CORRELATION BETWEEN IMPACT LOAD, UNIAXIAL COMPRESSIVE STRENGTH AND TENSILE STRENGTH OF BRITTLE ROCK

Abstract

The prediction of rock properties from indirect testing methods is important, particularly for preliminary investigations since direct methods are costly and time consuming. In this study, the correlation of the uniaxial compressive strength and brazilian tensile strength of rocks with impact energy was investigated. To carry out impact test on the rock specimen, a test setup was fabricated. Three types of model rocks, prepared from Plaster of Paris-sand mix, low strength concrete and medium strength concrete have been used for this study. The UCS and Brazillian tensile test results were correlated with the impact test results and the results were statistically analysed. A strong correlation between UCS and impact energy was found for all data. The correlation between Brazillian tensile test and impact energy is not as strong as the correlation between ucs and impact energy. As part of this study, the predictability of the UCS and Brazilian tensile strength of rocks from sound was also investigated. A mobile application was used to measure sound in the impact test for every impact on the rock specimen. The second part of the study includes a case study for comparison of the existing empirical equations for predicting penetration of projectiles into concrete with the penetration results from impact test setup. The results were statistically analysed and a correlation was developed between penetration calculated by empirical equations and those by impact test carried out in laboratory.