This 1.5km long section of line between two tunnels stands in the shadow of an 80m high chalk cliff which has had a long history of rock falls. This has led to disruption of train services and damage to the rail infrastructure. A permanent solution needed implementing to ensure the safety of rail passengers and to keep the line open.
The access to both the crest and in particular the toe of the face was limited and somewhat constricted. In order to get the materials, plant and other equipment onto site, cranes ranging from 90t through to 250t were used to lift materials over the line during a series of long T3 possessions.
After being lifted into place our fleet of 5t excavators fitted with lightweight drill masts were able to work at the toe. This allowed the installation of foundations and holding down bolts for catch fences to be completed with minimal disruption to the rail network.
The high risk upper sections of the face were stabilised using A-Frame drilling rigs; installing 2,500m2 of active ‘TECCO’ rockfall mesh, secured by 350 no. 3m mesh dowels and supplemented by 7m long reinforcing rock bolts.
Along the lower sections of the face 1200 linear metres of high tensile catch fences were installed. These ranged from 500kJ to 1000kJ in capacity and with heights ranging from 2 up to 4m acting as containment for any additional rockfall outside of the meshed areas.
Duration: 8 Months
Client: Costain / Network Rail
Location: Samphire Hoe, Dover