Research Center for Geomechanics and Mining Practice Problems, Saint-Petersburg Mining University, Saint-Petersburg, Russia:

M. D. Ilinov, Head of Laboratory, Candidate of Engineering Sciences, Ilinov_md@spmi.ru
V. A. Korshunov, Leading Researcher, Candidate of Engineering Sciences
G. B. Pospekhov, Leading Researcher, Associate Professor, Candidate of Geological and Mineralogical Scientists
A. N. Shokov, Senior Researcher, Candidate of Engineering Sciences

From the standpoint of modeling of real-life rock mass processes, the main problems of mechanical rock testing are connected with the limitation of sampling and low quality of samples; with weak representativity of actual data to model rock mass structure, stresses strains, rock failure mechanism and testing conditions, as well as with the deficient information content of modern determination procedures. The authors put forward an integrated approach to the analysis of mechanical properties of rocks, within which the tests are accompanied by the models of deformation and failure processes running in a real-life rock mass. In particular, it is recommended to model stress redistribution in a sample similar to the complex nonuniform stress state of rock mass, when a number of types of failure materialize (tension, shear and quasi-plastic deformation under high pressure). It is necessary to modify the approach to the rock mass strength assessment by plotting a family of failure envelopes for representative rock mass structures using the pooled data of integrated direct, indirect and correlation methods of sample properties determination. To this effect, the tests of the regular shape samples should be supplemented by the tests of the irregular shape samples using spherical indenters, to provide a complete set of strength characteristics of representative rock structures. When it is impossible to carry out the integrated testing, it is recommended to find basic characteristics of strength and deformability of rocks from correlation dependences based on the elementary information on functional characteristics of monolith samples.

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