2018 Volume 59 Issue 5 Pages 747-753
Tensile stresses likely occur in the rock masses around large or intricately shaped caverns. Hydraulic fracturing for oil, gas, or geothermal development requires a deep understanding of crack extensions under tensile stress. Computer simulation is helpful for the estimation of such deformation and failure of in-situ rocks and requires a mechanical model representing complex rock behaviors under tension. The authors’ research group previously proposed the variable-compliance-type (VC) model for rocks and examined the model under compression. In this study, the applicability of the VC model was investigated under uniaxial tension. The close relation between the VC model and the microscopic failure mechanisms of crack extensions under uniaxial tension was clarified using the linear elastic fracture mechanics and the damage mechanics. Based on the relation, the VC model was modified to reproduce the deformation and failure under uniaxial tension. Then the model was validated by comparing the simulated and experimental results of complete stress-strain curves in both dry and wet conditions, loading-rate dependence, and creep deformation of various rocks under uniaxial tension. In addition, the applicability of the model to numerical simulation programs and the future subjects were discussed.