ABSTRACT
Vibratory deep compaction utilizes, as its main tool, a depth vibrator creating horizontal vibrations when working in the ground. Process variations of the vibro replacement stone column method include both material and equipment variations. When concrete or mortar as backfill material replaces stone or gravel these columns are generally called vibro concrete columns or vibro mortar columns. They are preferably used in soils needing improvement which are generally not or only marginally suitable for treatment by vibro replacement. From a multitude of similar small diameter piling methods being installed for ground improvement purposes in soft soils at relatively close spacing, the controlled modulus column method utilizes a special displacement auger that penetrates the ground to the predesigned depth essentially without spoil. Since vibro concrete columns are generally quasi by definition executed for the improvement of very soft soils, an adequate quality assurance program is indispensible.
