Analytical study of the post-closure behaviour of a deep tunnel in a porous creeping rock mass

The deferred behaviour of underground cavities is often encountered in geotechnical engineering. This paper presents an analytical approach for the post-closure behaviour of a deep tunnel inside a rock mass considering both creep and hydromechanical couplings. Creep, supposed slower than hydraulic flow, is described by a linear Norton-Hoff law in the particular case of an elastically incompressible rock mass (i.e. Poisson's ratio ν=0.5). The resolution uses Laplace transform and Stehfest's algorithm. Numerical examples are carried out to enlighten the hydromechanical responses around the tunnel and to show the consistency of the solution.