$446$ : $"$In what ways does geotechnical engineering contribute to the safety and stability of civil infrastructure? Explore the key principles and methods employed in geotechnical investigations to assess soil and rock properties. Discuss how this data informs the design of foundations, slopes, and retaining structures to mitigate risks such as settlement, landslides, and liquefaction. Analyze case studies highlighting the importance of site characterization and geotechnical analysis in ensuring the resilience and longevity of various infrastructure projects."