ABSTRACT
When excavating a tunnel near existing infrastructures, one of the major challenges is to minimize the risk of causing damages on them by induced deformations or vibrations. A necessary tool to be provided in these situations consists in real-time automatic monitoring systems with threshold alarms, coupled to emergency procedures and coordinated with infrastructure owners. The aim is to be continuously aware and ready for unforeseen situations and, hence, to avoid unacceptable disservices and consequent costs, such as interruption of service in adjacent infrastructures. During construction works commissioned by the Federal Road Office of Switzerland to widen existing Stalvedro tunnel along A2 highway in Switzerland, such concept was successfully applied and obtained results are herein described. Drill and blast excavation was performed dealing with adjacent highway tunnel and an upper crossing railway tunnel. Moreover, an open-cut 35 m high at the north portal was excavated in a complex geology.
