交通荷载作用下软基加筋道路变形机制研究

Mechanisms of reinforced pavements on soft clay under traffic loading

为研究交通荷载作用下考虑软土软化效应的软土地基加筋道路动力响应问题,以室内动三轴试验为基础,通过回归分析得到了软土在循环荷载作用下动模量衰减的经验公式,编制了用户子程序。将该公式导入有限元分析软件中,采用有限元对软基加筋与不加筋道路在交通荷载作用下的动力响应进行了对比分析,研究了软基加筋道路的作用机制。结果表明,软土的软化特性对软基加筋和不加筋道路的动力响应有明显影响;加筋的效果随着荷载作用次数的增大而逐渐变大;加筋可以约束土体的水平变形,减小道路的整体沉降和不均匀沉降以及减小交通荷载影响软土地基的深度。

In order to study the dynamic response of reinforced pavements on soft clay under traffic loading, cyclic triaxial tests were first conducted to investigate the effect of initial deviator stress, loading frequency, overconsolidation ratio, and cyclic stress ratio on softening behavior of clay. The empirical equation for softening of clay was proposed by regression analysis. The equation was imported into FEM program through compiled subroutine. Dynamic response of unreinforced and geogrid reinforced pavements was studied by FEM in order to investigate mechanisms of reinforcement. FEA results indicated that softening behavior of clay had visible effect on the performance of urtreinforced and reinforced pavements. The effect of reinforcement increased with the increase of loading number. Geogrid reinforcement can provide lateral confinement at the bottom of the base layer and reduce surface deformation and nonuniform settlement. The effect of reinforcement was also shown to reduce the influenced depth of clay under traffic loading.