... produce the macroscopic response of the rocks. The role of inter-granular bond strength, initial microfractures present, and inter-granular bond stiffness were investigated. It was found that initial micro-fractures present in a rock sample is the main reason for producing the bi-modularity in rock...

... pinnacle ridge upstream oil & gas alteration microfracture journal breccia matrix permeability research deformation propylitic alteration kennedy taupo volcanic zone strength Rock Mechanics for Natural Resources and Infrastructure Development Fontoura, Rocca & Pavón Mendoza (Eds) ©...

... for the d.eter:mined elastic parameters. In particular the orientation and distribution of existing microfractures, as well as their readiness for activation under load are crucial for the interpretation of the obtained results. ,. , RESUME: Le "Stainzer Plattengneis fait partie d'une zone n5gionale ductile de...

... ABSTRACT: Strain gauge, acoustic emission and scanning electron microscope observations were used to identify and characterize the development of stress-induced brittle microfractures in samples of Lac du Bonnet granite loaded in uniaxial compression. Results suggest that initial cracking...

..., microfracturing activity begins at low stresses and accelerates rapidly as the fracture strength is approached. In creep tests, similar microfracturing occurs in time, resulting in creep. All inelastic properties of brittle rocks can be explained by this brittle process. As the fracture strength is approached...

..., under confining pressure 500 (brittle), 1000 (transitional), and 1500 (ductile) bars. Microscopically the fractures are observed from quite early stages, immediately after the initial loading. The cumulative length of microfractures increases proportionate to the residual strain. As loading indreases...

... contains a brief discussion of the deformational response of rock at low stress levels in terms of structural discon- tinuities represented by grain boundaries, grain boundary microfractures and grain orientation. A theoretical relationship and corresponding model is developed, in terms of plastic...