2022 Volume 71 Issue 2 Pages 181-188
Water saturation conditions in underground rock masses vary with place and time. Hence for estimating the deformation, failure, and time dependent behavior of rock around underground openings, it is essential to consider water saturation in rock mechanical models. In this study, on the basis of recent experimental results, the effect of water saturation was implemented in the variable-compliance-type model based on non-linear viscoelastic theory. The previous variable-compliance-type model possessed the three constants of which values change with a change of water saturation and have been unformulated. In contrast, the constants for water saturation and for time dependence were separated in the proposed model with adopting a new function of stress. Uniaxial compression strength tests and creep tests of andesite were simulated with this proposed model. The calculated results of the stress-strain curves and their water- and time-dependence were coincident with the experimental results. It was found from the calculated and experimental results that the effects of water saturation and strain rate on strength are convertible and that the effects of water saturation and creep stress on creep lifetime are also convertible. These results indicate that creep lifetime in arbitrary water saturation conditions is estimated from the strain rate dependence of strength using the model.
