How do soil mechanics principles influence the design and construction of deep foundation systems in civil engineering projects? Explain the theoretical basis for selecting appropriate foundation types, such as driven piles, drilled shafts, or caissons, based on soil characteristics, load$-$bearing capacity, and settlement considerations. Explore the role of geotechnical investigations and laboratory testing in assessing soil behavior and informing foundation design parameters. How can theoretical insights from soil$-$structure interaction analysis contribute to optimizing foundation performance and ensuring long$-$term structural stability in diverse geological contexts?