Dublin Port Tunnel - Excavation of an 11.8 m diameter urban motorway tunnel

Every year more than 2,000,000 heavy goods vehicles pass through Dublin Port. The vehicles contribute to serious traffic congestion in the city centre of Dublin. The Dublin Port Tunnel was planned to connect Dublin Port to the M1 Motorway in the north of the city and remove a predicted 9000 vehicles a day from the centre. The twin tube road tunnel will be approximately 4.5 km long with each tube having two lanes of carriageway. Sections of the tunnel at the north and south were constructed by cut and cover methods with the central 2.6 km of route being constructed by bored tunnelling methods. The central section passed under a large number of residential properties. The NMI Consortium was awarded the design and build contract in December 2000. The consortium consisted of Nishimatsu, Mowlem and Irishenco. Nishimatsu were responsible for the design and construction of all the civil works related to the bored tunnels. The geology along the tunnel alignment consisted of approximately 500 m of Dublin Boulder Clay with the remaining section in the Dublin Formation that comprised carboniferous limestone with inter bedded shales. The predicted geology, worksite availability, contract programme and environmental requirements led to the selection by Nishimatsu of two different 11.8 m diameter TBMs. A hard rock TBM excavated two 2.2 km drives mainly within the Dublin Formation. The second machine was an Open-Face type TBM equipped with two intermediate decks and three excavator arms and excavated two short 330 m drives in boulder clay. Both machines were refurbished and supplied by Herrenknecht. Both tunnels were lined with a structural concrete segmental primary lining and an in situ concrete secondary lining containing polypropylene fibres. The precast concrete linings consisted of six segments and a key. The lining utilised hydrophilic gaskets. A number of tests were conducted to demonstrate the designed cruciform joints could be adequately sealed. The secondary lining provided fire resistance to the primary lining and a smooth finish for painting, luminescence and cleaning. The contract specified a fire resistance period to a modified hydrocarbon fire curve and full-scale fire tests were carried out to demonstrate compliance at TNO in the Netherlands. The tunnels pass under a large number of residential properties. During tunnel construction ground borne vibration, regenerated noise and settlement would occur. Extensive predictions and assessments were undertaken in advance of construction. A research project was initiated on these aspects that continued as the construction work progressed. The settlement, vibration and noise were continually monitored reviewed and analysed. (A). "Reprinted with permission from Elsevier". For the covering abstract see ITRD E124500.

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  • Authors:
    • GOTO, J
    • THOMPSON, S
    • SQUIRES, S
    • MIZUNO, S
  • Publication Date: 2004-7

Language

  • English

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Filing Info

  • Accession Number: 01011577
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Dec 19 2005 3:18PM