Evaluation of the Effectiveness of Geosynthetic Encased Granular Column in Soft Soil Improvement by Numerical Method and Field Experiment

The Unit cell model is used to research the effectiveness of geosynthetic encased granular column (GEC) for VIFONE II factory area at LONG AN province, VIET NAM in soft ground improvement. Settlement of ground is determined by applying Plaxis 2D simulation software; from that, computed results by Plaxis 2D is analyzed, compared with the field monitoring results. Research results show that in case of granular column without geosynthetic, as using “Soft soil” model, resulted data by Plaxis are approximately similar to those observed from field monitoring with an error of 8.3% up to 22.8%. As applying geosynthetic encased granular column (GEC) in case of loading less than 100 kPa, the difference of settlement between ground reinforced by granular column and by GEC is not significant, only from 0.2% up to 3.2%. The difference of settlement of ground reinforced by granular column with and without geosynthetic reduces from 15.1% to 6.8% corresponding to loading from 400 kPa to 800 kPa.