2023
LONDON - SOUTH EAST - United Kingdom
BERKELEY GROUP
GCL
FN Conway
Southall Waterside Development, West London Reinforced Embankment Solution Problem
View of the new Southall Waterside Access Road
Final compaction operation
Paralink being laid flat and wrapped back as per design
Challenge
The Southall Waterside development is a large-scale regeneration project in West London, designed to transform a 45-hectare former gasworks site into a vibrant new neighbourhood alongside the Grand Union Canal. A critical component of this development is the Western Access route, which provides essential infrastructure connectivity to the site.
This access route includes a new road constructed across three engineered embankments and two integrated bridges within a confined 0.75-hectare brownfield area. The scheme also incorporates pedestrian footways and a dedicated cycle lane, crossing key water features including the Yeading Brook and the Grand Union Canal.
During construction, unforeseen ground conditions presented a significant engineering challenge. Ground investigations identified weak Made Ground within a historic infilled canal arm, resulting in reduced load-bearing capacity and variable subsoil conditions. These issues posed a risk to the stability of the proposed embankments, particularly given their required heights of up to 6.1 metres. A robust ground improvement and reinforcement solution was therefore essential to ensure long-term performance, stability, and safety of the infrastructure.
Solution
To overcome the challenging ground conditions at Southall Waterside, a basal reinforced embankment solution using Paralink high-strength geosynthetic reinforcement was implemented. A single horizontal layer of Paralink was installed at existing ground level to improve load distribution and enhance overall embankment stability.
Extensive ground remediation works were carried out prior to installation. The unsuitable Made Ground was excavated to depths of between 1.0 and 1.5 metres below original ground level. The excavated area was then backfilled with lime- and cement-stabilised Class 9E material to create a stronger and more uniform foundation. A layer of crushed concrete was subsequently placed above this to form a stable working platform and improve load transfer.
The reinforced embankments, typically 4.0 metres in height and reaching up to 6.1 metres at their maximum, were further supported by concrete retaining walls along their edges. This approach ensured structural integrity within the constrained site footprint and maintained the geometry required for the road and bridge infrastructure.
The Paralink reinforcement was installed on the approach embankment to the east of the Grand Union Canal, with earthworks design managed by CGL and installation carried out by FN Conway. The embankment fill comprised Class 6N-IBAA material at the core for strength and durability, with Class 6N/6I material placed behind retaining walls to ensure compatibility and performance.
This engineered solution successfully addressed poor ground conditions, enabling the safe construction of critical infrastructure for the Southall Waterside development. By combining ground improvement techniques with high-performance geosynthetic reinforcement, the project achieved a stable, durable, and cost-effective embankment solution in a complex urban environment.
Used Products
