Dilatancy anisotropy and the response of rock to large cyclic loads
Dilatancy anisotropy and the response of rock to large cyclic loads
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DOI：
10.1029/jb084ib10p05525
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发表时间：
1979-09
影响因子：
--
通讯作者：
C. Scholz;T. Koczynski
中科院分区：
文献类型：
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作者：
C. Scholz;T. Koczynski
对花岗岩和花岗岩进行了三轴压缩循环疲劳试验研究。结果发现，这些岩石在循环加载过程中逐渐发展出蠕变，其形式与蠕变曲线非常相似。膨胀在所有情况下都是高度各向异性的。这种各向异性是由花岗岩中的裂隙微结构和岩石中的残余应力控制的。发现断裂面的走向通常形成为垂直于最大导磁率的轴。在循环加载过程中增加的粘性被认为是由渐进的粘性蠕变加上循环本身产生的额外损害造成的。前者导致一个显着的加载速率对疲劳的影响，后者的循环振幅对疲劳的复杂影响。没有稳定的疲劳压力被发现的围压高达300 MPa。断裂时的总应变随峰值应力的增大而增大，随加载速率的增大而减小。三种类型的开裂被证明会导致开裂：1型，应力诱导开裂; 2型，应力腐蚀开裂; 3型，疲劳开裂。岩石破裂对哪种类型的破裂比较敏感。
An experimental study of cyclic fatigue of granite and diabase in triaxial compression was conducted. It was found that dilatancy progressively developed during cyclic loading of these rocks with a form in time very similar to a creep curve. Dilatancy was in all cases highly anisotropic. This anisotropy was controlled by the crack microstructure in the granite and by the residual stress in the diabase. The strike of the fracture plane was found typically to form normal to the axis of maximum dilatancy. Increasing dilatancy during cyclic loading was found to be caused by progressive dilatant creep plus additional damage produced by the cycling itself. The former leads to a pronounced loading rate effect on fatigue, the latter to a complex effect of cycle amplitude on fatigue. No stabilization of fatigue by pressure was found for confining pressures up to 300 MPa. The total dilatant strain at fracture was found to increase strongly with peak stress and decrease with increasing loading rate. Three types of cracking are shown to result in dilatancy: type 1, stress-induced cracking; type 2, stress corrosion cracking; and type 3, fatigue cracking. Rock fracture is sensitive to which type is prevalent.