ABSTRACT
The “convergence-confinement” method, based on the simplified scheme of a circular tunnel under isotropic in situ stress, represents a useful tool for analyzing ground-lining interaction in preliminary design stages. In the paper, the stress-flow conditions around a tunnel driven through a saturated elastic or elasto-plastic medium are investigated. As common problems in soil mechanics, the stability and the deformation of a structure can be assessed under short- and long-term conditions. The same approach has sometimes been adopted in tunnel design by utilizing the characteristic curve of the tunnel evaluated separately for undrained and steady-state drained conditions. The applicability of such a simplified method is discussed by comparing it to the results of the fully-coupled model.
