考虑时间间歇效应的粉土永久变形特性单级和分级加载动三轴试验研究  

Characterisation of Permanent Deformation Behaviour of Silt by Using Both Single-stage and Multi-stage Repeated Load Triaxial Tests Considering Time Intermittent Effect

作　　者：梅慧浩[1,3] 聂如松 冷伍明[1,2] 李亚峰[1] 陈郗西 MEI Huihao;NIE Rusong;LENG Wuming;LI Yafeng;CHEN Xixi(School of Civil Engineering,Central South University,Changsha 410075,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway,Central South University,Changsha 410075,China;China Railway 11th Bureau Group Co.,Ltd.,Wuhan 430061,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学重载铁路工程结构教育部重点实验室,湖南长沙410075 [3]中铁十一局集团有限公司,湖北武汉430061

出　　处：《铁道学报》2021年第12期94-104,共11页Journal of the China Railway Society

基　　金：国家自然科学基金(51878666)。

摘　　要：列车动荷载对路基的作用过程中存在时间间歇阶段,而在以往的动三轴试验中该时间间歇效应常被忽略。利用动三轴仪,对粉土(路基填料)开展考虑间歇效应的单级和分级加载动三轴试验,分析间歇阶段对粉土的轴向应变发展规律的影响,研究单级和分级间歇加载方式下粉土的累积塑性应变行为特征。结果表明:间歇阶段的存在对提高试样抵抗永久变形的能力有积极作用,在动三轴试验中必须考虑时间间歇效应对累积塑性应变的影响。提出的新方法能较为准确地利用分级加载的试验结果预测单级加载下累积塑性应变的发展规律。研究结果对于深刻认识路基的永久变形特性,建立单级加载和分级加载动三轴试验之间的联系具有参考价值。Time intermittent stage exists in the process of train-induced dynamic load acting on the subgrade,which is often neglected in the previous repeated load triaxial(RLT)tests.The single-stage and multi-stage RLT tests considering time intermittent effect were conducted on silt(subgrade filling)specimens using an RLT apparatus to analyze the effect of the intermittent stage on the development of axial strain.The dynamic behaviours of accumulated plastic strain in the single-stage and multi-stage RLT tests were also studied.The results show that the existence of the intermittent stage plays an active role in improving the ability of the specimens to resist permanent deformation.The effect of time intermittent effect on accumulated plastic strain must be considered in RLT tests.The new method presented in this paper can accurately predict the development of accumulated plastic strain under single-stage loading according to the experimental results of the multi-stage RLT tests.The research results have reference value for deeply understanding the permanent deformation characteristics of subgrade and establishing the relationship between single-stage and multi-stage RLT tests.

关 键 词：时间间歇阶段 列车动荷载 动三轴试验 累积塑性应变 分级加载 

分 类 号：TU431[建筑科学—岩土工程]