Abstract:
Soil liquefaction is one of the main reasons for substantial building damage during past earthquakes across the world. However, current standards for designing structures on liquefiable ground still rely on empirical approaches developed for the post-liquefaction consolidation settlement of the free-field soil. As a result, researchers tried to understand the primary mechanisms of building displacement on softened soil by performing numerical and experimental studies. One of the main drawbacks of these studies is that they assume the structures to be isolated without considering the influence of the nearby buildings on their behaviour. The interaction of adjacent structures on liquefiable ground, also known as structure-soil-structure interaction, has caused significant damage to buildings during past earthquakes. Despite the few laboratory tests that highlighted this interaction's importance, a thorough understanding of this problem requires sensitivity analyses using validated numerical models. However, the complex nature of this interaction, the lack of decent experimental data and the shortcomings of the available constitutive models and modelling techniques have hindered the development of validated numerical models.
This study develops fully-coupled, dynamic finite difference numerical models to study the interaction of adjacent structures on liquefiable ground. The research presents some recommendations to improve the accuracy of the numerical modelling of structures on liquefiable ground. Subsequently, this thesis develops three different modelling approaches for studying this complex interaction and validates them by comparing the results against the experimental data from two centrifuge tests. The modelling approaches include: 1) 2-D modelling using the PM4Sand constitutive model, 2) 2-D modelling using the P2PSand constitutive model, and 3) 3-D modelling using the P2PSand constitutive model. After choosing the most efficient approach considering the accuracy of the results and the runtime of the analyses, this thesis concludes with extensive sensitivity analyses to find the influence of the soil, building and earthquake characteristics on this interaction on liquefiable ground.
The results of this study provide insight into the mechanisms governing the performance of adjacent buildings on softened soil and guide the future design of buildings, especially in dense urban environments.