Compositional and structural anisotropy of Winnipeg soils — a study based on scanning electron microscopy and X-ray diffraction analyses

Abstract

Samples of Winnipeg tan silt, brown clay, grey clay, and grey plastic clay were examined using X-ray diffraction and the scanning electron microscope (SEM). These same samples from the Winnipeg Floodway test site had been the subject of an extensive investigation by Freeman, who had shown that they were anisotropic in shear strength and permeability.Evidence was obtained that the presence of non-clay minerals in varves, veins, and inclusions in otherwise clayey material was a cause of anisotropy. Clay particle horizontal orientation and the presence of horizontal planes of uniformly graded silt are further reasons for anisotropy. In addition photographic data were obtained of shape, size, and grouping of the soil particles.