Multiscale Fracture-Damage Modeling of Multiphase Porous Media: from Fracking to Landslide
Despite considerable efforts made in the development of advanced computational methods, the simulation of severe damage processes in porous media (such as fracking and landslide) remains challenging due to the complex material damage mechanisms, extreme deformations as well as hydro-mechanical couplings of water, air and solid in geomaterials. This work first discusses a stabilized and nodally integrated fluid pressure projection method to achieve a stable equal-order reproducing kernel approximation for the mixed hydro-mechanical formulation. By using the implicit gradient approximation, stabilization terms associated with the gradients of strain and fluid pressure fields are introduced into the mixed formulation at very low computational cost. Next, a damage particle method which approximates fractures by a set of damaged particles is presented. For each damaged particle, a continuum damage mechanics model is adopted as a smeared type description of the equivalent crack segment at the nodal position, and a dissipation energy-based scaling law is introduced to address the mesh dependency issues. In addition, a micro-crack informed anisotropic permeability model is formulated to describe the enhanced fluid flow along crack paths. Finally, the proposed meshfree computational framework is applied to the simulations of fracking processes and landslide events with results validated against experimental observations.