A Case History in the Fraser River Basin on Different Liquefaction Triggering Assessments and Considerations for Their Use

Geotechnical engineers often need to complete geotechnical site investigations with one of the outputs being the completion of liquefaction triggering assessments. Typically, these assessments rely on empirical procedures that have been developed from seismic case history data and use of various in situ test methods. The numerous investigation methods available each have their own different considerations for their use for these assessments such as the application of test specific or more general correction factors. In a perfect world, the liquefaction triggering conducted by the different assessment methods would yield the same level of liquefaction susceptibility for the same soil unit. Unfortunately, differences between the outputs of the triggering procedures and other epistemic uncertainties often occur leading to inconsistencies. This paper presents a case study from a recent project in the lower mainland reviewing different investigation methods and their respective liquefaction triggering assessments. In addition, lab tests conducted on undisturbed samples were compared to the empirically based triggering methods.