commit 5441c00dbbb949a104613d8c453545d37c2cba49
parent 76eb1fda78781efe4bc83141688d0834d6ebae2d
Author: Anders Damsgaard <anders@adamsgaard.dk>
Date: Mon, 21 Oct 2019 10:27:24 +0200
Merge branch 'master' of https://git.overleaf.com/5d108663123e620bea96dc22
Diffstat:
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/continuum-granular-manuscript1.tex b/continuum-granular-manuscript1.tex
@@ -123,7 +123,7 @@ A common implementation is a regularized form where shear stress vanishes when s
In these forms the shear stress is still limited to the Mohr-Coulomb value at higher rates \citep{Schoof2006, Bueler2009, Schoof2010}.
However, the Coulomb-frictional parameterizations do not describe the actual sediment deformation, but describe the basal friction felt by the flowing ice.
Shear deformation is known to deepen under increasing effective normal stress \citep{Fischer1997, Iverson1999, Boulton2001, Damsgaard2013}, and this may be a primary ingredient for growth of subglacial topography \citep[e.g.,][]{Schoof2007}.
-In order to model soft-bed sliding and till continuity, a model is necessary that accurately describes subglacial shear strain while being in accordance to Mohr-Coulomb friction and sediment near-plastcitiy.
+In order to model soft-bed sliding and till continuity, a model is necessary that accurately describes subglacial shear strain while being in accordance to Mohr-Coulomb friction and sediment near-plasticity.
The discrete element model for sediment deformation by \citet{Damsgaard2013} includes Coulomb-frictional physics and sediment strain distribution, but is far too detailed and costly for coupled ice-till computations.
@@ -152,6 +152,7 @@ For a given material, the critical-state ratio between shear stress and normal s
The dependence allows for empirical relationships where $\mu(I)$ takes form of a highly non-linear Bingham rheology.
Tuned to experiments on simple granular materials, the material is more rate dependent at large inertia numbers (i.e., ``landslide regime'').
With smaller inertia numbers, the behavior smoothly transitions to a ``pseudo-static regime'' of near rate independence ($I < 10^{-3}$).
+
Similarly, shear-zone porosity was in monodisperse materials found to linearly depend on $I$ \citep{Pouliquen2006}.
The relationships for strength and porosity act as constitutive relations, making continuum modeling of granular flows possible.
\citet{Pailha2008} and \citet{Pailha2009} demonstrated simple coupling of the continuum granular model to pore-pressure dynamics.
