ABSTRACT
In Singapore, peaty soil deposit poses a difficult problem in civil engineering project. The low shear strength and high compressibility of peaty soils have caused difficulties in excavation and construction of foundation. Chemical soil stabilisation is an extensive method that has been used for improving the properties of soft soil. Cement is the most widely used additive for soil stabilisation due to its high strength and availability. The primary objective of this paper is to examine the shear strength characteristics of peaty soil treated with cement. The shear strength of the peaty soil-cement mixes was studied in the laboratory. Peaty soils from a site in Singapore were used in the study. Other variables included in the study were cement content and curing time. The test results showed that the undrained shear strength of peaty soil was improved with addition of cement. The logarithmic of shear strength of the peaty soil-cement mix increased in a linear fashion with cement content generally except at high cement content where water in the soil was insufficient for the complete hydration process. The rate of shear strength improvement was most rapid within the first few days of addition of cement to the peaty soil. The products of the chemical reaction between the peaty soil and cement were ascertained through X-ray diffraction.
