Poroelastic compaction length (${\ell }_c$)

For a skeleton with Young modulus $E$, undeformed solid fraction ${\varphi }_0$, grain-fluid density difference ${\rho }_s-\rho$, and reference gravity $g_0$, the hydrostatic poroelastic compaction length isIt is the depth over which self-weight changes the solid fraction appreciably.