On boundary condition in tunnels under partial saturation

Abstract

A new hydraulic boundary condition modelling the hydraulic transfers between porous medium and ambient atmosphere occurring during gallery excavations is described. It combines two modes of water exchanges in partial saturation: seepage and evaporation flows. Numerical simulations of a gallery excavation in dilatant geomaterial are carried out in isothermal conditions. The results show the influence of hydric boundary condition on the convergence of the gallery and the importance of the determination of vapour transfer coefficient between atmosphere and porous medium.