A packaged modelling method to overcome the limitations of the current numerical modelling practices.

  • Cutting-edge numerical modelling technology without a need for specialist knowledge
  • Tested and Validated against numerous real life case examples worldwide

A unified material model that gathers the most notable recent advances in rock mechanics

IUCM was developed with the intention to address the limitations of the current material models used for rock mechanics. The role of a material model is to implicitly represent the underlying failure mechanisms that are in place without explicitly including the micro-structures, block interactions, or the fracturing process. Therefore, a suitable material model is one that can correctly represent the primary controlling mechanisms that occur during the process of rock mass loading and failure.

The IUCM gathers the most notable and widely accepted previous research work in the area of rock mechanics and integrates them into a unified constitutive model that can better and more accurately predict the stress-strain relationships in a continuum model. Several back-analyses and validation studies completed during the development of this model confirmed its applicability for a broad range of ground conditions, from intact-brittle hard rock to heavily jointed and ductile rock or anisotropic conditions.

In developing this model, the use of any new theory or technique was avoided where possible, and all the adopted processes were based on well-accepted and widely applied rock mechanics techniques and theories.

Most suitable material model for analysis of anisotropic rocks in sedimentary or metamorphic deposits

IUCM explicitly accounts for rock strength anisotropy. IUCM provides a mean to derive the anisotropic properties of the rock through a simple procedure where intact anisotropic properties obtained from laboratory tests are downgraded into the rock mass properties using the Hoek-Brown criterion. This results in two Hoek-Brown failure envelopes depending on the orientation of loading.

Key features and benefits of the IUCM

  • A detailed and transparent description of all the model’s components. This includes step by step instructions on the procedures that were implemented in each of the model’s algorithms.
  • The method has been extensively validated using several well-documented and well-known mining case histories.
  • A detailed guideline for selection of input parameters.
  • Full description of the current known limitations of the method.
  • The method offers considerably more reliable modelling outcomes in more complex ground conditions.
  • IUCM only requires four compulsory input parameters for isotropic rocks and three additional input for anisotropic rocks. All these inputs can be obtained from conventional laboratory testing and rock mass characterisation, which are often available in most mining projects.
  • Application of the IUCM requires much less expertise than other inelastic methods.


  • Vakili, A. 2016, An improved unified constitutive model for rock material and guidelines for its application in numerical modelling, Computers and Geotechnics, Volume 80, December 2016, Pages 261-282, ISSN 0266-352X, http://dx.doi.org/10.1016/j.compgeo.2016.08.020.(http://www.sciencedirect.com/science/article/pii/S0266352X16301884).

  • Sweby, G, Dight, P & Potvin, Y 2016, ‘A numerical modelling case study - correlation of ground support instrumentation data with a three dimensional inelastic model’, Ground Support 2016: Eighth International Conference on Ground Support in Mining and Underground Construction / Lulea Sweden.

  • Roache, B. 2016, ‘Mining in extreme squeezing conditions at the Henty mine’, Ground Support 2016: Eighth International Conference on Ground Support in Mining and Underground Construction / Lulea Sweden.

  • Watson, J.M., Vakili, A. and Jakubowski, M., 2015. Rock strength anisotropy in high stress conditions: a case study for application to shaft stability assessments. Studia Geotechnica et Mechanica, 37(1), pp.115-125.

  • 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 (AusRock 2014), The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 167‐180.

  • Mahabadi, O.K., Cottrell, B., Vakili, A. and Pitman, W. (2014). Numerical simulation of a shaft and loading pocket developed through squeezing talc-ultramafics. DFNE 2014. October 2014, Vancouver, Canada.

  • Vakili, A 2017, 'The improved unified constitutive model: a fine-tuned material model tailored for more challenging geotechnical conditions', in J Wesseloo (ed.), Proceedings of the Eighth International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 387-400. (https://papers.acg.uwa.edu.au/p/1704_27_Vakili/)

  • Talebi, R; Roache, B; Vakili, A; ,Understanding and Modelling Squeezing Ground Conditions at the Ballarat Gold Mine,,,,,,

  • Styles, TD; Vakili, A; ,Slope Angle Versus Slope Height–The Basis of an Empirical Tool for Slope Design Within Fractured Rock Masses using IUCM,ISRM International Symposium-EUROCK 2020,,,,2020,International Society for Rock Mechanics and Rock Engineering

  • Ford, A; Lucas, D; Vakili, A; ,Validation of the improved unified constitutive model for open pit applications,Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering,,,953-968,2020,Australian Centre for Geomechanics

  • Lucas, D; Vakili, A; Hutchison, BJ; ,Three-dimensional numerical modelling for successful design of steep slopes at the Kanmantoo copper mine,Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth,,,1083-1096,2020,

  • Watson, Julian Matthew; Vakili, Abouzar; Jakubowski, Mateusz; ,Rock strength anisotropy in high stress conditions: a case study for application to shaft stability assessments,Studia Geotechnica et Mechanica,37,1,115-125,2015,Sciendo

  • Vakili, A; Harvey, F; Greaves, H; ,Forecasting mine seismicity–towards a more established methodology,The Fourth Australasian Ground Control in Mining Conference. Sydney, NSW,,,207-222,2018,