Analytical modelling of a deep tunnel in a viscoplastic rock mass accounting for a simplified life cycle and extension to a particular case of porous media

Abstract

AbstractAn analytical approach to the viscoplastic behaviour of a rock mass around a deep tunnel in different stages of a simplified life cycle is presented. The viscoplasticity is modelled by means of a simple (linear) Norton–Hoff's law. First, the solution for a dry rock mass is presented, then an extension to a particular case of a porous saturated rock mass with a Poisson's ratio of 0.5 is examined. Some numerical examples are carried out to show the consistency and relevance of the solutions. Parametric studies illustrate the influence of key parameters such as rock mass viscosity and time of lining emplacement. This analytical approach constitutes a useful reference to test more complex numerical simulation and makes it possible to obtain practical estimations of the poromechanical behaviour of underground structures.