Abstract: The soil-cement mixed column method has the advantages of high utilization rate of the in-situ soil, less environmental impact of in the mixing installation and lower construction cost. This method is widely used in the ground improvement projects. There are many factors affecting the settlement of the soil-cement mixed column composite foundations. The research on the load transfer mechanism and the settlement estimation method is not well-developed, and there is no matured and widely accepted design methodology available. The effective column length and the optimal column-soil modulus ratio are the key factors to control the settlement of the composite foundation, while the selection of the column spacing and the replacement ratio needs to systematically consider the engineering safety and the construction cost. In addition, the load transfer mechanism of the column is validated, and the major settlement estimation methods of the composite foundation are compared in this paper.

Key words: Soil Cement Mixed Column Composite Foundations, Settlement Influencing Factors, Load Transfer, Settlement Estimation