Autumn

| STRONG |
On track for Rail
Acton Town to Chiswick Park
Embankment Stabilisation
This recently completed scheme
for LUL, with a value of c £2.5m,
required a number of solutions
at 5 separate locations between two
stations on the District Line.
The first 3 locations were
undertaken during two weekend
track possessions utilising road/rail
plant to install 161 5 metre driven
steel piles infilled with 1100 concrete
planks, the void between the track
and the new structure was raised
with 250 tonnes of compacted gravel
wrapped in a geo textile membrane; a
new trackside walkway and safety
handrail completed the works.
The next two locations were
undertaken during traffic hours as
access, whilst restricted, was
possible from the highway, a partial
road closure allowed scaffold access
to the failing embankments, which
were in a confined area between the
track and local residences. A reduced
dig operation was undertaken at
both locations, each of which were
accessed from a single entry point,
removing 1250 tonnes of spoil and
installing temporary works to
support the adjacent track prior to
reconstruction of the embankments.
The LUL design had specified the
raising of the existing lower
retaining wall by 1.7m and a revised
profile created using a new
proprietary system Ram Wall. This
comprises of a galvanised steel grid
installed and fixed in sections to an
agreed pattern to give structural
strength, infilled with a lightweight
Maxit aggregate which reduced the
loadings on the higher embankment
compared to traditional fill
materials. Over 1400m 3 of Ram Wall
and 1900m 3 of Maxit were installed
over the 280m length of the two
sites, making it the largest scheme
built using the system.
The structures were capped with
150mm of seeded topsoil, with a new
walkway and safety handrail
installed.
During the construction of these
works Clancy Docwra tendered for,
and has been awarded, a 5 year
framework for earthworks and
embankment stabilisation with LUL.
Gants Hill Ventilation
Shafts VP50 &VP50a
One of many ventilation shafts on
the LUL Central Line, Shafts
VP50 and VP50a surface at a
roundabout on the busy A12 trunk
road. Both brick built structures had
been identified as having defective
steelwork supporting the safety grills
protecting the opening.
Scaffolding was erected under TfL
traffic management incorporating a
birdcage deck enabling access to the
defective steel and to protect the
track below.
Safety grills to VP50a were removed
and all supporting steelwork to the
5metre diameter shaft was prepared
and repainted using a three coat
system, prior to the reinstalling and
securing the grills
Shaft VP50 was a smaller rectangular
shaft over a machine room not the
track, but requiring equal protection
and a different solution. The lighter
steel work supporting the safety grill
had deteriorated to the point where
replacement was required; following
the strip out of the old structure new
galvanised steelwork was manufactured
and installed to include new safety grills.
Project Manager Mark Driscoll
confirmed that the project with a
value of £28k, which was secured as
part of £1.6m package awarded under
the LUL Civils Lot B Framework, has
progressed well and to the
satisfaction of both LUL and Tfl.
14 | Autumn Issue