Construction of Raw Sugar Silos Using Dynamic Replacement

Abstract

Two raw sugar silos, each 55 m high, have been constructed on improved ground in Al Khaleej Sugar Factory located in Dubai’s Jebel Ali area. The preliminary geotechnical investigation indicated that the upper 6 m of soil was composed of loose to dense silty sand followed by weak bedrock, and that it was not possible to construct the silos without implementation of special foundation measures. Ground improvement by dynamic replacement was chosen as the most affordable technical solution. Treatment was carried out by initially excavating the ground to the working platform level. For each silo, the impact points were individually excavated and backfilled with crushed rock. A rock filled shear ring trench was also realized at the periphery by excavating the silty sand to the depth of 2 m. The project faced special challenges due to the vicinity of an existing sugar silo at a minimum distance of 10 m from the works, the presence of a highly cemented and previously unidentified sand layer in parts of one of the silos, and a high groundwater table. A total of 29 Menard Pressuremter Tests (PMT) were carried out after soil improvement to verify that acceptance criteria had been satisfied.