Analytical study of mine closure behaviour in a poro-elastic medium

This paper is concerned with the hydro-mechanical behaviour of an underground cavity abandoned at the end of its service life. Deterioration of the lining support with time leads to the transfer of the loading from the exterior ground to the interior backfill, both of which are of poro-elastic behaviour and saturated with water. This loading transfer is accompanied by an inward cavity convergence and an outward water flow, leading to a complex space-time evolution of pore pressures, displacements and stresses. An entirely explicit solution to this problem is developed, using Laplace transform. A few numerical examples are given to illustrate the hydro-mechanical behaviour of the cavity and highlight the influence of key parameters such as backfill stiffness and rate of lining support deterioration.