Reliability-based approach for robust geotechnical design

Abstract

Although geotechnical engineers have to deal with uncertainty and risk all the time, it is not common to talk about uncertainties and risk in the profession. Uncertainties are often addressed indirectly through the choice of safety factors and design criteria or wording in design guidelines. Reliability theory, which is used to calculate risk, provides the framework to account for uncertainties in a systematic manner. In this paper, notions of hazard, exposure, vulnerability, risk, risk management, acceptable risk, and reliability-based geotechnical design are addressed, and the State-of-Practice is exemplified with several case studies. The examples illustrate the quantification of uncertainty in geotechnical calculations, reliability-based foundation design, the assessment of hazard, vulnerability and risk, and the treatment (through mitigation measures) of risk under different design situations. The case studies include the settlement predictions for an embankment, the stability of underwater slopes subjected to earthquake hazard, the run-out distance for a quick clay slide, the reliability-based design of offshore piles, the breach of embankment dams and the evaluation of mitigation measures. Challenges and emerging issues like climate change, cascading events and the management of the risk posed by extreme events are discussed; and recent developments, such as stress testing and Bayesian networks, for dealing with these challenges are presented.