Consolidation behavior of soft clay

ABSTRACT Storing contaminant soils, such as dredge materials, sludge and mine tailings, and reclaiming contaminant soil storage areas back into the economy has arisen as an important economical and environmental problem in today's world. It is clear that this reclamation will only become possible after successful prediction and modelling of behaviour of soil in the storage areas. In order to accurately predict the non-linear deformation behaviour of high water content soils under its own weight and/or through surcharge loading, it is imperative that we obtain both a mathematical model that will accurately predict the physical event, and also, to solve this mathematical model, the physical properties of the soil. The scientific studies in the last thirty years have revealed important discoveries regarding the deformation behaviour of high water content soils. Determination of consolidation properties of high water content clays under its own weight and/or very little effective stress is currently not possible through the classic experimental methods. A new experimental technique, dubbed "Seepage Induced Consolidation Test" by hnai (1979), was developed to more realistically study the consolidation behaviour of such high water content soils under seepage forces. This experimental setup was further developed by Abu-Hejleh, Znidarcic and Barnes (1996) through simulation of seepage forces using a flow pump applied to the soil sample. The goal of this thesis was to determine the consolidation properties (specifically the "variation of void ratio with effective stress (e-av )" and "coefficient of permeability with void ratio (k-e)" relationship) of high water content soils that are deposited in areas where they are subject to compression under their own weight and/or surcharge loads. A seepage induced testing system was built at the Yildiz Technical University Soil Mechanics Laboratory, and this system was used to investigate three different clay samples that were prepared in a slurry style mix. The experimental results were observed to be consistent with the relationships proposed in the literature for the "variation of void ratio with effective stress" and "coefficient of permeability with void ratio" during consolidation of high water content soils. Keywords: Saturated soft soil, consolidation, seepage induced consolidation test. xv