Roller Compacted Concrete under the Barrage Fuse Plug-A Technically Superior and Cost Effective Solution

摘要

Ghazi Barotha Hydropower Project is an off channel project on river Indus in Pakistan completed in 2003. The project has an installed capacity of 1, 450 MW of electricity. As a part of the project a barrage has been constructed over Indus river at Ghazi. The barrage incorporates a fuse plug to pass PMF of 46, 000m3/s. In the event of breach of the Fuse-plug embankment it is required that the foundation of the embankment should not erode so that plastic concrete cut-off wall connection to the embankment remains intact and subsequent reconstruction could start without delay. Several solutions were considered to control the erosion at the embankment base. Finally it was decided to provide a concrete pad under the entire foundation of embankment and the top of cut- off wall connected to it. Considering the huge size of the pad and construction time constraints it was not feasible to construct this pad with conventional concrete. Major part of the pad was therefore constructed using Roller Compacted Concrete (RCC). About 143,000m3 of RCC was placed in 73 days well within the schedule time. This paper describes the process of selection of RCC base pad under the fuseplug embankment, its design characteristics and control over its properties during construction.