Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth
Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth
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DOI：
10.1016/j.ijsolstr.2012.05.009
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发表时间：
2012-09
影响因子：
3.6
通讯作者：
Y. Nara;K. Morimoto;N. Hiroyoshi;T. Yoneda;K. Kaneko;P. Benson
中科院分区：
文献类型：
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作者：
Y. Nara;K. Morimoto;N. Hiroyoshi;T. Yoneda;K. Kaneko;P. Benson
与地质材料断裂韧性相关的信息对于我们理解拉伸断裂至关重要，特别是在受高湿度影响的地质和岩石工程项目中。在这项研究中，我们进行了一套全面的断裂韧性测试的一套关键岩石类型在空气中，在不同的相对湿度和恒温，以调查断裂韧性的相对湿度的影响。为此目的选择了三种砂岩和两种火成岩。我们表明，断裂韧性值随相对湿度的增加而降低。此外，我们发现当岩石中含有蒙脱石等膨胀性粘土时，断裂韧性的降低更为显著。由于蒙皂石在水的存在下易于膨胀，因此当相对湿度高时，强度和因此抗裂纹扩展性降低。因此，我们解释了随着含水量的增加，膨胀粘土的降解后，断裂韧性下降。它还表明，随着湿度的增加，断裂韧性的下降是不太显着的亚临界应力强度因子的测量值的同时减少。这可能是由于应力腐蚀对断裂韧性的影响很小。我们得出结论，岩石中的裂纹扩展是受湿度的影响，粘土含量是一个重要的影响因素，断裂韧性和亚临界应力强度因子的变化。
Information relating to the fracture toughness of geomaterials is critical to our understanding of tensile fracturing, and in particular in geological and rock engineering projects that are subjected to elevated moisture levels. In this study, we conducted a comprehensive set of fracture toughness tests on a suite of key rock types in air under different relative humidities and at constant temperature in order to investigate the influence of relative humidity on fracture toughness. Three sandstones and two igneous rocks were chosen for this purpose. We show that the value of fracture toughness decreases with increasing relative humidity. In addition, we find that the decrease in fracture toughness was more significant when the expansive clay such as smectite was included in rock. Since smectite is prone to expanding in the presence of water, the strength and thus crack growth resistance decrease when relative humidity is high. Therefore, we interpret the decreasing fracture toughness upon the degradation of expansive clays with increasing water content. It was also shown that the decrease of the fracture toughness with increasing humidity is less significant than the concomitant decrease in the measured value of the subcritical stress intensity factor. This was likely as a result of stress corrosion having little influence on the fracture toughness. We conclude that crack growth in rock is affected by humidity, and that clay content is an important contributing factor to changes in fracture toughness and subcritical stress intensity factor.