洪家渡面板堆石坝分期填筑方案研究

洪家渡面板堆石坝最大坝高179.5 m,坝顶长度427.79 m,坝体基础部位上下游方向最大宽度500 m,总填筑量900万m3,平均填筑强度30万m3/月,在填筑期内90%的时间内是一条路上坝.因此,洪家渡面板堆石坝现场的客观条件决定了坝体填筑做不到全断面上升,只能分期填筑,分期挡水度汛.垫层料的开裂、面板的开裂和脱空与坝体的填筑分期、大坝的填筑速率密切相关,合理的填筑方案会避免或大大减小面板发生拉伸性裂缝和弯曲性裂缝的可能性.洪家渡面板堆石坝经过反复的方案比较、计算,在总结了天生桥面板堆石坝经验与教训的基础上,得出了合理的大坝填筑分期方案,预测出洪家渡面板堆石坝开裂问题较小.

Research on staged-filling scheme about concrete-faced rockfill dam of Hongjiadu hydropower station

The maximum height of the concrete-faced rockfill dam of Hongjiadu hydropower station is 179.5 m and the dam crest length is 427.79 m. The maximum streamwise width of dam foundation is 500 m. The total filling quantity is 9 million m~3, with fill intensity of 0.3 million m~3 per month on an average, and only one access way to the dam was available in 90% of filling construction period. The field condition of the dam determined that full section filling and rising of dam cannot be realized and the filling construction and retaining water in flood season should be carried out in stages. The cracking of bedding material and cracking and separation of face slab from bedding material have close relation to filling-stage division and filling velocity of the dam, reasonable filling scheme can avoid or greatly reduce the possibility of tensile and bending cracks of face slab. Through repeated scheme comparison and computation of the concrete faced rockfill dam of Hongjiadu hydropower station, and on the base of experience and lesson summarization on Tianshengqiao hydropower station, the reasonable staged-filling scheme was designed and it was predicted that the crack problem of the concrete faced rockfill dam of Hongjiadu hydropower station was minor.