摘要
风积沙具有颗粒均匀、结构松散、保水性差、天然含水率小以及抗剪强度低等特点,作为路基基床底层填料,已应用于沙漠铁路建设中。以风积沙填料为研究对象,开展一系列不同应力水平的动三轴试验,探究风积沙填料累积塑性变形随振次的变化规律,提出风积沙试样塑性行为判定准则,建立了考虑动应力幅值、含水率及围压的风积沙累积塑性应变预测模型。试验结果表明:不同动应力幅值条件下,风积沙试样的累积塑性应变随振次的关系曲线表现为稳定型、临界型和破坏型3种类型。幂函数能很好地描述风积沙累积塑性应变速率ε̇_(p)与循环振次N的关系,在此基础上,建立了考虑动应力幅值、含水率及围压的风积沙累积塑性应变预测模型。研究成果可为风积沙路基在循环动荷载下的沉降预测、基于应变控制原则的路基设计和动力稳定性评估提供参考。
Aeolian sand has the characteristics of uniform particles,loose structure,poor water retention,low natural moisture content and low shear strength.As the filler for the bottom layer of subgrade bed,it has been used in desert railway construction.In this paper,a series of dynamic triaxial tests with different stress levels were carried out to explore the change rule of accumulated plastic deformation of aeolian sand filler with the number of loading cycles.A prediction model of accumulated plastic strain of aeolian sand considering dynamic stress amplitude,stress level and moisture content was established.The test results show that the relationship curve between accumulated plastic strain and number of loading cycles of aeolian sand samples can be divided into three types,which are the stable,critical and failure under different dynamic stress amplitudes.Power function can well describe the relationship between accumulated plastic strain rate of aeolian sand and the number of loading cycle.On the basis,an accumulated plastic strain model considering the dynamic stress amplitude,moisture content,and confining pressure is proposed.These research results can provide reference for settlement prediction of aeolian sand subgrade under cyclic dynamic load,subgrade design based on strain control principle and dynamic stability evaluation.
作者
聂如松
钱冲
刘婞
阮波
祁延录
赵加海
NIE Rusong;QIAN Chong;LIU Xing;RUAN Bo;QI Yanlu;ZHAO Jiahai(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;Xinjiang Railway Survey and Design Institute Co.,Ltd.,Urumqi 830011,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第9期2609-2619,共11页
Journal of Railway Science and Engineering
基金
乌鲁木齐局集团有限公司科技研究开发计划课题(WLMQ-KGHZGS-HRTL-GGB-2020-0032)
国家自然科学基金资助项目(51878666)。
关键词
风积沙
动三轴试验
累积塑性应变
预测模型
aeolian sand
dynamic triaxial test
accumulated plastic strain
prediction model
