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通过不同应力水平下土工格栅的蠕变试验,分析了三种应变类型随应力和时间的变化过程,提出ε=ε(σ,t)形式的土工格栅本构模型,采用有限元程序ABAQUS的用户材料子程序UMAT对本构模型进行了二次开发,并将计算模型的结果与试验数据进行了比较。蠕变试验数据表明在一个受力区间内各种应变随着应力的增加都急剧增长,该区间是进行土工格栅蠕变特性研究的重要区域。计算模型结果表明编程后的能很好地吻合短期蠕变变形试验数据,并能合理预估长期蠕变变形的趋势。完成的土工格栅材料模型可以放入工程结构寿命计算中的材料库,实现土工格栅合理设计的量化分析。
Through the creep test of geogrids under different stress levels, the change process of three kinds of strain with time and stress is analyzed. The constitutive model of geogrid with ε = ε (σ, t) is proposed. The finite element program ABAQUS User Material Subroutine UMAT is used to develop the constitutive model for the second time. The results of the computational model are compared with the experimental data. The creep test data show that all kinds of strain increase sharply with the increase of stress in a stress zone, which is an important area for geogrid creep research. The calculation results show that the programmed data can well match the short-term creep deformation test data and can reasonably predict the trend of long-term creep deformation. The completed geogrid material model can be put into the material library of the life of engineering structure to realize the quantitative analysis of geogrid rational design.