An Embedded Finite Element Method (E-FEM) for Fluid Flow and Coupled Hydro-Mechanical Analysis in Fractured Porous Media

This study presents a new numerical approach based on the E-FEM, utilizing a multi-layer framework for modeling subsurface seepage phenomena in deformable porous media with natural fractures. The proposed method integrates a discrete strong discontinuity approach for the displacement field with a coupling finite element framework for the fluid pressure field. In the mechanical problem, a kinematic condition is introduced to facilitate the transmission of crack openings (without the need for additional degrees of freedom), modelled simply using shear and normal stiffness, to the neighboring nodes. Furthermore, the new approach enables the independent modeling of fluid flow in both the porous bulk and the fractures, with coupling between the two achieved without introducing extra degrees of freedom into the system. Since only standard shape functions are utilized in both deformation and fluid fields, the implementation remains straightforward, eliminating the need for specialized integration procedures within split subdomains (commonly required with X-FEM). As a verification example, a porous rectangular domain with multiple fractures is analyzed to assess the performance of the proposed method against a reference solution. A good agreement is observed between the two solutions, demonstrating that the proposed method can significantly enhance the modeling of coupled problems in geomechanics and geo-energy applications.

کلیدواژه ها:

Hydro-mechanical coupling ، Fractured porous media ، Embedded discontinuities ، Coupling finite elements