Inspecting the Effects of Organic Content on Compaction and Consolidation Characteristics of Organic Soil Models

Abdulaziz Al-Kifae, Muhannad Abdullah Hamad


The main objective of this study is to investigate the behavior of different organic soils percentages under consolidation and compaction. For this purpose, a model of organic soil samples made by the use of leaves of the Eucalyptus tree as an organic matter and then mixed with inorganic silty clay soil taken from a specific district in Baghdad city at three levels (0% as mineral soil, 20% as organic soil, and 40% as highly organic soil or peat by dry weight). The reason of make such models was that because there is no natural organic soils in Iraq with the needed percentages. The physical and the engineering properties of the mixtures where determined by conducting a series of laboratory tests including Atterberg limits, compaction, and consolidation tests. The chemical properties of the mixture where determined by the chemical composition and the pH tests. The results showed that the Atterberg limits (liquid limit L.L. and plastic limit P.L.) are increased with the increase of the organic content (O.C.), while the plasticity index (P.I.) is decreased at (20%, O.C.) then increased slightly at (40%, O.C.). The maximum dry density (M.D.D.) decreased with the increase of the organic content, while the optimum water content (O.W.C.) increased with the increase of the organic content and this concerned with compaction characteristics. Compressibility characteristics showed that the increase in the organic content made a clear increase in the whole compressibility parameters (compression index Cc, coefficient of consolidation Cv, and secondary compression index Cα).    


organic matter; Atterberg's limits; compaction characteristics; consolidation.

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