  We perform a novel analysis of the granular texture of a granular bed close
to stability limit. Our analysis is based on a unique criterion of friction
mobilisation in a simulated two-dimensional packing. In this way, we recover
the bimodal character of granular texture, and the coexistence of weak and
strong phases in the sense of distinct contacts populations. Moreover, we show
the existence of a well-defined subset of contacts within the weak contact
network. These contacts are characterized by their important friction, and form
a highly coherent population in terms of fabric. They play an antagonistic role
with respect to force chains. We are thus able to discriminate between
incoherent contacts and coherent contacts in the weak phase, and to specify the
role that the latter plays in the destabilisation process.
