Soil improvement work by vibroflotation

Vibroflotation method has been employed for the foundation soil improvement of two power and desalination plants. The subsoil conditions from site investigations performed at these sites are mainly of sand with trace of silt or silty sand. An extensive field trial program was carried out to determine the most suitable vibroflotation treatment program for the project site. The foundation soil was improved using the treatment procedure determined from the results of field trial program, together with the quality control criterion. A continuous sounding is found to be important for the selection of appropriate soil improvement method. Field vibro trial program was beneficial to the effective soil improvement work for these projects. Cone penetration test is found to be useful for quality control work in cohesionless soil, while plate loading test seems to be a good alternative for cohesive soil. The foundation treated with stone backfill shows that stone column is very effective in reducing the foundation settlement and resisting shear failure.