Investigation into the fractal scaling of the structure and strength of soil aggregates

The hierarchical nature of soil structure is examined by measuring the physical properties of a range of aggregate sizes obtained using repetitive fracture. Fractals are used to assess the change with aggregate size of the specific volume, the proportion of pre-existing cracks which link to form the aggregate failure surface, and the aggregate failure stress. The pore size distribution, evaluated using mercury porosimetry and the application of the box counting algorithm to thin sections and thick sections, is also used to obtain a fractal dimension, D. Our results show that D depends upon the measurement approach for mass fractal scaling. This finding may limit the application of fractals to predict the scaling behaviour of soil physical properties.