Geotechnical engineering is the study of the behaviour of soils under the influence of loading forces and soil-water interactions. This knowledge is applied to the design of foundations, retaining walls, earth dams, clay liners, and geosynthetics for waste containment.
Geotechnical engineering is the science that explains mechanics of soil and rock and its applications to the development of humankind. It includes, without being limited to, the analysis, design and construction of foundations, slopes, retaining structures, embankments, roadways, tunnels, levees, wharves, landfills and other systems that are made of or are supported by soil or rock.
In further paragraphs, the application of Geotechnical Engineering is briefed in crisp for better understanding.
Transportation : Geotechnical engineers are responsible to ensure that roads, highways and railroads are properly, designed and maintained to ensure their longevity.
Deep Foundation : All buildings, high-rise structures, bridges, towers, antennas, and essentially everything you see around has a foundation that is carefully designed by a geotechnical engineer to transfer the loads to the ground.
Landslides: Geotechnical engineers are responsible to design excavations so that they remain stable, as well as stabilize natural slopes that may threaten public safety.
Underground Structures: Geotechnical engineers are responsible for the design and construction of tunnels, subways, and underground facilities that are used in subways, underground highways, railroads, waterways and waste storage.
Dams: Geotechnical engineers are responsible for the design, construction, maintenance and monitoring of thousands of dams that are providing water storage and leisure areas to millions.
Surface Characterization: Geotechnical engineers perform a variety of tests on site or the laboratory to characterize the subsurface conditions. That way, the properties of the soils and rocks are characterized, softer soils , fractured rocks, faults, caverns and sinkholes can be identified before building at the surface.
Landfills: Geotechnical engineers are involved in the design of landfills to ensure that solid waste is isolated from the environment and that public health is protected. Modern landfills are sophisticated engineered infrastructure systems that have very few similarities to waste dumps.
Offshore Structures: Geotechnical engineers are responsible for the stability of foundations of offshore platforms and energy facilities that are used for oil and gas extraction as well as wind power.
Deep Excavations: Geotechnical engineers are responsible to ensure the stability of deep excavations, by Shoring. Such shoring systems allow the execution of deep excavations in urban areas which is vital for construction of underground metros, drainages, subways in the middle of a city adjacent to existing subways, structures, or infrastructures.
Ground Improvement & Soil Stabilization; Geotechnical engineers use principles of physics and chemistry to modify the characteristics and properties of the subsurface so that it can support civil infrastructure that it would not be able to otherwise.
Scour & Erosion: Soils tend to erode when subjected to natural processes, and especially in extreme weather that may involve, rainfall, snowfall, tornadoes, hurricanes and floods. Geotechnical engineers devise strategies to mitigate against scour and erosion.
Contamination and Site Remediation: Geotechnical engineers are commonly engaged in the cleanup or remediation of sites that have been contaminated and represent a health to the environment. Geoenvironmental engineers use numerous techniques to remove the contaminants from the ground, many times, without even excavating the ground.