Seepage is an occurrence in which a liquid or gas flows or passes
slowly through small opening.
It is often a
critical problem in building foundations, depend on the permeability of the
soil and pressure gradient, essentially the combination of forces acting on
water through gravity.
For foundations area, dewatering is needed to bring down water level
sufficiently to facilitate construction and permanent cut off of seepage
necessary at times to keep the foundation dry. Besides, seepages also must be
controlled or cut off to keep the pavement bases or sub-bases dry.Seepage
should be minimised through the barriers isolating the waste in the waste
containment systems. Thus, the safety of
embankment dams depends to a large extent on seepage control and minimization
of its potential to erode soil particles.
Uncontrolled presence and migration of water beneath pavement slabs
will be a huge costing issues for the government and constructor. When the
water is accumulated in the base or sub-base layers beneath a pavement slab due
to traffic loads, cracks in the pavement might occurred to become an outlets
for pumping of the pressurized water. Repeating pumping of this water might erode
the base materials and lead to slab instabilities and failures.
Furthermore, the presence of water in soils alter force balance and
may disturb the static equilibrium of soils. The flow of water induces seepage
stresses in direction of flow in the hydrostatic stress condition. The
hydrostatic and hydrodynamic forces may together significant enough to make
slope and retaining structures unstable. So, the accidences of landslides and
retaining structure failures often occur shortly after a rainfall. When poorly
drained, the accumulated water will also find a path to release its energy.
To control the energies of water, several engineered seepage layers
are used in infrastructure systems which are filters and drainage layers placed
around groundwater wells, underneath pavement structures and within zoned dams.
The designs are used to dissipate the pore pressures of water safely and
prevent erosion and transport of soil particles. The structural failure of dams
and pavements is often related directly to inadequate performance of these
layers. This shows that the design layers is an importance task in a civil
All in all, a civil engineer should have a good understanding and
well design of seepage control for a civil engineering project to reduce the
risk of nature disaster occurrence.