Poroelastic solution to the Brazilian test

The fully-coupled, poroelastic solution for the time-dependent stress and pore fluid pressure of a hollow or solid, cylindrical specimen of porous, fluid-saturated rock undergoing the diametral compression test is derived and presented. The long-time asymptote of the poroelastic solution for the case of solid specimen recovers the related elastic solution of Hondros.⁹ Findings reveal the nontrivial trend and substantial effect of the pore fluid pressure disturbances on the rock effective stress. The failure of solid cylinder is predicted to occur instantaneously after the compressive load is applied, yet, at a point away from the specimen center point. Conversely, delayed failure of hollow cylinder may occur after the pore fluid disturbances within the specimen diminish.