This grant provides funding for a theoretical and experimental study of soil-pile interaction problems. The fundamentals of a framework for the analysis of piles subjected to combined loading, based on insights into the mathematical form of the displacement field around the pile, calculus of variations and energy principles, will be developed. A series of load tests will be performed on half-section instrumented model piles installed in a half- circular chamber containing a plexiglass boundary along its diameter. The displacement field in the soil around model piles will be studied during the installation and loading stages using the Digital Image Correlation (DIC)technique. The model pile-soil interface behavior will be captured by both image analysis and conventional sensors. These experiments will provide data that will be useful in the establishment of the general mathematical form of the displacement field around loaded piles. Validation of the general theoretical framework will be done by comparison with results of a number of load tests on instrumented model piles.
The proposed work will help bridge knowledge gaps that currently exist in the understanding of the soil-pile interaction process. The framework for 3D soil-pile interaction analysis and the results of the experiments will establish the basis for accounting for the effects of soil layering and spatial heterogeneity of soil properties on pile resistance, which will allow future development of theories that will enable engineers to quickly analyze problems that at present can only be analyzed with very costly and time-intensive 3D FEA. The availability of an analysis that can take into account spatial variability in the ground will be useful in a variety of applications, including the assessment of the need to retrofit existing structures and the effectiveness of ground engineering interventions to mitigate seismic risks. This will be particularly useful as the United States works on retrofitting and building new infrastructure, which requires both the assessment of existing and design of new pile foundations.
