II. Answer the following questions.

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1. What is done first to blast the rock?

2. How are holes bored?

3. Where do workers pack explosives?

4. When doesn’t the tunnel require extra support?

5. Why do workers insert long bolts through the rock?

6. How does a tunnel-boring machine work?

7. When do worker hold the soil in place with bolts, steel ribs and sprayed concrete?

8. Tunneling beneath bodies of water is more dangerous, isn’t it?

9. What tunnels are cheaper?

10. Do you know any submerged tunnels?

LANGUAGE FOCUS

I. Match the words with their synonyms.

1. Drill a) trench

2. Excavate b) mesh

3. Need c) permanent

4. Perilous d) require

5. Ditch e) bore

6. Net f) dangerous

7. Constant g) muck

8. Girder h) remote

9. Blasted rock i) beam

II. Match the words with their opposites.

1. Solid a) pack

2. Extract b) remote

3. Add c) cheap

4. Long d) behind

5. Complete e) separate

6. Expensive f) permanent

7. Connect g) start

8. Ahead h) short

9. Temporary i) soft

III. Fill in the words: feet, shallow, circular, mining, steel, conditions, waterproofed, cost, dangerous, downward.

The … industry has been the primary constructor of shafts. Depth of several thousand … are common. In public works projects, such as sewer tunnels, shafts are usually only a few hundred feet deep and because of their high … are avoided in the design stage whenever practical … shafts find many uses. Being essentially vertical tunnels, shafts involve the same problems of different types of ground and water …. Inflowing water is far more … during construction and generally intolerable during operation. Hence, most shafts are concrete-lined and …, and the lining installation usually follows only a short distance behind excavation. The shape is usually …, although, before current mechanized excavation methods, mining shafts were frequently rectangular. Mining … is called shaft sinking. In soil, shallow shafts are frequently supported with interlocking … sheet piling held by ring beams.

FOLLOW UP ACTIVITIES

Speak on:

Basic procedures in tunneling operations.

The construction of tunnels.

Unit 8: FAMOUS TUNNELS

Lead in:

1. What famous tunnels do you know?

2. Why are they called famous?

Find the following terms and memorize their meaning.

bank blow into determination divergence draw off duct banquet brick cylinder bricklayer chamber compressed air controversy drainage enlarge exhausts engineering failure fraction heading internal combustion lining motor traffic

flooding frames impede impel inch leaks prop propel purposes survey technique temporary underwater tunnel screw sealing shaft shield shotcreting sinking surface approach

Text 1: The Mersey Tunnel

1. The Mersey tunnel is one of the biggest underwater tunnel of the world. What other underwater tunnels do you know?

2. What are the construction techniques of underwater tunnels?

3. What are the purposes of underwater tunnels?

The cities of Liverpool and Birkenhead are joined by a tunnel which goes under the river Mersey. It is the famous Mersey Tunnel, one of the biggest underwater tunnels in the world. Its total length is over two and a half miles. During the year 1956 more than 10 million vehicles used the tunnel. Its construction has been a great engineering achievement. The work started in December 1925 on the Liverpool side and a few months later on the Birkenhead side. It had been decided to approach the work by driving from each bank of the river two pilot headings, an upper and a lower one, which would meet under the middle part of the river. Vertical shafts were sunk on both sides of the river and the excavation work began. At first the working face of the heading was broken up by compressed air drills, later explosives were used. The headings met on the 3rd of April, 1928, twenty-seven months after the work had begun. The divergences in line and level were found to be a fraction of an inch, showing how accurately and correctly the survey work and the determination of working levels had been done. The next stage of the work was the enlarging of the pilot headings into the full-sized tunnel. Steel, cast iron and concrete were used in lining the tunnel. From the very start it was realised that the ventilation of a tunnel of such length, which was to be used by vehicles propelled by internal combustion, would be a very difficult problem. Finally, a system of ventilation was adopted in which air is blown into the tunnel through ducts at roadway level and drawn off along the roof through exhausts. The Mersey Tunnel was completed in 1934. It was opened on the 18th of July, 1934. At the time it seemed a complete solution of the communication difficulties that had existed between Liverpool and Birkenhead. Today it is obvious that the solution has been only temporary. The ever-increasing exports from the port of Liverpool and the rapid development of Merseyside as an industrial centre have resulted in a great increase in motor traffic through the tunnel. Plans are now being made for the use of the space between the walls supporting the reinforced concrete roadway at the lower level of the tunnel (1840).

