Seismic performance of adjacent mat-supported structures on liquefiable soil: validation of numerical model using centrifuge tests

Abstract

Adjacent structures can interact with each other through the underlying soil during earthquakes. This interaction, which is more common in dense urban areas, is known as structure-soil-structure interaction (SSSI) and can modify the response of each structure. However, there is a lack of understanding of the mechanisms governing this interaction, especially when the structures are located on loose liquefiable soil. As a result, the current state of practice for designing structures on liquefiable soils completely ignores this interaction. In this study, a fully-coupled, finite difference model is developed using FLAC and the PM4Sand constitutive model. The results are compared to two centrifuge tests to validate the developed model. This validation can be helpful in understanding the capabilities and limitations of the model. This validation can also help researchers and engineers to perform extensive parametric studies to better understand the problem of SSSI involving liquefaction and use it in structural design. The results show that the numerical model can capture the generation of pore water pressure under the structures and also estimates foundation accelerations well. Additionally, the calculated structure settlements and rotations generally match the centrifuge tests.