土工格栅加筋路堤的非线性数值分析

Non-linear Numerical Analysis of Embankment Reinforced with Geogrids

针对非均质软土地基上土工格栅的加筋效应进行了二维及三维有限元对比分析,阐明了这2种方法各自的适用性。随后对加筋层数、加筋位置、加筋间距、软基模量及路堤填筑速度进行了系统的三维敏感性因素研究。数值计算结果表明:路堤及路面施工引起的地基变形主要发生在软弱土层中,且其最大值位于软土层中部;铺设在路堤底部的、相距为0.25 m左右的2层土工格栅对于路堤及软基的加筋效果最佳;为了减小工后变形,需要减缓路堤的填筑速度,就本文描述工况而言,比较合理的路堤填筑速度为2.5 cm/d左右。上述研究成果有助于优化软弱地基上加筋路堤的设计与施工。

The reinforcing effects of geogrids on non-homogeneous soft ground are investigated through 2D and 3D FEM with their results compared with each other, and their applicability are clarified. Subsequently, layer number, paving location, lay interval, elastic modulus of soft soil and construction speed of embankment are taken as sensitivity factors in the 3 D numerical models. It was concluded from the numerical calculations that （1） the main ground deformation due to construction of the embankment and pavement occurred in the top soft stratum, and the maximum value happened at the middle part; （2） there is the optimum reinforcing effect on the embankment and soft ground with two-layer geogrids disposed at the bottom of the embankment which is 0.25 m from each other; （3） in order to decrease the post-construction deformation of the soft ground, it is needed to slow the construction speed of the reinforced embankment, and 2.5 cnr/d is a realistic construction speed for the conditions presented here. The results from this study would contribute to optimize the design and construction of the reinforced embankment on the soft ground.