Title: A Coupled u-p SPH Framework for Large Deformation Modeling of Fluid-Saturated Granular Flows

Author (Table Talk): Enrique del Castillo, Princeton University

Abstract:

In this work we develop a strongly-coupled u-p version of the Biot-Zienkiewicz equations for saturated porous or granular media using a single particle layer, two-phase (solid and fluid) framework within the meshfree Lagrangian smoothed particle hydrodynamics (SPH) method. The formulation results in an explicit rate equation for the pore pressure, while allowing for compressibility of the fluid phase. We discuss the formulation and its limitations from a numerical point of view and verify it against poroelasticity benchmark problems. Next, we model saturated granular flows in the form of column collapse tests and retrogressive landslides occurring in saturated sensitive clays under quasi-undrained conditions. We compare our results using the strongly-coupled framework against a penalty-method type formulation for undrained conditions, and our results emphasize the importance of using strongly-coupled hydromechanical modeling even for quasi-undrained conditions, contrary to the predominant practice in the retrogressive landslide modeling literature, as the structural features of the landslides vary significantly when pore pressure dissipation and coupled effects are included.