Dublin Port Tunnel
London Bridge Associates (LBA) had a significant involvement in this tunnelling infrastructure project which was undertaken for Dublin City Council and the National Roads Authority in Dublin, Ireland between 2001 and 2006 at a cost of £300m
Skills Tunnelling, Project Management
Value Est. £300m
Alleviating Congestion in Dublin
The Dublin Port Tunnel Project links the M50 C-Link motorway system surrounding Dublin, with Dublin Port. The tunnel route passes under densely populated areas of the city, a major railway interchange, open parkland and the main north-south arterial route into Dublin. The main purpose of the project is to alleviate the traffic congestion within the city by removing heavy goods vehicles from the city’s roads.
Complex Tunnel Project
The project consists of over 2.6km, 10.84m diameter twin bored tunnel, 1.9km of cut-and-cover twin tunnels constructed within open-cut and diaphragm walls plus a section mined under a pipe canopy installed underneath a mainline railway system. The bored tunnels were constructed using a “hard rock” TBM within limestone and an open-face shield TBM within boulder clay. Cross passages were built using drill-and-blast techniques with associated ground stabilization by rock bolting and sprayed concrete linings. Vehicle laybys and emergency cross passages with cavern spans in excess of 17m were also constructed by drill and blast and included installed secondary linings.
LBA’s key Managing and Auditing role
LBA played a major role as part of the Construction Supervisor’s team, managing and auditing the works on behalf of the Client and administering the design-and-build contract. Key personnel supervised and audited the TBM drives and railway crossing works. Further support being given in coordination of the Contractor’s geotechnical, geological and instrumentation activities. LBA had staff directly involved in the assessment of the Client’s commercial interests, including a significant role resolving contractors claims and submissions.
Compliance monitoring and planning
The progress and compliance monitoring of the Contractor’s programme to completion was also undertaken, with additional planning requirements including third-party interface issues, being managed by the team.
Highlights of Dublin Port Tunnel dig
- The successful completion of the bored tunnels beneath the densely populated area of North Dublin with minimum disturbance to the local community and negligible effect on the overlying structures, was a significant milestone in the Project.
- The completion of the pipe-jack canopy with no detrimental effects on the railway system itself, despite lying only 3.5m beneath the mainline & local railway system within poor ground conditions and being exposed to large tidal influenced water-table fluctuations.
- The subsequent success of the major temporary works and excavations for the main works beneath the canopy.
Engineering Excellence in Adverse Conditions
This aspect of the Project demonstrates an ability of LBA staff to design, construct and manage major civil engineering works in severe adverse ground conditions.
The Project was awarded the Fleming Award 2003 for the excellence of the geotechnical design and construction of the northern open-cut works within an existing dual-carriageway road system.