A New Way to Analyze Liquefaction Triggering and 2 Common Mistakes Engineers Make with Liquefaction 

This presentation was given by Prof. Scott Olson (University of Illinois) and me on June 11, 2021 to the San Diego Chapter of the Earthquake Engineering Research Institute (EERI). It was recorded and shared here with you!
Abstract: Since the introduction of the Seed & Idriss simplified procedure in 1971, liquefaction triggering analysis for sands has continuously been expanded and refined. Questions of soil compositional susceptibility to liquefaction triggering were addressed using the “Chinese Criteria” for more than 20 years until observations by Bray and Sancio (2006) from the 1999 Kocaeli earthquake in Turkey revealed that some fine-grained clayey soils can also trigger in liquefaction. Therefore, considerable uncertainty today exists around the topics of liquefaction susceptibility and triggering of fine-grained and transitional soils. Using (1) a new method for quantifying soil type/behavior called DQ (Saye, Olson, et al. 2017); (2) a novel approach for considering the liquefaction triggering boundary that removes the need for fines content estimation and correction; and (3) an expanded database of 401 liquefaction/non-liquefaction case histories from a variety of soils ranging from clay to course sands, we (Saye, Olson, and Franke 2021) introduce new probabilistic and deterministic models of liquefaction susceptibility and triggering for ALL CPT-compatible soils. These newly-published models demonstrate excellent fit with many of the “tricky” case histories from recent events including Christchurch. Additionally, we (Franke and Olson 2021) identify and present two common design practices in the use of probabilistic liquefaction triggering models that are potentially introducing significant error in many projects. Practical solutions to these erroneous practices are proposed and summarized.
Link to download the paper on the new common origin method for predicting liquefaction triggering: ascelibrary.org/doi/abs/10.10...
Link to download the paper on understanding the two common mistakes that engineers are making in using probability of liquefaction in their designs: ascelibrary.org/doi/abs/10.10...