ABSTRACT
Extension of line M1 to the N-E outskirts of Milan (€ 85.135.081,82 for 1.9 km gallery) was found to be extremely complex in the management of numerous problems that were difficult to foresee. The project based for tender was carried out taking into account a reference groundwater level, on average stable, which, since design for tender until the award of the works, underwent an extremely high increase, of more than 5 m in 18 months, and has continued to increase by another 5 m in the 4 years following the assignment of the works. The unexpected increase of water table has made the execution and management of the project since its assignment extremely complex, implying the need to develop a variant project, which has required the definition of additional interventions for the execution of the provisional civil works, especially the consolidation for the traditional excavation of tunnel. During the course of the works, the principal company of the JV, for matters not connected to this contract, declared its failure. The execution of the works was entrusted to the 2nd principal company of the JV, which did not substantially fulfill the obligations envisaged leading to delays and failures with consequent termination of the contract. Now, work has been entrusted to the second classified company in the call for tenders, which has resumed work, albeit with the problems related to the restart of a partially completed and flooded/abandoned building site for over 2 years.
