We Owe a Lot to Marc Isambard Brunel and Thomas Cochrane. Why? They Conceived a Very Ingenious Way of Digging Modern Tunnels.

175 Years Ago The First Modern Tunnel Was Built, Inspired By A Burrowing Animal

Share to email Share to facebook Share to twitter Share to linkedin Share to google I deal with the rocky road to our modern understanding of earth Opinions expressed by Forbes Contributors are their own. March 25, 1843, the first tunnel constructed under a river was opened to the (paying) public.

 From article, (March 25, 1843, the first tunnel constructed under a river was opened to the (paying) public. After eighteen years of work, the 1,300 feet long Thames Tunnel was finally finished.

At the time it was considered impossible to build under a river. In fact, in 1828 a water leakage into the tunnel caused the drowning of six workers. Work at the tunnel was stopped until two engineers came up with an ingenious solution. Marc Isambard Brunel and Thomas Cochrane got inspiration from a mollusk, revolutionizing tunneling thereafter. Teredo navalis, the naval shipworm, is a species of saltwater clam, a marine bivalve mollusk, with a strongly reduced shell. At the front end of the reddish, wormlike body of the animal there are two triangular, calcareous plates, used by the animal to rasp burrows into wood.

 Supposedly one day Brunel and Cochrane observed one of the burrows in a plank of a wooden ship, anchored in the harbor of London. The animal uses a secretion to cover the inner walls of its burrow with a thin layer of limestone, leaving only the front free, where it continues to dig, using the hard plates. Brunel and Cochrane used a similar method to finish the Thames Tunnel.  Miners would dig at the front of the tunnel, protected by a movable wooden framework. Immediately behind the miners, workers would secure the tunnel, covering the walls with bricks and concrete.

The tunneling shield method is still in use today. The front of the tunnel is excavated, be it with explosives or a modern tunnel boring machine. Immediately after, just some feet away from the unstable rock, the walls of the tunnel are secured with steel arches or concrete, strong enough to support the weight of the mountain.)

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