HR: 1340h
AN: T33C-1487    [Abstracts]
TI: Stabilized low-order finite elements for simulating coupled solid deformation and fluid flow in fault zones
AU: * White, J A
EM: joshua.white@stanford.edu
AF: Stanford University, Civil and Environmental Engineering Stanford University, Stanford, CA 94305, United States
AU: Borja, R I
EM: borja@stanford.edu
AF: Stanford University, Civil and Environmental Engineering Stanford University, Stanford, CA 94305, United States
AB: In fluid-saturated sediments and sedimentary rocks, we recognize that the presence of the pore-fluid can serve to impose an incompressibilty constraint on the solid matrix in the limit of undrained conditions or fast loading rates. While such situations are commonly encountered in practice, they pose a challenge for the numerical analyst. From a finite element point of view, incompressibility constraints will often lead to non-physical oscillations in the pressure field unless special care is taken to use stable combinations of pressure and displacement interpolations. Unfortunately, many seemingly natural combinations of mixed interpolations---e.g. linear interpolations for both displacements and pressure---are unstable. The relatively high computational burden associated with standard stable elements has limited the widespread adoption of fully-coupled geomechanical models, especially for large three-dimensional simulations. In this work we explore a stabilizing modification of the coupled balance equations that allows for the use of low-order mixed elements while avoiding non-physical pressure oscillations. The improved efficiency of this technique is a step toward making large-scale, fully-coupled three-dimensional simulations feasible. We demonstrate the efficacy of the technique for simulating coupled solid deformation and fluid flow in fault zones.
DE: 3225 Numerical approximations and analysis (4260)
DE: 5120 Plasticity, diffusion, and creep
DE: 8020 Mechanics, theory, and modeling
DE: 8045 Role of fluids
DE: 8118 Dynamics and mechanics of faulting (8004)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting