Abstract: Soil pressure cells were installed directly under the cementmixed soil column and the surrounding soils in the plate static loading tests. The ratio of the vertical stress on the column over the stress on the adjacent soils is therefore obtained. The stress ratio change and the ultimate bearing capacity of the composite ground can be obtained throughout the loadsettlement relationship during the static plate loading tests. This approach is a new way of improving the understanding of the mechanism between the cement mixed columns and the soils.

Key words: Soil Mixing Columns, Composite Grounds, Column soil Stress ratio, Working Mechanism