A Comprehensive Review of the Nonlinear Response of Soil Deposits and its Implications in Ground Response Analysis

Abstract

Site response analysis evaluates the seismic response of soils to be further utilised in the safe infrastructural design in seismic-prone areas. The conventional approach considers 30 m depth of soil deposit to estimate the response through 1D equivalent linear analysis. The role of nonlinearity of soils and frequency content of the response spectra especially in deep basins with soft soils is mostly ignored. Recent studies highlight the significance of depth of soil deposits, ground motion intensity, and earthquake frequency in addition to site conditions. Latest modifications in seismic codes have aimed to incorporate these effects using depth-dependent ground motion models and the specification of multi-period response spectra. The current paper presents a comprehensive review of the studies featuring the nonlinear response of soils documented during earthquakes, followed by an explanation of the basic mechanisms of nonlinear behaviour of soils and the effects of various input parameters on the site response. Current seismic provisions are also reviewed and the recent developments to incorporate the effects of these parameters for sustainable future seismic designs are discussed. The available guidelines for the selection of the input parameters for an appropriate site response analysis are presented. It is concluded that the unwarranted negligence of nonlinear behaviour and the influence of input parameters may seriously undermine the seismic performance of structures, which is a grim precursor to widespread destruction in future earthquakes. This review is an endeavour to emphasise the importance of nonlinear behaviour and other influencing factors in seismic design. © 2023, The Author(s), under exclusive licence to Indian Geotechnical Society.