ABSTRACT
TBM (tunneling boring machine) is widely employed in very dense urban area to minimize the risk of possible surface settlements onto the existing structures. The evaluation of the soil structure interaction is undertaken through analytical evaluations in conjunction with finite element analysis. The aim of this paper is showing a quite original approach of this technique to the existing Brenner railway line. The first step was to evaluate the expected settlements through empirical, analytical, and numerical models and, so evaluate the influence of the settlements on railway. Once evaluate the risk, the contractor decided to support the railway in operation with a temporary support constituted by a structural grid of steel beams to create a semi-elastic system during the TBM excavation. In this way, the designer achieved that the possible settlements due to the TBM excavation would not interfere with the operation of the existing railway.
