Physical Properties And Compression Behavior Of Artificial Organic Soils

Organic matters widly exist in natural soils such as sediments, polluted dredged sludge and various contaminated soil. Organic matters have significant effect on physical properties and compression behavior of soils which influence the treatment of soils.In this study, Taizhou clay (mainly contain illite), kaolin and bentonite were adopted to prepare artificial organic soils by adding different organic matter (humic acid, fulvic acid and potassium humate). A series of oedometer tests and physical properties tests were performed on artificial organic soils. The main works in this study are as follows:(1) For artificial organic soils prepared with humic acid, the specific gravity and the content of clay particle decrease with the increase in organic content. The influence of humic acid on Atterberg limits changed with the clay mineral compositions of tested samples. Liquid limit of Taizhou clay and bentonite decrease with the increasing organic content while plastic limit stay the same approximately. The Atterberg limits of kaolin increase slightly with increasing organic content.(2) For artificial organic soils with fulvic acid or potassium humate, Atterberg limits of Taizhou clay and kaolin increased with increasing organic content. Potassium humate promote Atterberg limits up more than fulvic.Liquid limit of bentonite with water-soluble organic matter decrease when organic content increasing..(3) Oedometer tests were performed on artificial organic soils prepared with humic acid. The specimens had the same initial void ratio, soils with higher organic content presented higher compressibility at lower stress level. The coefficient of consolidation icreased with increasing organic content at the same stress level.(4) Oedometer tests were performed on artificial organic soils prepared with fulvic acid. The result shown that compression behavior of organic soils prepared with fulvic acid depend on eL-The compression curve of orgaic soil which has higher eL above the orgaic soil which has lower eL-Fulvic has a significant effect on decreasing the coefficient of consolidation.(5)The change of compression parameters caused by various organic matter was discussed. For artificial organic soils prepared with humic acid, with the increase in organic content, coefficient of consolidation increase but intrinsic consolidation parameters decrease. An inverse relationship was found on artificial organic soils prepared with fulvic acid. Based on the test result of physical properties and research productions that have been obtained, compression behavior were determined by physical properties influenced by organic matter.