Evaluation of liquefaction return period based on local site classes: performance based logic tree approach

Abstract

Lots of research work is being carried out to evaluate the liquefaction susceptibility. The main objectives of these studies are to identify the regions which are vulnerable to liquefaction. In the present study, an attempt has been made to predict the liquefaction susceptibility based on corrected SPT and CPT values required to prevent the liquefaction for given return periods. The evaluation of liquefaction susceptibility requires the calculation of two parameters, seismic loading and the soil resistance. In most of the studies, the seismic loading will be evaluated based on probabilistic methods and the evaluation of soil resistance will be done based on deterministic analysis. In this study an attempt was made to predict the corrected SPT and CPT values required to prevent liquefaction for South Indian Peninsula using probabilistic performance based methods. In order to account for the epistemic uncertainties in the models, a logic tree approach was adopted in the analysis. The contour curves showing the spatial variation of SPT and CPT values required to prevent the liquefaction for return periods of 475 and 2500 years are presented here.