Incorporating Effects of Uncertainty in Geotechnical Parameters via Partial Factors Derived from Probabilistic Analysis

Geotechnical engineering frequently encounters significant uncertainties in soil properties and environmental conditions. While design has traditionally relied more on deterministic approaches, the increasing complexity of projects now calls for a shift towards probabilistic frameworks and the second generation of the Eurocode has now included a detailed guideline for reliability-basedverification of limit states in design and assessment of geotechnical structures. Probabilistic methods offer substantial advantages for evaluating uncertainties in input parameters and their effects on analysis outcomes. However, since current codes are structured around partial factors, practicing engineers often prefer designs expressed in these terms. Translating probabilistic analysis results into partial factors can thus enhance the accessibility of the framework for decision-making under uncertainty. This paper presents approaches for interpretingresults from probabilistic analyses using partial factors, ensuring alignment with code requirements. Examples from slope stability and bearing capacity analyses are included to illustrate these approaches.

Keywords: Uncertainty, Probabilistic analysis, Partial factor, Reliability index, Consequence class, Variability class.