Shear Fracture and Slip Weakening Behavior on Granite under High Pressure and High Temperature Water Conditions
Toru TAKAHASHI and Toshiyuki HASHIDA
Abstract:In this study, the triaxial deformation experiments were conducted to investigate the temperature and pressure effects on fracture strength of a granite using slip-weakening model. The experiments were conducted at temperatures and pressures up to 600 _C and 150MPa under water environment. Experimental results show that the peak differential strength decreases with increasing temperature. In contrast, the slip-weakening behavior shows temperature insensitive within the temperature range of this study except 600 _C conditions. We measured the fracture energy using slip-weakening curve at various temperature and pressure conditions. From our experimental results, under the same effective normal stress conditions, we could not observe the effect of temperature and pressure in our experimental conditions. Since the tectonic stresses applied to rock mass are constant at the geothermal field, these results suggest that it is available to apply the slip-weakening model to explain the crack propagation behavior in geothermal field. Key Words:Rock, Shear Fracture, Slip-Weakening, Triaxial Deformation, Supercritical Water, Geothermal Energy