géotechnique

Geotechnical engineering, or géotechnique in French, is a branch of civil engineering that studies the behavior of earth materials and their interaction with structures. It covers soils and rocks as engineering media, the influence of groundwater and loads, and how to ensure stability, safety, and performance of built works. The field integrates geology, materials science, and structural analysis to inform foundations, earthworks, and retaining systems.

Key topics include site characterization, soil and rock mechanics, ground stability, and ground improvement. Practitioners predict settlement and bearing capacity, evaluate soil-structure interaction, and assess hazards such as landslides, bearing failures, and liquefaction. Applications span shallow foundations, deep foundations, tunnels, slopes, embankments, dams, and excavations.

Methods include field investigations (drilling, boreholes, sampling, geophysics and CPT), laboratory tests (grain size, Atterberg limits, triaxial and oedometer tests), and numerical and analytical models (limit equilibrium, finite element). Results guide design, construction, and risk management, including drainage, compaction, grouting, and reinforcement as ground improvement techniques.

Professionals called géotechniciens or soil engineers perform assessments and design recommendations. The discipline relies on codes and standards issued by national and international bodies and interfaces with geology, hydrogeology, structural engineering, and environmental disciplines. Geotechnical design aims to ensure safety, serviceability, and durability of infrastructure.

History and scope: Modern geotechnical engineering emerged in the late 19th and 20th centuries, with contributions from Karl Terzaghi, Arthur Casagrande, and others. It continues to evolve through advances in soil and rock mechanics, testing, and computational modeling, shaping planning and construction of infrastructure worldwide.