Crossrail project: managing geotechnical risk on London’s Elizabeth line

Abstract

Understanding the ground and the specific geotechnical risks it presented was critical for successful delivery of Crossrail, the £14·8 billion project to deliver the Elizabeth line east–west railway across London, UK. Focusing specifically on the central tunnelled section, this paper describes the broad geological setting of the scheme and what were initially perceived to be the key geotechnical hazards. It further describes, with selected examples, how through detailed desk studies, targeted ground investigations and comprehensive client-led interpretative reporting, the specific risks posed by these hazards were more clearly defined. Appropriate mitigation was then developed both during design and delivery to eliminate or reduce these risks to manageable levels.