Fracture Stiffness And Aperture As A Function Of Applied Stress And Contact Geometry

An analytical model that assumes variable height asperities and full interaction between them has been developed and implemented numerically to study the behavior of a single fracture under stress. The model has been used to calculate specific stiffness and aperture profiles for specified fracture geometries. The formulation takes account of the deformation of the half-planes defining the fracture which is shown to lead to changes in aperture geometry that are not predicted by other asperity models. A parameter sensitivity stud shows that specific stiffness varies significantly depending on the size of the asperities, their height distribution, and their spatial orientation. Curves of stress vs. specific stiffness generated with the model are found to agree in shape and magnitude with those obtained in the laboratory for rock specimens.