长期荷载作用下土工格栅蠕变特性的试验研究

为探讨长期荷载作用下土工格栅的蠕变特性,在不同的外加荷载和环境温度的各种组合条件下,进行土工格栅的室内蠕变试验,以此获得格栅的蠕变关系曲线、载荷-应变等时曲线及拉伸模量的变化特征,并进行综合对比分析。根据试验与分析发现:荷载水平、环境温度和材料生产工艺是影响土工格栅长期蠕变特性的重要因素。进而,采用时温叠加原理,对于某一给定环境温度下确定土工格栅长期强度的经验估算模式和蠕变强度折减系数。试验结果与理论分析为土工格栅加筋结构长期工作性能的分析与评价提供参考依据。

An experimental study on the creep behavior of geogrids under long-term external loading

The creep behaviour of geogrids is fundamental to evaluating the long-term performance of geogrid-reinforced earth structures under long-term external loading.A series of creep tests of geogrids are conducted in the laboratory under different combinations of external loads and surrounding temperatures.The characteristics of the creep curve,the isochronous load-strain relationship and the tensile modulus of geogrid are obtained.A comprehensive comparative study of the test data is also made.Based on the experimental results and theoretical analyses,it is shown that the creep behavior of geogrids is significantly influenced by load level,surrounding temperature and fabrication workmanship.Furthermore,a method based on the principle of time-temperature superposition is applied to establish empirical formulae for estimating the long-term strength and the reduction factor of creep strength of geogrids.The proposed model can be very useful for analysis and evaluation of the long-term performance of geogrid-reinforced earth structures when the creep behavior of geogrids is taken into account.