Ana Nicuta. EVALUATION OF THE IMPROVEMENT FOR A DIFFICULT FOUNDATION SOIL USING VIBRATED BALLAST COLUMNS. SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 14th SGEM GeoConference on SCIENCE AND TECHNOLOGIES IN GEOLOGY, EXPLORATION AND MINING, 2014. https://doi.org/10.5593/sgem2014/b12/s2.044