How Does In Situ Stress Rotate Within a Fault Zone? Insights From Explicit Modeling of the Frictional, Fractured Rock Mass

We quantitatively investigate the spatial stress variations within fault zone rock mass by explicitly incorporating macroscopic fractures into a 2D multilayer model. Based on elastic crack theory, we first derive unified constitutive law for frictional fractures, featuring and plastic shear deformation shear-induced dilatancy. To honor varying degrees of damage across zones, model is composed densities randomly oriented from layer to layer. Under boundary conditions specific global mechanical response each related local fracture deformation. show that major principal always rotates toward limiting angle 45° with respect plane differential invariantly decreases increasing density. Approaching core, mean can either increase or decrease, depending whether strikes at high (>45°) low (<45°) regional stress. Accumulated also results in decrease effective Young's modulus Poisson's ratio fractured mass, respectively. Both properties pore pressure affect modulating fracture-associated relative proportion components. Our illuminates systematic situ stresses mature fault.