Pells, PJN 2008, 'Assessing Parameters for Computations in Rock Mechanics', in Y Potvin, J Carter, A Dyskin & R Jeffrey (eds), SHIRMS 2008: Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium, Australian Centre for Geomechanics, Perth, pp. 39-54, https://doi.org/10.36487/ACG_repo/808_118
(https://papers.acg.uwa.edu.au/p/808_118_Pells/)
Abstract: Estimation of rock mass stiffness and shear strength parameters is fundamental to the validity of most applied mechanics calculations for rock mechanics design purposes. Estimation of such parameters is very difficult and has to be based on rock mass characterisation. Currently the Hoek–Brown approach using GSI is widely used for assessing stiffness and shear strength parameters. However, there appear to be few test data to support the parameters determined using this method. This paper presents case studies for both rock mass modulus and rock mass shear strength in an attempt to assess the validity of the approach of using GSI and the Hoek–Brown criterion. It is concluded that for some rock masses the method works well, but in other cases can give very misleading assessments of stiffness and shear strength parameters. It is also concluded that further work is required in collecting and analysing good case studies in order to provide guidelines for the profession.