Deep vibro compaction (vibroflotation) is a ground improvement technique, which has been worldwide strongly used for deep compaction of granular soils for decades. However, the methods for quality control of the compaction works are still largely empirical in nature and therefore often unreliable. There is currently no approved method for a reliable continuous compaction control for this ground improvement technique available. In contrast to conventional testing methods, a workand vibrator-integrated testing tool is required. That means the deep vibrator should not just serve as a compaction device but at the same time as a measurement tool, too. The presented doctoral thesis intends the development of the scientific basis for a system for work-integrated compaction control, based on the three-dimensional motion behaviour of the deep vibrator. For this purpose, fundamental experimental investigations were executed with an extensive test program. The compaction process was investigated in the scope of large-scale field tests. Additionally to the movement behaviour of the vibrator body, various process parameters and ground accelerations were recorded. The outcomes of the experiments provided new insights into the highly complex soilvibrator interaction system. They disclosed numerous previously less-known mechanisms during the compaction process. Based on the measurement data, a simplified analytical model of the soil-vibrator system was developed. The present analytical modelling allowed an indication of increasing soil stiffness due to vibro compaction. Moreover, it made an identification of fundamental physical processes in the compacted soil body possible. This way, compaction success could be quantified by a parameter called state-dependent stiffness indicator, which was derived directly from the monitored vibrator movement. Deep vibro compaction obtains the production of a uniform, quasi-homogenous compacted soil body. For this reason, the control of the compaction works must be undertaken three-dimensional, covering the depth and the ground surface. The execution of the ground improvement in compaction patterns makes a systematic control of the soil body ideally possible. The outcomes of the current doctoral thesis provide fundamentals for the application of the deep vibrator as a measurement tool for this purpose. Additionally to the vibrator movement, specific machine parameters and the measured wave field on the ground surface can be applied for this aim.