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This isotropic material uses a strain-dependent permeability tensor as formulated by [36]: $$\begin{equation} \mathbf{k}=k\left(J\right)\mathbf{I}\,,\label{eq502} \end{equation}$$ where, $$\begin{equation} k\left(J\right)=k_{0}\left(\frac{J-\varphi_{0}}{1-\varphi_{0}}\right)^{\alpha}e^{\frac{1}{2}M\left(J^{2}-1\right)}\,.\label{eq503} \end{equation}$$ When $\alpha>0$ , pore closure occurs as $J\to\varphi_{0}$ from above, in which case $k$ reduces to $0$ . Setting $\alpha=0$ and $M=0$ produces a constant permeability. In the limit of infinitesimal strains, $$\begin{equation} k\left(J\right)=k_{0}\left(1+\left(M+\frac{\alpha}{1-\varphi_{0}}\right)\left(J-1\right)+\mathcal{O}\left(\left(J-1\right)^{2}\right)\right)\,.\label{eq:perm-HM-Taylor} \end{equation}$$