Modification of capillary pressure by considering pore throat geometry with the effects of particle shape and packing features on water retention curves for uniformly graded sands

Accurate estimation of capillary pressures at pore throats during pore network simulation is made by acquiring the effective distribution of non-wetting fluid and its effective shape factor. The suggested method is applied to authentic pore structures of synthetically assembled sphere packings and natural sands. Results highlight that the irregularity of pore throat tends to increase as particle shape becomes irregular while the effective shape factor of 0.8 can be consistently applicable regardless of particle shape. The modified water retention curve well captures experimental results. Packing density and gradation effects are less predominant compared with the effect of capillary pressure correction.