大朝山水电站全断面碾压混凝土双曲拱围堰施工

大朝山水电站工程全断面碾压混凝土双曲拱围堰体形复杂，基础覆盖层厚度变化很大，气候条件特殊，施工难度大。施工中采用围堰基础分块浇筑、深槽置于覆盖层上、堰体混凝土不分缝通仓连续浇筑等技术措施，有效地保证了碾压混凝土连续快速施工。在2个月内，堰体浇筑上升了40.5m。首次成功地在碾压混凝土中大掺量地使用PT掺和料，为大坝碾压混凝土施工积累了宝贵的经验。

Construction of double-curvature arch cofferdam with full-section RCC in Dachaoshan Hydropower Station

The double curvature arch cofferdam with overall RCC in the Dachaoshan Hydropower Station is complex in its body type, varying greatly in the thickness of foundation overburden layer, particular in climate conditions and difficult in construction. The technical measures such as the block placement in the foundation of cofferdam, the deep channel in overburden layer and the continuous full face pouring without joint for cofferdam body concrete were adopted in the construction, so that the continuous quick RCC construction was effectively guaranteed. Within two months, the pouring of cofferdam body rose 40.5m. It firstly applies a large amount of PT admixture to RCC successfully, which provides valuable experience for RCC construction of dam.