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 repe titive fracture. Fractals are used to assess the change with aggregate size of the specific volume, the proportion of pre-existing cracks wh ich link to form the aggregate failure surface, and the aggregate fail ure stress. The pore size distribution, evaluated using mercury porosi metry and the application of the box counting algorithm to thin sectio ns 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 t o predict the scaling behaviour of soil physical properties.