160. Translate the text from English into Russian in writing.

Tunnel boring machines (TBM) excavate tunnels with a circular cross section through a variety of rock strata. They can be used to bore through hard rock or sand and almost anything in between. Tunnel diameters can range from a meter (done with micro- TBMs) to 15 meters. Tunnels of less than a meter or so in diameter are more typically done by horizontal directional drilling rather than by TBMs.

A TBM has the advantages of not disturbing surrounding soil and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in built-up areas. The key disadvantage is cost. TBMs are expensive to construct, difficult to transport and require significant infrastructure.

References:

http://science.howstuffworks.com/engineering/structural/tunnel2.htm

http://science.howstuffworks.com/engineering/structural/tunnel3.htm

UNIT 3. TUNNEL JOBS.

Vocabulary.

surveyor – геодезист

ironworker – монтажник металлоконструкций; слесарь-арматурщик; слесарь-монтажник

cement mason – бетоноукладчик

construction crew – строительная бригада

metal fabricator – изготовитель металлоконструкций

rebar worker – арматурщик

explosive worker – взрывник

maintaining – эксплуатация, обслуживание

potential hazards – потенциальные опасности

mudslide – оползень

rock fall – обвал породы

estimate – оценка

authorization – разрешение

exact quantity – точное количество

final measurements – заключительные измерения

specialized shop – специализированная мастерская

reinforced metal bars – армированные металлические прутья

to predict – предсказывать, делать предположения

to be deemed safe – считаться безопасным

to begin scheduling – начать планирование

to supervise – контролировать

to displace rocks and soil – сдвигать, перемещать камни и почву

to assemble – собирать

to install – устанавливать to smooth the ground – выровнять землю

to pave a road– вымостить дорогу

to run power lines – запустить линии электропередач

to install lights – установить освещение

Dozens of different professionals are involved in designing, building, and maintaining tunnel systems. Geologists, surveyors, civil engineers, ironworkers, cement masons, and construction crews generally put in hundreds of labor hours to ensure that a tunnel is safe, reliable, and well-maintained. Most tunnel jobs, especially those involving the construction and maintenance of structures, are city government positions, though private companies are frequently contracted to perform highly specialized work in the development of a new tunnel.

Urban geologists and surveyors take measurements and record information about the area where a tunnel is to be built. They figure the appropriate length, width, and height for a new tunnel, and attempt to predict the risk of potential hazards, such as mudslides, rock falls, earthquakes, and collapsed support systems. Geologists also make sure that the construction of a new tunnel will not disrupt ecosystems or break the peace of people who reside in the area.

Once an area of land is deemed safe and initial measurements have been made, civil engineers get to work designing the structure. Professionals determine the exact size and shape of the new tunnel, draw blueprints, calculate the expected costs of materials and laborers, and estimate the time needed to complete construction. They present their designs to city government officials for authorization and begin scheduling the different phases of the building process. Many civil engineers spend significant amount of time at the build site to supervise the construction of new tunnels.

Many different types of skilled laborers work in tunnel jobs that involve the actual building of new structures. Highly-trained explosive workers and blasters take final measurements and calculate the exact quantity of explosives needed to displace rocks and soil. They carefully place and detonate explosives to clear the way for construction crews. Ironworkers and metal fabricators assemble and install large beams, trusses, and columns to provide the basic framework for the tunnel. Some professionals cut, shape, and bend materials in specialized shops according to blueprints, and others lift, weld, and bolt them into place at the job site.

Professional cement masons and rebar workers hold very important tunnel jobs. They first create forms out of metal or wood to provide the framework for concrete panels and columns. Workers pour cement around reinforced metal bars in the forms and allow it to dry. Cement masons then clear any excess concrete and smooth finished panels.

Other tunnel jobs involve the construction and maintenance of roads or railways that travel through structures. Construction crews smooth the ground, pave roads, and paint lines, and electricians are contracted to run power lines and install lights. Building a reliable structure involves extensive communication and cooperation between professionals in all tunnel jobs.

Ask and answer the questions to the text.

1. What specialists are involved in constructing and maintaining tunnel systems?

2. Are most tunnel jobs positions government or commercial?

3. What are the geologists and surveyors responsible for?

4. What obligations are imposed on civil engineers?

5. Who authorizes the design of a new tunnel?

6. What important tunnel jobs do explosive workers and blasters hold?

7. What do ironworkers do?

8. What kind of work do cement masons and rebar workers perform?

9. What do specialists do for maintenance of roads or railways?

10. What does the building of a reliable structure involve?

Exercises: