【摘要】 基于低温动三轴试验,对列车荷载下青藏冻结粉质黏土的动应变发展情况进行研究,得到冻结粉质黏土的回弹应变和累积塑性应变随振动次数、动应力幅值、冻结温度和初始含水率而变化的规律。结果表明:①青藏冻结粉质黏土回弹应变在加载初期迅速减小,振动一定周次后随振动次数的增加不均趋于稳定;②累积塑性应变随着振动次数的增加呈增大趋势,且表现出稳定型、破坏型和临界型三种形态;③冻结粉质黏土的回弹应变和累积塑性应变随着动应力幅值增加和冻结温度升高而增大;④初始含水率越高,冻结粉质黏土的回弹应变越小、累积塑性变形越大。研究成果对我国冻土地区铁路路基长期动力稳定型评价及路基设计具有重要参考价值。更多还原

【Abstract】 The paper reports the results of laboratory dynamic triaxial test that aimed to investigate the dynamic strain induced by train loading.The effects of the numbers of load application,freezing temperature and water content on resilient and accumulative plastic strains of frozen silt clay are studied.The test results show that:①The resilient strain decreases rapidly at the beginning of loading,and tend to be constant at certain vibration numbers for saturated frozen soils.②The accumulative plastic strains increase with the vibration numbers and can be classified by three types,stable type,critical type and failure type.③The resilient and accumulative plastic strain increase with the increasing the dynamic stress amplitude and ascending the freezing temperature.④With increasing the initial water content,the accumulative plastic strain of frozen silt clay increases,however,the resilient strain of frozen silt clay decreases.All conclusions are very important for railway subgrade design and long-term dynamic stability evaluation in frozen soil region.更多还原