Studies on Mechanical and Poromechanical Behaviors of Brittle Rocks

Underground engineerings often encounter ground water during their construction and operating. Studies on coupling mechanism between pore pressure variation and rock deformation are thus essential for stability and durability analysis in underground engineerings. This work presents the laboratory and numerical investigations on anisotropic mechanical, poromechanical and fluid transport behaviors of sandstone. Triaxial compression tests were performed to study the mechanical behavior. Effective Biot¿s coefficients in axial and lateral directions as well as permeability in axial direction were measured at different stress level. A plastic damage model was proposed based on discrete approach. The modified Coulomb-type plastic yield and damage evolution criterion were given for each family of weakness sliding planes. Boit¿s coefficients was introduced by micromechanical analysis, the permeability was divided into two parts: matrix permeability and permeability induced by cracks. Based on the plastic damage model, an anisotropic poroplastic damage model was developed within Biot¿s theory. The comparisons between numerical simulations and data presented good accordance.