Brown, IR & Wood, PJ 2023, 'The case for using three-dimensional limit equilibrium stability analysis', in PM Dight (ed.), SSIM 2023: Third International Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, pp. 927-938, https://doi.org/10.36487/ACG_repo/2335_63
(https://papers.acg.uwa.edu.au/p/2335_63_Brown/)
Abstract: At the previous Slope Stability in Mining conference, in 2021, Dr John Read claimed that there are geological and mathematical uncertainties in the method used for 3D limit equilibrium (LE) stability analyses. We acknowledge the valid issues raised by Dr Read, and our paper explains how we have developed a software system that provides a reliable 3D LE analysis for slopes in complex geology. Our experience with developing 3D LE software (TSLOPE) began in 1989 when we were able to show that the 3D LE analysis of the stability of a proposed canyon landfill in Southern California gave a much higher Factor of Safety than that calculated for a 2D section along the axis of the canyon. We have discarded many of the methods used in 2D LE software packages as they do not achieve full force and moment equilibrium and are a relic from a time when we were limited by computational ability. Our paper discusses the background and underlying theory supporting our 3D LE software and provides comparisons of 3D and 2D analyses carried out using the same geological model.

Keywords: slope stability, 3D, limit equilibrium, Spencer’s method, TSLOPE