In Non-Assoc MC (Zambrano et al. 2022), the inertial coefficient is incorrectly calculated. The viscous coefficients need to be correlated using a diameter $D$ in meters and not in mm. The formula in the paper is
$$I = D \dot{\epsilon_{q}} \sqrt{\rho_{s}/p'}$$
where,
I: Inertial Coeff.
$\dot{\epsilon}$: Deviatoric Strain rate
$\rho_s$: Particle (solid) density
$p'$: confinement pressure (Mean effective stress)
The formula in the paper is
$$I = D \dot{\epsilon_{q}} \sqrt{G_{s}/p'}$$
where,
I: Inertial Coeff.
$\dot{\epsilon}$: Deviatoric Strain rate
$G_{s}$: Particle (solid) specific gravity
$p'$: confinement pressure (Mean effective stress)
In the code $p'$ is in [kPa] and D in [mm]. $p'$ in kPa cancels the scaling from the density term being converted to specific gravity but D in [mm] is wrong. The viscosity parameters need to be recalibrated to match the experimental data.