非饱和粉质黏土冻结温度和冻结变形特性试验研究

发布时间：2018-05-06 00:01

本文选题：非饱和粉质黏土 + 冻结温度　；参考：《岩土工程学报》2017年08期

【摘要】：为掌握冻土冻结变形规律,揭示冻结变形机理,采用自行研制的温控体变仪精确测量不同饱和度、孔隙比土样的冻结变形,为计算冻土的体积含冰量,对非饱和粉质黏土冻结温度进行了测量。室内试验结果及其数据分析表明:(1)非饱和粉质黏土冻结温度(冰点)主要由土样初始基质吸力决定,基质吸力越大,冻结温度越低。(2)非饱和粉质黏土冻结变形随饱和度变化存在两种截然不同的机制,饱和度较低时,冰水相变影响较小,土体呈冻缩特征;饱和度较高时,冰水相变占主导作用,导致土体结构破坏,呈冻胀特征。(3)非饱和粉质黏土冻结体应变与土体体积含冰量和初始孔隙比具有良好的经验关系,可以基于体积含冰量和初始孔隙比预测土体冻结体应变,其中体积含冰量由土体冻结温度、温度、饱和度、干密度计算得到。
[Abstract]:In order to understand the freezing deformation law of frozen soil and reveal the mechanism of freezing deformation, the freezing deformation of soil samples with different saturation and void ratio was accurately measured by using the temperature controlled body variation instrument developed by ourselves, in order to calculate the volume ice content of frozen soil. The freezing temperature of unsaturated silty clay was measured. The indoor test results and data analysis show that the freezing temperature (freezing point) of unsaturated silty clay is mainly determined by the initial matrix suction of the soil sample, and the larger the matrix suction is, The lower the freezing temperature, the lower the freezing deformation of unsaturated silty clay has two different mechanisms with the change of saturation. When the saturation is low, the effect of ice water phase transition is small, and the soil is frozen shrinkage, and the ice water phase change dominates when the saturation is high. The frozen body strain of unsaturated silty clay has a good empirical relationship with the volume ice content and initial void ratio of the soil, and can be used to predict the frozen body strain based on the volume ice content and initial void ratio. The volume ice content is calculated by calculation of freezing temperature, temperature, saturation and dry density of soil.
【作者单位】：北京交通大学城市地下工程教育部重点实验室;多年冻土地区公路建设与养护技术交通行业重点实验室青海研究观测基地;
【基金】：国家自然科学基金项目(51479001,41471052) 中央高校基本科研业务费专项项目(2014JBZ013) 北京市自然科学基金项目(8152024)
【分类号】：TU411

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