Feldversuch zum Rüttelstopfsäuleneinbau und Betrachtungen zur Hohlraumaufweitung.

Field test on the vibro replacement stone column installation and considerations on cavity expansion Vibro replacement stone columns are used for ground improvement worldwide in coarse‐grained as well as fine‐grained soils. However, the changes in the soil's state due to the stone column installation including the induced vibration have not yet been investigated sufficiently. In the first part of the article, the effects of the stone column installation are investigated using a field test. It is shown that the installation in coarse‐grained soils can lead to an improvement in the structural properties of the surrounding soil. Based on the field test, a theoretical comparison of different cavity expansion processes is presented in the second part of this paper using simplified numerical examples. For that purpose, the expansion of a cavity in the soil due to (1) a monotonic and (2) a cyclic loading is investigated using a hypoplastic constitutive model. Both cases are compared to investigate their ability to simulate the column installation process. However, a qualitatively different soil behaviour is observed: A monotonic expansion will result asymptotically in the critical state of the soil, while a cyclic expansion leads to a compaction and/or a stress relaxation depending on the permeability. Therefore, neglecting the cyclic deformation of the soil in simulating the stone column installation seems to be inappropriate. [ABSTRACT FROM AUTHOR]