The 18 th Glossop Lecture: Variability and ground hazards: How does the ground get to be 'unexpected'?

Abstract

This paper is based on the 18 th Glossop Lecture, asking why, in engineering, ‘understanding the ground’ is critical for the safety and financial success of the project, and yet ground conditions are still frequently misunderstood. It explores what blocks both our understanding of ground variability and the associated risks, why some sediments are predictably more variable than others, and why variability can actually be a good thing. Examples from the Lambeth Group (56.25 to 55 million years) and the London Clay Formation (54.5 to 51.5 million years) of SE England are used (Figure 1) , but most of the concepts covered are also relevant to many other ages and similar types of sedimentary geology, worldwide.