On 14 February, Dubai construction was thrust again onto the global stage when Elon Musk, the world’s richest man, announced plans to explore the development of an underground Dubai Loop transportation system, along the lines of the Las Vegas Convention Centre Loop project in the US.

Dubai has typically made headlines globally by constructing the world’s tallest towers. As the city becomes increasingly congested on the surface, it is taking some of its largest construction projects underground.

With Musk’s backing, the Dubai Loop scheme is the most high-profile tunnelling project launched to date. It involves carving a futuristic transport system underneath Dubai. The initial phase of the project is currently being studied by Dubai’s Roads & Transport Authority (RTA) in partnership with The Boring Company, which is owned by Musk. It will cover 17 kilometres (km) and have 11 stations, with the capacity to transport over 20,000 passengers an hour.

The project highlights the importance of expanding underground infrastructure in the Middle East region. This is mostly necessitated by the pressure that rapidly growing cities have put on existing transport and utility networks, particularly in major urban centres such as Dubai, Riyadh and Doha.

Underground opportunities

Projects that involve tunnelling, such as metro rail systems, underground highways and pedestrian walkways, are deemed key enablers in reducing congestion and optimising land use.

The recently completed metro systems in Riyadh and Doha are examples of how underground rail networks can facilitate efficient urban mobility, and more such schemes are planned. 

Without these subterranean projects, cities risk being stuck in a permanent state of gridlock, with longer commute times and decreased productivity. At the same time, tunnelling allows urban planners to integrate sustainable transport solutions, as well as large-scale utilities networks, without disturbing existing cityscapes, thereby enhancing connectivity and economic growth.

These developments signal a major shift in engineering priorities, with regional governments investing in underground transport, sewerage and metro extensions to accommodate their growing populations and infrastructure needs.

While the tower crane-dotted skylines of urban centres in the GCC attract attention, delivering major projects underground is an equally impressive engineering feat. Tunnelling under busy cities requires advanced excavation techniques, careful planning and coordination to avoid disruptions.

More tunnelling work is expected as Dubai takes another significant step forward in tackling its ongoing traffic problems [with] a new metro link

UAE tunnelling projects

Tunnelling work forms a significant portion of the Dubai Metro Blue Line extension. Awarded in December for AED20.5bn ($5.5bn), the project includes 15.5km of underground track and five subterranean stations. When operational in 2029, the Blue Line will significantly expand Dubai’s metro capacity, linking major residential and commercial hubs.

More tunnelling work is expected as Dubai takes another significant step forward in tackling its ongoing traffic problems by starting the procurement process for its next metro link: the Gold Line.

Although the technical details of the project have yet to be revealed, it is expected that tunnels will form a major component of the scheme given that the new line will run through busy urban areas where there is little space to build overground. 

The Gold Line will start at Al-Ghubaiba in Bur Dubai. It will run parallel to – and alleviate pressure on – the existing Red Line, before heading inland to Business Bay, Meydan, Global Village and residential developments in Dubailand.

As a first step, the RTA has sent a request for proposals to companies for the lead consultancy role on the multibillion-dollar project.

The UAE’s Etihad Rail also began a study of the tunnels required for the high-speed railway line connecting Abu Dhabi and Dubai in January. The survey works are ongoing on the Jaddaf and Dusup tunnels that will serve the high-speed rail link. Initial plans for the project include tunnelling works totalling 31km.

Another major tunnelling project in the UAE is the $22bn Dubai Strategic Sewerage Tunnels scheme. The client, Dubai Municipality, is preparing to tender its first packages, which include deep tunnels that will stretch 42km in Jebel Ali and 16km in Warsan.

The project will be delivered under a public-private partnership model, with international consortiums competing for contracts. Once completed, these tunnels will replace the traditional wastewater network, reducing energy consumption and enhancing long-term sustainability.

Saudi schemes

In Saudi Arabia, Riyadh is preparing to expand its metro network with the addition of a Line 7 and an extension to the existing Line 2.

The total length of Line 7 will be about 65km, of which 47km will be underground. The line will have 19 stations, 14 of which will be underground.

The project involves constructing a metro line linking the Qiddiya entertainment city development, King Abdullah International Gardens, King Salman Park, Misk City and Diriyah Gate. 

In March, the Royal Commission for Riyadh City (RCRC) gave consortiums until 15 June to submit their bids for a design-and-build contract for the construction of Line 7.

The planned Line 2 extension is 8.4km long, of which 7.1km is underground, and three out of its five stations will be built underground. The RCRC is expected to award the construction contract this year.

In January, the kingdom also completed the phased roll-out of the Riyadh Metro network. The current network comprises six lines spanning about 176km, of which 74km is constructed underground.

These numbers indicate that over 42% of the overall network is underground, highlighting the growing importance of tunnels in the kingdom’s plans to improve infrastructure in its most densely populated cities.

Tunnelling works are also a key component of the plans to improve the stormwater drainage system in Jeddah, where the municipality is preparing for the construction of the King Abdullah Road-Falasteen Road tunnel.

The three-year scheme involves constructing 5.3km of tunnels with an internal diameter of 7.2 metres using tunnel boring machines (TBMs) and another 3.4km of tunnels with a diameter of 3.5 metres driven by pipe jacking or TBMs.

At the kingdom’s Neom gigaproject, city planners are looking to find solutions to many of the problems faced in existing cities and, as a result, tunnels and large-scale underground utilities corridors are being built at the beginning of the project. For example, the development’s Delta Junction tunnels will serve as a railway junction connecting the Spine infrastructure corridor with the Neom Connector rail link to the Oxagon industrial zone. 

The project involves 26.5km of tunnelling work that will be split into a north and a south lot. The construction works are expected to begin this year as the client is evaluating the revised proposals submitted by firms in November last year.

Kuwait Metro will feature extensive tunnelling … ensuring minimal disruption to existing roads while integrating with future transport networks

Further tunnel projects

Beyond the Gulf, Egypt has a long history of tunnelling projects, as it has had to deal with crippling congestion and urban overcrowding for decades. In the 1980s, work was completed on two major projects that involved tunnelling: the first phase of the Cairo Metro system and the Greater Cairo wastewater project, which involved the construction of sewage tunnels on the east and west banks of the Nile. 

Today, Cairo’s tunnelling projects include the Cairo Metro Line 4 project. Spanning 42km with 39 stations, it involves over 20km of tunnels.

Meanwhile, in Morocco, national railway operator L’Office National des Chemins de Fer (ONCF) is constructing a tunnel project in Rabat.

In February, ONCF announced a 3.3km tunnel to be constructed under the Bou Regreg river at an estimated cost of MD1.4bn ($140m). The tunnel will connect the Sale and Agdal stations in an effort to alleviate traffic.

Similarly, the long-awaited Kuwait Metro will feature extensive tunnelling to navigate the dense urban fabric of Kuwait City, ensuring minimal disruption to existing roads while integrating with future transport networks. 

Qatar’s expansion of Doha Metro, meanwhile, requires additional underground infrastructure to connect developing areas and support the country’s vision for a comprehensive public transport system. 

Mecca Metro, already serving millions of pilgrims, is also set for further expansion, likely involving significant tunnelling to facilitate smoother access to holy sites while overcoming geographic constraints. 

In Oman, the Muscat Metro project is likewise expected to link key districts while preserving the city’s landscape and avoiding disruptions to arterial roads by introducing underground sections. 

All of these projects show that tunnels will play an important role in the region’s future as it strives to create cities with more efficient and environmentally sustainable transit and utilities systems.