Railway embankment failure trends and monitoring – lessons learned from the Anglia route

Railways in the UK were constructed before the establishment of modern geotechnical engineering practice. Climate change and the associated greater frequency of extreme weather events are having impacts on earthworks stability, with risks to public safety. Many embankments on Network Rail's Anglia route have shown gradual degradation through their steep upper slopes and progressive failure within predominantly clay embankment material and underlying soft deposits. A regional holistic view allows identification of common geotechnical trends and risk categorisation to better enable prioritisation of asset management. Understanding when to intervene is crucial, and monitoring the behaviour of earthworks is a vital asset management tool to control risk and extend lifespan. To be a wise investment, slope instrumentation must be properly thought out in line with a detailed interrogation of the site and alongside a well-developed conceptual model. Automated monitoring can bring greater control and allow more accurate evaluation of interventions, but must be assessed in line with prioritising large areas with limited budgets. Correct targeting of ground investigation and ensuring sufficient and reliable data can optimise mitigation and provide confidence of the engineering fix.