Study of subcritical crack growth in andesite using the Double Torsion test
Study of subcritical crack growth in andesite using the Double Torsion test
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DOI：
10.1016/j.ijrmms.2005.02.001
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发表时间：
2005-06
影响因子：
7.2
通讯作者：
Y. Nara;K. Kaneko
中科院分区：
文献类型：
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作者：
Y. Nara;K. Kaneko
亚临界裂纹扩展是引起岩石力学行为时间相关性的主要原因之一。双扭（DT）试验常用于研究岩石中的亚临界裂纹扩展。DT试验有三种方法，每种方法具有不同的加载条件：恒定载荷（CL）法、恒定位移（CDR）法和载荷松弛（RLX）法。RLX方法是方便的，因为亚临界裂纹扩展的大范围的数据可以得到一个单一的实验运行。在这项研究中，安山岩亚临界裂纹扩展进行了研究，使用DT试验的RLX方法。为了确定DT试样中导向槽的适当形状，使用矩形、半圆形和三角形截面槽进行测试。矩形槽试样的试验结果再现性最高。因此，这是DT试样的合适导槽形状。DT试验也进行了不同的水蒸气压力，调查亚临界裂纹扩展的影响。结果表明，较高的水蒸气压有利于裂纹的扩展。此外，安山岩亚临界裂纹扩展的激活能确定从实验结果，并在不同的温度，湿度和应力条件下的裂纹速度值进行了理论计算。可以从理论上预测各种环境和应力条件下的裂纹速度。
Subcritical crack growth is one of the main causes of time-dependent behavior in rocks. Double torsion (DT) tests have often been used to study subcritical crack growth in rocks. There are three methods used for the DT test, each with different loading conditions: the constant load (CL) method, the constant displacement (CDR) method, and the load relaxation (RLX) method. The RLX method is convenient, because the wide range of data of subcritical crack growth can be obtained with a single experimental run. In this study, subcritical crack growth in andesite was investigated using RLX method of the DT test. To determine the appropriate shape for the guide groove in DT specimens, tests were performed using rectangular, semi-circular, and triangular section grooves. The level of reproducibility of the test results was highest for specimens with a rectangular groove. Hence, this is an appropriate guide groove shape for DT specimens. DT tests were also performed for different water vapor pressures to investigate the effects on subcritical crack growth. The results showed that crack growth was facilitated at higher water vapor pressures. Additionally, the activation energy for subcritical crack growth in andesite was determined from the experimental results, and the crack velocity values for various temperature, humidity, and stress conditions were calculated theoretically. The crack velocity can be predicted from theory for various environmental and stress conditions.