GR8 GEO participated in 2020 Liquefaction Experiments and Analysis Projects (LEAP-2020) research program by performing Type-B (blind) numerical simulations for seven (7) of the centrifuge tests using the Ta-Ger constitutive model implemented in FLAC to predict the seismic response of a sheet-pile retaining structure supporting liquefiable soils. The present paper presents the Type-B predictions in comparison with the experimental results. Calibration of the Ta-Ger model based on available laboratory DSS data focused on capturing the liquefaction resistance for a large range of cycles, the post-liquefaction rate of shear-strain accumulation, the overburden effects and realistic shear stress-strain responses. A single numerical model was built in FLAC in prototype scale in accordance with the design geometry of the LEAP 2020 testing program. Numerical analyses were performed varying only the input seismic motion applied to the model. Numerical analyses captured the primary mechanisms of the system response such as liquefaction in the free-field, negative pore pressure behind the wall accompanied by the outward rotation of the wall.
Our team had the closest predictions for the largest number of centrifuge tests compared to the other program participants (a total of 10 teams from around the world participated in the numerical modeling exercise using more than 6 different constitutive models). A paper in the LEAP 2020 Workshop Proceedings will soon be published. Stay tuned!
