ABSTRACT
The 57 km Lyon-Turin Euralpin Tunnel (TELT) between France and Italy is under construction. The underground works in the highly squeezing zone, known as “Houiller Convergent,” are executed using the conventional method. Reconnaissance works began in 2002, with the Saint-Martin-La-Porte SMP4 site (2014-2022) completing its last phase. This publication describes the approach for studies on the remaining works in the zone, analyzing data from previously executed works to manage the terrain’s highly variable and deformable behavior. The methodology includes analyzing over 200 convergence measurements in the south tube, spanning approximately 1 km. A back-analysis was first conducted by applying an analytical law for time-dependent displacements proposed by Sulem et al. (1987). An inverse approach based on the convergence-confinement method was then used to define the short-term geomechanical parameters. The research presented here is crucial for the ongoing studies, aiming to mitigate uncertainties and minimize risks associated with the excavation.
