Rail Analysis India June Digital Magazine 2018 | Page 36

Article | 37
Placing a layer of Techgrid PP within sub ballast above
geotextile. The ballast layer for example is subjected to
repeated dynamic and cyclic loadings, as well as elevated
temperature.
Project - Stabilization of Tracks at Kharagpur Junction
for platform 1 & 3
Site Condition – After visiting the site, it was observed
that Track bed was in distressed condition, there was water
leakage at some locations on the track bed resulting in moist
condition. Track bed settlement was also observed at multiple
locations.
Techgrid PP act as a working platform underlying over
weak soil by supporting the load of construction equipment,
preventing excessive deformation of subgrade and facilitating
proper compaction of granular layer /sub ballast. Techgrid PP
improves the performance of ballast and sub ballast /blanket
layers of railway track bed.
Solution – After a careful evaluation of the project requirements
and site conditions, given solution is that the existing ballast
should be removed and redone using PP Biaxial Geogrid and
Nonwoven Geotextile. The proposed section is as follows:
Placing a geotextile on the interface of sub-ballast and the
sub base. The geotextile gives a tensioned member effect
and will act as a separator to separate the mixing of the large
base particles with the sub-base. This will also give effective
load distribution. The pumping of fines from subgrade to sub-
base is reduced.
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