Ground response analysis and liquefaction for Kalyani region, Kolkata

The main focus of this research is the ground response analysis and liquefaction potential analysis of AIIMS Kolkata based on SPT-N values at six different locations. The analyses are performed for the earthquake magnitude Mw = 7.0 and peak ground acceleration of 0.170 g. For this, Equivalent-linear Earthquake Response Analysis (EERA), Nonlinear Earthquake Response Analysis (NERA), and PLAXIS-2D software are utilized. In ground response analysis, various parameters such as shear stress, peak ground acceleration, relative displacement, and amplification ratio are evaluated. In liquefaction potential analysis, the factor of safety against liquefaction is calculated from different methods, such as the simplified method, EERA, and NERA, and their results have been compared. Further liquefaction potential index is also evaluated for the same earthquake magnitude and PGA using the factor of safety value evaluated from liquefaction potential analysis and ground response analysis for all the borehole locations. It is observed from the results that the equivalent linear analysis gives conservative results when compared with those obtained from the nonlinear analysis. Moreover, the simplified method too fails to predict the liquefaction susceptibility of certain regions that are found to be prone to liquefaction from the EERA and NERA analyses.