Geotechnical engineering is a branch of civil engineering that focuses on the behavior of earth materials, such as soil and rock, and their interaction with structures built on or in them. Geotechnical engineers work to understand the physical properties of soil and rock, assess the stability and strength of foundations, slopes, retaining walls, and other earth structures, and provide recommendations for construction projects to ensure their safety and durability. This field also involves soil testing, site investigation, and design of foundations for buildings, bridges, dams, and other infrastructure projects. Geotechnical engineering plays a crucial role in ensuring the safe and efficient design and construction of various civil engineering projects.