Structural Drainage

Sprayed Concrete, Deckdrain - Wembley Rail Depot, London, UK

Client Chiltern Railways
Contractor

Shotcrete Services

Consultant TPS Carillion
Product

Deckdrain Drainage Geocomposite

Quantity

3000m²

Benefits

All-in-one drainage & barrier

High flow capacity

Excellent bonding with shotcrete

Fast and safe installation

Project Description

The Chiltern Railways site near Wembley Stadium in London required remediation works, adding soil bank stabilisation and a new retaining structure to protect the rail network below. The existing top footpath also required reconstruction and stabilisation due to frequent traffic.

Chiltern Railways approached TPS Carillion and Shotcrete Services to provide long-term and reliable solutions for this site.

The Challenge

The requirement was to design a retaining structure that would enable fast installation and meet design requirements on this sensitive location.

Network Rail safety of workforce measures favoured a sprayed concrete wall structure to reduce the number of operations and time. One of the main challenges of sprayed concrete was to produce a cost effective design to meet all the required standards, whilst providing adequate drainage and without having to use multiple geosynthetics layers or large quantities of drainage stone.

Therefore, it was essential to install an effective drainage system to alleviate hydrostatic pressure behind the structure, with weep holes set into the base of the concrete wall to allow the flow of water into the storm drain. The geosynthetic solution required a high performance geocomposite drainage and water barrier that was compatible with sprayed concrete.

The Solution

The contractor Shotcrete Services worked with ABG to develop a geosynthetic solution that would meet requirements, whilst providing the required drainage flow capacity and effective barrier to ensure long-term performance.

Following a successful trial, the BBA certified ABG Deckdrain 700S/ST170 geocomposite drainage was approved. Deckdrain geocomposite, with its impermeable HDPE cuspated drainage core, provided an excellent bond with shotcrete. The geocomposite was installed against the stabilised embankment, with spider fixings screwed onto soil nails. Then A393 mesh and 225mm thick C32/C40 steel fibre reinforced concrete wall was sprayed to the bank.

This Deckdrain drainage composite sheets were sealed with Abseal Butyl Tape 1S50 and the installation was completed on time. Drainage performance was reported to be adequate.

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 this project.

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

Additional information