Geomechanical Rock Properties Using Pressure and Temperature Dependence of Elastic P- and S-Wave Velocities

Abstract

It is important and meaningful for understanding the geomechanical properties of rock and providing guidance on analyzing and simulating the formation processes of engineering, geophysical, geothermal, civil and underground engineering projects. Variation in geomechanical properties of metamorphic rock, such as, seismic velocities (P-and S-wave) density deformation, is observed with the increase in pressure and temperature, Poisson’s ratio, elastic modulus, bulk modulus and shear modulus, are analyzed herein. A simple laboratory method, which measure seismic velocities has increasingly been conducted to determine the geomechanical properties of rock materials. Three metamorphic rock samples were selected for laboratory testing. Laboratory testing were done on cube samples of dry rocks in a true triaxial apparatus. First, P and S wave velocities were measured at 12–100 MPa pressure and at 20–600 °C temperature. Measurement showed that P and S wave velocities increase with increasing pressure and decrease with increasing temperature. Second, the wave velocities are used to calculate the geomechanical properties at lower to higher pressure and temperature. Furthermore, it was found that pressure and temperature have a significant effect on the change of geomechanical properties of rocks. These results contribute to a reliable estimate of geomechanical properties of rocks.