Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It is important in civil engineering, but is also used in military, mining and petroleum or any other engineering concerned with construction on or in the ground. Geotechnical engineers use principles of soil mechanics and rock mechanics to investigate subsurface conditions and materials. This is to determine the relevant physical/mechanical and chemical properties of these materials.
Ground improvement refers to a technique that improves the engineering properties of the soil mass treated. The properties are modified by shear strength, stiffness and permeability. A geotechnical engineer can determine and design the type of foundations, earthworks, and pavement subgrades required for the intended man-made structures to be built. Foundations are designed and constructed for structures of various sizes such as high-rise buildings, bridges, medium to large commercial buildings and smaller structures where the soil conditions do not allow code-based design.
Geotechnical engineers also look at coastal and ocean engineering. Costal engineering can involve the design and construction of wharves, marinas and jetties. Ocean engineering can involve foundation and anchor systems for offshore structures.