COMPREHENSION CHECK

I. Decide whether the following statements are true or false according to the text:

1. The Mersey Tunnel is one of the most famous underwater tunnels in the world.

2. Two pilot headings, an upper and a left one, were decided to be driven from each bank of the river.

3. The working face of the heading was broken by latest explosives.

4. The divergences in line and level were found to be a fraction of an inch, showing that engineers and designers were a bit inaccurate in their calculations.

5. Ventilation wasn’t considered to be a very big problem.

6. The air was exhausted at the roof level.

7. The tunnel proves to be a solution of the communication difficulties.

8. Plans are now being made for constructing a parallel tunnel along the main one.

9. Now the tunnel carries 10 million vehicles a year.

10. Its total length is over 4 kilometers.

II. Answer the following questions:

1. Prove that the tunnel was quite popular after it had been completed.

2. What was new about the construction of the tunnel?

3. What was used to break up the working face?

4. What did the divergences in line and level show?

5. Why was the ventilation in the tunnel realized a problem?

6. How was the ventilation system arranged?

7. What are the plans to solve communication difficulties between Liverpool and Birkenhead?

LANGUAGE FOCUS

III. Match the meanings of these terms with their definition:

1. heading	a. a difference between two or more things
2. communication	b. examine the condition of anything
3. explosive	c. form a layer over the inner surface of something
4. fraction	d. pipe or system by which waste gases are expelled
5. survey	e. connection or means of access
6. exhausts	f. horizontal passage made in preparation for building a tunnel, or in a mine.
7. line	g. small part, piece, or amount
8. divergence	h. a substance that can cause an outburst

IV. Complete the following table:

noun	verb	adjective
divergence
	to explode
		accurate
determination
		long
	to adopt
solution
	to ventilate
communication
		strong

V. Using the words from the table above complete the following sentences:

1. They have to _____ the problem with the ventilation.

2. To avoid divergences in line and level, the engineers had to be very _____ with their survey.

3. To _____ the road is not an easy task.

4. Your calculation _____ considerably from mine.

5. The _____ of this system of ventilation resulted in imroving indoor comfort.

6. Breaking up the working face of the heading is done with the help of _____.

VI. Make up the sentences from the words below:

The Holland Tunnel

1. has, providing, with, more than, from Canal Street, link, two traffic, to Jersey City, direct, a, two tubes, 8, 000 feet long, lanes, in each for automobiles, trucks, and buses. 2. was, to traffic, and New Jersey, the Port Authority, which, of New York, tunnel, is operated, The, by, opened, in 1927. 3. used, and construction, of the tunnel, still, vehicular, The, throughout, method, building tunnels, the world, the basis for, and principles, form, in the design

VI. Complete the text with the words below:

westbound, authority, tubes, vehicles, motor, conditions, vehicular, lanes

The Lincoln Tunnel, also used by motor__(1)__, provides a link between 38th Street in midtown Manhattan and Weehawken, N.J. The tunnel, operated by the Port __(2)__ of New York and New Jersey, is the only three-tube underwater __(3)__ tunnel in the world. Two of its __(4)__ are over 8, 000 feet (2, 400 meters) long, and the third is about 7, 500 feet (2, 290 meters) long. Each tube has two __(5)__ for vehicular traffic. The center tube, used for eastbound, __(6)__, or two-way traffic as __(7)__ require, opened in 1937. The north tube, for westbound traffic, opened in 1945. The south tube, used for eastbound traffic, opened in 1957.

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