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As we all know, the Great Wall is the treasure
of China - even the world. It really is a great masterpiece of mankind,
with its beautiful scenes and grand construction. What many people
may not know, however, is that in different periods of Chinese history
the material of the Great Wall is different in different areas.
Before the use of bricks, the Great Wall was mainly built from earth,
stones and wood. Due to the large quantity of materials required
to construct the Great Wall, the builders always tried to use local
sources. When building over the mountain ranges, the stones of the
mountain were exploited and used; while in the plains, earth was
rammed into solid blocks to be used in construction. In the desert,
even the sanded reeds and juniper tamarisks were used to build the
Great Wall.
Before and during the Qin Dynasty (221BC-206BC), because the earth
buildings could withstand the strength of weapons like swords and
spears and there was low technology of productivity, the Great Wall
was basically built by stamping earth between board frames. As such,
only walls of plain earth or earth with gravel inside were built.
No fortresses were constructed along the wall, nor bricks used in
the construction of gates at the passes. Some of the walls were
even made only from piles of crude stones. Around Dunhuang City
in Gansu Province, Yulin City in Shaanxi Province and Baotou City
in Inner Mongolia, sites can still be found from the Great Wall
of Qin, the Great Wall of Han and the Wall of Zhao. The Wall of
Zhao was built during the Warring States Period using board frames,
and the layers of earth can still be clearly seen.
During the period following the Han Dynasty (202BC-220AD), earth
or crude stones were still popular building tools. The construction
material did not reach a new level until the middle of the Ming
Dynasty (1368-1644); however the principle of using local material
was maintained. Three hundred million cubic meters (393 million
yards) of earthwork were used in the construction of the Great Wall,
and with the appearance of large brick and lime workshops, some
parts were also built with these new materials.
Bricks were used in a lot of areas during the Ming Dynasty, as well
as materials such as tiles and lime. Attempts were always made to
produce the materials locally, so kiln workshops were established
to burn the crude material. In a construction team there was Material
Supply Department. For example, in Juyongguan Pass names of supply
departments such as kiln workshops, stone ponds and material supply
departments were recorded. Some materials, such as the timbers for
the construction of the passes, did have to be transported from
outside areas when there were none available locally.
Bricks were more a convenient material than earth and stone as their
small size and light weight made them convenient to carry and thus
quickened the speed of construction. Bricks are also the ideal material
to bear the weight. According to a sample experiment experiencing
gravity and erosion over a hundred years, the compressive strength,
resistance to freezing and absorbency of the bricks of the time
are similar to today's common bricks. A huge brick from a hundred
years ago showed a high level of technological skill for that time.
For further ease of construction, different shapes of brick were
also burned and made to stuff into different positions.
Stone, however, still has its advantages. Stones cut in rectangular
shapes were mostly used to build the foundation, inner and outer
brims, and gateways of the Great Wall. In the Badaling section,
the Great Wall is made almost entirely of granite, some of green
and white stones and some of white marble. The stone material was
found to better resist efflorescence than bricks.
It is not only because of the high level of productivity of the
time that hard material like bricks and stones were used in the
construction of the Great Wall, but also because of the development
of weapons. Before the Ming Dynasty, the Great Wall was built from
board frames and, although not very solid, could withhold simple
weapons like swords, spears and bows. But during the Ming Dynasty,
gunpowder became available. The musket, blunderbuss and cannon appeared.
Due to the use of these weapons, more solid bricks and stones were
required to build a stronger Great Wall.
The Great Wall of China embodies the great systems of defense created
during the wars of the time; moreover it indicates a great achievement
in architecture.
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