A combined method of determining the physicomechanical properties of rocks

Abstract

We suggest a combined test method based on indentation of a plane punch. The main problem in devising a combined test method was to obtain, in a single scheme of loading on a limited piece of rock, a complex of strength, elasticity, plasticity, and creep characteristics. The method which was devised permits testing on rocks in a complex state of stress either in atmospheric conditions or under varying hydrostatic pressure. The method is sensitive to anisotropy of the properties of the rocks.The basis of our suggested test scheme was a scheme of loading by indentation of a plane punch. The scheme of loading in a complex state of stress has an elastic solution with the possibility of interpretation of the stress compenents by tests on isotropic and transversely isotropic media such as sedimentary rocks [1][2][3][4][5][6][7].According to the well-known contact problem in the theory of elasticity, the pressure under the base of a circular plane punch of radius a pressed into an elastic half-space by a force P, with a pressure q(x, y) in the region A outside the punch, is given by P(x, y) = --.