The graphical representation of planar pore patterns in soils

Abstract

Many soils, not necessarily only those with a high clay content, develop at low moisture contents a system of pores, in which one of the principal geometrical axes is much shorter than the other two (planar pores). The spatial orientation of such planar pore patterns is considered here to reflect significant aspects of the functional or physical fabric of the particular soils. Quantitative graphical methods are described to express the orientation characteristics of single cross sections and of series of parallel cross sections through such planar pore patterns. The procedures are demonstrated on a number of Australian soils with different clay contents. It is shown that very distinct indications of preferred orientation of planar pores, and sometimes elongated skeleton grains, occur in all these instances. It is considered that the significance of the quantitative description and analysis of soil planar pore patterns extends far beyond the significance of these patterns themselves, as they can be expected to be an expression of the depositional and/or stress-strain history of the particular soils. As such they should be of paramount importance in the study of the mutual relations between soil fabric and soil mechanical behaviour.