The Effects of 2-D Bedrock Profile on Site Specific Seismic Amplifications in Leda Clay

The primary objective of the research is to understand the significance of the effect of bedrock profile on the seismic amplifications in soft soil deposits. Inclined soil-bedrock interfaces lead to simultaneous p- and s- wave loading on soils, and whether ignoring them may lead to design deficiencies. The response of a site in Orleans with a deep Leda clay deposit at the center, but with a concaved bedrock profile, is evaluated using 2-D numerical analysis. The seismic response of Leda clay on a hypothetical horizontal bedrock (representing conventional practice), and two different natural bedrock basins has been studied. The NBCC-2015 design spectra compatible earthquake shaking was considered. The comparisons between the conventional practice and the response of the 2-D basin demonstrate that assessment of the cyclic loading intensity is significantly affected by the basin shape. This indicates that ignoring basin geometry effects might lead to unsafe liquefaction susceptibility assessments.