Stabilité du front de taille d’un tunnel dans un milieu frottant approche cinématique en calcul à la rupture

Abstract

The face stability of a shallow tunnel in sand is investigated in this paper. Using the yield calculation approach and particularly the upper bound theorem of plas- ticity, a method is proposed to obtain a limit value for the internai pressure ensuring face stability. Two kinds of two-dimensional mechanisms are consi- dered. In a first part attention is given to a tunnel which is deep enough so the ground surface effect can be neglected. The influence of geometrical and geotechnical parameters is studied. The case of shallow tunnels is then consi- dered, for which the effect of surface loads is also analized. Finally, calcula- tion results obtained by the herein proposed method are compared with experi- mental results from centrifuge tests.