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ADAPTING NEW PROJECTS TO THE PRESERVATION OF BURIED ARCHAELOGICAL REMAINS
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After
assessment in concert with the
technical studies branches, that is, after several exploratory excavations have been carried out
to define the nature of the remains, how deep they are buried, their thickness and the nature of
the ground that bears them :
- Either it appears that the remains are well enough buried to let construction go ahead
as planned;
- Or, special foundations can be
put in place to ensure the preservation of the remains beneath the new
buildings.
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Special foundations
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If it turns out that specific foundations only
preserve part of the remains, a preventative
archaeological excavation is carried out to protect the information destined to
disappear. Several foundation building techniques can be used on the same
project according to the nature of the remains to be protected: their depth, the weight
and design of the new buildings, their environment. Thus today, there are five special types of
foundations supporting the Musée archéologique de Saint-Romain-en-Gal. During the past
fifteen years numerous public and private buildings have been built
on special foundations in the Vienne urban area.
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Management of the Vienne urban area’s archaeological heritage
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Two techniques are currently being used :
- One is "ribbed, reinforced frames, on
restored and compacted soil". This
technique completely preserves the remains, if there is enough space between the top of the remains
and the base of the foundations. In some cases, the finished floor may be raised in comparison with the
surrounding ground.
- The other is "steel-reinforced piles
driven in and connected by horizontal beams or longitudinal
girders". This technique is only acceptable if the intervals
between the piles (most often between 9 and 11 m.) are wide, for the
entire thickness of the remains they are driven through is completely
destroyed. If the intervals are too narrow they will prevent any future
archaeological analysis of the remains, if they were to be excavated
during the demolition of the building. Nevertheless, the pile driving
technique sometimes has to be used, for example, to avoid any
differential subsidence when there are adjoining ancient buildings.
Generally the piles are sunk blind : the width of the intervals between
them allows for a very low destruction rate.
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