ABSTRACT
The factors of safety used in conventional geotechnical practice are based on experience, which is logical. However, it is common to use the same factor of safety value for a given type of application, such as F = 1.3 for short-term slope stability or F = 3.0 for erosion and piping, without regard to the degree of uncertainty involved in the calculation in a particular instance. Through regulation or tradition, the same safety factor value is often applied to conditions that involve widely varying degrees of uncertainty. This is not logical.
