Reliability of Geotechnical Seismic Isolation (GSI) for Reducing Earthquake Effects

Abstract

The article investigates the interaction between soil cushion–based geotechnical seismic isolation, the foundation, and the superstructure with the aim of improving the reliability and stability of buildings located in seismically hazardous regions. The main objective of the study is the numerical modeling of the seismic reliability of buildings equipped with geotechnical seismic isolation in the form of soil cushions, as well as the probabilistic assessment of foundation deformation growth and the dynamic response of the structure under earthquakes of a given intensity. The research methodology includes theoretical analysis, numerical modeling using the finite element method implemented in PLAXIS 2D, interpretation of the obtained results, and reliability assessment based on probabilistic methods that account for statistical heterogeneity and random effects. The performance of soil cushion–based seismic isolation systems made of sand, gravel, and sand reinforced with a geogrid layer was analyzed. Reliability indicators related to foundation settlement and the probabilities of exceeding allowable accelerations at the foundation level and at the top of the building were determined. The results show that the application of geotechnical seismic isolation (GSI) leads to a reduction of horizontal accelerations by approximately 16% at both the foundation base and the top of the structure. Probabilistic analysis indicates that the probability of exceeding the allowable acceleration at the top of the building decreases from 27% to 7.84%, while the reliability index increases to βat = 1.42 (a 73% improvement). These findings confirm the high efficiency of soil cushion–based geotechnical seismic isolation and demonstrate its potential for practical application as an affordable, reliable, and adaptable solution for reducing seismic risk in engineering practice.