Modelling of Consolidation Settlements of Organic Soils

ABSTRACT: Organic soils are characterized by their high organic contents, high initial water contents, high compressibility, and low shear strength. Organic soils exhibit high volume changes under loading conditions and undergo significant primary consolidation and continuous long-term secondary consolidation settlements. The mechanical behaviour of organic soils is complex and requires extensive soil testing to obtain representative geotechnical parameters to model its behaviour. This paper includes a review of the key constitutive models that could be utilized to model soft soils. Afterward, finite element analyses were developed using PLAXIS 2D for a well-documented case study of an embankment on soft clay deposit. The finite element model is validated against field measurements using different constitutive soil models to investigate their adequacy in modelling organic soil behaviour. Then, the recommended soil model was used to simulate available laboratory tests (i.e., consolidation tests) of organic soils with different organic contents to verify the limitations and drawbacks of the recommended constitutive model. As a result of this review and the numerical modelling analyses, an approach to simulate the consolidation behaviour of organic soils has been developed.