The system of reliable deformational precursors of highly stressed rock samples failure

Abstract

Phenomena of anomalous deformation of rocks compressed up to failure have been studied in the laboratory on rock samples. A system of reliable deformational precursors of the failure stage has been developed. The system includes long-term, middle-term and short-term precursors. The threshold of dilatancy and the turning point of deformational curve are recognized as long-term precursor. The middle-term precursor is determined as a point of the increment sign change of the specific volume deformation. The short-term precursor is characterized by the specific volume deformation increments jump. The acoustic emission research method had been used to control the deformational and failure process. There was a tight correlation between the deformational precursors system of failure and the mesocracking process under the loading. Mathematical model of self equilibrium stresses had been successfully used to describe the anomalous deformations distribution.