Stress trajectories in the neighborhood of fault zones

摘要

Stress trajectories around faults have been simulated with a 3-D finite element model. based on 8-nodel brick elements in five layers. Preliminary simulations imply that stress trajectory deflections in the neighbourhood of fault zones can be expected if there is a large geomechanical contrast between the fault zone and the adjacent rocks and it far field stress anisotropy is small. On the other hand, if the horizontal stress anisotropy is large, significant stress deflections appear unlikely to occur near a fault. Within a 'softer' fault zone #sigma#_H will be oriented approaximately perpendicular to the fault trace: within a 'harder' fault zone #sigma#_H wil be aligned approximately parallel to the trend. Magnitudes of maximum and minimum stress are modelled for soft and hard fault simulations. Significant modifications in stress magnitudes developed in the vicinity of the fault zones.