Why do civil engineering projects often require extensive theoretical understanding? Discuss the significance of theoretical knowledge in planning, designing, and executing civil engineering operations. Explore how theoretical principles such as structural analysis, fluid mechanics, and material science contribute to optimizing construction processes and ensuring the safety and durability of infrastructure. Consider the role of theoretical frameworks in addressing complex challenges, such as environmental sustainability, resource management, and resilience against natural disasters, within the realm of civil engineering. Additionally, evaluate the importance of ongoing research and innovation in advancing theoretical models to meet evolving needs and challenges in the field.