engleski

Sustainable Ground Improvement by Stone Columns

Ground improvement presents a technological procedure that increases the bearing capacity of ground, reduces. i.e. controls total and differential settlements, reduces the time needed for deformations to take place, reduces ground permeability, removes water from ground completely by creating inner drainage systems, increases the erosive ground stability, and reduces the liquefaction risks. Ground improvement can be brought about by means of various technologies. Due to the increased need for the heavy infrastructure objects’ foundation works in extremely difficult conditions, the technologies, ground improvement techniques have been hurriedly developed. Generally speaking, natural ground is turning into a new material through the processes of ground compaction and mixing. According to this the object safety depends on the quality of the new material. The ground improvement methods, selection of an adequate foundation structure, and improvement efficiency control method can make it possible to quantify the efficiency of the operations and to manage the risks. The paper presents the Croatian experience in designing, executing and quality control of ground improvement by means of stone columns using the method of deep vibration compaction. The gravel or broken stone columns are installed into the coherent, i.e. poorly permeable ground types by pressing and vibrating, and then these columns take over additional loads. Along with the neighbouring ground, such granular material built in with vibrators has got higher stiffness and yields better resistance to shear. Whereas the foundation soil’ s bearing capacity increases its settlement decreases. Due to the high permeability of stone columns, the consolidation time is significantly shorter. The ground improvement technology by means of stone columns is from the economic standpoint remarkably more convenient than conventional foundation works. The realization time is relatively short, and the procedure adjustable to field conditions. The foundations works on the future construction object can start immediately after the ground improvement has been completed. Only natural materials are built-in into the ground, which makes this procedure ecologically very acceptable, as well.

ground improvement; stone columns; settlement; bearing capacity; quality control

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