Lacustrine soilsp.Marine soils p.Aeolian soils p.Colluvial soils p.Organic soils and peat p.Engineering in peat land p.Development of peat land and types of peat p.Undisturbed sampling p.In situ tests p.Engineering properties of peat and organic soils p.K_o Behaviour p. 94 Summary p. 95 Deformation characteristics of peat p. 97Recent advances in the geotechnics of organic soils and peat p. 171

Peat commonly occurs as extremely soft, wet, unconsolidated surface deposits that are integral parts of wetland systems. Cement is widely used for the stabilization of peat by deep mixing method. This paper presents the results of the shear strength parameters of study models (fibrous, hemic and sapric peats stabilized with columns formed by dry mixing method). The columns were formed of peat treated with cement in different proportions. Triaxial test was performed after curing the samples for 28 days to evaluate the shear strength parameters. The results showed that the shear strength of peats can be improved significantly by the installation of cement stabilized soil columns. The amount of cement used to form the column and its diameter were observed to influence the strain-stress graph of peat reinforced. Furthermore, the result showed that the effect of cement was the highest on sapric peat due to its physico-chemical properties.

The effects of aggressive peat nature (pH) on the strength of peat treated by cement and cement-sodium silicate grout were investigated by evaluating the changes in unconfined compressive strength, moisture content, and scanning electron microscopy (SEM) of samples with time in different pH media. The results indicate that peats treated by cement-silicate have higher strength than peats treated by cement, due to an increase in pH value of the media. Furthermore, cement and cement-silicate are highly effective in reducing the moisture content and void ratio of the treated peats. The microstructures of treated peats support the laboratory test results.

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