Abstract Water can strongly affect the mechanical behavior of granular materials. In this study, numerical simulation is conducted to investigate the effect of water content described by saturation on the collapse of granular columns. A coupled CFD-DEM model is adopted for the wet granular materials from pendular state to capillary state (saturation from 30 to100%), and the discrete element-liquid bridge model is adopted for the wet granular materials of pendular state (saturation less than 30%). The influence of saturation, particle radius, and friction on the shape of the deposit is studied, and the final deposit boundary is fitted by a bilinear model. In addition, the fluidity is studied by the motion of mass center of granular materials. Numerical examples show that within the saturation range from 0.1 to 0.5% and from 30 to 100%, the water has an obvious effect on final deposit shape. Within the saturation range of 0.5–30%, the water has little effect on the final deposit shape. For the saturation range of 0.1–0.5%, the fluidity decreases with the increase of saturation, and when the saturation is more than 30%, the fluidity increases with the increase of saturation. The study revealed the influence of interstitial water on the fluidity of granular materials, which is significant for the researches of geological engineering problems, such as landslides.Graphical abstract
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