Full three-dimensional modelling has been developed and is implemented for many sites where engineering structures are built. Such computer models of the subsurface allow for a more sophisticated handling of subsurface data leading to, for example, better dimensioning of geotechnical units, the evaluation of hazard and risk, foundation design, tunnel routing, planning and building, etc. Other applications are the back-analysis for completed civil engineering projects to verify the correctness of assumed and estimated ground models and parameters, the verification of the correctness of constitutive models for ground behaviour and the use of back analysis to improve building methodologies or equipment. The paper illustrates some of these advantages with a number of state-of-the-art applications of three-dimensional modelling in engineering geology and geotechnical engineering, highlighting a number of key issues when computer-aided 3D modelling is used: the definition of geotechnical (homogeneous) zones, scale and detail, uncertainty and likelihood of the developed model.
