We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Durham University

Research & business

View Profile

Publication details for Professor Ashraf Osman

Osman, A. S & Birchall, T. J. (2014), Modelling tertiary creep in geomaterials using a continuum damage mechanics approach, in Soga, Kenichi, Kumar, Krishna, Biscontin, Giovanna & Kuo, Matthew eds, International Symposium on Geomechanics from Micro and Macro. Cambridge, UK, CRC Press, London, 705-708.

Author(s) from Durham


Tertiary creep is often observed in soft rocks and it represents a problem in a mining environment.
Tertiary creep behaviour appears due to progressive micro cracking of the material and would result in a
loss of strength and stiffness, which may eventually lead to failure and a complete loss of load carrying capability
of the material. In this paper, the authors combined the continuum damage mechanics within the framework
of hyperplasticity, thus encompassing viscoplasticity and damage within a single theory. The authors
present a family of models which obeys the laws of thermodynamics. The entire constitutive behaviour is derived
from two scalar potentials; a free energy potential which provides the elasticity law, and a dissipation
potential which provides the yield function, the direction of plastic flow and the evolution of a damage variable.
No additional assumptions are required. These new models require only few parameters which have physical
meanings and are capable of capturing tertiary creep observed in soft rocks.