Precision Measurements of Pore Pressure Gradient and Solid Deformation in a Flow-Compacted Poroelastic Medium

When subjected to sufficiently high fluid pressure gradients, poroelastic media are observed to deform due to viscous drag on their solid matrix. The steady-state deformations and, by extension, fluid pressure gradients are generally nonlinear; a given segment of solid backbone needs to counterbalance both the local pressure gradient and any impinging upstream solid matrix. In order to close our theoretical understanding of these nonlocal effects, we empirically investigate the interrelation between material deformation, pore pressure gradient, and volume flux for a given pressure head. To measure these quantities, we subject a latex sponge constrained within a cylindrical cell with a rigid, permeable outlet to uniaxial flow driven by a fixed pressure head. Both the wall friction and the material properties of the sponge influence the interpretation of the experimental data; we discuss in detail our approach to mitigating and modelling these complicating effects.