The mechanical properties of very soft clays, silts and organic soils can be improved with deep mixing, a soil improvement technique in which stabilising agents, such as lime and/or cement are mixed into the soil in-situ by using auger-type mixing tools. Deep mixed columns are nowadays extensively used to reduce settlements and improve the stability of embankments and foundations constructed on soft soils. The problem analysed involving a regular arrangement of columns under an engineering stmcture, such as embankments or strip footings, is a fiilly three dimensional problem. As 3D analyses are computationally very expensive, an enhanced 2D technique using the so-called volume averaging technique has been developed as part of this research. The basic idea is to describe the column-improved ground as a homogenized composite material and map the the 3D problem into 2D.