A72 Peebles Road Widening Reinforced Soil Retaining Wall Solution Along River Tweed

The A72 road in Peebles, Scotland, which runs alongside the River Tweed, had been suffering from progressive structural deterioration and increasing traffic congestion. The narrow carriageway struggled to accommodate modern traffic volumes, particularly heavy vehicles, resulting in a weakened road verge and frequent damage to the existing retaining walls.

As vehicles attempted to pass along the constrained route, repeated loading and edge overruns compromised the stability of the highway boundary. This not only reduced the lifespan of the infrastructure but also created ongoing safety risks for road users. The restricted width of the road further contributed to traffic delays and inefficiencies, making it a key concern for the local authority.

To resolve these issues, Scottish Borders Council initiated a highway improvement scheme to widen the road by approximately three metres. The project, which began in August 2018 and ran for ten months, required the replacement of the existing low-height retaining wall and river revetment, along with the installation of a new safety barrier compliant with current standards.

However, the site presented complex engineering challenges. The road sits above a steep নদ slope leading down to the River Tweed, leaving minimal working space for construction. With no existing verge and very limited footprint, designing a retaining solution that could support the widened highway without encroaching on the river was particularly demanding.

A cost-effective and space-efficient solution was developed by MHB Consultants using a hybrid reinforced soil retaining wall system. The design combined the benefits of tied-back gabion structures with Terramesh reinforced soil technology to create a stable and durable solution within the constrained site conditions.

The retaining structure extended approximately 150 metres along the River Tweed and reached heights of up to six metres. By integrating a tied-back system, the design maximised stability while minimising the footprint, making it ideal for the steep slope and limited access environment.

Maccaferri provided technical expertise throughout the design and construction process, as well as supplying and installing the Terramesh System. Collaboration with Albion Drilling ensured the successful installation of the tied-back elements, enabling the structure to perform effectively under load and over the long term.

Environmental protection was a key consideration during construction. An environmental clerk of works was appointed by Scottish Borders Council to monitor site activities and ensure minimal impact on the surrounding landscape and river ecosystem.

The £2.2 million road improvement scheme has now been successfully completed. The upgraded A72 delivers improved traffic flow, increased road safety, and enhanced structural resilience. The use of reinforced soil technology and gabion retaining walls has provided a sustainable, long-term solution tailored to the challenging riverside environment.