The civil engineer specialized in geotechnical engineering applies the principles of civil engineering to analyze and predict the behavior of terrestrial crustal materials such as soils and rocks. The geotechnical engineer participates in a very wide field of work within the civil engineering framework, since most of the structures require foundations or backings to be supported on the ground. In geotechnical engineering, the civil engineer analyzes and designs different types of foundations such as footings, driven piles, piles of pre-excavated shaft, tiles, and foundations for different types of structures such as buildings, bridges, towers, and offshore platforms. The civil engineer also designs and analyzes retaining walls, slope stability, earth dams, road embankments, canals, tunnels, airfields, and drainage systems. Through these properties and scientific and empirical knowledge, an engineer is trained to find appropriate, affordable and secure solutions to the problems that are encountered on a daily basis. Civil engineers consider the analysis and design the effects of earthquakes and other dynamic forces.