A New Parameter for the Evaluation of Mixing Quality in Deep Soil Mixing

The blade rotation number is the typical parameter used to evaluate the degree of mixing during the installation of deep mixing (DM) elements. Several limitations in the use of such quality index occur when a tool geometry different from the standard vertical shafts equipped with a series of blades is utilized in the field. Cutter soil mixing (CSM) represents one of such cases. CSM differs significantly from conventional DM methods, since it makes use of two sets of cutting wheels rotating around horizontal axis to produce rectangular panels of improved soil rather than one or more vertical rotating shafts creating circular stabilized columns. For this reason, an alternative mixing quality index related to energetic principles has been defined in this paper based on the comparison between strength and permeability results obtained from in-situ and laboratory specimens. The first outcomes seem to confirm the capability of the new index to describe the differences in quality in both types of samples.