饱和土排水蠕变特性对比研究

发布时间：2018-03-05 13:11

本文选题：饱和土　切入点：k_固结蠕变实验　出处：《应用基础与工程科学学报》2017年05期 　论文类型：期刊论文

【摘要】：利用室内改装的应力控制式三轴仪,以淤泥土、粉土、粉细砂(中密、密实)为研究对象,通过k_0固结三轴排水蠕变试验探讨了饱和土的排水蠕变特性.3种土样轴向蠕变规律均为稳定衰减型,但粉细砂的轴向蠕变与密实度有一定关联.3种土样体变规律存在一定差异性,淤泥土的体变随时间呈现剪缩与剪胀交替性,而粉土整体剪缩.砂土体变随时间变化则受围压和密实度的影响较大,体变总体呈剪胀性状,且砂越密实,受剪时围压越低,越易发生剪胀.3种土体蠕变系数与应力水平密切相关,均随应力水平增大而增大,而与围压值关系不大.但这种增长关系,对于黏性土(淤泥土、粉土)基本呈直线关系,而粉细砂并不呈线性,用指数增长关系描述更合适.最后,采用Merchant和Burgers蠕变模型拟合试验数据,发现应力水平S0.8时两个蠕变模型均能达到较好拟合效果,S0.8时均存在弊端有待进一步修正.
[Abstract]:Using the stress control triaxial instrument modified in the laboratory, silt soil, silt, silt and fine sand (medium density, dense) were used as the research object. The creep behavior of saturated soil is studied by means of k0 consolidation triaxial drainage creep test. The axial creep behavior of 3 kinds of soil samples is stable and attenuated. However, there are some differences between axial creep and density of fine silt. There are some differences in the variation of soil samples, and the deformation of silt soil is alternately shear-shrinkage and shear-expansion with time. The variation of sand body with time is greatly affected by confining pressure and compactness, and the overall deformation of silt is shear-expansion, and the denser the sand is, the lower the confining pressure is. The creep coefficient of shear swelling is closely related to stress level and increases with the increase of stress level, but has little relation with confining pressure. However, the relationship between creep coefficient and confining pressure is linear for clay (silt soil, silt soil). But fine silty sand is not linear, so it is more suitable to describe it with exponential growth relationship. Finally, Merchant and Burgers creep models are used to fit the test data. It is found that the two creep models can achieve good fitting effect at stress level S0.8 and both have some drawbacks to be further corrected when the stress level is S0.8.
【作者单位】：南京大学金陵学院;南京水利科学研究院;华侨大学福建省隧道与城市地下空间工程技术研究中心;
【基金】：水利部土石坝破坏机理与防控技术重点实验室开放基金项目(YK915006) 国家自然科学基金项目(51774147) 福建省高校杰出青年科研人才培育计划(2016年度)
【分类号】：TU41

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