Modeling coupled fluid-grain deformation within fault zones Conference Paper uri icon

abstract

  • Shear of faults often concentrates within a layer of" fault-gouge"-granular fragments produced by wear of the wall rock during shear. The pores between the grains are in many cases filled with fluid, and the fluid pressure in this granular layer controls the strength of the whole fault zone according to the law ofeffective stress'. We study coupled granular- deformation and fluid pore pressure changes within a shearing layer, using a new two-scale two-phase model: the grains are modeled at the grain scale using a granular dynamics algorithm, while the fluid is simulated on a slightly coarser Darcy porous-flow scale. The formulation for the fluid is based on first principles and is general enough to account for the fluid response to both elastic and inelastic finite deformation of the granular matrix. Using both simple analytical predictions under an infinite stiffness assumption and fully coupled …

publication date

  • January 1, 2009