3D-SIMULIQ · 3D Seismic Interaction of Multi-Structure-Soil Systems during Liquefaction

Earthquake-induced liquefaction is a major cause of infrastructure failure, leading to service disruptions, costly repairs, and loss of life. As urban development expands into liquefaction-prone regions, understanding soil–structure interaction (SSI) during liquefaction is critical. Traditionally, SSI studies have focused on isolated structures, yet modern cities feature high-density developments both above and below ground, with tunnels and basements interwoven with buildings and transport networks. Although liquefaction affects aboveground and underground structures in fundamentally different ways, the multi-structure-soil interaction (MSSI) in combined above- and underground structure systems (AUSS) remains poorly understood, both numerically and experimentally.To bridge the gap, the 3D-SIMULIQ project will establish an integrated framework to understand, model, and predict liquefaction impacts on coupled structure systems. Systematic element-level tests will first be conducted at ETHZ Soil Testing Laboratories to quantify cyclic soil and interface response (WP1). The state-of-the-art beam centrifuge at the ETHZ Geotechnical Centrifuge Centre will then be employed to conduct physical model tests at the system level, with increasing complexity from SSI to MSSI. The experimental results will support the development of a novel numerical framework that reduces computational cost without compromising accuracy, making advanced liquefaction modelling more accessible for researchers and practitioners (WP3). The validated framework will then be applied in extensive parametric simulations to extend experimental findings and produce robust, practical design guidelines (WP4). With strong dissemination, exploitation, communication, and project management plans (WP5-6), 3D-SIMULIQ will advance fundamental understanding of liquefaction hazards and contribute directly to the resilience and safety of urban environments in earthquake-prone regions of the EU and beyond.