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彭丽云, 刘建坤. 正融粉质黏土在循环荷载作用下的变形特性研究[J]. 岩土工程学报, 2010, 32(4).
引用本文: 彭丽云, 刘建坤. 正融粉质黏土在循环荷载作用下的变形特性研究[J]. 岩土工程学报, 2010, 32(4).
Deformation properties of thawing silty clay under cyclic loading[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(4).
Citation: Deformation properties of thawing silty clay under cyclic loading[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(4).

正融粉质黏土在循环荷载作用下的变形特性研究

Deformation properties of thawing silty clay under cyclic loading

  • 摘要: 采用MTS动三轴仪,对正融粉质黏土进行了循环荷载作用下的单轴试验,研究了土样冻前含水率、顶端冷却温度、顶端融化温度和动应力幅值对土样变形特性的影响。试验结果表明:①正融土样的累积塑性应变随其顶端冷却温度的升高、动应力幅值的增加而增大;随冻前含水率的增加先减小后增大,且以最优含水率为其转折点;顶端融化温度对其影响较小;②对正融土而言,除存在临界动应力外,还存在一个临界冷却温度,当冷却温度高于该值,土样在若干次循环荷载作用下出现破坏;当温度低于该值,土样在循环荷载作用下的塑性累积变形最终趋于稳定;③正融土能够承受的动应力幅值大于同含水率下的融土所能承受的动应力幅值,尤其对高含水率土样,这种现象更加明显;④给出的正融粉质黏土的累积塑性应变和动应力幅值、加载循环次数,累积塑性应变和顶端冷却温度、加载循环次数和之间的关系式能够和试验数据吻合良好,可以对正融土的累积塑性应变进行简单预测。

     

    Abstract: Through the unconfined compression tests on thawing silty clay under cyclic loading by using an MTS dynamic triaxial apparatus, the deformation property analysis is made, and the influences of water content, amplitude of cyclic loading, cooling temperature and thawing temperature on the upside of the samples are taken into consideration. Some conclusions are drawn: ①The accumulated deformation of thawing silty clay increases with the increase of cooling temperature, and the soil with the higher amplitude of cyclic loading exhibites larger deformation. The thawing soil with the optimum water content expresses the lowest deformation and the influence of thawing temperature on soil deformation is very limited. ②Except for a critical dynamic loading, a critical cooling temperature is observed in thawing silty clay, the soil with the cooling temperature lower than that expresses the stable state of deformation after cyclic loading, and the soil with the cooling temperature higher than that will fail after some cyclic loading. ③Higher ability against the cyclic loading is observed of thawing soil than that of thawed soil, especially for the soil with the higher water content. ④The empirical model for deformation of thawing silty clay is given, which is in good agreement with the test data and can be used to predict the accumulated deformation of thawing silty clay simply.

     

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