Effect of Friction Packing Limit and Drag Model for Predicting Soil Fluidization Behavior due to Pipeline Leakage

Soil fluidization can trigger severe disasters, such as the failure of dams, settlement of buildings, and formation of sinkholes. The present study investigates leakage-induced soil fluidization using two-fluid model coupled with the kinetic theory of granular flow. The effect of friction packing limit, FPL, and drag law is assessed, which are crucial parameters in modelling transitions in granular flow regimes. FPL is the threshold value of the solid volume fraction beyond which frictional stresses become significant. It was found that the hydrodynamics parameters such as cavity dimensions and solid phase velocity were considerably affected by FPL. Gidaspow drag law fairly predicted soil fluidization compared to other investigated models. It was observed that inaccurate specification of these parameters may lead to unrealistic predictions of flow behaviour, such as early erosion or excessive fluidization.