| 热水条件下黑云母断层泥的摩擦强度与稳定性 |
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| 引用本文： | 路珍,何昌荣.热水条件下黑云母断层泥的摩擦强度与稳定性[J].地球物理学报,2014,57(4):1123-1132. |
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| 作者姓名： | 路珍 何昌荣 |
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| 作者单位： | 中国地震局地质研究所, 地震动力学国家重点实验室, 北京 100029 |
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| 基金项目： | 国家自然科学基金(41274186);地震动力学国家重点实验室自主项目(LED2012A01)资助 |
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| 摘 要： | 黑云母是自然界常见的层状硅酸盐矿物，其摩擦系数不高且化学稳定性好，对其摩擦性质的关注可能会对弱断层的研究有所帮助.本次工作选取的实验温度条件对应于典型地壳强度模型中脆塑性转化带的范围，为300 ℃和400 ℃.有效正应力为200 MPa，孔隙水压包括10 MPa和30 MPa，在此条件下对黑云母模拟断层泥进行摩擦实验研究.实验得出黑云母的摩擦系数平均在0.36左右.速度依赖性随温度升高速度弱化的程度增强，表现为300 ℃为十分微弱的速度弱化，而在400 ℃出现了黏滑行为，代表了更强的速度弱化.显微结构中同时出现了脆性剪切变形和塑性扭折变形，但决定宏观力学性质的显然是脆性剪切变形.在黑云母存在的情况下，本研究的实验结果有助于理解大陆地壳脆塑性转化带中地震的可能性和弱断层深部的变形机制、宏观力学行为以及地震活动.
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| 关 键 词： | 黑云母 摩擦系数 速度依赖性 地震成核 |
| 收稿时间： | 2013-05-10 |
The frictional strength and stability of biotite under hydrothermal conditions |
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| LU Zhen,HE Chang-Rong.The frictional strength and stability of biotite under hydrothermal conditions[J].Chinese Journal of Geophysics,2014,57(4):1123-1132. |
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| Authors: | LU Zhen HE Chang-Rong |
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| Institution: | State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China |
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| Abstract: | Biotite is one of the commonest phyllosilicate minerals in nature with low strength and relatively high chemical stability. Investigation on its frictional properties helps to understand the compositional ground of weak faults. We carried out frictional experiments of biotite gouge at effective normal stress of 200 MPa, pore pressure of 10 MPa and 30 MPa, and temperatures of 300 ℃ and 400 ℃ which correspond to the temperature range of brittle-plastic transition zone. The main results obtained in this work are frictional coefficient and velocity dependence. The coefficient of friction of biotite is about 0.36, significantly lower than the muscovite case. The mechanical data show weak velocity weakening at 300 ℃, whereas stick-slips occurred at 400 ℃ indicating stronger velocity weakening. Microstructures of deformed samples show both brittle shear bands and kink bands due to plastic glide in the basal plane, but evidently the mechanism that controls the macroscopic behavior is sliding along the brittle shear bands. The results in this study may help understand the possibility of earthquake genesis in a brittle-plastic transition zone and the mechanical behavior of weak fault zones in the continental crust. |
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| Keywords: | Biotite Coefficient of friction Velocity dependence Earthquake nucleation |
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