Are large differential stresses required for straight fracture propagation paths?
Fracture growth geometries in linear elastic materials are sensitive to the ratio between the remote differential stress, or T-stress, and the fracture driving stress. Two mechanically interacting fractures follow straighter paths for greater values of this ratio. We demonstrate that the degree of curvature that develops between two mechanically interacting fractures is also controlled by such factors as sub-critical fracture growth and fracture surface roughness. Sub-critical fracture growth limits the development of fracture curvature by decreasing the fracture driving stress needed for propagation. Fracture surface roughness can affect the development of fracture curvature by limiting the magnitude of the shear displacement discontinuity that can be accommodated along the fracture. Thus, propagation paths for two mechanically interacting fractures can be quite straight even in the presence of small to moderate differential stresses. Consequently, the absence of fracture curvature does not necessarily imply a high differential stress state.
Journal of Structural Geology
- Pub Date:
- June 1994