Research on Installation Technology of Floating Stone Columns

In this study three already finished projects in Lithuania were investigated, the problems faced in the projects were examined, and the main advantages and drawbacks of the chosen geopile installation technology were identified. Three alternative solutions for geopile installation were selected for the investigation: driving a hollow steel pipe into the ground using a deep vibrator and using geosynthetic material to reinforce soils (A1); driving a closed-ended hollow steel pipe into the ground and using geosynthetic material to reinforce soils (A2); driving an open-ended hollow steel pipe into the ground and using geosynthetic material to reinforce soils (A3). Those alternatives were evaluated according to the following criteria: geopile installation cost (K1), level of mechanization (K2), load bearing capacity (K3), installation options (K4), impact on the environment (K5), duration of the installation of geopiles (K6). In order to find out the significance of the evaluation criteria a survey questionnaire and a ranking procedure were used. The same order of criteria importance, namely K1˃K3˃ K2˃K4˃K6˃K5, was obtained using the selected rank-order weighting method. Basing on the selected criteria, a rational option for geopile foundations was identified using the multi-criteria assessment method TOPSIS. The results show that driving an open-ended hollow steel pipe into the ground and using geosynthetic material to reinforce soils (A3) is the most rational option for the installation of geopiles in the investigated finished projects in Lithuania. This article is based on Master thesis topic “Research on installation technology of geopiles”.