WET News

november 2015 WET NEWS 13 bursting head positioned, the pulling rods from the burster rig were attached to the front- end of the pipe eating head mandrel. Working together to provide up to 250t of force at the pipe eating head, the Perforator unit jacked the assembly head forward whilst at the same time the burster rig pulled the assembly towards its operating pit. Not only did this provide sufficient thrust to the bursting head to fracture the old pipe but also enough pressure to ensure the new pipe passed into the ground effectively. Simultaneously to the push / pull operation, the displaced earth and fragments of the broken pipe were transferred back down the permanent steel sleeve by the auger spiral and removed to the surface by skips from the jacking pit, preventing excessive compacting of earth at the upsizing head. The pulling force from the HB100 also ensured that the pipe eating head remained on the same line and level as that of the old pipe. The steel carrier pipe was extended at the end of each push / pull stage by welding on a new 3m long section at the jacking rig end. During the pipe eating works, both machines had to work hard with instances throughout the operation where the HB100 burster rig operated at its maximum tonnage capacity. Towards the end of the replacement run, as the pipe eating head approached the burster rig position, jacking was paused so that the thrust wall of the burster could be removed. The burster rig was disconnected and the final few meters of the installation was completed using the auger rig alone so that the pipe eating head and the lead edge of the sleeve pipe could be extended into the burster pit. The replacement works were successfully completed and the remaining spoil and old, now broken, pipe cleaned from the steel carrier pipe. A 600mm diameter twin wall PE sewer pipe was inserted through the sleeve pipe and connected at either end to the remainder of the sewer network at both new and existing manholes. Waste control One of the biggest timing difficulties came from the lack of storage space at the pipe jacking pit which meant that each individual 3m steel pipe section had to be brought in from off-site to be available for installation in the jacking frame just as it was needed. The route through the woodland made this a difficult journey with each pipe section. The use of this innovative trenchless technique also meant that waste control was more easily managed with the only waste produced being that created to dig the operations pits and that removed from the sleeve pipe by the auger string. The trenchless option also meant that the carbon footprint of the works was also very much reduced as compared to potential alternative installation methods. Peter Taylor, managing director of Pipeline Drillers, says: "This was not an easy project by any means. The logistics bordered on nightmarish with limits on equipment size, site storage, transportation and precise timing. However, our crew worked extremely well with George Leslie's workforce to safely and efficiently complete what was something of a unique project under challenging circumstances in an excellent timeframe." The pipe eating head approaching the end of the replacement run. note the fracturing original pipe in the foreground The pipe eating head attached to the pulling rods from the U mole burster SUPPORTED BY Sara Venning Chief Executive Offi cer Northern Ireland Water Brian McHugh Finance & Network Assets Director Utility Regulator Dave Foster Director of Regulatory and Natural Resources Policy Department of the Environment Paddy Brow Living with Water Programme Manager Department for Regional Development John French Chief Executive Offi cer The Consumer Council Tony Harrington Director of Environment Dŵr Cymru Welsh Water Jim Fitzpatrick Broadcaster, journalist and independent producer EXPERT SPEAKERS INCLUDE: CHAIR: WATER NORTHERN IRELAND CONFERENCE 25 FEBRUARY 2016 | BELFAST DELIVERING A LONG-TERM STRATEGY Now in its seventh year, the WWT Water Northern Ireland Conference, Networking Dinner & Exhibition is the only event that brings all the major stakeholders together to discuss the current and future pressures facing the sector. ● Stay up-to-date with the latest developments in the Northern Ireland water sector ● Meet the stakeholders who can directly impact your business ● Put yourself at the forefront of opportunities for collaboration BOOK NOW www.wwt-ni.net SUPPORTED BY WWTwaterNI-265x185ad.indd 1 19/10/2015 14:51

• Cover