Mechanics of poroelastic geologic media susceptible to damage

The classical theory of poroelasticity developed by Biot (1941) deals with the time-dependent response of the fluid-saturated porous media derived from the coupling of the mechanical deformations and the deformations of pore fluid. The classical theory of poroelasticity has been successfully applied to a range of problems of interest to geomechanics and biomechanics. The brittle poroelastic media can experience alterations in poroelasticity properties resulting from the generation and/or growth of micro-defects. The effects can be modelled by appeal to continuum damage mechanics. Damage-induced alterations can influence the consolidation behaviour of a damage-susceptible poroelastic medium. Continuum damage mechanics concepts can be incorporated within the theory of poroelasticity to model the damage-induced alterations in poroelasticity properties. This thesis deals with the development of a computational procedure for modelling the damage-induced alterations in both elasticity and hydraulic conductivity characteristics of a brittle poroelastic medium. Furthermore, the evolution of damage can also exhibit a stress state-dependency. The computational procedure has also been extended to include the stress state-dependent evolution of damage in brittle poroelastic media. The alterations in the elastic stiffness and the hydraulic conductivity are characterized through a damage evolution function with relationship to distortional strain invariant. The stress state-dependency of the damage process is governed by the state of the volumetric strains. It is assumed that an overall decrease in the volumetric strains does not result in damage evolution.; The computational procedure that accounts for damage-induced evolution of stiffness and hydraulic properties and stress state dependency in damage evolution are used to model practical problems of interest in geomechanics, applied mechanics and civil engineering. The fluid pressure development within a spheroidal fluid inclusion surrounded by a damage-susceptible poroelastic medium has been examined through the computational procedure. The computational procedure has also been used to study time-dependent translational displacements of a rock socket embedded in a damage susceptible soft rock and the procedure has been also applied to examine the time-dependent in-plane displacements of a flat elliptical rigid anchorage. The computational results indicate that the consolidation behaviour of the brittle poroelastic media can be significantly influenced through consideration of the damage-induced alterations in both the elastic stiffness and the hydraulic conductivity, the latter property exerting a greater influence. The dependency of the evolution of damage to the state of stresses can also influence the consolidation of a poroelastic medium.