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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。
The MTS dynamic triaxial apparatus was used to test the uniaxial properties of the feldspathic silty clay subjected to cyclic loading. The effects of water content before freezing, top cooling temperature, top melting temperature and dynamic stress on the deformation characteristics of soil samples Impact. The results show that: (1) The cumulative plastic strain of the as-melted soil samples increases with the increase of the cooling temperature at the top and the increase of the dynamic stress amplitude, decreases first and then increases with the increase of moisture content before freezing, Moisture content is its turning point; the melting temperature at the top has little effect on it; ② For the positive melting earth, there is a critical cooling temperature in addition to the critical dynamic stress. When the cooling temperature is higher than this value, Under the action of cyclic loading, the failure occurs under the action of cyclic loading. When the temperature is lower than this value, the plastic cumulative deformation of the soil specimen tends to be stable under the cyclic loading. ③ The dynamic stress amplitude of the normal-melting soil is greater than that of the earth- The dynamic stress amplitude can be sustained, especially for high water content soil samples, which is more obvious. (4) The cumulative plastic strain and dynamic stress amplitude, loading cycle number, cumulative plastic strain and tip The relation between the cooling temperature, the number of loading cycles and the sum of the loading cycles can be in good agreement with the experimental data and can be used to simply predict the cumulative plastic strain of the as-melted soil.