  We study the rheology of dry and wet granular materials in the steady
quasistatic regime using the Discrete Element Method (DEM) in a split-bottom
ring shear cell with focus on the macroscopic friction. The aim of our study is
to understand the local rheology of bulk flow at various positions in the shear
band, where the system is in critical state. The general(ized) rheology has
four dimensionless control parameters that relate the time scales of five
significant phenomena, namely, the time scales related to confining pressure
$t_p$, shear rate $t_{\dot{\gamma}}$, particle stiffness $t_k$, gravity $t_g$
and cohesion $t_c$, respectively. We show that those phenomena collectively
contribute to the rheology as multiplicative correction functions.
  While $t_{\dot{\gamma}}$ is large and thus little important for most of the
data studied, it can increase the friction of flow in critical state, where the
shear gradients are high. $t_g$ and $t_k$ are comparable to $t_p$ in the bulk,
but become more or less dominant relative to $t_p$ at the extremes of the free
surface and deep inside the bulk, respectively.
  We also measure the effect of strong wet cohesion on the flow rheology, as
quantified by decreasing $t_c$. Furthermore, the proposed rheological model
predicts well the shear thinning behavior both in the bulk and near the free
surface; shear thinning develops to shear thickening near the free surface with
increasing cohesion.
