Impact of intergranular bonds on morphology transition of two-phase fluid-induced deformation

We conduct experimental and theoretical investigations into the previously unexplored effects of intergranular bonds within cohesive granular skeletons on multiphase flow dynamics. We illuminate that fluid forces can become large enough to surpass bond strength, leading to bond breakage and fracture initiation as capillary numbers increase. A first-ever phase diagram of five distinct fluid-fluid-grain displacement morphologies is established under varying flow and cohesion conditions. Through dimensional analysis, we propose a fracturing number ${N}_{f}^{*}$ = 1 as a theoretical threshold to characterize the onset of fluid-induced fracturing in cohesive media.