Effect of strength properties on displacement magnitude and fracturing amount inside a large open pit prone to toppling

Abstract

The study has presented a sensitivity analysis of a rock mass prone to toppling due to the variation of the strength parameters. The data from the Lornex pit at the Highland Valley Copper Mine, Canada, was used to calibrate and validate a discrete element model (UDEC-DM) that allows the fracturing of intact material. The numerical model presented in this study was used to monitor displacement at four different points to study the effects of variation of three rock mass strength properties (friction, cohesion, and tensile strength) on displacement. The amount of fracturing due to the variation of strength properties was also measured and averaged along three of the most possible failure paths where fracturing is of high intensity. The findings have shown that friction and cohesion have less effect than the tensile strength. The percent of fracturing and displacement decreases as the tensile strength increases. The tensile strength of the intact rock has a pronounced effect on fracturing and displacement, however, both friction and cohesion have an insignificant effect on both aspects of fracturing and displacement in this block toppling movement. The tensile strength is extremely important in practice and should be always evaluated; moreover, its effect on fracturing amount should not be underestimated.