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DIAGRAM LABEL COMPLETION
TEST 143 READING PASSAGE 1
You should spend about 20 minutes on
Questions 1-6
which are based on
Reading Passage 1 below.
[Note: This is an extract from READING PASSAGE 1 about Roman tunnels]
The Romans, who once controlled areas of Europe, North Africa and Asia
Minor, adopted the construction techniques of other civilizations to build
tunnels in their territories
The Persians, who lived in present-day Iran, were one of the first civilizations to
build tunnels that provided a reliable supply of water
to human settlements in
dry areas. In the early first millennium BCE, they introduced the qanat method of
tunnel construction, which consisted of placing posts over a hill in a straight line,
to ensure that the tunnel kept to its route, and then digging vertical shafts down
into the ground at regular intervals. Underground, workers removed
the earth from
between the ends of the shafts, creating a tunnel. The excavated soil was taken
up to the surface using the shafts, which also provided ventilation during the work.
Once the tunnel was completed, it allowed water to flow from the top of a hillside
down
towards a canal, which supplied water for human use. Remarkably, some
qanats built by the Persians 2,700 years ago are still in use today.
They later passed on their knowledge to the Romans, who also used the qanat
method to construct water-supply tunnels for agriculture. Roma qanat tunnels were
constructed with vertical shafts dug at intervals of between 30 and 60 meters. The
shafts were equipped with handholds and footholds to
help those climbing in and
out of them and were covered with a wooden or stone lid. To ensure that the shafts
were vertical, Romans hung a plumb line from a rod placed across the top of each
shaft and made sure that the weight at the end of it hung in the center of the shaft.
Plumb lines were also used to measure the depth of the shaft and
to determine
the slope of the tunnel. The 5.6-kilometer-long Claudius tunnel, built in 41 CE to
drain the Fucine Lake in central Italy, had shafts that were up to 122 meters deep,
took 11 years to build and involved approximately 30,000 workers.
By the 6th century BCE, a second method of tunnel construction appeared called
the counter-excavation method, in which the tunnel was constructed from both
ends. It was used to cut through high mountains when the
qanat method was
not a practical alternative. This method required greater planning and advanced
knowledge of surveying, mathematics and geometry as both ends of a tunnel had
to meet correctly at the center of the mountain. Adjustments
to the direction of the
tunnel also had to be made whenever builders encountered geological problems or
when it deviated from its set path. They constantly checked the tunnel’s advancing
direction, for example, by looking back at the light that penetrated through the
tunnel mouth, and made corrections whenever necessary. Large deviations
could happen, and they could result in one end of the tunnel not being usable. An
inscription written on the side of a 428-meter tunnel, built
by the Romans as part of
the Saldae aqueduct system in modern-day Algeria, describes how the two teams
of builders missed each other in the mountain and how the later construction of a
lateral link between both corridors corrected the initial error.