Subcritical crack growth in rocks in an aqueous environment
Subcritical crack growth in rocks in an aqueous environment
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DOI：
10.1071/eg08102
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发表时间：
2007-12
影响因子：
0.9
通讯作者：
Y. Nara;M. Takada;T. Igarashi;N. Hiroyoshi;K. Kaneko
中科院分区：
文献类型：
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作者：
Y. Nara;M. Takada;T. Igarashi;N. Hiroyoshi;K. Kaneko
亚临界裂纹扩展是岩石随时间断裂的主要原因之一。在本研究中，我们研究了蒸馏水（pH = 5-7）和氢氧化钠水溶液（NaOHaq，pH = 12）中岩石的亚临界裂纹扩展，并将结果与空气中的结果进行了比较。我们还研究了水环境中 pH 值的影响。我们使用安山岩和花岗岩进行所有测试。我们通过受控温度条件下的双扭转试验确定了裂纹速度与应力强度因子之间的关系。我们发现水中的裂纹速度高于空气中的裂纹速度，这与其他表明水中裂纹速度增加的研究结果一致。然而，当我们将 NaOHaq 的结果与水的结果进行比较时，我们发现即使周围环境的 pH 值不同，相同应力强度因子下的裂纹速度也没有变化。这一结果与氢氧根离子加速岩石中亚临界裂纹扩展的公认认识并不相符。我们得出的结论是，裂纹尖端的 pH 值影响亚临界裂纹扩展，而不是整体 pH 值，后者影响很小。
Subcritical crack growth is one of the main causes of time-dependent fracturing in rock. In the present study, we investigated subcritical crack growth in rock in distilled water (pH = 5–7) and in an aqueous solution of sodium hydroxide (NaOHaq, pH = 12), comparing the results to those in air. We also investigated the effect of the pH in an aqueous environment. We used andesite and granite for all our tests. We determined the relationship between the crack velocity and the stress intensity factor using the double-torsion test under conditions of controlled temperature. We showed that crack velocities in water were higher than those in air, in agreement with other research results indicating that crack velocity increases in water. When we compared our results for NaOHaq with those for water, however, we found that the crack velocity at the same stress intensity factor did not change even though the pH of the surrounding environment was different. This result does not agree with the accepted understanding that hydroxide ions accelerate subcritical crack growth in rocks. We concluded that the pH at the crack tip influences subcritical crack growth, and not the bulk pH, which has little effect.