task : $9\mathrm{.}90$#"How does the integration of theory into civil engineering practices contribute to the advancement and sustainability of infrastructure development? Explore the foundational theories underpinning civil engineering disciplines such as structural mechanics, geotechnical engineering, transportation engineering, and environmental engineering. Investigate how theoretical frameworks inform decision$-$making processes in design, construction, and maintenance phases of infrastructure projects. Analyze case studies showcasing the application of theoretical concepts in solving real$-$world challenges, addressing issues like structural integrity, environmental impact, and urban planning. Additionally, assess the role of ongoing research in refining and expanding theoretical knowledge to meet evolving societal needs and technological advancements in the field of civil engineering."