Structural Drainage

Sprayed Concrete, Deckdrain - Network Rail, Werrington, UK

Client Network Rail

Morgan Sindall / BAM Ritchies


Consultant Tony Gee and Partners LLP

Deckdrain Drainage Geocomposite




– All-in-one drainage & barrier
– High flow capacity
– Excellent bonding with shotcrete
– Fast and safe installation
– Significant 55% carbon saving


Project Description

As part of a study into increasing capacity and reducing journey times on the East Coast Main Line (ECML) for long distance, high speed passenger services; Network Rail identified that a new grade separated junction at Werrington would be required. Through an option selection process it was determined that a dive-under would allow slow moving freight traffic to pass below the ECML.

The site is situated at Werrington Junction, 5km to the northwest of the city centre of Peterborough. The existing land was primarily agricultural with a relatively high water table.

Network Rail appointed Morgan Sindall to implement the scheme, with Mott MacDonald and Tony Gee appointed as partners to undertake the detailed design.

The Challenge

Since the new tracks will pass below the ECML at circa 8m below existing ground level, ramps of a suitable gradient (1 in 110) are required to bring the tracks back to the level to connect to the existing railway. The ramps required a solution that considered a number of factors; such as construction cost, minimising land take and construction duration. The chosen solution for a section of one ramp was a 60 degree soil nail slope with concrete facing to ensure long-term stability of the naturally present clay.

The challenge was to design a retaining structure that would reduce required excavations, enable fast installation, reduce transport cost, enable substantial carbon savings and meet design requirements on this sensitive location.

The Solution

ABG worked with the designer to develop a geosynthetic solution that provides the required drainage flow capacity and acts as an effective barrier to ensure long-term performance.

The BBA certified ABG Deckdrain 700S/ST170 geocomposite drainage was specified for this application. Deckdrain geocomposite, with its impermeable back HDPE cuspated drainage core, provided an excellent bond for the shotcrete, requiring reduced excavation and saving a significant 696 tonnes of carbon. The geocomposite was installed against the embankment and 10m long soil anchors were drilled and grouted to achieve the required stability.

Two layers of reinforcement mesh were installed and a 250mm thick shotcrete wall was sprayed to the bank.

ABG Deckdrain 700S/S170 Geocomposite for vertical wall drainage

The ABG Service

ABG provided design assistance and technical support during the design, trial and installation of the project.

Contact ABG today to discuss your rail structural drainage project specific requirements and discover how ABG past experience and innovative products can help.

Additional information