Investigations on the Settlement Behavior, Shear Strength and Classification of Fine-Grained Soils with Organic Components

Organic components, with a very large specific surface, are able to bind large quantities of water and can extensively affect bearing capacity. Even small portions of organics in soil can crucially change soil behavior with regard to water absorption. Particularly for construction practices, an important characteristic of organics is degradability. This process can take place under aerobic or anaerobic conditions. The breakdown process in aerobic decomposition is highly dependent upon available oxygen. The consequence of an intensive oxygen supply is a pronounced reduction in volume of the organic matter in each soil zone to almost zero, which in turn is associated with settlement in the entire soil mass. If oxygenation in respective soil zones is small, settlements may be so tiny as to be indistinguishable from ordinary creep. Investigations were performed to examine settlement behavior as well as influence on shear strength, and more closely describe the variable as a function of organic components. Furthermore, a more accurate classification of these soils should become possible.