Seismic Liquefaction Assessment of an Existing Facility in the Lower Mainland using PM4SILT and PM4SAND

September 26, 2024

New developments are planned at an existing facility, which is comprised of three structures, with the outer two founded on ground improvement (GI). According to National Building Code of Canada 2020, new upgrades must be post-disaster operational given the 2,475-year earthquake. To assess the response of the highly liquefiable Fraser River Sand deposits underlying the site, seismic deformation analyses were carried out using FLAC 8.1. The PM4Sand and PM4Silt constitutive models were used to simulate the cyclic behaviour of the liquifiable soils. The results indicated that the GI reduces the settlement of the structures but has less of an effect on reducing horizontal displacements. Sensitivity analyses showed that relatively flat slopes (< 5 %) significantly increase the lateral displacements when there is a continuous layer of liquefiable soil. As well, extending the GI zone further improved the vertical displacements but led to higher horizontal displacements because the shear zone below the extended GI zone was also lengthened.

Tabatabaei, H., V. Nguyen, A. Port and D. Klassen. 2024. “Seismic Liquefaction Assessment of an Existing Facility in the Lower Mainland using PM4SILT and PM4SAND,” in Proceedings of GeoMontreal 2024. Resilient Geosciences for Future Generations, 15-18 September 2024, Montreal, QC.