Application of Image Analysis Techniques to Microstructure Studies in Geotechnical Engineering

The microstructure (fabric*) of granular soils is defined as the spatial arrangement of particles and associated voids (Brewer, 1964; Oda, 1972). Research has shown that the microstructure of granular soils play important roles in the soils’ engineering behavior and properties. It is also believed that the behavior of granular materials can be evaluated by studying their micro-structures. Techniques for studying microstructure of granular soils include nonoptical and optical methods. The nonoptical methods are mainly used to determine the pore size distribution and coordination number of granular materials (see Juang, 1981; Oda, 1977). For the optical methods, a microscope, either light or electron, is used to extract information from thin sections or photographs of thin sections. Quantitative analysis is performed manually using a microscope equipped with a mechanical stage and a point counter (Oda, 1976; Mitchell et al., 1976).