LEEB HARDNESS TEST FOR ROCK JOINT WALL COMPRESSIVE STRENGTH EVALUATION

Abstract

The Joint Wall Compressive Strength (JCS) parameter introduced by Nick Barton significantly influences predictions of rock discontinuity shear strength but current methods in obtaining this parameter are insufficient. A correlation equation for laboratory prepared intact rock specimens of sufficient size produced by Corkum et al. in 2018 has the capability of predicting the JCS value from a hardness value obtained with the Leeb hardness device. This device has the sensitivity required to predict the hardness of a weathered rock joint wall which makes it the ideal tool for this function. However, the methodology for application on rock surfaces of various conditions required consideration and study. To understand the validity of the strength value predicted, a thorough examination of what the hardness readings consist of was considered as being of paramount importance.