Circle the correct answer.
Dozens of different professionals … in designing, building, and maintaining tunnel systems.
involve
are involved
involved
Urban geologists and surveyors …and record information about the area where a tunnel is to be built.
take measures
take matters
take measurements
They figure the appropriate length, width, and height for a new tunnel, and … the risk of potential hazards, such as mudslides, rock falls and so on.
attempt to produce
attempt to predict
attempt to forecast
Once an area of land … safe and initial measurements have been made, civil engineers get to work designing the structure.
is deemed
is denied
deems
Many civil engineers spend … at the build site to supervise the construction of new tunnels.
significant number of time
significance amount of time
significant amount of time
. …explosive workers and blasters take final measurements and calculate the exact quantity of explosives … to displace rocks and soil.
Highly-training/ needed
Highly-trained/ needed
Highly-trained/ needing
Ironworkers and metal fabricators assemble and install large beams, trusses, and columns … the basic framework for the tunnel.
to provide
provides
provided
Some professionals cut, shape, and bend materials in … shops according to blueprints, and others lift, weld, and bolt them into place at the job ….
specialized/ site
specializing/ site
specialized/ side
Cement masons then clear any … concrete and smooth finished panels.
exceed
excellent
excess
Construction … smooth the ground, pave roads, and paint lines, and electricians … to run power lines and install lights.
screws/ are contracted
crews/ are contracted
crews/ are constructed
Use the phrases below to tell your partner three facts about one of the tunnel jobs. Your partner has to guess the job.
(Перестроила в столбик, может быть зря? Надо ли все заглавные?)
GET GOOD SALARIES WORK PART-TIME
USE A COMPUTER WORK LONG HOURS
WORK SHIFTS WORK INDOORS
WORK OUTDOORS WEAR A UNIFORM
WORK WITH THEIR HANDS WORK 9 to 5
START EARLY IN THE MORNING
A: They usually work 9 to 5. They use a computer. They don’t work outdoors.
B: Are they designers?
References:
http://www.wisegeek.com/what-is-a-boring-machine.htm
UNIT 4. TUNNEL CONSTRUCTION TECHNIQUES.
Vocabulary.
review – обзор
mining construction – горное строительство
overlapping – совмещение
bulk excavation – объёмное копание, объёмное рытье
road deck – пролётное строение моста
environmental impact – воздействия на окружающую среду
disruption – нарушение
emissions – выбросы
drilling rig – буровая установка
equipment – оборудование
competent rock –крепкая порода; твёрдая порода
TBM – туннелепроходческая машина
rock cutter – резец породный
waste – отходы
duration – продолжительность
roadheader – проходческий комбайн
backhoes – экскаваторы
grouting – закрепление грунтов
sequential – последовательный
well–proven – хорошо зарекомендовавшей себя
similar – аналогичный
designated – назначенный
appropriate – соответствующий
to include – включать
to accommodate – вмещать to adopt – внедрять, принимать
to carry out – осуществлять
to undertake – предпринимать
to measure – измерять
to relocate – передислоцировать
hence – следовательно
Рис. ??
Methods of tunneling vary with the nature of the material to be cut through. All the tunnelling techniques reviewed for possible use include cut and cover, drill and blast, bored tunnelling and sequential mining construction.
1. Cut and Cover Tunnelling. Cut and cover tunnelling is a common and well-proven technique for constructing shallow tunnels. The method can accommodate changes in tunnel width and non-uniform shapes and is often adopted in construction of stations. Several overlapping works are required to be carried out in using this tunnelling method. Trench excavation, tunnel construction and soil covering of excavated tunnels are three major integral parts of the tunnelling method. Most of these works are similar to other road construction except that the excavation levels involved are deeper. Bulk excavation is often undertaken under a road deck to minimise traffic disruption as well as environmental impacts in terms of dust and noise emissions and visual impact.
2. Drill and Blast. This tunnelling method involves the use of explosives. Drilling rigs are used to bore blast holes on the proposed tunnel surface to a designated depth for blasting. Explosives and timed detonators are then placed in the blast holes. Once blasting is carried out, waste rocks and soils are transported out of the tunnel before further blasting. Most tunnelling construction in rock involves ground that is somewhere between two extreme conditions of hard rock and soft ground. Hence adequate structural support measures are required when adopting this method for tunnelling. Compared with bored tunnelling by Tunnel Boring Machine (see below), blasting generally results in higher but lesser duration of vibration levels. A temporary magazine site is often needed for overnight storage of explosives.
3. Bored Tunnelling. Bored tunnelling by using a Tunnel Boring Machine (TBM) is often used for excavating long tunnels. An effective TMB method requires the selection of appropriate equipment for different rock mass and geological conditions. The TBM may be suitable for excavating tunnels which contain competent rocks that can provide adequate geological stability for boring a long section tunnel without structural support. However, extremely hard rock can cause significant wear of the TBM rock cutter and may slow down the progress of the tunnelling works to the point where TBM becomes inefficient and uneconomical and may take longer time than the drill-and-blast tunnelling method.
4. Sequential Excavation Method. This method is also known as the New Austrian Tunnelling Method (NATM). The excavation location of a proposed tunnel is divided into segments first. The segments are then mined sequentially with supports. Some mining equipment such as roadheaders and backhoes are commonly used for the tunnel excavation. The ground for excavation must be fully dry for applying the NATM and ground dewatering is also an essential process before the excavation. Another process relates to the ground modifications such as grouting, and ground freezing is also common with this method in order to stabilize the soil for tunnelling. This method is relatively slow but is found useful in areas where existing structures such as sewer or subway could not be relocated.
Answer the questions to the text.
What are the main tunneling techniques?
How do they differ?
Speak on Cut and cover tunneling technology.
When is Drill and Blast Method used? What’s the advantage of it?
What is the key element of the tunnel construction Bored technology?
What does the New Austrian Tunneling Method technology allow?
Exercises: