Design of Sand Moving Operation: Back Analysis and Settlement Prediction

Ground improvement by prefabricated vertical drains (PVD) and additional surcharge loading is a robust method that is widely used in the practice of reclamation. Detailed design provides a reasonable estimation for a contractual purpose. However, during the construction, monitoring system and back-analysis are frequently used to (1) deal with the high-variability nature of the soft soils, and (2) achieve an optimum effectiveness of soil improvement. In this paper, the sand moving operation in the construction of Gemalink International Container Terminal at Cai Mep River, Vung Tau is presented. In this design, the back-analysis was carried out (by using D-Settlement programme and NEN-Bjerrum soft soils model) to capture the evolution of soil compressibility and to predict the long-term settlement of the reclamation area during operation and give recommendations on whether the surcharge load should be increased, can be decreased or completely removed (i.e. moving from the sub-zone of satisfaction to other critical sub-zones).