The Middle East and North Africa are not typically hot beds of tunnelling activity. Apart from metro projects in Cairo and Dubai, attention is more often paid to the hand bored tunnels that Palestinians have dug under the Egypt/Gaza Strip border in order to smuggle in food and other goods. However the region is coming under closer scrutiny by the tunnelling community as regional governments invest billions of dollars in upgrading heir infrastructure.
Much of this new focus is in the Gulf Cooperation Council (GCC) states particularly the UAE, Qatar and Saudi Arabia. “Twenty to 30 years ago it was impossible to think that Gulf States would ever embark upon tunnelling or metro schemes but under the new 2030 development plans regional governments are reclaiming the city and utilising the third dimension,” says Martin Knights, chair of the International Tunnelling Association.
The most significant development in the Gulf’s tunnelling sector to date has been the $7.6bn Dubai metro project which has involved significant tunnelled sections under the Dubai Creek. The first line, the 52km Red Line, was originally scheduled to open in September 2009 and cost $4.5bn. However although trains have been running since September 2009, eight of the 18 stations are still to be completed. The second 23km Green Line, has been delayed from March 2010 to August 2011. The contractor consortium is led by Japan’s Obayashi Corporation, with Kajima Corporation, Mitsubishi Heavy Industries and Turkey’s Yapi Merkezi.
Despite the cost and time overruns the project remains a major achievement for a part of the world with no previous experience of TBMs or light rail. Of the first 70km of light rail system, 13km were tunnelled using three 9.56m diameter Mitsubishi EPB-TBMs over 10 separate drives.
Plans for extensions of the metro are currently on hold as Dubai weathers the financial storm battering its state owned development companies and affecting governmental infrastructure spending, however Knights expects Dubai’s metro will be extended in the future. Other states, he says, are also pursuing tunnels for metros, utilities and road links. “In the future I believe we are going to see the use of strategic tunnels linking islands in the region, instead of bridges and causeways.”
Abu Dhabi, which neighbours Dubai and is one the capital of the seven states that make up the United Arab Emirates, has the most tunnelling potential with plans that include a metro of its own. The emirate’s first bore, using a 6.3m diameter EPB – TMB is scheduled to launch in December as part of a 40km sewer tunnel known as the ‘strategic tunnel enhancement programme’
This new collector is designed to replace the existing pumped wastewater network consisting of more than 50 pumping stations with a new gravity sewer system. A total of six contracts will be awarded for the scheme including three for the main sewer, two for the connection pipework and one for a new pumping station. To date Italy’s Impregilo is the only company to have been awarded one of the major contracts for the mid section of the tunnel in September 2009.
The main bore will run from Abu Dhabi Island in the north down to a pumping station at the new Al Wathba sewage treatment works on the mainland in the south. It concerns a 14.5km long section with a 5m internal diameter that makes up the central piece of the sewer. Contracts for the first section, a 17km stretch from Abu Dhabi Island to Mussafah on the mainland with a 4m internal diameter, and the final piece, a 10.5km section with a 5.5m internal diameter are being evaluated by Abu Dhabi’s highest authority the xecutive Council.
A total of eight EPBMs will be used on the bore to remove 1.2 million cubic metres of fill. So it is not surprising to hear that Germany’s Herrenknecht is to establish a TBM manufacturing joint venture in Abu Dhabi with a local partner Aabar Investments. “We set up the new joint venture ‘Herrenknecht Tunnel-Boring International LLC’ together with Aabar Investments PJSC, a partner that is well networked and held in high esteem in the Middle East,” says a Herreknecht spokesperson. “The business objective is the continuous market development of mechanized tunnelling in the MENA region (Middle East and Northern Africa).”
The German giant is already supplying a TBM to Qatar, which is increasing stormwater storage in the capital of Doha, and in Saudi Arabia it is supplying drilling equipment to Saudi Aramco for a new 3km oil pipeline.
“In total, we see the region as a growth market with promising perspectives such as ongoing and upcoming tunnel projects for metro and sewage systems,” says the spokesperson.
In Abu Dhabi the information currently being collected on ground conditions for the sewer tunnel, which will be up to 100m deep, will be shared with the Department of Transport for the planned metro scheme. This is particularly critical in Abu Dhabi which is prone to large sub-surface voids. “Regional geological formations lend themselves to casting formations. These can be discrete or sometimes widely connected. You have to carry out very, ery good site investigation,” says Knights. “And be mindful of your pump rates when grouting.”
Just north of the UAE, Qatar has been following Abu Dhabi’s sewer plans and in May invited pre-qualification bids from consultants to advise on creation of its own deep sewer tunnel. According to the bid invitation published by the Public Works Authority (Ashgal) the existing sewerage system, consisting of shallow sewers and pumping stations, is becoming overloaded due to the pace of development in the capital Doha. “A major tunnelled interceptor scheme is proposed in the Doha South sewage treatment works catchment to reduce the number of pumping stations and to meet the long term needs of Doha,” says the document. “The existing Doha South STW will at some time in the future be relocated to a new site to the south and the existing site utilised as a treated sewage effluent (TSE) storage and distribution centre.”
The scheme is expected to consist of five packages including the deep sewer tunnel, connecting sewers, a new pumping station and a new treatment works. The deadline for prequalification bids was the 1st June.
Further afield in the Middle East Damascus in Syria, Amman in Jordan, Kuwait City, Baghdad in Iraq, Tehran in Iran and Riyadh in Saudi Arabia are all planning metros and are keen to learn from pioneering Dubai’s experiences – both good and bad. In North Africa, Egypt is extending its metro by adding a third line. A Vinci Construction Grand Projects led consortia is undertaking a 3.5km, 9.5 diameter bore under the River Nile. Construction is scheduled for completion in mid 2011.
With so many projects planned and several underway it is no wonder that the industry is excited about the regional opportunity. However this is tempered with an air of caution as governments reevaluate their growth forecasts after the global downturn. In Abu Dhabi for example the sewer tunnel contract awards have been delayed and the project pushed back to ensure that demand is adequate, and Dubai has suspended development of two new metro lines. But overall sentiment in the region is that a lot of major projects are going to get underway within the next five years. “Underground construction is going to increase in this part of the world like we have never seen before,” says Knights.
One of Dubai’s recently built metro stations
