Technical Stream | TC221 Virtual Session | Mechanical Behaviour of Mine Waste | Time (AEST) 09:45 - 10:45
Abstract
Evaluating the shear strength of mine waste rock containing particles of metre scale is a challenging task because commercial laboratory testing devices can only accommodate samples composed of particles a few centimetres in size. The shear strength empirical model of Barton & Kjærnsli (1981) is therefore frequently used to assess the nonlinear shear strength of very coarse granular material for stability assessment of mine waste dumps. According to the model, the stress-dependent structural component of the shear strength is dictated by the uniaxial compression strength of the parental rock, the degree of roundness of the constitutive particles, D50 particle size and the porosity of the material. This structural component is added to the basic friction angle determined on sawn surfaces of the rock to determine the material shear strength. In this article, we discuss practical methods for collecting the information required as input to the model. We also show the implementation of a Bayesian approach for the inference of the model parameters using the results of large-scale direct shear testing and the improvement of the estimation by considering additional information on the material. The approach allows for the customisation of the model parameters to consider a material characterised by high particle strength and a pronounced particle size-shape correlation, due to the sedimentary origin of the parental rock.
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