different distribution of additional stress in the trapezoidal subgrade, the settlement of the foundation surface along the width of the subgrade presents an uneven phenomenon of "large in the center but small in two sides". Foundation compression layer and embankment packing layer are the key deformation areas of subgrade structure before foundation reinforcement and embankment packing layer is the key deformation area of subgrade structure after foundation reinforcement. There is differential settlement between pile and soil due to unbalanced distribution of forces and there is maximum shear strain between pile and sand-gravel cushion.