土工格栅经验型蠕变模型及其参数试验

为了探讨土工格栅在长期荷载作用下的蠕变特性,在不同荷载级别和环境温度的各种组合条件下,针对不同规格的土工格栅进行了长期室内蠕变试验,并根据对蠕变试验结果的综合对比分析,探讨了土工格栅蠕变曲线、荷载-应变等时曲线的一般特征。试验与分析结果表明:荷载级别、环境温度、格栅强度与生产工艺是影响土工格栅长期蠕变特性的重要因素。结合粘弹性理论建立了反映土工格栅蠕变特性的三参数经验型本构模型,提出了合理确定模型参数的试验方法,并通过与试验结果对比,分析了荷载级别和环境温度对蠕变模型参数的影响。所建议的格栅蠕变模型能有效地对土工格栅加筋结构长期工作性能进行分析与评价。

Experiment on Empirical Creep Model and Its Parameters of Geogrids

In order to discuss creep behavior of geogrid under long-term load,a series of creep tests for various types of geogrids were conducted in laboratory under different combinations of the load and environmental temperature.Based on the experimental results,comparative analyses were performed to examine characteristics of isochronal curves between load and strain,creep curves of geogrids.On the basis of the experimental results and theoretical analyses,it is shown that creep behavior of geogrids is dependent remarkably on load levels,environmental temperature,strength and production process of geogrids.Furthermore,an empirical constitutive model with three parameters based on visco-elasticity was proposed for geogrids and a rational method based on experimental tests was presented for defining the relevant parameters of the proposed nonlinear creep model.Finally,the influences of both load level and environmental temperature on the parameter in the empirical model were examined.The test results and the proposed model of geogrids are instructive for analysis and evaluation of long-term performance of geogrid-reinforced earth structures.