Calibration and assessment of sand-based constitutive models for gravel cyclic response via numerical single element analyses

This paper focused on the sand-based excess pore pressure generating constitutive models, PM4Sand, UBCSand, and URS/Roth we selected to model liquefiable gravel, as a critical component to our study on the effects of gravelly soil liquefaction on the performance of CentrePort, under the 2016 $M_w$7.8 Earthquake in Kaikōura, New Zealand. Upon review of the model documentations, we highlighted and compared their formulations with emphases in the key aspects of soil dynamic response. The models were calibrated to match project specific gravel-based laboratory Cyclic Resistance Ratio (CRR) curves. We also performed extensive single element analyses to examine critical aspects of the soil’s seismic response, including modulus reduction and damping, effects on liquefaction triggering from overburden stresses, and static shear bias. The analytical results are compared to well established sand-based relationships, as well as more recently published gravel-based results. Based on the findings, recommendations were made for future researcher and practitioners working on numerical forward and back analysis dealing with potentially liquefiable gravelly soils.