Authors: Sullivan, TD


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Sullivan, TD 2013, 'Global slope performance index', in PM Dight (ed.), Proceedings of the 2013 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth, pp. 55-80,

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The evaluation of the performance and risk of excavated slopes is a complex esoteric task. Slope designers are always faced with gaps and uncertainties and in many cases the conditions as exposed are significantly different to the design predictions. In theory these issues may be addressed with detailed, rigorous investigations, analysis and models. But experience shows that even this approach is not always successful and surprises occur. The paper presents a simple empirical system for predicting the current and future performance of excavated slopes. The system is the result of decades of experience with the design and evaluation of 100s of slopes excavated for both mining and civil purposes. The examples include a very wide range of slope heights, slope angles, environments and material types. The experience also covers the full spectrum of operational performance, from stable slopes, to complete collapse. In very simple terms three principal elements contribute to the stability of excavated slopes; intact strength, geological structure and groundwater. The Global Slope Performance Index (GSPI) is based on these three elements divided into five indices. These indices are each rated with a linear numerical scale and then combined into a simple algorithm, the GSPI. The index has been benchmarked against actual slope performances and demonstrated by statistical analysis, which allows the likelihood of different slope performances and risk to be determined based on the Global Slope Performance Index.

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