In the general complex of problems on the destruction of rocks, an important place is occupied by the development of a theory of strength and the improvement of methods of testing them. As a result of the research conducted, new concepts of the properties of rocks and the mechanism of their failure have emerged. The article deals with the relationship between the theory of strength and the mechanism of failure and presents methods for constructing stress diagrams and their interpretation. ...

The paper by A. M. Penkov and A. S. Bondarchuk summarizes the results of an experimental study of stresses in steel ropes. On the basis of the method developed by the authors it is shown that the discrepancy between the experimental and theoretical data is from 22 to 29% in the direction of reducing the safety margin.