应力途径与岩石的摩擦滑动
STRESS PATH AND FRICTIONAL SLIDING OF ROCKS
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摘要: 用双剪法对济南辉长岩和点苍山大理岩进行了摩擦滑动实验.实验中的应力变化方式有两种.A 型实验:先使断层面上的正应力增加到一定值,然后保持正应力不变,并增加剪应力使断层发生粘滑;B 型实验:先使断层面上的正应力增加到一定的值,保持正应力不变,并增加剪应力到断层发生粘滑前的某一应力状态,再保持剪应力不变,减小正应力直到粘滑发生.实验表明,B 型实验中岩石的摩擦强度高于 A 型实验.A 型实验中粘滑发生前有声发射率增加的前兆,B 型实验中粘滑发生前看不到声发射率的明显增加.由实验得到一个启示,即闭锁断层的开锁可能采取两种形式:一种是冲开闭锁,即以剪应力的增加使断层发生错动;另一种是解开闭锁,即以正应力的减小使断层发生错动.断层的粘滑采取哪种形式,由断层带的应力变化途径决定.Abstract: Frictional sliding experiments with Jinan gabbro and Diancangshan marble are made by the bishear test method. There are two types of stress change in the experiments. Type A: The normal stress on the fault plane is increased first, then it is kept constant and the shear stress is increased until stick-slip happens; Type B: The normal stress on the fault plane is increased first, keeping it constant and the shear stress is increased to a certain value before stick-ship, then the shear stress is kept constant and the normal stress docreased until the happening of stick-slip. The experiments show that the frictional strength of rocks in type B experiments is higher than that in Type A, There is precusory increase of AE rate before stick-slip in Type A, but this has not been observed in Type B. It is suggested that there are two forms of dislock-ing of the locked faults: Dislcking by rushing, the fault movement is caused by an increase of the shear stress; Dislocking by relaxing, the fault movement is caused by a decrease of the normal stress. The form of stick-slip of faults is determined by the path of stress change in fault
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[1] 耿乃光、姚孝新、陈颗、许东俊,应力途径的研究,中国地震,1, 61——66, 1985
[2] 耿乃光,应力减小引起地震,地震学报,7, 445——451, 1985,
[3] 耿乃光,由岩石力学实验研究地震前兆,地球物理学报〔待发表).
[4] Brace, W. F., Byerlee, J. D., Stick——slip as a mechanism for earthquakes, Science, 153, 990——992, 1966.
[5] Byerlee,J. D., The mechanics of stick——slip,Teczonophysics, 9, 475——486, 1970.
[6] Scholz,C. H., Molnar, P. M., Johnson,T.L.,Detailed studies of frictional sliding of granite and implication for the earthquake mechanism, J. Geophy. Res., 77, 6372——6406, 1972.
[7] Ohnaka,M,Frictional characteristics of typical rocks,J. Phys. Earth, 23,87——112, 1975.[1] 耿乃光、姚孝新、陈颗、许东俊,应力途径的研究,中国地震,1, 61——66, 1985
[2] 耿乃光,应力减小引起地震,地震学报,7, 445——451, 1985,
[3] 耿乃光,由岩石力学实验研究地震前兆,地球物理学报〔待发表).
[4] Brace, W. F., Byerlee, J. D., Stick——slip as a mechanism for earthquakes, Science, 153, 990——992, 1966.
[5] Byerlee,J. D., The mechanics of stick——slip,Teczonophysics, 9, 475——486, 1970.
[6] Scholz,C. H., Molnar, P. M., Johnson,T.L.,Detailed studies of frictional sliding of granite and implication for the earthquake mechanism, J. Geophy. Res., 77, 6372——6406, 1972.
[7] Ohnaka,M,Frictional characteristics of typical rocks,J. Phys. Earth, 23,87——112, 1975.
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