Effect of temperature variation on the behaviour of Bushveld rocks: comparison of laboratory test and numerical modelling results

Abstract

This paper presents the result of the research carried out on the effect of temperature on the Bushveld Igneous Complex (BIC), South Africa. The BIC has high virgin rock temperature. If the platinum mines advance to ultra-deep levels, then the virgin rock temperature at a depth of 5 km will be approximately 140°C. Hence, there is a need to improve the understanding of the behaviour of rock under high temperatures. Five rock types were tested in a 2600 kN servo-controlled testing machine. The testing was done at a controlled loading rate and a confining pressure 0, 10, and 30 MPa within temperature range of 20–140°C. Comparison was made between the results obtained from the laboratory experiments and numerical modelling. It was observed from the stress–strain behaviour of the samples that an increase in temperature results in the reduction of the Young's modulus and peak strength.