Abstract: In the ground improvement practice, the design parameter of the area replacement ratio in composite soils with different column spacings, the conventional equivalent circular area conversion method is traditionally used, which requires higher spatial abstract capability and requires many calculations. This article introduces a concept of minimum repetitive unit to select the cell of column and soil and the application on the calculation of area replacement ratio of composite soils under different column spacings and distributions. Compared with the conventional method, this method is easier to understand and has the advantage of simple calculation. This proposed method can provide guidance for the soil improvement practitioners for estimating the area replacement ratio.

Key words: minimum repetitive zone, composite soils, replacement ratio, estimation methods