Landslide Hazard Assessment for National Rail Network

Abstract

There have been a number of high profile reports of landslides on the national rail network of Great Britain (comprising England, Scotland and Wales) over recent years. Events range in size from small wash out failures (St. Bees, Cumbria) to well publicised large failures causing major longer term disruption (Hatfield Colliery, South Yorkshire). In conjunction with negative media attention, derailment and damage to railway infrastructure, failures along the rail network have the potential to cause injury and loss of life.The national rail network comprises ten strategic routes that cover a variety of terrains and geologies. The British Geological Survey (BGS) have produced, for Network Rail, a high level susceptibility model of landslide hazard from Outside Party Slopes adjacent to the strategic rail network. This assessment was compiled based on Geographic Information System (GIS) techniques and historical landslide records (landslide inventory). The model was designed to give a high level overview of potential landslide hazard to Network Rail senior management and individual Route Asset Managers.The national study adopted a fixed buffer style analysis of each 5 chain section (∼100 m length) of the entire railway network. It included event data from the BGS National Landslide Database superimposed on mapped data from the BGS GeoSure land instability susceptibility model and geologically mapped landslide polygons. The National Landslide Database is the most comprehensive inventory of landslide events in Great Britain. The BGS GeoSure slope instability layer provides a scientifically based 1:50 000 scale assessment of national susceptibility to natural slope failure.The results of this study have been provided as a spatially attributed dataset with total hazard susceptibility scores A (low)–E (high). Maximum hazard scores are attributed for both up and down- track and 5 chain length for the full network. A high score indicates where conditions imply a significant potential for future landslide hazard. Further refinement of the hazard layers are being developed by BGS to include specific landslide processes such as Rockfall, Earthflow and Debris Flow hazards.