土工格栅加筋高路堤与超载预压排水固结非线性有限元分析

Nonlinear Finite Element Analysis of Reinforcing Geogrids Applied in High Embankment of Highway and Excess Preload

土工格栅是一种常用的路堤加筋材料,可有效地减少路堤沉降和侧向位移.超载预压排水固结是常用的地基处理方法.采用DP模型模拟土体的非线性、面-面接触单元考虑筋、土界面的非线性,并由若干个桁架单元通过在与土接触点处铰接连接来模拟土工格栅,通过有限元程序分析了加筋前后高路堤的竖向位移和侧向位移.从计算结果显示出,对于填筑高度在10～15 m左右的高路堤,加筋路堤能有效减少竖向位移20%,减少侧向位移50%,并较填筑高度为5 m左右的加筋路堤对减少路堤竖向位移与水平位移的效果显著.分析结果与实测结果基本吻合.

The geogrid is a general material of reinforced embankment, it is very effective to reducing horizontal and vertical displacements of the embankment. The excess preload is general foundation treatment method. The author carried out analysis of horizontal and vertical displacements of reinforced embankment and non-reinforced embankment with 2-D finite element. DP model is chosen to consider the nonlinearity of soil, the changing-status nonlinearity is considered by surface-to-surface contact element and the geogrid is modeled by the truss element which is jointed at the contact point with soil. The analysis examines that vertical and horizontal displacements of 10-15 m reinforced embankment can be reduced by 20% and 50% , and that the improvement of geogrid is more effective to reducing horizontal and vertical displacements of the embankment than 5 m reinforced embankment. The results of analysis are in good agreement with the data of actual measurement.