Horizontalverspannung nicht bindiger Böden durch die Rütteldruckverdichtung mit Tiefenrüttler (experimentelle und numerische Untersuchungen)

Horizontal stress state of non-cohesive soils due to deep vibro compaction with depth vibrator – Experimental and numerical studies. Vibratory compaction methods for deep-reaching improvement of non-cohesive soils have been used since the 1930s. Either depth vibrators or top vibrators can be applied. The design of the compaction process as well as the subsequent quality control is still based almost exclusively on empirical relationships. In this context, the use of indirect ground exploration methods like dynamic probing or cone penetration tests and the work-integrated recording of process parameters has become established. This paper presents experimental investigations to assess the change in horizontal stress in the subsoil due to deep vibro compaction with depth vibrator. The aim is to provide a basis for a better understanding of the increase in stiffness and strength of improved non-cohesive soils. Furthermore, results of a highly simplified numerical simulation for estimating the stress changes are discussed in abbreviated form. A large-scale compaction experiment was realized. At two test fields with different compaction grid the inclinodeformeter was used the first time for this application. Additionally, conventional compaction control techniques (dynamic probing and cone penetration tests) were performed. Besides the qualitative development of the stress change over depth, the influence of the compaction grid spacing could be measured.