Centrifuge modeling and analysis of soil structure interaction under biaxial dynamic excitations

The paper presents a centrifuge test of a level site consisting of granular soil deposits and an embedded structure subjected to various bi-axial base excitations. The test was conducted at RPI NEES centrifuge facility to assess the dynamic response characteristics of soil-structure interaction (SSI) under multidimensional conditions. Synthetic sinusoidal waves were used as base excitations to test dense model under biaxial shaking. A dense array of accelerometers was used to monitor the deposit response (beneath and outside of the structure, along with pore water pressure transducers. The observed acceleration and pore pressure are used along with non-parametric identification procedures to estimate the corresponding dynamic shear stress-strain histories. The measured results along with the obtained histories are used for two purposes. First, to shed light on the mechanisms of soil-structure interaction under biaxial shaking. Secondly, to show the difference in soil behavior at different locations beneath the footing when subjected to biaxial shaking. The later objective is evident when comparing soil stress-strain loops and dilation behavior at locations beneath the structure, and those measured in the free field.