冻结黄土的单轴试验及其本构模型研究

发布时间：2018-11-08 20:22

【摘要】：冻土的强度及变形行为受加载速率及环境温度效应的影响。以冻结兰州黄土为对象,开展了一系列不同温度及加载速率下的常规单轴压缩、变速率压缩及加卸载蠕变回弹试验。基于常规单轴压缩试验结果,考虑了加载速率对变形行为的影响;通过变速率压缩试验,引入了一个与加载速率相关的率敏感性系数,构建一个新的考虑率效应的冻土强度关系式,解决了由试样离散性而对率效应试验研究带来的不利影响;运用加卸载蠕变回弹试验实现了对冻土变形中弹性、塑性变形的解耦,并获得了率无关弹性模量。以此为基础,在一定的温度、加载速率范围内建立了考虑率效应及温度效应的冻结黄土单轴唯像本构模型。通过试验验证,该模型能较好地模拟冻结黄土在不同温度和不同加载速率条件下的应力应变行为。
[Abstract]:The strength and deformation behavior of frozen soil are affected by loading rate and ambient temperature effect. A series of conventional uniaxial compression, variable rate compression and creep springback tests were carried out at different temperatures and loading rates for frozen loess in Lanzhou. Based on the results of conventional uniaxial compression tests, the effect of loading rate on deformation behavior is considered. Through the variable rate compression test, a rate sensitivity coefficient related to the loading rate is introduced, and a new formula for the strength of frozen soil considering the rate effect is constructed, which solves the adverse effect of the sample dispersion on the rate effect test. The elastic and plastic deformation of frozen soil is decoupled by creep springback test of loading and unloading, and the rate-independent elastic modulus is obtained. On this basis, a uniaxial constitutive model of frozen loess is established in the range of temperature and loading rate, considering the rate effect and temperature effect. The experimental results show that the model can well simulate the stress-strain behavior of frozen loess at different temperatures and loading rates.
【作者单位】：中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室;中国科学院大学;南京师范大学虚拟地理环境教育部重点实验室;
【基金】：国家自然科学基金项目(41630636,11502266,41401077) 甘肃省科技重大专项项目(143GKDA007)
【分类号】：TU444

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