Reliability Increasing of an Estimation of Rocks Strength by Non-destructive Methods of Acoustic Testing Due to Additional Informative Parameters

Abstract

Forecasting the strength of rocks by non-destructive methods is a way of assessing the stability of the rock mass in the vicinity of underground excavations, quarries and wells. Regression relationships between rock strength and the velocities of longitudinal and transverse elastic waves are widely used in practice for the evaluation of strength. However, these velocities are insensitive and uninformative in the initial stages of crack development and in cases where the rock is formed from multiple components; this leads to a decrease in the reliability of the strength assessment. Using other informative parameters that characterise signal loss (such as the damping coefficients of elastic waves in the rock, acoustic quality factors, etc.) can increase measurement reliability. This report presents the results of laboratory investigations into the dependencies between the longitudinal and transverse wave velocities, the acoustic quality factor (Q factor) and the tensile strength during bending tests carried out on dolomites from the Genaldon Deposit and the gypsum-containing rocks of the Novomoskovsk Deposit. The possibility of their practical application in the evaluation of rock strength using the velocities of elastic waves and other informative parameters is discussed.