Archaeologists have discovered typical techniques applied in building
the Dai La Citadel in the 8th century at an excavation site at the
junction of Dao Tan-Nguyen Khanh Toan in downtown Hanoi.
At three excavation holes on a total area of 600sq.m, scientists have
found various layers of citadel walls built by clay compressed with
tiles, clay blocks compressed by wooden hammers and by human feet, and
big natural block of clay.
Tong Trung Tin, Rector of
Vietnam Archaeology Institute said the crucial skill resulting in the
steadiness of the citadel lies on a 50cm-thick layer of clay compressed
by nails.
Ceramic tile pieces dating back to the Tran dynasty
(1225-1400) and an earlier period were found compressed tightly with
clay on a layer 0.2m thick and 1.2m wide.
There was also a V
channel running between the tile clay compressed wall and the outer
citadel wall, which was guessed to be an exit way around the citadel
under the Tran reign.
Two layers of clay compressed
with gravel have also been unveiled at a depth of 4.5m, which has also
contributed to the solidity of the wall.
Various
layers of clay dating back to the 8-9th century, the Ly dynasty
(1009-1225) and the Tran dynasty making up the 7m-high wall proved the
theory that the Dai La Citadel was carefully renovated under Ly-Tran
reigns, scientists said.
They hold that the Dai La
Citadel was used as a dyke to prevent the inner citadel area from being
flooded by the To Lich River.
Between the clay layers,
scientists have found four tombs, including two brick-built ones and a
clay-built one from the 9-10th century. The rest of the clay-built tomb
was found in a layer dated back to the 17-18th century.
Dai La Citadel, built in 767 and underwent many improvements over
time, was the former name of Thang Long Citadel, today’s Hanoi.-VNA