Mechanical behavior of frozen clay under constant- and varying-temperature and strain rate shear
Mechanical behavior of frozen clay under constant- and varying-temperature and strain rate shear
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DOI：
10.3208/jgssp.jpn-08
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发表时间：
2015-08
期刊：
影响因子：
--
通讯作者：
Jin-Yen Wang;S. Nishimura
中科院分区：
文献类型：
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作者：
Jin-Yen Wang;S. Nishimura
本文报道了一系列冻结粘土的三轴压缩试验。试验在-2、-5和-10℃下进行，各向同性正常固结400kPa。在恒定或变化的应变速率和温度下剪切试样，并讨论了其观察到的强度及其对这些因素的依赖。结果表明：在试验条件范围内，抗剪强度随应变速率的增加呈对数线性增加；由给定温度下的抗剪强度归一化，或由给定应变速率下的抗剪强度归一化，分别与应变速率和温度形成独特的关系。如果将恒温应力-应变曲线作为主干关系，一般可以预测给定应变在变温条件下的应力。同样的观察结果可能也适用于应变率，如等速规则所描述的那样。当应变大于5%时，偏差应力的影响与强度的影响相似。在这些应变水平下，应力-应变曲线表明冻结试样处于充分塑性阶段。上述温度和应变速率效应的特征相对简单，可用于建立一般速率相关的冻土热力学模型。
This study reports a series of triaxial compression tests on frozen clay. The tests were performed on reconstituted Kasaoka Clay frozen at -2, -5 and -10 o C from isotropic normal consolidation of 400kPa. The specimens were sheared at constant or varying strain rates and temperatures, and their observed strength and its dependence on these factors are discussed. The results show that, within the investigated range of conditions, the shear strength increases log-linearly with an increase in the strain rate. The shear strength normalized by that at a given temperature, or by that at a given strain rate formed unique relationships against the strain rate or the temperature, respectively. The stress in a temperature-varying condition can generally be predicted for a given strain if constant-temperature stress-strain curves are considered as backbone relationships. The same observation is probably true for the strain-rate, as described by the isotache rule. These effects are similar on the deviator stress for strains larger than 5% as on the strength. At these strain levels, the stress-strain curves suggest that the frozen specimens were at a sufficiently plastic stage. The above features of temperature and strain rate effects are relatively simple to formulate and will be useful in developing a general rate-dependent thermo-mechanical model for frozen clays.