An introduction to keeping lessons alive in engineering geology

In the evening of 1959 the residents of Frejus, France, were devastated by a deluge of water flowing from the collapsed Malpasset dam. By the following morning they would learn that the disaster had claimed the lives of over 400 of their neighbours. Today, the remains of the Malpasset dam squat over the Le Reyran, both as a memorial to the disaster and as a sobering warning to keep the lessons alive. The Malpasset Dam is a classic case-study in Engineering Geology, and was the subject of the honorary lecture given by Pierre Duffaut at the 2018 Annual Conference of the Engineering Group of the Geological Society. Our conference theme explored how we might keep such lessons alive, and how this preservation may lower risk in the future. Our honorary presentation is summarised in Larouzee and Duffaut (2019), which describes how both the failure in identifying and interpreting risk from ground conditions, together with a breakdown of risk management during operation, contributed to the disaster. While there have been significant improvements in minimising risk in engineering geological projects over the past 60 years, our industry examines only a tiny proportion of the ground during site investigation, and the lifetime of a structure can extend well beyond those of the design engineer. This lack of knowledge both at the point of construction and diminishing through time means that risk will always be embedded in engineering geology. Knowledge of ground conditions and their risk should not sit buried and decomposing within repositories but constantly stoked through practice and discussion. Thematic collection: This article is part of the ‘Keeping lessons alive in engineering geology’ available at: https://www.lyellcollection.org/cc/keeping-lessons-alive-in-engineering-geology