Influence of grading and mineralogy on the behaviour of saprolites

Soils originating from chemical decomposition do not undergo any sorting in their grading resulting in a well-graded material. Their composition may be influenced by weathering in one or more aspects, e.g. particle size, particle size distribution, mineralogy or particle morphology. Each of these aspects and their effects on the mechanical behaviour have been studied separately in the past. To identify the dominant parameters a series of standard oedometer tests was carried out to investigate the influences of the grading and mineralogy on the Normal Compression Line (NCL) separately. This was achieved taking the most and least decomposed granite sampled at a same location and reconstituting them to the same grading to study the influence of mineralogy or reconstituting one of them to both the gradings to study that of grading. In the first case, the NCLs were practically coincident, while in the second they were further apart, showing that the grading has greater importance in determining the mechanical behaviour in compression.