Case study on seismic analysis of piled raft foundation for nuclear building in Western India

Increases in energy demand and aim for minimum carbon dioxide footprints have escalated the need for more nuclear power plant (NPP) projects worldwide. Most of these upcoming NPPs are designed to be constructed in moderate to severe seismic zones on soft and medium soil deposits, and may therefore experience significant vertical and lateral deformations due to non-uniform loads from the structures and earthquake loading. Combined piled raft foundations (CPRFs) are widely accepted to address these issues without compromising economy and safety. The aim of the present study was to assess the seismic performance of a CPRF to support an upcoming nuclear building in the alluvial deposit of Western India. A three-dimensional finite-difference study using Flac3D software was performed, and the effects of input motion on the responses of the CPRF were evaluated. The input bedrock-level motion was generated using deconvolution analysis in DeepSoil software. The findings from the finite-difference analysis underscore the significant impact of inertial and kinematic soil–structure interaction on the design outcomes of CPRFs. The CPRF was found to meet the stringent design criteria for accommodating such critical megastructures within alluvial soil formations. Ultimately, this study offers invaluable insights to practising engineers, equipping them with essential design parameters for constructing nuclear facilities atop CPRFs.