Ground risk and rail asset management in East Anglia

The Network Rail Anglia region has 1091 km of earthworks, many of which are steep-sided embankments constructed of locally won fill materials in Victorian times. In order to extend the serviceable lifespan and to ensure the safety of the public with the ever-increasing demand on railway infrastructure, understanding the geological and geotechnical risks is of critical importance. Approaches to control risks and optimise mitigation works were adopted on the Control Period 5 framework with collaborative partners Network Rail, Volker Fitzpatrick and Atkins. Owing to budget constraints, harder engineering fixes applied early in the framework such as sheet-piled walls could no longer be readily adopted. Embankment renewal projects took on a more staged approach using shorter-design-life solutions with sustainable benefits. Detailed interrogation, phased investigation and zonation of sites allowed the targeting of higher-risk areas and intervening at a greater number of sites within the region, meeting Network Rail asset policy objectives. Slope movement monitoring combined with more detailed approaches was integral in assessing the instability causation, effective mitigation design and assessing performance during and following construction. A continued monitoring of lower-risk untreated areas and a future works strategy plan allowed greater control and proactive management of the asset.