Lonato | Italy

EPB technology pushed to the limit due to hydrogeological difficulties and work pressures to carry out the critical project on the new high- speed railway line between Brescia and Padua.

The Lonato tunnel crosses alluvial and moraine formations in the presence of high-pressure suspended aquifers, with frequent very hard blocks of large dimensions immersed in the sandy-gravel matrix.

These characteristics, combined with numerous undercrossings of motorway, industrial, agricultural and civil infrastructure, are at the limit of feasibility for mechanised excavation in general, regardless of the specific technology used to control the excavation face under pressure.

The extreme abrasiveness of these formations also requires continuous management in terms of maintenance to the head and excavation chamber, both of which are subject to veritable reconstruction work at intermediate stages along the tunnel.