The inherent spatial variability of geo-material properties influences material behaviour and geo-structural response [Hicks and Onisiphorou, 2005]. It also leads to uncertainty in design due to incomplete knowledge regarding in-situ conditions, and thereby leads to the need for statistical definitions of material properties, probabilistic analysis, and global response quantified in terms of reliability and probability of failure [Hicks, 2007]. Spatial variability is particularly important due to structural response typically being governed by the soil profile, with failure mechanisms often following the weaker zones within the soil [Griffiths and Fenton, 2000; 2001; 2004; Hicks and Samy, 2002a; Hicks and Spencer, 2010]. Moreover, the need for adequate representation of soil properties and their variation has been recognized in geotechnical design codes, with the European Union’s Eurocode 7 [Eurocode 7, 2004] introducing the concept of characteristic values into the design process [Hicks and Nuttall, 2012].