SOIL DEFORMATION ANALYSIS DURING TBM EXCAVATION: COMPARING THREE DIFFERENT TBM TECHNOLOGIES USED DURING THE CONSTRUCTION OF THE TOULOUSE METRO LINE B

摘要

The construction of tunnels in Toulouse molasses by a conventional method and three different pressurised closed-face TBM lead to small volume losses and surface settlements, without any risk of damage to existing buildings.The monitoring of horizontal and vertical ground movements around the tunnel showed an unusual deformation scheme, maximum horizontal movements being twice maximum vertical movements. This is due to the highly overconsolidated character of the molasses, which gave also a very flat settlement or heave (for TBM method) trough in the vicinity of the tunnel axis.