Evaluation of Liquefaction Potential Considering Vs Uncertainty With 1D Random Field for Typical Kolkata Soils

This study assesses liquefaction susceptibility at two typical soil deposits in Kolkata, incorporating shear wave velocity (Vs) uncertainty using Toro randomisation combined with a 1D random field. The analysis considers variations in three key parameters: Vs uncertainty (σlnVs), earthquake magnitude (Mw), and peak ground acceleration (PGA), each examined at three levels. At each site, 27 parametric combinations are evaluated, with 400 randomised profiles per combination, resulting in 10800 simulations per site and a total of 21600 simulations across both sites. A MATLAB-based framework was developed to automate Vs randomisation and repeated simulations. Liquefaction severity is assessed using three indices: Liquefaction Potential Index (LPI), Liquefaction Severity Index (LSI), and post-liquefaction Settlement. Cumulative probability curves are generated for all parametric combinations, providing hazard insights. Additionally, LPI, LSI, and Settlement values are mapped against the corresponding Vs, 20 values, and limiting Vs, 20 values are proposed to restrict damage severity. The results highlight significant differences in severity classification across indices, with LPI being the most conservative, followed by Settlement and LSI.