OGS

A strain dependent intrinsic permeability model.
The model was proposed in [44] and it was further investigated in [45] .
The model takes the form of
\[ \mathbf{k} =f(\epsilon_v) e^{b_1 {\bar\epsilon}^p}\mathbf{k}_0 \]
with
\[ f(\epsilon_v)= \begin{cases} 10^{b_2 \epsilon_v}, & \epsilon_v <=0\\ 10^{b_3 \epsilon_v}, & \epsilon_v >0 \end{cases} \]
where
\( \epsilon_v \)  the volumetric strain, 
\( {\bar\epsilon}^p\)  the equivalent plastic strain, 
\(\mathbf{k}_0\)  the initial intrinsic permeability, 
\(b_1,\,b_2,\,b_3\)  the three parameters. 
No additional info.
Used in no endtoend test cases.