Lower bound limit analysis of unsupported vertical circular excavations in rocks using Hoek-Brown failure criterion

Kumar, J and Rahaman, O (2020) Lower bound limit analysis of unsupported vertical circular excavations in rocks using Hoek-Brown failure criterion. In: International Journal for Numerical and Analytical Methods in Geomechanics .

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Abstract

The stability of vertical unsupported circular excavations in rock media, obeying generalized Hoek-Brown yield criterion, has been investigated by using the lower bound finite elements limit analysis. An axisymmetric analysis, composed of a planar domain with a mesh of three-noded triangular elements, has been carried out. The optimization problem is dealt with by using the semidefinite programming technique avoiding the need of either smoothing the yield surface or making any assumption associated with the circumferential stress (�θ). A detailed parametric study has been executed, and the effects of different input material parameters, namely, geological strength index (GSI), yield parameter (mi), and the disturbance factor (D) on the results have been studied. For different height to radius ratios of the excavation, the computed results are presented in the form of nondimensional stability numbers. Failure mechanisms have also been investigated for a few typical cases. The results from the analysis have been compared with that evaluated separately with the application of the software OptumG2.

Item Type:	Journal Article
Publication:	International Journal for Numerical and Analytical Methods in Geomechanics
Publisher:	John Wiley and Sons Ltd
Additional Information:	Copyright of this article belongs to John Wiley and Sons Ltd
Keywords:	Application programs; Excavation, Axisymmetric analysis; Generalized hoek browns; Geological strength index; Hoek Brown failure criterion; Limit analysis; Lower bound limit analysis; Semi-definite programming; Yield criteria, Failure (mechanical)
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	04 Mar 2020 10:49
Last Modified:	04 Mar 2020 10:49
URI:	http://eprints.iisc.ac.in/id/eprint/64646

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