RESULTS OF QUALITY CONTROL ON THE BODY CONCRETE OF KAZUNOGAWA DAM

摘要

Kazunogawa Power Plant is a pumped storage power plant with the maximum power generation output of 1 600 MW, being constructed in Yamanashi Prefecture by Tokyo Electric Power Co., Inc. Kazunogawa Dam is the lower dam of the power plant, which was built as a concrete gravity dam with a crest height of 105.2 m and a dam volume of 622 x 10~3 m~3. RCD method was adopted for placement of dam concrete. For Kazunogawa Dam, attempts were made to reduce cost and construction period, by adopting a new design and construction method in which unit binder content of the concrete is reduced to 110 kg/m~3 for placement with a lift of 1 m. The placement of lean concrete at a high lift required more precise quality control measures. Thus, in addition to ordinary quality control measures, the quality of concrete was confirmed using cores sampled during winter season when placement works were halted, and new systems were developed and applied for quality control, namely the total VC values control system for fresh concrete and real time control system for compaction. Concrete placement work for the dam started in August 1995, which was completed in November 1997. Results of construction management and quality control activities yielded satisfactory results, and construction cost as well as period were reduced significantly by, adopting a unit binder content of 110 kg/m~3 and 1-m lift, compared to conventional methods using 75-cm lift.