Protecting rail services at Samphire Hoe

At Samphire Hoe, UK, a 1.5-km section of line between two rail tunnels stands in the shadow of an 80-m high chalk cliff that has a long history of rock falls. In the past this has led to disruption of train services and damage to the rail infrastructure, and a permanent solution was needed to ensure the safety of rail passengers and to keep the line open.

This project was made difficult by the limited access to both the crest and, in particular, the toe of the cliff face. In order to get the materials, plant and equipment onto site, cranes were used to lift materials over the railway line during a series of extended line closures .

Once in place, our fleet of 5-t excavators was able to work at the toe. Combined with the use of rope access systems, this allowed us to complete the works with minimal disruption to the network.

The upper sections of the face were assessed as high risk for rockfall and were stabilised by using A-frame drilling rigs to install 2,500 m2 of active TECCO rock fall mesh secured by 350 mesh dowels reinforced by 7-m rock bolts.

Along the lower sections of the face, 1200 m of high-tensile steel catch fences were installed. These range from 500 to 1000 kJ in capacity and from 2 to 4 m high, and provide containment for any additional rock fall outside the meshed areas.