Project: Embankment Stabilisation between Pinner and South Harrow

Owner: Metronet Rail

Contractor: Skanska

Designer: Pell Frischmann / OTB Engineering Ltd.

Purpose: Retaining toe walls along re-graded embankments.

RamWall Type: 8m diameter 200mm x 200mm galvanised RAMWALL mesh plus 5m diameter, 50mm x 50mm galvanised facing mesh, 25mm rebar spikes.

RamWall Fill: Used railway ballast.

Major embankment reprofiling and stabilisation works were undertaken between Pinner and South Harrow on the Metropolitan Line by Metronet Rail. These require construction of 1.5m and 2m retaining walls at the toes of the embankments where they abut adjacent properties.

Here the available space for construction is very restricted, particularly as the slopes incorporate a toe drain immediately adjacent to the retaining walls.

RamWall was selected because of its versatility and ease of construction in a constrained space using only site labour.

In total about 160m of RamWall is scheduled and in order to meet the required 120-year design life the steel gauge of the RamWall and facing mesh has been increased and galvanised. In addition a new mechanical mesh-fixing system has been introduced to speed construction and improve long-term maintenance.