Visco-Elastic Behavior of Fractured Rock

首先讨论了一个非常简单的变柔度型本构方程，该方程适用于裂隙岩石。本构方程可以在蠕变、松弛、恒应变率、恒应力率等几种加载条件下进行解析求解，并可以检验这些加载条件之间的时间依赖关系。此外，在本研究中，对6块岩石进行了单轴压缩直至破坏后区域的试验。随着加载速率的增加，所有试件的强度都增加，破坏后区的应力-应变曲线向右移。然而，应力-应变曲线的斜率并不随加载速率而有意义的变化。需要注意的是，加载速率增加10倍时，强度的增长存在一个与含水率无关的值。结果表明，对于所有岩石样品，计算结果与实验结果吻合较好。

At first, a very simple constitutive equation of variable compliance type is discussed, which can be applicable to a fractured rock. The constitutive equation can be solved analytically for several loading conditions such as creep, relaxation, constant strain rate, constant stress rate and allows to examine the relations of time dependent behavior among these loading conditions.Also in this study, six rocks were tested in uniaxial compression up to the post-failure region. With increase of loading rate, it was found for all samples that the strength increases and stress-strain curve in the post-failure region shifts to the right-hand side. The slope of the stress-strain curve, however, does not change meaningfully with loading rate. It should be noted that the increase of strength with 10 fold increase of loading rate has a certain value which does not depend on moisture content.The constitutive equation was used to simulate the loading rate dependency under uniaxial compression tests. It was found that the calculated results give a good approximation to the experimental results for all sample rocks.