In areas underlain by an irregular patterns
of gravel or sand lenses in a matrix of clay layers, any
structures built directly over the edge of such lenses may
suffer serious structural damage as a result of unequal
subsidence rates of their foundations.
Again, making this information available
prior to the decision to build may avoid human hardship as well
as undue costs of construction and/or remediation. A thorough
understanding of subsurface conditions is therefore a
prerequisite before plans are drawn up for urban housing
projects, etc.
A word of caution: engineering geological
site investigations are not what is meant here, as these are
usually carried out after a decision to build in a
certain location has been taken. Instead, urban geological
advice should be provided before an area is earmarked
for construction (essentially a land-use planning exercise), in
which case a substantive reduction in foundation costs can be
achieved.
Next >>>
|
