Spectacular Tunnels Around the Underworld

Tunnel is one of the most unglamorous and overlooked structures in civil engineering, despite all the hard work required in its construction. It can perform what other structures fail to do in transporting cars, trains or even water. For one of our neighbours down south, its metro tunnels also double up as part of its civil defence system.

Tunnel builders and the machine manufacturers are competing against each other to build the longest or the biggest diameter tunnel. The record for the biggest tunnel now stands at more than 15m diameter.

Let's look at some of the world's major tunnels in order for us to better appreciate this hidden civil engineering structure.

1. Seikan Tunnel

Seikan Tunnel is a 53.9 km long tunnel and is the longest mixed road and rail tunnel in the world, linking Honshu and Hokkaido. The labourious construction process which drilled through an earthquake prone area was completed in 1983 at the cost of $5 billion, and 34 lives. Its completion has been considered one of the greatest achievements in civil engineering.

2. Channel Tunnel

Channel Tunnel is one of the most celebrated engineering achievements of the modern era, and the idea for its construction is dated back during the 1800. With its length of 50 km, it is the second longest tunnel in the world after Seikan tunnel, but its undersea section, which is 39 km, is the longest in the world. It was opened to public in 1994 at the cost of £10 billion.

3. Trans Tokyo Bay Tunnel

This tunnel is part of the Trans Tokyo Bay Highway consisting of 4.4 km of bridge and 9.6 km of undersea tunnel, with two man-made islands and linking Kawasaki City in Kanagawa Prefecture and Kisarazu City in Chiba Prefecture on the other side of the Tokyo Bay. With a diameter of 13.9m, it is the largest tunnel in Asia at the moment. The whole highway opened in 1997 with the cost of $11.2 billion and saves the commuters from passing the congested part of Tokyo.

4. Groene Hart Tunnel, Holland

This tunnel is part of the high speed railway line connecting the Netherlands and Belgium and is expected to open in mid 2009. At the moment, it is considered the largest tunnel in the world with a diameter of almost 14.87m.

However, works are ongoing for the construction of the largest tunnels in Madrid and Shanghai with the diameters of 15.2m and 15.4 respectively.

5. North East MRT Line, Singapore

This line became the world's first completely underground, automated and driver-less rapid transit line with the cost of $5 billion. It is 20km long and connects central Singapore with the north-eastern part of the island.

6. SMART Tunnel, Kuala Lumpur

SMART tunnel is a dual-purpose tunnel combining stormwater bypass tunnel and double-deck motorway. With the diameter of 13.28m, it is the second largest tunnel in Asia after the Tokyo Bay tunnel. It was like building 4-storey high structure underground.

SMART is an acronym for Stormwater Management and Road Tunnel, and probably the only 'smart' element of the project is the idea to combine the two functions of the tunnel for flood mitigation and also for reducing traffic congestion. Money can only be collected from traffic and not from stormwater, hence the introduction of the motorway section of the project.

7. Cu Chi Tunnel
As far as tunnels are concerned, none have more impact on the history of the nation other than Cu Chi tunnel network in Ho Chi Minh City, Vietnam. This system of secret tunnels greatly helped the Vietcongs in their fight against the Americans. It served as a military base of operations, planning and storage areas. The tunnel network also served as a communication links for Vietnamese troops.

8. Gaza Strip Tunnels

There are about 750 tunnels under Gaza Strip and they are considered a lifeline for the people of Gaza facing the oppression by Israel and supported by Egypt. The tunnels are between 0.8km to 1.4km long and about 15m to 30m deep.

Considering the depth of the tunnel (and the hard strata encountered with the depth) and the available machineries in the area, the constructions of the tunnels are really a remarkable feat. The builders might know nothing about the state-of-the-art tunnelling methods used in the other tunnelling projects in the developed countries, such as tunnel boring machines of various types, New Austrian Tunnelling Method (NATM) or any other methods available, and unlikely use any ground improvement techniques during the construction. Sheer grit and determination to fight for their deen and their people drive them to perform such an unimaginable task.

For Cu Chi tunnels and Gaza tunnels, they are symbols of the struggle against oppression and occupation. Those who built Cu Chi tunnels have seen the benefits of their hard work, and Insya Allah, the oppressed people of Gaza will also see the fruits of their struggle soon.

Men can be destroyed but cannot be defeated, and the struggle will continue until the victory is achieved. For tunnellers, they will continue digging and drilling until they reach the breakthrough. For the tunnel builders of Gaza, their struggle will go on until victory is achieved.