The effects of inertia on crack growth in poroelastic fluid-saturated media

A closed-form asymptotic solution is provided for the stress, pore pressure and displacement fields near the tip of a Mode I crack, dynamically running in an elastic fluid-saturated porous solid. The Biot theory of poroelasticity with inertia forces is assumed to govern the motion of the medium. At variance with the quasi-static case where the crack-tip is effectively drained, for rapid transient crack propagation, the pore fluid has no time to diffuse away from the crack-tip.Both a qualitative analysis and the obtained asymptotic solution reveal that the pore pressure near the crack-tip displays the same square root singularity as stress in the solid skeleton. Previous analyses have neglected the inertia of the fluid and obtained a regular pore pressure.