Projects in the Middle East and particularly the Gulf region have traditionally relied on drill and blast methods to remove hard rock and create underground spaces, or roads through mountainous regions, but times have changed. Today almost all countries in the Middle East from Qatar and the UAE to Iran and Iraq are planning to bring in TBMs to fulfil their new underground infrastructure plans.
By far the biggest driver is metro projects. By 2020 Kuwait, Doha, Abu Dhabi and Riyadh are all expecting to have light rail systems. And the nature of the growth of these busy cities, which do not have public transport networks, means that new rail systems will need to go underground.
Dubai’s Road Transport Authority (RTA) has led the way in creating a metro in the Middle East, which opened in 2009, and Doha in Qatar looks to be the next city to begin construction of a light rail project. “Qatar has declared that by 2030 it needs to be self-sustaining providing a high standard of living for all that live there. To be a world class city you need a world class transport system, one where 40 per cent of all journeys are made by public transport,” explains deputy chief executive officer of Qatar Railways Company Geoff Brian Mee. Mee was outlining the plans at the Middle East Economic Digest (MEED) Qatar Infrastructure Projects conference in London in July.
Qatar Railways Company is developing a USD 35M railway system known as the Qatar Integrated Railway Project, that comprises 200km route of heavy rail links to Saudi Arabia and Bahrain, a light rail network for Doha, a people mover underneath the business district of West Bay and an LRT (light rail transit) system for the 35 hectare Lusail real estate development, which is currently under construction to the north of Doha. A major catalyst for the project is the award of the World Cup in 2020 but Mee is keen to stress that this is not the main reason for the rail network. “The project is a milestone on the way to providing a public transport network for Qatar, and the World Cup is a milestone in the development of that public transport network , but that isn’t what we are designing it for. It is about building something that is fit for purpose for Qatar as it grows.”
For the tunnelling industry the implications of the Qatari investment plans are enormous. Mee estimates that the metro alone will require 12 TBMs, and the West Bay people mover another two machines. “The metro is going to be one of the most dramatic public transport systems attempted anywhere in the world. To go from a greenfield site to four major metro lines in one bound has never been attempted before. The scale of this job really makes the hair on the back of your neck stand up on end,” says Mee. “None of the team that are doing this have ever attempted to spend USD 35bn in 10 years. But then no one else has either and we are looking for a lot of friends to help us with that.”
Qatar’s fast track metro
The metro itself consists of a route length of 350km over four lines, red, gold, blue and green. Mee considers the red most important as it is this north/south connection that will link the New Doha International Airport with central Doha while at the same time running through the business districts, into the huge Lusail real estate project and then on to Al Shamal in the north. “It will be the heaviest used. It links all of the high population density parts of Doha. The green and golden lines link into the suburbs and the blue line creates an orbital railway that links all the rest of it together.”
A total of 110km or 31 per cent of the metro is set to be tunnelled and in order to meet the public transport criteria laid out by the FIFA World Cup Committee, QRC must complete the first phase of the metro by 2020. “That means about 12 contracts worth up to USD 1.5bn going on at the same time in the middle of a highly populated city. That is at least 12 TBMs. No one has ever attempted to run 12 TBMs at the same time in the city so that will be a big challenge,” says Mee. “If we haven’t finished phase One by 2020 we will not have time to commission it, test it, put it into public service and get people used to using it.”
This sets a challenging timescale for the project and procurement is now underway. The main construction packages will be let as design and build agreements and awards will be made from June 2012. “We will need most of the world’s expertise in design as these will be design and build contracts. We will only do 25 per cent of the design in house.”
At the London conference Mee urged firms to get into consortium as soon as possible in order to be well positioned for the expressions of interest which are due to be issued over the coming weeks. He also made it clear that individual companies need not apply. Prequalification will only be granted to consortia. “We have been telling the industry time and time again – we are not going to prequalify individual companies, we will only prequalify consortia that are capable of doing the civil engineering package in total.”
According to Mee this means design expertise, tunnelling and construction capabilities and equally importantly there must be some local Qatari involvement. “There is nobody in Qatar that has ever built a railway and there is no one that has built a railway in Qatar. The logical conclusion of that is that you have to tie together local specialists with international specialists.” In addition he says logistical planning in Qatar for all resources can be challenging. “Getting labour into Qatar is not easy so you need people who understand how to get through the immigration process. I would really recommend people form consortia with local companies. It would be a real shame if people put a lot of effort into bids and didn’t have those vital components.”
QRC envisages that boring of the four lines will begin from outside the city and move inwards enabling spoil to be removed from less congested areas. Upon completion by 2020 these central lines will then be extended further out to Dukhan in the west, out to industrial areas and the new Mesaieed Port in the south and also reach out north to Umm Slal and Al Shamal. The entire metro will be completed by 2026 (see figure 2, ).
At the same time as phase one of the metro QRC also wants to install an underground people mover beneath the existing main business district of West Bay. This will link into the red line of the metro and according to QRC will enable passengers to have a completely air conditioned journey from home to the office. The people mover is a key development for the busy business district which is facing huge parking problems. Estimates show that if the current area was to expand by more than 40 per cent, the city would face gridlock. In terms of construction the people mover will require 10km of single bore tunnel with an external diameter of 10.5m. There will be 19 stations and QRC estimate 143,000 boardings per day.
