development of a saturation-based mu(i)-rheology for wet granular materials using discrete element method

The discrete element method (dem) is used to establish a rheological model that relates the apparent viscosity of a granular material to shear rate, normal stress, and water saturation. a theoretical model is developed to determine water distribution and water-induced forces between particles for different saturations. the resulting forces are embedded in a 3d shear cell as a numerical rheometer and a wet specimen is sheared between two walls. a power law rheological model is obtained as a function of inertia number and saturation. it was found that up to a critical saturation, the apparent viscosity increases with saturation and is higher than that of the dry specimen. however, when the saturation exceeds a critical value, the viscosity suddenly drops below that of dry condition. to evaluate the model, the collapse of two-dimensional granular material on a horizontal rigid bed is studied using continuum-based numerical simulation which utilizes the proposed rheological model.