寒区混凝土劣化对重力坝抗震性能影响研究

Influence of concrete performance deterioration in cold area on seismic performance of gravity dams

为探究寒区混凝土性能劣化对重力坝抗震性能的影响,通过混凝土材料冻融循环试验和数值模拟开展了重力坝动力响应分析,得到了大坝在地震激励时的应力、位移和破坏等情况,并通过损伤因子及其对应损伤区域面积提出了重力坝整体损伤累积面积公式。研究结果表明:强震作用时,坝体损伤最明显的部位为下游折坡处和坝踵,冻融循环对大坝整体损伤程度有显著影响,在下游折坡处的冻融区域内配置抗冻混凝土能提升大坝整体抗震性能。研究成果可供寒区混凝土重力坝的抗震设计参考。

In order to explore the impact of concrete performance degradation on the seismic performance of gravity dams in cold area,the dynamic response analysis of a gravity dam was carried out through concrete freezing-thawing cyclic tests and numerical simulations.Based on the results of the material dynamic test,the damage of the dam during an earthquake was simulated,the stress,displacement and failure of the dam during the earthquake excitation were simulated,and an overall damage cumulative quantified area formula for the gravity dam was deduced using the damage factor and the corresponding area of damaged zone.According to the results,strong earthquakes caused the most obvious damage at the downstream slope turning point and the dam heel;the freezing-thawing cycle had a significant impact on the overall damage degree;placing frost-resistant concrete in the freezing-thawing area of the downstream slope turning point could improve the overall seismic performance of the dam.The conclusions can be applied to the seismic design of concrete gravity dams in cold areas.