Innovative insights into micropile seismic response: Shaking table tests reveal critical dependencies and liquefaction mitigation

Abstract This study presents a novel investigation into the seismic response of micropiles through shaking table tests, diverging from the predominant reliance on numerical analyses in assessing micropiles in liquefiable sites. Three models of shaking table tests were conducted using Iai scaling rules for physical modelling in 1-g conditions. The investigation reveals a significant dependency of micropile efficiency on the frequency of input motions. During the 2 Hz test, the entire model experienced liquefaction; however, in the 3 Hz test, there was a remarkable 29% reduction in excess pore water pressure. Additionally, the study explores the impacts of varying distances between micropiles and examines how liquefaction influences the induced peak accelerations at different depths within the soil media. Notably, recorded accelerations on the surface decreased by up to 76% in the free field tests during liquefaction. This comprehensive exploration advances our understanding of micropile behaviour under seismic conditions, offering valuable insights for soil improvement projects.