Quality control in deep vibrocompaction

Deep vibrocompaction (vibroflotation) is a method of ground improvement up to depths of 40 m. It has been successfully used since 1936. The major problem of this method is, that, inspite of its good performance, nobody knows exactly how the soil gets compacted. The methods of compaction control during the vibration are unreliably. The achieved compaction can only be verified after vibration. In this paper it is shown that information from the movement of the vibrator can be used as additional quality contro! and indicator for the degree of compaction. Such information can be analysed directly during compaction and offers thereby the possibility of an “on-line compaction control”.