Vakili, A 2017, 'The improved unified constitutive model: a fine-tuned material model tailored for more challenging geotechnical conditions', in J Wesseloo (ed.), Deep Mining 2017: Proceedings of the Eighth International Conference on Deep and High Stress Mining
, Australian Centre for Geomechanics, Perth, pp. 387-400, https://doi.org/10.36487/ACG_rep/1704_27_Vakili
The improved unified constitutive model (IUCM) is a result of collating the most notable recent research works in the area of rock mechanics and extensive back-analysis of mining case histories together into a unified material model. This model has proven to provide a considerably more reliable prediction of rock mass behaviour than currently available modelling methods. Also, a transparent presentation of the model components and a detailed guideline for selection of input parameters make the IUCM an excellent candidate to potentially become a standard material model for numerical modelling in rock mechanics. This model can possibly improve the numerical modelling practices through improved reliability, simplifying application, standardising input selection, simplifying third party reviews and enabling regeneration by third parties.
This paper first discusses the definitions, applications and limitations of conventional modelling methods. A practical and less theoretical introduction to the IUCM is then presented and finally, some case studies are shown where the predictive performance of this model is compared against the most commonly used material models.
Keywords: improved unified constitutive modelling (IUCM), advanced numerical modelling, constitutive model, material model
Alejano, LR & Alonso, E 2005, ‘Considerations of the dilatancy angle in rocks and rock masses’, International Journal of Rock Mechanics and Mining Sciences, vol. 42, no. 4, pp. 481–507.
Andrieux, PP, Brummer RK, Li, H & O'Connor, CP 2007 ‘Elastic versus inelastic numerical modelling of deep and highly stressed mining fronts’, in Y Potvin (ed.), Proceedings of the Fourth International Seminar on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 51–57.
Barton, N 2013, ‘Shear strength criteria for rock, rock joints, rockfill and rock masses: Problems and some solutions’, Journal of Rock Mechanics and Geotechnical Engineering, vol. 5, no. 4, pp. 249–261.
Barton, N & Pandey, SK 2011, ‘Numerical modelling of two stoping methods in two Indian mines using degradation of c and mobilisation of φ based on Q-parameters', International Journal of Rock Mechanics and Mining Sciences, vol. 48, no. 7, pp. 1095–1112.
Brown, ET 2008, ‘Estimating the mechanical properties of rock masses’, in Y Potvin, J Carter, A Dyskin & R Jeffery (eds), Proceedings of the 1st Southern Hemisphere International Rock Mechanics Symposium, vol. 1, Australian Centre for Geomechanics, Perth, pp. 3–21.
Diederichs, MS 1999, Instability of Hard Rockmasses: The Role of Tensile Damage and Relaxation, PhD thesis, University of Waterloo, Waterloo.
Diederichs MS, Kaiser PK, Eberhardt, E 2004, ‘Damage initiation and propagation in hard rock during tunnelling and the influence of near-face stress rotation’, International Journal of Rock Mechanics and Mining Sciences, vol. 41, no. 5, pp. 785–812.
Hajiabdolmajid, V, Kaiser, PK & Martin, CD 2002, ‘Modelling brittle failure of rock’, International Journal of Rock Mechanics and Mining Sciences, vol. 39, no. 6, pp. 731–741.
Martin, CD 1997, ‘The effect of cohesion loss and stress path on brittle rock strength’, Canadian Geotechnical Journal, vol. 34, no. 5, pp. 698–725.
Martin, CD, Kaiser, PK & McCreath, DR 1999, ‘Hoek–Brown parameters for predicting the depth of brittle failure around tunnels’, Canadian Geotechnical Journal, vol. 36, no. 1, pp. 136–151.
Read, RS 1994, Interpreting Excavation-induced Displacements Around A Tunnel in Highly Stressed Granite, PhD thesis, University of Manitoba, Manitoba, pp. 328.
Vakili, A 2016, ‘An improved unified constitutive model for rock material and guidelines for its application in numerical modelling’, Computers and Geotechnics, vol. 80, pp. 261–282.
Vakili, A, Albrecht, J & Sandy, M 2014, ‘Rock strength anisotropy and its importance in underground geotechnical design’, Proceedings of the Third Australasian Ground Control in Mining Conference, The Australasian Institute of Mining and Metallurgy, Melbourne, Carlton South, pp. 167–180.
Vakili, Α, Sandy, M & Albrecht, J 2012, ‘Interpretation of non-linear numerical models in geomechanics-a case study in the application of numerical modelling for raise bored shaft design in a highly stressed and foliated rock mass’, Proceedings of the 6th International Conference and Exhibition on Mass Mining, Canadian Institute of Mining, Metallurgy and Petroleum, Sudbury.