Trenchless Technology

Trenchless Technology

Trenchless technology is a family of methods, materials, and equipment capable of being used for the installation of new or replacement or rehabilitation of existing underground infrastructure with minimal disruption to surface traffic, business, and other activities. The Coffey Group use many techniques for Trenchless technology, including pipe ramming, pipe bursting, pipe jacking and displacement moles.

Coffey Experience :

Pipe Ramming

Wicklow Outer Ring Road - Pipe Ramming
Client: Wicklow County Council
Project Value: £84,000 (ex VAT)

Project Description:

The works involved the crossing of two large distribution mains 32m long under the existing National Road. No open cut method was allowed to be carried out on this road and therefore the ramming installation method was used.
A launch pit was constructed using sheet piled walls to create a safe working area at the required depth of -3.3m. Once formation was achieved a guide rail was set up underneath each pipe to the required level and angle. The Goliath pipe rammer which has the capacity to ram up to 3m diameter pipes was then placed on each rail and then proceeded to hammer the pipe into the ground.



Pipe Jacking

Tuam Town Pipeline – Pipe Jacking
Client: Galway County Council
Project Value: £12005,000 (ex VAT)

Project Description:

This project involved the pipe-jacking of a 1,200mm diameter pipe under a national primary route. As part of the Tuam town pipeline a 600mm diameter gravity sewer had to be laid across the N17 (National Primary Route). The depth of the excavation would have been 6,500mm and a two-way traffic system would have to be maintained while works were taking place. As this was a physical impossibility it was decided to install a launch and reception pit and jack a 1,200mm diameter pipe under the road as this was the most economical and safe method for completing the works. Once the pipe was jacked through the 1,200mm pipe invert was benched out to form a channel with the same flow characteristics as a 600mm diameter pipe. The length of the pipejack section was 37.5m from launch to reception.


Pipe Bursting

Keadue Sewerage Scheme Upgrade – Pipe Bursting
Client: Roscommon County Council
Project Value: £120,000 (ex VAT)

Project Description:

The works involved the re-lining of 220m of 225mm diameter concrete pipe with a 250mm ID HDPE pipe. The works involved the excavation of a reception shaft at one manhole and a launch hole at the other. The pipe bursting machine has the capacity of pulling 100 tons.


Displacement Moles

Dublin Outer Ring Road
Client: Fingal County Council
Project Value: £22m (ex VAT)

Project Description:

As part of the works on the construction of the Dublin Outer Ring Roads, a number of services had to be installed using trenchless technology. These restrictions were in place due to the high traffic volumes on the road that the services were required to traverse. A total of twenty four moles all of 125mm diameter and up to 20m long were used.


Coffey Group, Athenry, Co. Galway, Ireland Tel: +353 91 844356 Fax: +353 91 844519 Email: