Eastmain River Dam—A case history of mass compaction in earth dam construction

The OA-11 dam on the Eastmain River in the James Bay Region of northern Quebec was designed without conventional cofferdams. The river section of the dam was constructed by end-dumping and dozer pushing of granular fill and achieving closure and diversion of the river through a spillway located in a rock abutment on the south bank.The fill was then compacted by using the vibroflotation method. The fill thickness varied from 4.5 to 15 m, the compacted area being 68 000 m2 while the volume was about 725 000 m3.This paper gives the properties of the fill, the equipment used for compaction, the control method used to assure compliance with specifications, and the results of the compaction programme. Keywords: dam construction, compaction, density, vibroflotation, equipment.