大规模的异质性可以改变压力失效和加速地震释放的特征
Andrew Patton1, Thomas Goebel2, Grzegorz Kwiatek3
1Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW Calgary, Alberta T2N 1N4, Canada.
Physical review. E
|August 16, 2023
概括
脆性岩石中的大规模应力异质性改变了断裂特征. 划痕的花岩显示了加速的地震释放,没有关键点,与完整的样本不同,影响了故障预测.
科学领域:
- 岩石机械 岩石机械 岩石机械
- 地质物理学 地质物理学
- 材料科学是一种材料科学.
背景情况:
- 脆性岩石在高外部压力下失败,往往先于加速的地震释放 (增加声辐射能量).
- 临界点的存在和声辐射大小分布在故障附近的变化在不同实验条件下有所不同.
- 了解岩石破裂机制对于地质危险评估和资源勘探至关重要.
研究的目的:
- 调查大规模应力异质性如何影响脆性岩石的故障特征.
- 确定应力异质性是否影响临界点的存在和声辐射大小分布在故障之前的变化.
- 评估异质性在预测岩石压力失效中的作用.
主要方法:
- 三轴压缩实验是在恒定位移速率下对西方花岩样本进行的.
- 样本包括完整的标本和带有诱导的大规模应力异质性 (隙) 的标本.
- 监测了声辐射 (AE) 事件,以分析能量释放,大小分布和功率定律指数 (ε).
主要成果:
- 划痕的花岩样本表现出加速的地震释放,表明在故障之前增加了AE活动.
- 与完整样本不同,划分样本在故障之前没有显示一个关键点或AE大小分布的功率定律指数 (ε) 的变化.
- 完整的样本显示在故障之前的功率定律指数 (ε) 显著下降,与临界点行为一致.
结论:
- 大规模的应力异质性从根本上改变了脆性岩石中的故障过程.
- 异质性存在或不存在显著影响故障是否表现出关键点特征和AE大小分布的可预测变化.
- 异质性在压力岩石破裂的可预测性中起着至关重要的作用,这表明当前的模型可能需要对异质材料进行改进.
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