Unequal settlement in buildings is one of the main causes
of structural damage which often require expensive and difficult repair work.
Settlement however should not be confused with subsidence where the ground may
give way under load in instances such as where a load is placed on the soil
above an area where mine workings at some stage took place causing the shaft to
collapse. Settlement is not as severe as subsidence, Settlement may occur on
the vast majority of buildings and the majority of its damage may only be
visual rather than structural however it is important that methods are put in
place to limit or stabilise settlement in buildings.
can be caused by uneven compression of the foundation, shrinkage in timbers due
to an adjustment in the moisture content or undue loads being applied to the
building after its construction. This literature review will focus mainly on
the loads transferred from the foundation into the soil and will look at a
multitude of traditional and innovative methods to stabilise the soil to reduce
the effect of settlement on buildings ranging from pre-loading or pre-compression
to using a cement-ricehusk mix.
Innovative Methods for the stabilisation of settlement in
“Vibro-compaction, sometimes referred to
as Vibroflotation, is the rearrangement of soil particles into a denser
configuration by the use of powerful depth vibration. Vibro Compaction is a ground improvement process for
densifying loose sands to create stable foundation soils.”
With Vibro Compaction the joint effect of
vibration and water saturation via jetting rearranges loose sandy soils into a
more compacted and solid state. It is conducted using specialist machinery
which typically are equipped with a torpedo style vibrator that can range from
12 to 16 inches in diameter. It should be used primarily for larger buildings
as it would not be a cost-effective method for the construction of small single
dwellings or buildings. Vibro compaction is the most common method to prevent liquefaction
of soils in areas of seismic activities.