Assessing Soil Correlation Distances and Fractal Behavior

An essential parameter used in reliability analyses of geotechnical engineering systems, particularly foundations, and probabilistic modeling of soil profiles is the correlation distance, which is also known as the scale of fluctuation and the range of influence. This parameter is often difficult to measure, as it requires extensive field testing, which is usually beyond the scope of most geotechnical investigations, and is hence associated only with uncommon research studies. This paper presents the results of a number of investigations in clay and sand, which were designed to quantify the spatial variability and, hence, the correlation distance of these soils. The paper describes and makes use of random field theory, geostatistics, and fractal theory to facilitate the assessment of spatial variability and the correlation distances in both the vertical and horizontal directions.