Abstract: The compacted soil-cement mixed column is a typical friction type of column and is commonly used in the treatment of large area of soft soils. To investigate factors that might impact the interface contact characteristics of the column-soil, a series of direct shear tests were conducted. These factors are: cement content, soil moisture content, normal stress on the side of the column and curing age. The test results indicate that there is an optimum cement-soil ratio for the side friction behavior. The interface shear influence zone correlates with the normal stress and the international friction angle. The curing age will affect the cohesion and the internal friction angle and therefore, improves the shear strength of the interface.

Key words: Column-Soil Interface, Soil-Cement Mixed Soil, Direct Shear Tests, Side Friction Resistance