Segment manufacture for the precast initial lining for Riverside Badlands tunnel on California’s Inland Feeder project

Hexagonal concrete segments were used on the 32km-long Mohale Tunnel in Lesotho Our long experience in tunnel planning, design and construction means we have unrivalled expertise in designing tunnel linings using a range of materials – from cast iron, steel and concrete to a combination of these to meet specific customer requirements. And with a specialist team of lining designers which includes internationally recognised experts, we have the skills and expertise to assist in all aspects of tunnel linings.

We have established ourselves as one of the leading practitioners in the design and implementation of the sequential excavation method, also known as NATM, and have pioneered its application in soft ground tunnelling in the UK, and now in the USA.

Our leading capabilities in tunnel lining development and design have been recognised through two major tunnelling awards. The Institution of Civil Engineers’ London Association gave a special mention for engineering innovation for the use of NATM on the Heathrow Express rail link trial tunnel and our design for the Channel Tunnel precast concrete lining won an award from the Concrete Society.

Leading advances in tunnel liningsHistorically, Mott MacDonald has been closely linked with developments and technological advances in tunnel linings. In the 1940s we led the way with the first use of concrete tunnel segments on London’s Central Line. In the 1960s we developed the flexible concrete linings for London Underground’s Victoria Line and the concrete/steel composite tunnel linings designed and installed in the Mersey Kingsway tunnels. For the Great Belt Eastern Railway Tunnel we designed concrete linings incorporating epoxy-coated reinforcement to minimise potential corrosion. And we extended this expertise for the segmental linings to the St Clair River crossing between the USA and Canada.