Riyadh Metro construction 'will be a challenge'
Underground work could affect the stability of surrounding buildings
The construction of Saudi Arabia's Riyadh Metro will bring huge technical challenges, according to a civil engineer lecturer at King Saudi University (KSU).
The $22bn Riyadh Metro will require engineering which has never been seen in the Kingdom before.
"This kind of engineering project is being undertaken in the Saudi capital for the first time. There will be trials and misses," Ibrahim A. Al Hammad, who is also a member of the board of directors of the Saudi Council of Engineers (SCE), told Arab News.
He explained how a man hole 30m deep and 10m wide would be dug.
"Equipment has to be brought in and the tunnel has to be dug horizontally under the ground. Although this is a common procedure, the workers could be exposed to risk in the manhole due to failures during construction," he said.
However, he said during any construction work of this type there will always be risks such as these. For example, in China accidents had taken place during the construction of similar projects. Therefore, extra safety precautions should be put in place.
"Most of the accidents in engineering projects I have seen took place underground and not above ground where high-rise buildings have been constructed," Al Hammad said.
And along with safety risks, Al Hammad believes underground projects are more likely to go over budget than high-rise building developments.
"Engineers sometimes change their assessment. They stop work and the machines break down which may take a few months to fix. This would mean project delay," he said.
"A few months' delay also costs money and the question about whether the client or contractor should bear the cost is often a source of conflict."
He also warned that digging a manhole and tunnel could affect the stability of the foundations of the buildings nearby.
"Take Olaya Street, for instance. Most of the buildings along the road are low-rise, except for Al-Faisalia and the Kingdom Tower whose stability will be affected," he explained.
In a bid to combat any stability problems, sensors will be used which will signal if nearby buildings have strong foundations.
"If the engineers discover that the foundations of these buildings are not strong enough, work will have to be paused in order to find a solution," he said.
Existing, unused man holes in Riyadh which are in the line of the subway, are being filled up.
But despite the potential issues, Al-Hammad says he believes the construction of the metro system is a positive move for the capital.
"In fact, it has come a bit late probably because the Saudi capital is not as large as other cities which have constructed subways such as London, Paris and Shanghai," he said.
The metro is scheduled for completion by the end of 2018.