Why understanding geology matters for engineering design

Engineering projects worldwide rely on the sub-surface as their foundation, yet our understanding of the geological subsurface characteristics is limited. Each soil particle, pebble, and boulder carry an origin story, and understanding how material came to its current state profoundly impacts the performance of the structures. Overlooking geological history can lead to incorrect identification of geological characteristics during the design, which could affect the intended performance of the structures, examples include, subsidence in structures, dam failures and slope failures.

It is documented that one third of failed dams worldwide are linked to poor geological understanding at the site (P. Adams, 2024). Additionally, many dams remain unfilled and underutilised due to unforeseen geological complexities during construction and operation, elevating the risk of failure if used at full capacity. Further, poor understanding of the geological conditions in steep environments can lead to slope instability. This instability can affect infrastructure such as roads, retaining walls and bridges especially if these structures are built on deep-seated colluvium and unstable material. By comprehending regional and site-specific geology, we gain important insights and can develop solutions to mitigate these risks.

This paper explores the synergy between geological understanding and engineering design in addressing these challenges with two case studies. The case studies look at the geological aspect of why a design failed and what might be missed or overlooked without geological understanding.