Energetic Formulation of Large-Deformation Poroelasticity

TL;DR

This paper introduces a variational energy-based continuum mechanics framework for modeling large-deformation poroelasticity, enabling accurate simulation of complex geomechanical processes involving nonlinear solid deformation and fluid transport.

Contribution

It develops a novel variational formulation for large-deformation poroelasticity, integrating energy principles with finite element analysis for complex porous media behaviors.

Findings

Successfully models large deformations in saturated and unsaturated media.

Analyzes problems like Terzaghi and Mandel with nonlinear solid behavior.

Demonstrates potential for improved numerical methods and data integration.

Abstract

The modeling of coupled fluid transport and deformation in a porous medium is essential to predict the various geomechanical process such as CO2 sequestration, hydraulic fracturing, and so on. Current applications of interest, for instance, that include fracturing or damage of the solid phase, require a nonlinear description of the large deformations that can occur. This paper presents a variational energy-based continuum mechanics framework to model large-deformation poroelasticity. The approach begins from the total free energy density that is additively composed of the free energy of the components. A variational procedure then provides the balance of momentum, fluid transport balance, and pressure relations. A numerical approach based on finite elements is applied to analyze the behavior of saturated and unsaturated porous media using a nonlinear constitutive model for the solid skeleton. Examples studied include the Terzaghi and Mandel problems; a gas-liquid phase-changing fluid; multiple immiscible gases; and unsaturated systems where we model injection of fluid into soil. The proposed variational approach can potentially have advantages for numerical methods as well as for combining with data-driven models in a Bayesian framework.