Thames Tunnel - First Tunnel Built Under River

In the early 19th century, London is one of the busiest ports in the world, and also a stone bridge aged 600 years on top of the River Thames has become too congested to be used. Despite the width of the bridge being 8 meters wide, only half of it is readily available for the roadway.

The road itself is shared among many vehicles back then on top of the pedestrians on the side. During peak time, getting across this bridge will take up to 1 hour long. It is clear that this new pathway did not function as a bridge but instead as a tunnel that goes underneath the River Thames.

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The idea at first seems impossible as it has never been done before by anyone.

The Mastermind Behind The Construction of The Tunnel

Many attempts have been made to build a tunnel under the River Thames a long time ago. In 1799, an engineer, Ralph Dodd has tried to build a tunnel between Gravesend and Tilbury but unfortunately failed in the end.

Later in 1805, a group of engineers from Cornwall tried to dig underground between Rotherhithe and Wapping but the clay underneath was too soft with a lot of water present. The mining engineers that were used to working with hard rocks were not capable of holding the water inside the tunnel.

The project was left as it is and the earlier engineers finally declare that the tunnel under the river cannot be built. But Marc Brunel thought otherwise as this excellent French engineer has run away from his country due to the French revolution and managed to make a name for himself in Britain.

Brunel believed that the tunnel under the Thames is not impossible to be built as he already thought of the whole plan of building it. He even put forward his ideas to Alexander I of Russia to build the tunnel under the Neva River in St Petersburg. But the emperor himself rejected his proposal and instead build a bridge.

Challenges and Obstacles of Building The Tunnel

Brunel managed to identify the issues faced by engineer, Cornwall and created a new technique in constructing the tunnel where this current technique has been used for the past 2 centuries. This technique is known as a tunneling shield.

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It is a temporary structure that shields the inside of the tunnel and protects the people inside as well as the materials from falling off or sinking. It was said that Brunel got his wisdom from the ability of the shipworm to dig pieces of wood that he found while working at the shipyard.

The shield tunnel of Brunel comprises huge metal beams, square-shaped with 36 spaces that have been divided into three stages. Every open space at the back will be closed at the front with an adjustable board. The part at the front will be shielded at the face of the tunnel and the worker will take out the board one by one in order to dig the back end with a specified depth that has been allocated.

Later the board will be pushed into the hole and screwed into its place before the next one is taken out. The whole process is repeated until the land behind all the board is dug up. After that, the whole metal rack will be moved towards the front and the new place where it has been dug out will be reinforced with bricks and mortar.

The shield of this tunnel was a new concept at the time but the progress itself was considerably slow at a rate of 8 to 12 feet per week. Despite the shield functions to prevent sedimentation and landslide, problems will definitely arise.

Dirty water and sewage from the River Thames drips on top of the tunnel and poisons the airway inside. Many miners including Brunel had fallen ill and experiencing diarrhea, headaches, and temporary blindness.

The pumps work 24 hours a day to remove the water inside the tunnel and during its downtime, the tunnel will be flooded with water at a few feet in height. In 1827, an accident has occurred inside the tunnel which caused a rapid influx of water inside.

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Brunel's son, Isambard Kingdom Brunel was forced to dive into the water to patch up the hole at the bottom of the river by using a bag full of clay to close the hole. Not just that, another incident in 1828 has also taken place where 6 workers died, and with Brunel left with no funds to manage, the project of the tunnel was once again abandoned.

The Advancement of Engineering Technology

The Thames Tunnel is a success of modern civil engineering but it came to a halt due to financial issues. The cost to build the tunnel is more than half a million pounds which is far more than its original cost. The plan to build the front entrance to place the wheeled vehicles was also a failure due to cost problems.

From the start, it was meant for pedestrians however it became a place of attraction for many tourists attracting almost 2 million visitors each year with a measly 1-cent entrance fee. In 1865, this tunnel was bought by London North Eastern Railway and was changed for railway use.

It then became a part of the London Underground and was used until 1962.

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