A new model of shear creep and its experimental verification
A new model of shear creep and its experimental verification
复制标题
一种新的剪切蠕变模型及其实验验证
DOI：
10.1007/s11043-020-09453-1
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发表时间：
2020-06-22
影响因子：
2.5
通讯作者：
Li, S. H.
中科院分区：
文献类型：
--
作者：
Wu, L. Z.;Luo, X. H.;Li, S. H.
蠕变对岩石工程安全起着至关重要的作用。在工程实践中，建立一个描述岩石蠕变行为的数学模型是很有帮助的。利用剪切流变仪对立方体泥岩试件进行了剪切蠕变试验。试验结果表明，当外加剪应力大于长期抗剪强度时，泥岩蠕变可分为稳定阶段和加速阶段。为了刻画泥岩样品的蠕变特性，本文提出了一种基于分数阶理论的变参数分数阶导数元。粘度系数被认为是一个变量。建立了描述岩石剪切蠕变的数学模型。新模型具有粘弹塑性特性，可以有效地描述岩石蠕变过程的两个阶段。剪切蠕变结果表明，新的剪切蠕变模型比西原模型和常参数分数蠕变模型具有更高的精度。敏感性分析表明，导数阶数对剪切蠕变的影响最大。
Creep exerts a significant role in rock engineering safety. In engineering practice, it is helpful to develop a mathematical model representing rock creep behaviors. We used a shear rheometer to carry out shear creep tests of cubic mudstone specimens. The experimental results indicate that the mudstone creep can be divided into steady and accelerated stages when the applied shear stress is greater than the long-term shear strength. To capture the creep characteristics of the mudstone samples, in this paper, we propose a variable-parameter fractional derivative element based on fractional theory. A viscosity coefficient is considered to be a variable. We develop a mathematical model describing rock shear creep. The new model shows a visco-elastic-plastic property, which can effectively characterize two stages of rock creep process. The shear creep results show that the new model of shear creep is more accurate than that of the Nishihara model and the constant-parameter fractional creep model. Sensitivity analysis demonstrates that derivative orders have the greatest effect on shear creep.