The interrelationship between chemical and mineral composition and aggregation and reaggregation of postlake cohesive soil

Abstract

Granulometric and aggregate content plays an essential role in the estimation of engineering-geological features of cohesive soil. The paper describes the results of studies of the chemical and mineral composition of aggregate fractions, the whole mass of soil samples and their clayey fractions. It has been proved that compounds of trivalent iron as well as carbonates/if they abound/play an important role in the structure of waterproof aggregates, but no influence of the organic matter has been observed. Calcium montmorillonites are the main clay minerals and they are much more concentrated in aggregates than the hydromicas and chlorites also occurring in clayey fractions. Pores are present both in the whole mass of soil and in the aggregates. Locally the surface of pores and edges of the aggregates are composed either of iron compounds or carbonates or streaks of clayey minerals, which is likely to increase the waterproofness of the aggregates. The results of the research can also be applied to the same type of soil from the regions of Central and Northern Europe.