| 水对高应变率扭剪变形实验中大理岩强度的影响 |
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| 引用本文： | 嵇少丞. 1987: 水对高应变率扭剪变形实验中大理岩强度的影响. 地震学报,9(2): 208-216. |
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| 作者姓名： | 嵇少丞 |
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| 作者单位： | 中国科学院地质研究所 |
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| 摘 要： | 利用 Kolsky 扭转棒作为实验装置,笔者在常温常压条件下对干燥的和潮湿的大理岩试样进行了一系列的动态简单剪切的实验变形研究,以期了解在高应变率(373-1-1736-1)时岩石中孔隙水对于岩石抗剪强度的影响.结果表明,孔隙水的存在不但没有降低,反而稍微提高了岩石的抗剪强度.结合前人在静态条件下的实验研究资料,笔者认为水对岩石变形的作用机制随应变率的变化而改变.在低应变率(例如:10-9-1)时,水对岩石变形的影响分别表现为压溶作用、应力侵蚀作用和降低有效应力的效应.压溶作用和应力侵蚀作用导致岩石强度的降低;而有效应力的降低则导致岩石强度的相对提高.
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THE EFFECT OF WATER ON STRENGTH OF MARBLE IN TORSIANAL SHEAR DEFORMATION AT HIGH STRAIN-RATE |
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| 1987: THE EFFECT OF WATER ON STRENGTH OF MARBLE IN TORSIANAL SHEAR DEFORMATION AT HIGH STRAIN-RATE. Acta Seismologica Sinica,9(2): 208-216. |
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| Abstract: | A series of dynamic deformation experiments have been carried out on both dry and wet marble samples, by means of the torsional Kolsky bar modified for simple shear, to explore the influence of pore water on the strength or fracture stress at several high strain-rates (373s-1 to 1736s-1). The temperature was 20℃, and confining pressure was 0.1 MPa. An alloy (AZ8GU) was used as the material for torsional bars (G = 26800 MPa, = 2800 kg/m3). The incident, reflected and transmitted torsional pulses were recorded using an oscilloscope. The shear stress, strain and strain-rate were evaluated from the recorded torsional pulse signals by using a mini-processor.Both dry and wet marble samples show brittle deformation behavior. The relation between strain-rate and estimated experimental fracture stress is: = 26.531n-150.16 for the dry sample and is:r = 27.211nr-143.76for the wet one, where is in MPa.According to the data of the present experiment and previous ones (Rutter and Mainprice, 1978; Henry, 1978), the possible deformation rate controlling processes at low temperature are discussed, and it is suggested that in the wet experiments at low strain-rate (e.g. 10-9 s-1) the effect of water on rock deformation is controlled by a pressure solution process, while deformation at intermediate strain-rate (10-7 to 10-3s-1) it is controlled by the kinetics of water assisted stress corrosion. During deformation at high strain-rate (>10-3s-1) the crack velocity is too high to give enough time for chemical reactions between water and minerals at the crack tip. But the noteable difference in mechanical behavior between dry and wet rocks may be interpreted as an effective shear stress effect.The geological implications of the results are discussed, and particular emphasis is given to their significance for the study of earthquakes. |
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