Stress corrosion and acoustic emission during tensile crack propagation in Whin Sill dolerite and other basic rocks
Stress corrosion and acoustic emission during tensile crack propagation in Whin Sill dolerite and other basic rocks
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DOI：
10.1111/j.1365-246x.1983.tb01911.x
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发表时间：
1983-10
影响因子：
2.8
通讯作者：
P. Meredith;B. Atkinson
中科院分区：
文献类型：
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作者：
P. Meredith;B. Atkinson
在环境空气和液态水中进行双扭转试验，建立了Whin Sill榴辉岩和Ralston侵入岩中单裂纹扩展的临界应力强度因子(KIC)和应力强度因子(KI)-裂纹速度(V)图。KIcfor Whin Sill辉绿岩为3.28MN m-3/2，Ralston侵入岩为2.58MNm=3/2，未达到应力腐蚀极限。在速度范围从5×10~(-4)~5×10~(-9)米S~(-1)范围内的惠斯山榴辉岩上进行了声响应监测。声发射率是间接测量裂纹速度的一种方法。KI-V图和KI-声发射率图的斜率在双对数坐标系中具有相似的斜率约为30。在裂隙速度为5×10~(-4)~10~(-8)米S~(-1)的范围内，拉尔斯顿侵入体的Ki-v曲线斜率从空气中的43.4降至水中的23.3。用两种互补的方法测得20°~75°C范围内辉绿岩的活化热为30.4×1.9和33~46kJ·mol~(-1)。声发射事件的幅度分布强烈地依赖于K_i和裂尖的“湿度”。随着KIcis的接近，大气中辉绿岩的b值从1.8下降到1.25，水中辉绿岩的b值从3.5下降到1.25。在KI大于0.8KI时，水和空气中试验的b值实际上是相同的。讨论了这些结果对地震力学的影响。版权所有©1983，Wiley Blackwell。版权所有
Double torsion tests in ambient air and liquid water have been used to establish critical stress intensity factors (KIc) and stress intensity factor (KI)‐crack velocity (v) diagrams for propagation of single tensile cracks in Whin Sill dolerite and Ralston Intrusive. KIcfor Whin Sill dolerite was 3.28 MN m‐3/2and for Ralston Intrusive was 2.58 MN m=3/2. No stress corrosion limit was encountered. Acoustic response was monitored during experiments on Whin Sill dolerite which spanned a velocity range from 5 × 10‐4to 5 × 10‐9m s‐1. The rate of acoustic emission was an indirect measure of crack velocity. The slopes of KI‐v diagrams and KI‐acoustic emission rate diagrams had similar slopes of c. 30 in double logarithmic coordinate frames. Slopes of the KI‐v curves for Ralston Intrusive fell from 43.4 in air to 23.3 in water, during tests which spanned a crack velocity range from 5 × 10‐4to 10‐8m s‐1. The activation enthalpy for dolerite between 20° and 75°C was determined by two complementary methods to be 30.4 × 1.9 and 33‐46 kJ mol‐1. Amplitude distributions of acoustic emission events depend strongly on KIand the ‘humidity’ at the crack tip. As KIcis approached, b‐values for dolerite in air decrease from 1.8 to 1.25, and for dolerite in water a decrease occurs in b‐value from 3.5 to 1.25. At KIgreater than 0.8 KIcthe b‐values for tests in water and in air are virtually identical. A discussion is given of these results in terms of their implications for earthquake mechanics. Copyright © 1983, Wiley Blackwell. All rights reserved