Milestones in the history of tunneling

Years / centuries	Purposes of tunnel
Ancient times	for irrigation, as pedestrian passages or to excavate temple rooms inside rocks

1.14. Summarize the text given above using expressions (page 67).

1.15. Study the text “Tools and Techniques” and complete the table.

tools and techniques	first used	advantages	disadvantages
1. Fire-setting	2000 B.C.	speeds up the work	toxic fumes and intense heat
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Tools and Techniques

Throughout the ages, people have developed all kinds of tools and techniques for digging tunnels. Some were more successful than others. Learn more about each one.

Fire-Setting

A n ancient technique in which the tunnel wall is heated with fire, then cooled with water. In the right conditions, the temperature change causes the wall to break off in chunks (куски). It was first used in a tunnel around 2000 B.C., to mine copper and gold from Egyptian mountains.

Do you know that Roman slaves built the enormous Cloaca Maxima, (one of Rome’s oldest sewer tunnels), using the fire-setting technique? The tunnel was so huge and impressive; the Emperor Augustus was d to have toured (объезжать) it in a ship. Thousands of slaves died in the tunnel from the toxic fumes (испарения) and intense heat, but fire-setting remained the standard tunnel digging method for well over 2,000 years!

H and Tools

Before there were explosives and tunnel-digging machines, workers used hand tools to carve tunnels. Hand tools were first used in a tunnel around 2000 B.C. to mine copper, gold, and salt from mountains in Belgium, France, and Portugal.

Do you know that in the Middle Ages, medieval armies launched (начинать) attacks on enemy castles (замок) by digging tunnels through sandy soil under moats (ров) using crude hand tools? The men dug tunnels not only to gain entrance to a castle, but to destabilize and topple (валить) it. They supported their tunnels with timbers, which they then burned to collapse the tunnel – and the castle as well.

E xplosives

Gunpowder, nitroglycerin, and dynamite allowed tunnel diggers to blast through mountains much faster than ever before. Gunpowder was first used in 1679, to build an underground section of the Canal du Midi, a canal connecting the Atlantic Ocean and the Mediterranean Sea. The tunnel was 157 meters long. Nitroglycerin was first used in 1867 to excavate the Hoosac Tunnel in North Adams, Massachusetts. That same year, Swedish physicist Alfred Nobel patented another blasting explosive called dynamite. Dynamite is based on nitroglycerin but is much safer to handle than nitroglycerin alone.

D o you know that one of the first tunnels to be excavated with gunpowder was the Harcastle Canal Tunnel in England in the 1700s and it was an absolute disaster (бедствие)? Gunpowder blasts struck (поражать) springs, which flooded the tunnel and delayed construction. To save time and money, the chief engineer built a very small and narrow tunnel. The tunnel was so tiny (2.2 meters wide by 3.6 meters high) that barges had to be “legged” from end to end. This meant that men lay on their backs on the barge deck and pushed (толкать) the barge through by walking their feet along the tunnel roof.

Compressed Air Drill

Compressed air drill is a drill that can rip (прорезать) through rock with ease. It was first used in a tunnel in 1866, in the Hoosac Tunnel, in North Adams, Massachusetts.

Do you know that the compressed air drill made life much easier for workers in the Hoosac Tunnel? The drill was safe and three times more effective than gunpowder. In the choking dust, the drills also had a welcome side effect (побочный эффект). Air blew out of the end of the drills and actually provided some fresh air in the stuffy Hoosac Tunnel. Before the compressed air drill, workers toiled (усиленно трудились) in hot, steamy tunnels without any ventilation!

T unnel Boring Machine (TBMs)

Tunnel Boring Machine is a 200-ton rock-chewing (пережевывать) machine designed to carve through rock. It was first used in a tunnel in 1957 to carve a sewer tunnel through shale and limestone in Toronto, Canada.

Do you know that TBMs are very picky (разборчивы) about the rocks they chew through? This is why geologists must monitor the rock at the head of every tunnel. On good days, TBMs can bore through rock at a rate of 250 feet a day. But when TBMs bite into rocks they don’t like, they grind to a halt (усердно трудится до остановки) and conk out (ломаться). Many tunnel engineers have been forced to abandon (оставлять) their TBMs because they can't back them out of the tunnel!

T unnel Shield

Tunnel shield is an internal frame, or shield, used to support loose earth in a tunnel while digging. It was first used in a tunnel in 1825, to excavate the Thames Tunnel, London, England.

Do you know that the idea for the tunnel shield was borrowed by a French engineer named Marc Brunel from nature and a helmet-headed shipworm (корабельный червь) gave that idea? The worm bore through wood, using the hard shell (остов) on its head as a shield. As it tunneled into the wood, the worm excreted a substance that formed a rigid (твердый) lining behind it!