The Swedish method of deep dry soil mixing (DSM) by forming lime-cement columns is a geotechnical purist’s solution to very soft soils, in that it modifies their behaviour rather than bypassing them using structural elements as in piling.
The technique is currently enjoying a surge of interest in the UK, thanks to the efforts of Keller Ground Engineering and its Swedish sister company LCM.
DSM is in essence a ground improvement technique, but one that is applicable in soils such as very soft organic silts, clays and peat, that previously were considered largely untreatable; at least in the UK.
And that is good news, because ground improvement methods are generally highly cost effective compared to harder-engineered solutions.
Keller senior geotechnical engineer John Judge believes the method has applications “anywhere where improvement of a soft clay into a stiff to hard clay is the answer”.
In fact, Judge believes the applications are almost limitless and is confident that in the next few years DSM will be more widely used “in ways that haven’t yet been thought of. It’s simply down to the imagination of the engineers.”