CEE Seminar Series Spring 2024 "In Situ, Dynamic and Cyclic Response of the Deep Medium Dense Sands at Portland International Airport"
School of Civil and Construction Engineering
Oregon State University
Host: Professor Anne Lemnitzer
Abstract: Deep (25 m), in-situ, blast-liquefaction experiments were conducted at Portland International Airport to provide a design basis for the deep soil mixing used to mitigate liquefaction-induced differential settlements below the South Runway without the possible effects of sample disturbance, small sample-size effects and artificial drainage conditions. This presentation describes the experimental approach, blast-induced ground motions and quantification and evaluation of dynamic constitutive soil properties from the linear-elastic to the nonlinear-inelastic regime with loading that produced direct simple shear-equivalent shear strains larger than 1%. Ground motions are interpreted in terms of the equivalent number of stress cycles, Neq and the cyclic stress ratios, CSRs, generated during blast-induced shearing. The resulting in-situ CRR-Neq curves are compared to those from SPT-, CPT- and Vs- and case history-based liquefaction triggering models, all of which were smaller than that associated with the in-situ cyclic resistance.
Bio: Stuedlein is professor of geotechnical engineering in the School of Civil and Construction Engineering at Oregon State University, which he joined in 2009 following a five-year period as consultant in Seattle. He is the chair of the Geo-Institute Soil Improvement Committee, editor at the ASCE Journal of Geotechnical and Geoenvironmental Engineering, and editorial board member at three other journals. Stuedlein has received several awards for his work, most recently the 2023 ASCE J. James R. Croes Medal and 2023 Fredlund Award. The results of his research have been disseminated through 150+ publications and consultation for PacNW firms and focuses on ground improvement and liquefaction mitigation, dynamic in-situ and cyclic laboratory testing, full-scale experimental and numerical investigations of soil-structure interaction and probabilistic geotechnics.
