Incorporating reliability methods into geotechnical engineering practice

Several factors of safety need to be introduced at various points in geotechnical engineering design dealing with uncertainty to provide a safety margin against failure. It should be noted that load and resistance factor design (LRFD) is one of the steps toward a probabilistic design process. The use of LRFD in geotechnical engineering is currently limited due to the wide variety of parameters, soil and geological conditions. Another limitation of using the well-known deterministic calculations or design methods is that of serviceability or performance. Serviceability is difficult to evaluate using deterministic methods. The use of a reliability method, in conjunction with the conventional design and analysis methods, offer several benefits such as probability of failure of each design option can be quantified or categorized in a semi-quantitative manner for comparison purposes. Another benefit is that the chances of poor performance or serviceability can be investigated.