The Joseph Gallagher Group has completed its latest microtunnelling project in Abu Dhabi. Joseph Gallagher International was engaged by Mechanical and Civil Engineering Contractors Company (MACE) LLC to complete a new pipeline on behalf of Abu Dhabi Sewerage Services Company (ADSSC). The new pipeline will serve local areas and communities in Abu Dhabi and is part of a longer-term plan to support population and infrastructure growth in the region.
Alex Allport Project Manager for Joseph Gallagher said: “This project has not been without its challenges, from significant heat, difficult ground conditions and of course COVID-19, but I am immensely proud of what the team has achieved.”
The pipeline was completed using 10 tunnel boring machines, which were ISEKI Microtunnelling Systems and three AVN Herrenknect machines all owned and operated by Joseph Gallagher Group and maintained directly by its engineers and support teams.
Challenging ground conditions
The microtunnelling machines were set-up for diameters ranging from 600 mm to 2,000 mm and customised to the varying ground conditions encountered. These included gravel, clay/mudstone, gypsum, sandstone, quartz, and sand. Individual drives varied in length from less than 100 metres to 670 metres. Alex commented: “Ground conditions changed frequently, sometimes within the space of a linear metre, so extreme caution and diligence was always required. We encountered large cavities at various locations, some requiring 800 cubic metres of concrete to fill them. Additionally, significant amounts of ground water were present across the project, all of which heightened the risk of flooding to our machines. It was not unusual to be facing 3 bar of water pressure at the face of the machine.”
Despite the challenging ground conditions a large part of the project’s success is testament to the resources, support, and agility of the Joseph Gallagher Group. This provided a real advantage to the project in terms of addressing any technical difficulties.
Early in the project, NRC Plant Limited (part of the Joseph Gallagher Group) deployed four crawler cranes to support the project, shipping these units from the UK to Abu Dhabi. The cranes ranged from smaller 5 t crawler cranes to a 90 t for lifting the tunnel boring machines into the shafts.
Specialist Plant Associates (SPA – part of the Joseph Gallagher Group) shipped high performance ventilation fans out to the project from the UK to help keep the machinery at as low a temperature as possible. Due to the significant heat at the project locations, maintaining a cool airflow with chillers into the tunnels was vital. SPA also dispatched grout pans which were used to grout the annulus of all 83 tunnel drives.
“The strength of the Group really comes into play on our international projects. We can oversee timelines, resources, and logistics, ensuring everyone is on the same page. The collective expertise that we can draw upon really does set us apart in our Middle East operations.” said Colm Dickey, Project Director for Joseph Gallagher Middle East.
At the height of the project, a multi-cultural team of over 200 people, including support from the UK, our people from Thailand, Egypt, India, Philippines as well as the UAE were all involved in bringing the pipeline to a successful conclusion. Steve Harvey, Group Managing Director, The Joseph Gallaher Group said: “It has been a massive credit to the project team in Abu Dhabi and the support teams in the UK in overcoming some of the biggest changes and challenges that can be faced in the region; and successfully completing the project safely, to a high standard and on time.”
The Joseph Gallagher Group, has other projects currently operating in the region, including Kuwait. Here it will be commencing work on the longest sea-outfall pipeline in the Middle East for WTE Wassertechnik EVN Group, under a joint venture with Al Hassanain. The Umm Al Hayman Wastewater Treatment Plant, one of the world’s largest wastewater projects is being built to treat effluent from southern Kuwait and to supply agriculture and industry with wastewater treated to the highest standards. www.josephgallagher.co.uk