Predicting the relationships between brittleness and mechanical properties (UCS, TS and SH) of rocks

Abstract

This paper presents the evaluation of uniaxial compressive strength (UCS) predicted from Shore hardness (SH) tests and to correlate brittleness concepts, which are derived from UCS, tensile strength (TS) and Shore hardness values of rock samples. Suggested empirical equations obtained from previous studies are summarised in order to predict UCS value of rocks from SH value. The data of UCS, TS and SH used in previous studies are limited and it was seen that the majority of correlation coefficients of the suggested empirical equations are low. However, the raw data used in this study showed a wide range of strength values of UCS (5.7 - 464 MPa), TS (0.5 - 30.5 MPa) and SH (9 - 100). A dataset containing 143 rock sample records from previous different studies, ranging from weak rock to very strong rocks, was used to investigate the relationships between SH and both UCS and three brittleness concepts. Regression analyses were performed and based on which empirical relationships between the physical-mechanical properties of rocks were developed. The relationships between SH and UCS, TS and Brittleness were investigated. The relationship between SH and the brittleness concept of B3 were found to be more significant than the other brittleness concepts. In this study, the physico-mechanical properties of the rocks investigated, present a wider range of data. Hence, the relationship established between UCS and SH is considered to be more reliable. Key words: Shore hardness, mechanical properties, brittleness.