Soil variability analysis for geotechnical practice

The heterogeneity of natural soils is well known in geotechnical practice. However, the importance of quantifying the resulting variability in geotechnical characterisation and design parameters is not adequately recognised. Variability should not be approached suspiciously. Rather, it should be accepted as a positive contribution to geotechnical design as its consistent modelling and utilisation lead, with limited additional computations and conceptual effort on the part of the engineer, to more rational and economic design. The paper presents a structured - though necessarily partial – review of approaches and methodologies for the quantification of soil variability, as well as selected examples of its utilisation in reliability-based geotechnical design.