Rail projects are not the only Qatari infrastructure requiring tunnelling. Plans for a crossing of the Doha Bay are set to include a 12km tunnel section. The route of the crossing is yet to be finalised but it will run north/south across the bay bypassing the busy city centre and enabling commuters to travel directly from the airport to the residential areas north of Doha. This section must be buried underground due to its proximity to the airport. However for the remaining sections of the crossing design competitions have been held to find an iconic bridge. Saad Khodr, senior transportation engineer, at the Ministry of Municipality and Urban Planning was also presenting at the MEED conference. “The concept was originally to have a 12km tunnel, broken up with an Island then some kind of a bridge. We also planned for a link to the Pearl,” he says. The Pearl is a residential area created offshore to the north east of Doha. “This was presented to his Highness but he didn’t like any of this. He wanted something special. He said go and do a competition.”
This led to the completion of four new concepts created by teams made up of both architects and engineers. The plans varied from a number of small bridges to a huge iconic crossing. These were once again presented to the Emir Hamad bin Khalifa al Thani who was still not convinced by the options shown. “His Highness said unless you bring something special that adds something to the Bay then I want it all to be a tunnel,” says Khodr.
As a result another consultant has been commissioned to develop another solution, but the plans have not yet been revealed. For the tunnelling sector though the Doha Bay Crossing will certainly need a tunneled section linking it in to the airport.
In the water sector Doha is also expected to build its own sewer tunnel project akin to the STEP project (Strategic Tunnel Enhancement Programme) in nearby Abu Dhabi. Details on the Qatari project are yet to emerge.
Good progress in Abu Dhabi
In Abu Dhabi the 41km sewer tunnel scheme is gathering pace as all three major tunnelling packages have been awarded with a combined value of over USD 700M.
The first contract for 15km of 5m internal diameter tunnel was awarded to Italy’s Impregilo in September 2009. This is for the central section of the sewer and also involves construction of three 16.2m internal diameter work shafts (WS5,WS6 and WS7) up to 60m deep and 110m of access passages. Three Herrenknecht EPBMs will be used for the bore which began in April 2011. By mid-July the first machine had progressed 333m between WS5 and WS4. The second machine was launched at the end of June and by mid- July had bored 16m between WS5 and WS6. The final TBM launch is imminent.
Impregilo was also successful in securing the second contract to be let, for 9.7km of 5.5m internal diameter tunnel that forms the end section of the sewer. This was awarded in November 2010 and also requires the construction of two 16.9m internal diameter work shafts (WS8 and WS9), up to 87m deep; two 6.9m id access shafts, a 60m connecting tunnel from WS9 to the pumping station and two 7m long adits from the access shafts to the bored tunnel. Site preparation is underway and construction of the work shafts is progressing with the diaphragm walls for WS8 now complete and those for WS9 underway.
A third contract for 16.1km of 4m internal diameter tunnel was awarded to Samsung C&T in February 2011. This forms the first part of the sewer and as such the five work shafts (WS1, WS2,WS3, WS3.1, WS4) are much shallower at between 25 and 36m. Their diameters vary between 13 and 17m. Work shaft three will form the main drive site. Shaft work is underway and Samsung C&T says it will complete its work by 2014.
The project manager CH2MHill tells T&TI that the successful launch of the first TBM in April 2011 has been the biggest achievement on the project to date, along with the swift installation of the next two machines in their launch shafts in May and June 2011. Key future milestones are the award of the link sewer contracts and the pumping station contracts which are yet to be awarded, along with the arrival of TBMs for the remaining tunnel sections.
Two contracts for link sewer packages are needed to create a 50km network of pipelines from 0.4 to 3m in diameter that will collect sewage and feed it in to the new sewer tunnel. Part of the rationale behind structuring the main tunnel and connection sewers in separate contracts is to enable both local and international firms to participate in the scheme. It is envisaged that local firms will be involved in link sewer construction. A sixth contract for a new deep pumping station at Al Wathba sewage treatment works is also yet to be awarded.
The scheme as a whole is designed to increase the sewage capacity of the fast growing emirate and replace the existing myriad of pumped mains with a gravity sewer and single pumping station.
Past president of the International Tunnelling Association Martin Knights expects that this is just the beginning for underground construction in Abu Dhabi and the wider Gulf. “You don’t necessarily think of Abu Dhabi as a tunnelling centre, we know about Tehran and Cairo but Abu Dhabi is really embracing the third dimension,” he says. “In Abu Dhabi the Department of Transport were originally planning a series of bridges to connect to the mainland. I said this is like Holland, it is perfect for immersed tube tunnels. So we did a workshop for them and they are now looking at immersed tubes.”
“Who would have thought that 20 years ago the region would be embracing underground technology at the rate that it is now. It is a booming centre,” he says.
Figure 1, Abu Dhabi’s 40km-long deep tunnel sewer system was divided into three contracts Figure 2, planned Qatari metro
