甘南地区黄土的动模量与阻尼比特性研究

发布时间：2018-03-29 02:21

本文选题：次生黄土　切入点：动本构关系　出处：《岩土工程学报》2017年S1期

【摘要】：通过室内动三轴试验,研究了甘南地区次生黄土的动本构关系,得到了模型参数,分析了甘南黄土的动剪模量比和阻尼比发展特征,提出了动剪切模量衰减模型和阻尼增长模型;并通过归一化处理和模型参数比较,对次生黄土与风成黄土动剪模量比和阻尼比的差异性进行了讨论。结果表明:次生黄土的动本构关系服从双曲线模型,模型参数a值较风成黄土无明显差异,但b值为相同条件下风成黄土b值的1.5~3倍,且模型参数与天然含水率、干密度等物性参数和固结围压不存在明显的相关性。次生黄土的初始动弹性模量E_(dmax)受固结条件、密度影响较大,相同条件下残坡积黄土的E_(dmax)较冲洪积黄土小。次生黄土的动剪模量比随动剪应变增大而减小,变化趋势满足负指数衰减模型;阻尼比随动剪应变的增大而增大,变化趋势服从对数关系;相比于风成黄土,其动剪模量比随动剪应变的增加衰减更快,阻尼比增长范围较窄,表明沉积环境对黄土动力特性的差异性影响显著。
[Abstract]:The dynamic constitutive relationship of secondary loess in Gannan region was studied by dynamic triaxial test in laboratory. The model parameters were obtained and the development characteristics of dynamic shear modulus ratio and damping ratio of Gannan loess were analyzed. A dynamic shear modulus attenuation model and a damping growth model are proposed, and the model parameters are compared by normalization treatment. The difference of dynamic shear modulus ratio and damping ratio between secondary loess and wind-formed loess is discussed. The results show that the dynamic constitutive relation of secondary loess is based on hyperbolic model, and the parameter a of the model is not significantly different from that of wind-formed loess. But the b value is 3 times of the b value of the wind-formed loess under the same conditions, and there is no obvious correlation between the model parameters and the physical property parameters such as natural moisture content, dry density and consolidation confining pressure. Under the same condition, the density of residual loess is smaller than that of alluvial loess. The dynamic shear modulus of secondary loess decreases with the increase of dynamic shear strain, and the variation trend satisfies the negative exponential attenuation model, and the damping ratio increases with the increase of shear strain. Compared with the aeolian loess, the dynamic shear modulus decreases faster than the following shear strain, and the damping ratio increases in a narrower range, indicating that the sedimentary environment has a significant influence on the dynamic characteristics of loess.
【作者单位】：中国地震局(甘肃省)黄土地震工程重点实验室;中国能源建设集团甘肃省电力设计院有限责任公司;
【基金】：中国地震局地震科技星火计划项目(XH16038Y) 国家自然科学基金项目(51408567,51478444) 甘肃省科技计划项目(1308RJZA153)
【分类号】：TU444

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