ABSTRACT
Bucharest Metro Line 5 will connect the city-centre to its Western side. It consists of a 6km twin-tunnel alignment and 9 underground stations. Tunnelling works are performed with two 6.6m diameter EPBs machines. Station Eroilor 2 will be an interchanging station connecting line M5 to the existing M1 and M3 and has been used also as launching shaft for tunnelling operations toward Opera Station. The passage of EPBs about 1m below the operating Eroilor 1 bottom slab represents the most critical point of the project, thus some specific excavation procedures and preliminary mitigation works have been foreseen and implemented by the Contractor. Furthermore, special EPB follow-up procedures, contingency plan, counter-measures in case of adverse structure behaviour and rail misalignments, have been developed in agreement with the Site Supervision. This paper discusses the issues encountered on site during the works, the monitoring results, the follow-up procedure and the resulting effectiveness of the whole tunnelling process.
