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

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

An 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!

Hand 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.

Explosives

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.

Do 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.

Дата добавления: 2015-10-31