Time dependent movements induced by tunnelling in stiff cohesive soils: a parametric study

摘要

Tunnelling in urban areas below the ground water table requires the adoption of construction techniques aimed to minimize both induced settlements and variations of the existing ground water conditions. A series of 2d, coupled FE analyses have been performed in order to study the time dependent effects of tunnel excavation and transient seepage towards the tunnel. The results obtained in the parametric study allow to define some non-dimensional groups controlling the problem, and to estimate the relative effects of different factors on the induced ground surface subsidence. In particular, the mutual effects of excavation rate, soil permeability and promptness of lining construction are shown and critically discussed.