考虑蠕变性土工格栅加筋挡土墙应力与变形有限元分析

FEM based numerical analysis of stresses and deformations of geogrid-reinforced earth retaining walls

土工格栅加筋挡土墙在岩土加固工程中得到了广泛应用。采用粘弹塑性流变模型考虑地基和填土的流变性,采用作者所建议的经验型粘弹性本构模型考虑土工格栅的蠕变性,对于土工格栅加筋挡土墙发展了非线性有限元数值分析方法,通过变动参数的对比计算与分析探讨了逐层填筑过程、加筋长度及间距布置方式等因素对土工格栅加筋挡土墙长期变形与应力特性的影响。计算与分析表明:填筑过程对面板侧向变形、格栅拉力与应变及地基中水平位移与竖向沉降具有较大的影响;加筋使墙后填土应力重新分布;面板位移、格栅拉力及应变在经历一段时间后趋于稳定状态。

The geogrid-reinforced earth retailing walls have been widely applied to geotechnical reinforcement constructions. A viscoelasto-plastic model is employed to consider the theological properties of backfills and foundation soils while the empirical nonlinear viscoelastic model proposed by the authors is used to take the creep behaviour of geogrids into account. The numerical analysis procedure based on finite element method is developed for evaluation of stresses and deformations of geogrid-reinforced earth retaining walls under long-term loading. The comparative computations are conducted to examine the effects of construction process, geogrid length and spacing on long-term performance of geogrid-reinforced earth retaining walls. It is shown that the filling process have a considerable influence on the lateral displacements of panel, pullout forces and strains of geogrid and horizontal and vertical deformations of foundation The geogrid used for reinforcement will induce the redistribution of stresses in backfill. Both rheological effect of soils and creep effect of geogrid seem disappear after a certain period.