Sand Densification Using Combination of Vibroflotation and Stone Column for Coastal Reclamation in Lampung, Indonesia

Abstract

In order to expand the coal stock pile terminal at Sumatera - Indonesia, certain sea shore areas are reclaimed with total area approximately 6 ha. Any main facilities are be placed on the reclamation area which containing of loose sandy material with varying depth down to 30 m below. The construction is facing several challenges due to seismic loading (earthquake) which induced liquefaction, sand boil that caused soil strength reduction as well as the settlement. To reduce the future bearing capacity failure of new stock pile area, soil improvement using combination of vibroflotation and stone column are considered. Trial densifications were conducted with optimum spacing was found to be 3-4 m. Target CPT tip resistance was set as reference for field quality control. Soil density target were controlled using CPT which considered fine content. Relative density of 60-70% were targeted to assess results.