LEDBURN JUNCTION: A CASE STUDY OF RAILWAY EMBANKMENT STABILISATION

As part of the West Coast Route Modernisation a new high speed junction has been constructed immediately south of Train Robber's Bridge at Ledburn embankment. The embankment has proved a historically high maintenance structure and consequently stabilisation of the embankment has been integrated with the modernisation. Instability of the embankment was indicated by deformation of the track and services and by the irregular slope profiles. Extensive ground investigation followed by geotechnical modelling was carried out to identify failure mechanisms and allow design of both the remedial measures and the foundations for new overhead gantries. Shear surfaces in the embankment foundation with a low residual strength were key to the observed deformations. The low factor of safety of the embankment required a structural solution and piling was chosen. Special measures were required to ensure safe construction within the railway environment. The associated buildability and safety problems were solved by utilising the strengths of the whole team, for example this enabled the temporary works to be incorporated into the permanent earthworks. This integrated approach to design and construction required close Client-Designer-Contractor working relationships and this was reflected in the ability to meet the tight programme whilst adapting to on site conditions. For the covering abstract see ITRD E123761.