Consolidation of weak bearing soils can be done by means of vertical and horizontal drains:
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©2014 Boskalis Polska Sp. z o.o.
Vertical drainage shortens consolidation
To reduce the the time of settlement,
a distance that pore water must cover to
flow out should be shortened. This can be
achieved by application of vertical
drainage. Pore water flows to the closest
drain and then runs off along it.  Thanks to
vertical drainage, the cosolidation time can
be reduced to even half a year. It means
that consolidation can be completed during
the project. In order to minimise latter soil
settlement, the installation of drains
requires temporary surcharge, for instance
gravel layer. In the end, the surcharge is
removed after the completion of
construction works.
Characteristics of a drain
MEBRA-DRAIN is a precast, flat, double
layer drain. Liner is made of high quality
polypropylene. Thanks to grooves at both
sides, high discharge capacity can be
obtained. The liner is embraced by solid
filter textile of high permeability.
The final result achieved by using vertical
drainage is associated with:
- its high durability
- bacteria and organisms resistance
- fastness to acids and solvents etc.
- slight durability loss during exploitation
- slight creeping due to stress
Soil consolidation by means of vertical
drainage is successfully applied to:
 - construction of roads, railway tracks,
airfields and embankments
- land reclamation
- construction of harbour structures
- land prepration under construction
- construction of storage yards and tanks
Advantages of MebraDrain
- it can be applied to all types of soil,
- low transportation costs (120,000 lm per
- low installation costs due to only a few
persons of crew,
- fast installation process: 2 to 5 thou. m/8h,
- up to 40 m installation depth,
- elasticity that ensuries functioning of the
drains even at large folding of drains during
- relatively small interference of soil layers
during installation
- easy supervision during works,
- a possibility to instal in different offsets
depending on required consolidation pace.
A combination of two soil consolidation
- vertical drainage
- surcharge supported by vacuum
technology concluded in new technology
- BeauDrain.
Here, vertical drains are placed
simultaneously with horizontal ones.
Installation device moves in a straight line
inserting vertical drains in offset from 1.0
to 2.0 m. Horizontal drainage is placed at
1.0-2.0 m below surcharge surface, where
vertical drains are cut off. A horizontal drain
is connected to vertical one and to vacuum
pomp. Afterwards a geomembrane strip
placed directly on the drain separates it
from air and soil. When a coulter moves
over a strip, it sinks into a drain. This
method allows to install c. 3000 m drains
a day.
Advantages of BeauDrain
- short installation period and clean work
site after installation
- no soil is excavated, thus preventing any
damage as a result of horizontal
deformation of the soil due to relaxation
and insufficient filling
- no supply of drainage sand or
removal/storage of removed soil
 - a large working depth is achievable
thanks to the use of vertical drains
- sand layers can be followed at a safe
- the use of vacuum pressure gives rise to
an increase in effective pressure; this
reduces the risks of instability in the case
of ongoing embankment creation
- the existing body of soil is used as a
sealing medium, thereby dispensing with
the need for a surface membrane
- the work site becomes available for other
activities immediately after installation and
remains so
- the barrier configurations can be adapted
to the soil type to be consolidated
- horizontal deformation in the event of
ongoing embankment creation is
considerably reduced
- the BeauDrain system also allows for a
considerable reduction of secular
settlements and settlement differences.
Click a thumbinal to enlarge
Soil consolidation works are carried out