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problem
Alternative design and construction of landfill liner systems using
Geosynthetic Clay Liners (GCLs) has become more and more popular
because GCLs have been accepted by engineers and regulators. In
fact, in many common categories of equivalency, GCLs are considered
superior to compacted clay liners (CCLs). But traditional geosynthetic
drainage composites for leachate collection and leak detection in
contact with a GCL layer suffer severe flow rate loss due intrusion
of the soft saturated GCL within the drainage structure.
solution
With GCLs acting as liners a problem exists because the GCL surface
will tend to press against the filter geotextile layer and intrude
into the flow channels of a drainage geocomposite. With most geosynthetic
drainage composites this is an important concern because geotextile
intrusion underneath any soil or substitute soil layer will restrict
design flow rates below desired performance levels.
The triplanar
configuration of TENAX GNT drainage net is designed to prevent such
geotextile intrusion and maintain high drainage levels for many
years under, over, or between soils and/or substitute soil layers.
The outside ribs of TENAX TENDRAIN hold the geotextile and soil
away from the drainage net core so that flow restricting intrusion
is minimized. TENAX TENDRAIN is the solution to solve interface
problems between geosynthetics clay liners, CGLs, and geosynthetics
drainage products by providing long term flow rate performance.
conclusions
At this landfill in Volusia County, Florida, a leak detection system
was developed which required a geonet that would limit intrusion
of the GCL into the flow channels of the geonet. The problem of
GCL intrusion results in a reduction of flow through the geonet,
a situation that was unacceptable on this project. Project engineers,
however, discovered that the structure of TENAX TENDRAIN was ideal
for use with GCLs because the very structure of TENAX TENDRAIN prevents
intrusion into the drainage channels.
TENAX TENDRAIN was therefore
deployed on this project in the leak detection system, to provide
rapid detection of any major breach in the primary liner system,
and to limit the head acting on the secondary liner to lengthen
the thickness of the LDS. |
geo@tenax.net