Stresses and Temperature Affecting Acoustic Emission and Rheological Characteristics of Rock Salt

Abstract

Synchronized acoustic emission and strain measurements were carried out in rock salt samples subjected simultaneously to different levels of uniaxial mechanical and incrementally increasing temperature effects. Methodological and hardware support of such measurements is described. Experimental dependences are obtained, which reflect changes in shear strains and acoustic emission activity of samples as functions of time and temperature for different axial stresses. As the stresses increase, rock salt transits to the stage of progressive creep at lower temperatures. The transition to each subsequent stage of the temperature effect is accompanied by an increase in the steepness of shear strains and activity-average acoustic emission. The patterns of changes in these parameters at the stages of steady and progressive creep of rock salt are analyzed. The advantages of using acoustic emission measurements to predict rock salt failure due to progressive creep, as well as their importance for solving the problem on estimating salt rocks properties in real thermobaric conditions for the construction and operation of underground gas storages are noted.