加筋挡土墙长期工作性能的黏弹塑性有限元分析

NUMERICAL ANALYSIS OF LONG-TERM PERFORMANCE OF REINFORCED EARTH RETAINING WALLS BY FEM BASED ON VISCOELASTO-PLASTICITY

随着工程上的广泛应用,作为设计中的关键技术问题之一,土工合成材料加筋挡土墙长期工作性能的合理评价日益得到重视,对此必须考虑加筋材料的非线性蠕变效应。对于加筋挡土墙,采用黏弹塑性流变模型和黏弹性本构模型分别考虑填土与土工合成材料的非线性蠕变性,合理考虑筋材与填土、填土与面板及面板之间的相互作用效应,同时在计算中反映逐层填筑过程,采用增量–初应变迭代法,对土工合成材料加筋挡土墙结构的工作性能评价发展了二维有限元数值分析方法。基于Denver黏性土试验挡土墙的试验结果确定计算参数,利用所建议的分析方法对Denver黏性土试验挡土墙进行了数值计算与分析,通过与实测结果及与常规方法的对比分析,论证了所建议的有限元数值分析方法的合理性及其可靠性。

Geosynthetics-reinforced earth retaining walls have been widely employed in geotechnical reinforcement engineering practice. As one of the key issues in design and construction of the reinforced earth structures, more attentions have been paid to the rational evaluation of long-term performance of reinforced earth structures. A numerical procedure based on finite element method is presented for analysis of behavior of deformations and stresses of reinforced earth structures. The nonlinear creep behaviors of both filling soils and geosynthetics used for reinforcement are taken into account by using the rheological models of viscoelasto- plasticity and nonlinear viscoelasticity respectively. Additionally, the interaction effects of reinforcement and fills, panel and fill as well as panel and panel are rationally considered by using Goodman＇s joint element model. The layer-by-layer filling process of backfills of retaining wall is also simulated. Nonlinear computations based on 2D FEM are numericallyimplemented by hybrid algorithm in which the incremental scheme is incorporated with iterations by using the initial-strain procedure. Based on the test results of Denver test wall of clay soil, the computational parameters are evaluated. The proposed method is applied to analyze of Denver test wall. The reliability and reasonability of the proposed method are verified through a comparison of the computed results with test data and other conventional methods. It is shown that the numerical results given by the proposed method are in well agreement with test results, and the proposed numerical method considering the creep effect can be used for evaluation of long-term behavior of reinforced earth structures.