大坝抗震安全性研究进展

论证了广大坝抗震安全性研究的实践与发展现状。目前大坝在地震作用下的应力与变形分析方法主要有拟静力法和动力响应分析法，并依据大坝混凝土的抗拉强度判断大坝的安全性；各国规范体现的抗震设防弹念和大坝材料的容许应力差别很大。坝址河谷不同高程处地震动状态不尽相同、河谷两恻同一高程处地震动也不一样。混凝土材料的强度与加载速度、应变速率有关；地震时大坝不同部位的应变速率不相同、同一部位的应变速率也随时间变化；混凝土的动态强度既与应变速率有关。也与应变历史等其它因素有关。大坝河谷地震动的输入机理和模型研究、混凝土的动态强度的变化规律探索、大坝抗震安全性评价准则的完善与创新等将有待深入。通过以上内容针对性分析，提出了大坝抗震评价的一些合理建议、方法以及进一步的研究方向。

Progress on seismic safety research of large dams

Practice and existing states of seismic safety research of large dams are demonstrated in this paper. At present, analysis means on the stress and deformation of the large dams under the action of earthquake mainly involve the quasi-static analysis and dynamic response analysis methods, and the judgment on the safety of the large dams is made in accordance with the tensile strength of mass concrete. There is a great difference in terms of antiseismic idea and the stress allowance of large dam material being stated in the specifications of different countries. There is also different intensity of earthquakes at different altitudes of river valleys on the dam site as well as at the same altitudes on either side of the river valley. The strength of the concrete material is related to the rate of loading and the strain rate. During the earthquakes, the strain rate varies at different positions of the dam and the strain rate at the same position also varies with time. The dynamic strength of the concrete is related to the strain rate as well as to other factors such as strain history. The research into the seismic input mechanism and the model of large dam river valleys, the varied rule of the dynamic strength of the mass concrete, and the improvement and innovation in the large dam seismic safety evaluation are expected to be deepened. Based on the analysis of the corresponding issues mentioned above, reasonable proposals, methods and further research directions for the large dam seismic evaluation have been put forth in this paper.