A potential stress indicator for failure prediction of laboratory-scale rock samples

Based on the two-dimensional renormalization group model, which can consider the stress transfer mechanism, in the present paper, the theoretical quantitative correlation between the threshold of the crack damage stress (sigma(cd)) and the uniaxial compressive strength (sigma(ucs)) was constructed. The results indicate that the normalized quantity sigma(cd)/sigma(ucs) decreases as the shape parameter m increases, and that it gradually tends towards a constant horizontal asymptote that is similar to 0.82. In addition, the experimental results of sigma(cd)/sigma(ucs) obtained in previous studies using different rock types were analyzed. From this analysis, it was found that the overall average and the standard deviation of sigma(cd)/sigma(ucs) for low-porosity rock samples is similar to 0.80 (+/- 0.10), which would appear to be approximately consistent with the theoretical solution. This preliminary study indicates that the normalized quantity sigma(cd)/sigma(ucs) might be an intrinsic property of low-porosity rocks and thus could be regarded as a potential indicator for the failure prediction of laboratory-scale rock samples.