岩滩水电站厂坝混凝土快速施工技术

Rapid Operation Technique of Concrete of Powerhouse-dam at Yantan Hydropower Station

关键词:  常态混凝土  碾压混凝土  高流态混凝土  预应力锚固  滑模  筑坝技术

Key words:  normal concrete  roller compacted concrete (RCC)  high-flowability concrete  prestressed anchorage  slip form  dam construction techniques

摘要:

关键性工艺和措施是:优化混凝土配合比,采用机制石灰岩人工砂石料,碎石按80mm~40mm,40mm~20mm,20mm~5mm分级,大石;中石:小石组合比例为30:40:30,人工砂石料合石粉量12%~15%,水泥用量55kg/m³,高掺粉煤灰105kg/m³,占胶凝材料66.4%,掺用TF减水缓凝剂,混凝土Vc为15s±5s。投料顺序为碎石→水泥→水、外加剂→砂、粉煤灰,拌和时间150s~180s。缆车或汽车直接入仓或皮带机运料入仓,汽车转料。层面结合允许间隔时间为混凝土的初凝时间。碾压根据震动碾各自性能和振激力大小而定。坎身排水孔采用人工拔管造孔。常态混凝土和碾压混凝土(RCC)同步上升。常态混凝土浇筑温度控制在15℃~16℃,RCC控制在25℃以内。

Abstract:

The main technic and measures included:To optimize the mix proportion of concrete,crushed limestone sand and aggregate was used, in which the aggregate was classified by the size of 80 mm-40 mm, 40 mm-20 mm and 20 mm-5 mm with a combination ratio of 30%, 40% and 30%. The stone dust was controlled between 12% and 15%. The cement usage was 55 kg/m³,and as much as 105 kg/m³ of fly-ash was used as the mixture, which made up 66.4% of the cementing materiales. The TF water-reducing retarder was used, and the concrete's V. value was controlled within 15 ±5 s; The raw materils was feeded into the mixer plant in sequence of aggregate→cement→water and agent→sand and fly-ash. The mixing time was 150 s-180 s. The conveyer transfers the mixture with truck. The allowable time interval for the combination between each lift was the concrete's initial setting time, and the compacting time was depended according to the performance and vibrating strenth of each vibrating roller. The drain holes inside the dam body was manually made by pulling out the pipes. The normal concrete was rised simultaneously with the RCC. The placing temperature of normal concrete was controlled between 15℃ and 16℃, while the RCC under 25℃.