Ground Improvement Using Prefabricated Vertical Drains with Preloading for Port Park Area at Chittagong, Bangladesh

A container yard was constructed for handling of loaded containers at Port Park area of Chittagong Sea Port in Bangladesh covering an area of 60,700 m2 (15 acres). The sub-soil within the yard contained layers of very soft to soft strata of clayey silt/silty clay at depths of 1.0–3.5 m below the existing ground level. Ground improvement using prefabricated vertical drains with preloading was undertaken to pre-consolidate the sub-soils. The maximum settlements measured during the field monitoring period varied from 220 to 415 mm and the settlements were almost completed after 30–52 days of preloading. Predictions with and without considering smear effects had shown to provide an upper bound and lower bound of the consolidation time, respectively.