CENTRIFUGE MODELING OF SESMIC SOIL-STRUCTURE INTERACTION IN SOFT CLAY

Centrifuge modeling is a valuable tool used to study the response of geotechnical structures to infrequent or extreme events such as earthquakes. A series of centrifuge model tests was conducted at 80g using an electro-hydraulic earthquake simulator mounted on the C-CORE geotechnical centrifuge to study the dynamic response of soft soils and seismic soil-structure interaction (SSI). Soil beds were composed of the artificial clay “glyben” to simulate soft soil profiles. Several earthquake-like shaking events that included linear to nonlinear behavior were considered with base peak accelerations between 0.1g and 0.54g (prototype scale). The acceleration records at different locations within the soil bed and at its surface along with the settlement records at the surface were used to analyze the soft soil seismic response. In addition, the records of acceleration at the surface of a foundation model partially embedded in the soil were used to investigate the seismic SSI. A spectral analysis of the results showed that the stiffness of the soil deposits had a significant effect on the characteristics of the input motions and the overall behavior of the structure. The peak surface acceleration measured in the centrifuge was significantly amplified, especially for low amplitude base acceleration. The experimental results provided measured data that can be employed to verify and validate numerical analyses used to model site response characteristics of soft soil deposits.