Design decisions in geotechnical engineering typically need to be made under considerable uncertainty, both regarding presentgeotechnical conditions and future events occurring during the service life of the structure. To optimize the utility of societalinvestments, design decisions should consider the life cycle cost (LCC) and not only the construction cost. This paper investigates theapplicability of Bayesian statistical decision theory to assist in this decision making. The paper illustrates the concepts with a practicalexample, where a geotechnical engineer considers three design alternatives for the foundation of a road embankment: pre-fabricatedvertical drains with a surcharge, end-bearing and floating dry deep mixing columns. The effect of a potential extreme groundwaterdrawdown event on the LCC of these alternatives is analyzed and discussed. Concluding remarks are made on the relevance of suchdesign tools in a structured risk management in geotechnical engineering projects.
QC 20221110