高铁站场宽路基复合地基二维模型适用性分析

Applicability analysis of two dimensional modeling methods for wide embankment composite foundation in high speed railway stations

为评价二维建模方法在高速铁路站场宽路基复合地基中的适用性,以京沪高铁济南西站站场路基为例,根据5种方法建立相应二维模型分析复合地基受力及变形特征,并与三维模型计算结果及实测结果进行对比。研究表明:在分析地基沉降、桩土应力和路基坡脚水平位移时,等弹性模量法计算结果精度最高;但在分析地基超静孔隙水压力和边桩弯矩时,所有二维模型结果均不可靠,此时须采用三维模型进行分析。

Three dimensional(3D)modeling of some complex pile composite foundations in high speed railway can be very complicated and time-consuming. So it is a common way to simplify 3D models into two dimensional(2D) models in current research,however,the applicability of different 2D modeling methods remains unclear. In this research,taking Ji′nanxi station in Beijng-Shanghai high speed railway as an example,five different 2D models are established to study their applicability by comparing the results of 2D models with that of 3D models and site measurement data. The study shows that 2D models can provide acceptable results for the development of settlements,stress of pile and soil,as well as lateral displacements. The method which remains the same elastic module and area replacement ratio yields the best results out of all 2D models. But a 3D model is necessary for the generation and dissipation of excess pore water pressures in foundation and bending moments of pile close to the toe of embankment,because 2D models give incorrect results.