ABSTRACT
A phenomenological strength criterion for brittle polycrystalline materials (including rock) in multi-axial stress states is proposed. This criterion allows for the strength of materials to be assessed practically with any combination of principal stresses. It is based on the maximum distortion energy theory. It does not contain parameters which could require additional evaluation (excluding uniaxial compressive and tensile strength data). The results well agree with the available experimental data. This criterion can be used for assessment of strength of brittle polycrystalline materials, such as rocks and concrete, for strength analysis of concrete structures and their foundations by numerical methods.
Proposed criterion can also be used to assess the strength of the riprap. This conclusion is confirmed by numerous experiments conducted for a number of rockfill dams in Mexico, as well as to evaluate the strength of rockfill materials under uniaxial loading, which can be used as a classification parameter.
The process of material destruction is always associated with the release of the energy expended for loading.
The failure process of a material is always connected with the energy consumption. Work performed by external forces leads to the accumulation of energy by the constituting elements of the material structure; failure of the material suddenly releases part of the cumulative energy.
The researches carried out indicate that there is a close relationship between rupture energy and intensity of the stress applied at the moment of failure. This relationship is valid for both the uniaxial and triaxial strength tests confirming that during the failure process there is a simultaneous mobilization of the tensile and shear strengths whereas the rupture energy is the result of energy distortion.
