APPROACHES CONSIDERED TO OVERCOME UNCERTAINTIES AT ÇINE DAM

Çine Dam is being built on the river of Çine for flood control, irrigation and energy purposes. The dam type was originally designed as rockfill with claycore but, during the construction stage it has been changed to RCC. The main reasons for this change were the distance, the quality and the place of clay borrow area; the chance to build spillway on the dam body so as to avoid some serious geotechnical problems expected at the original spillway area, to have shorter diversion tunnels, to place power intake on the dam body and the early completion of the dam. After excavation has been completed for RCC foundation, it was found out that the dimensions of the fault located upstream of the dam were larger than the estimated value. Similarly foundation rock was worse than what is estimated for the high strength RCC dam. This situation increased the cost of the dam significantly due to foundation and fault treatment. Consequently, DSI investigated the possibilities of reducing cementitious content for the purposes of decreasing required consolidation grouting and of diminishing precooling cost for the dam body itself. Seismic design was also reviewed for required RCC strength and foundation treatment. While DSI was planning to use membrane to reduce cementitious content and thus foundation treatment and precooling cost, the contractor accepted to make discount from the contractually defined unit price of RCC in the contract with some reduction in grouting at the foundation of the dam by taking the full responsibility. As a conclusion considerable amount of cost saving is provided for the construction of the Project.