铁路高填方CFG桩复合地基沉降分析

Settlement Analysis of High-fill CFG Pile Composite Foundation for Railroad

目的研究高填方CFG桩复合地基的沉降变形规律,为同类型工程项目的施工提供参考。方法以新建长株潭城际铁路与长石铁路联络线CSLLXZQ-1标高填方CFG桩复合地基工程为背景,采用ABAQUS软件建立高填方CFG桩复合地基三维模型,针对该工程路堤填筑高度相对较高的情况,采用“生死单元”方法模拟高填方路堤的分层填筑过程,并将模拟计算结果与沉降实测结果进行对比研究。结果随着高填方CFG桩复合地基桩长、桩径、垫层厚度分别增大100%、33.3%、66.6%,桩间距减少40%时,复合地基沉降量分别减少63.2%、46.9%、7.9%、61.3%。结论在数值模拟中采用“生死单元”方法分级加载来模拟高填方路堤荷载,与实测结果更加吻合。

The settlement deformation law of high fill CFG pile composite foundation is studied to provide reference for the construction of the same type of project.Based on the CSLLXZQ-1 elevation fill CFG pile composite foundation project of the new Changsha-Zhuzhou-Xiangtan intercity railway and the Changsha-Shijiazhuang railway connection line,the three-dimensional model of high fill CFG pile composite foundation was established by ABAQUS software.In view of the relatively high filling height of the embankment,the‘birth and death unit’method was used to simulate the layered filling process of high fill embankment,and the simulation results were compared with the measured results of settlement.With the increase of pile length,pile diameter and cushion thickness of high fill CFG pile composite foundation by 100%,33.3%and 66.6%respectively,and the decrease of pile spacing by 40%,the settlement of composite foundation decreases by 63.2%,46.9%,7.9%and 61.3%respectively.In the numerical simulation,the‘birth and death element’method is used to simulate the load of high fill embankment,which is more consistent with the measured results.