A stabilized two-phase PD-FEM coupling approach for modeling partially saturated porous media

In the present manuscript, a stabilized two-phase PD-FEM coupling approach is developed for simulating deformation and fracture propagation in partially saturated porous media. Under the assumption of passive air pressure, the two-phase coupled model is derived based on the generalized Biot's theory. Two separate layers with different discretizations are coupled to solve the multiphase system, where the deformation and fracture of the solid phase is captured by the non-ordinary state-based peridynamics (NOSBPD) layer, while flow fluids are modeled by the finite element method (FEM) layer. Variables dependent on the capillary pressure, such as water saturation and permeability, are incorporated into the coupled model through the experimentally determined functions. Stabilization introduced via the Polynomial-Pressure-Projection technique, permits using low-order interpolation functions for the pore pressure field and coarse discretization for the PD layer. The accuracy of the proposed stabilized two-phase model is evaluated by two benchmark problems having either analytical or experimental data. The ability of the proposed formulation to simulate fracturing in a partially saturated porous medium has been studied for two problems: an edge crack subjected to mode I loading and fluid-driven fracturing.

Automated summary

In this paper, a stabilized two-phase PD-FEM coupling approach is developed for simulating deformation and fracture propagation in partially saturated porous media. The method couples two discretized layers to accurately capture the deformation and fracture of the solid phase and the flow of fluids. Variables related to capillary pressure are incorporated into the model through experimentally determined functions.