期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2018
卷号：170
期号：2
页码：022141
DOI：10.1088/1755-1315/170/2/022141
语种：English
出版社：IOP Publishing
摘要：The stress level associated with crack initiation is an important damage threshold in rock failure process, which can be applied in the prediction of brittle failure in tunnels. In the present study, the uniaxial and triaxial compression tests are conducted on two sets of hard sandstones, while the dilation strains and AE counts are employed to characterize the crack accumulation. The crack initiation stress is then determined through the inflection point on strain and AE curves. Furthermore, two crack initiation modes: the splitting mode for low confinements and the sliding mode for high confinements are presented by analysing the fracturing mechanism. Based on the derivation of maximum tensile stress around the rock defects, an improved crack initiation criterion is proposed to predict the σci of confined rocks. In the new criterion, the frictional components on crack surface are considered by introducing the parameter mci, which can be applied for various types of rocks as well. At last, the triaxial compression test data of different rock types are reviewed to verify the reliability and applicability of the new criterion. The results indicate that the new criterion can predict the crack initiation stress of confined rock with high accuracy.
