Numerical Analysis of Soil Improvement for a Foundation of a Factory Using Stone Columns Made of Different Types of Coarse-grained Materials

Stone columns made of coarse-grained materials and crushed stone are one of the most-used technologies for soil improvement all over the world. Stone columns improve the strength and deformation properties of subsoil and reduce the time required for the consolidation of fine-grained soils. The impact of the improvement depends on the properties of the original subsoil as well as the properties of the coarse-grained materials used for the stone columns. The article deals with the effects of the properties of coarse-grained materials for stone columns on the settlement and consolidation times of improved subsoil for the foundation of a factory. Numerical modeling as a 2D task was performed using Plaxis geotechnical software. The numerical analysis included two methods of modeling stone columns in a plane strain model, i.e., one method often used by practical engineers in the region of Slovakia, and one modified method, which allowed for a more accurate determination of the final settlement and consolidation time. The method modeled stone columns as continuous walls, and the compaction of the soil between the stone columns was taken into account. The results showed that the type of coarse-grained material can significantly affect the final settlement and time of consolidation. Stone columns made of quarry stone were suitable in the given geological conditions regardless of the design of the mesh, while stone columns made of pebble gravel were suitable only with a mesh of 1.5 x 1.5 m.