Since 1995 Mott MacDonald has been involved in an intensive
development programme identifying, innovative and cost-effective
ways to upgrade the condition and to extend the usage of ageing and
distressed earthworks for London Underground. Techniques used
include tied or anchored mini-piled walls, lime columns to
stabilise clay embankments as well as horizontal in situ soil
mixing to stabilise loose ash on embankment shoulders.
Embankment stabilisationMore recently
these skills have been used to assist Midland Zone of Railtrack to
upgrade similar earth structure where repeated maintenance is
causing significant delays to normal operation of the railway and
as well as requiring repetitive costly short term
maintenance.
In addition, we are developing a proactive maintenance strategy for
distressed earthworks for the Highways Agency Area 3. This has also
included the use of lime to stabilise an embankment in Gault Clay
near Gatwick.
Ash stabilisationOur award-winning
design and supervision of the stabilisation of a large cutting on
the M25 (using dowel piles), is an example of the strategic
solutions we are able to deliver.