Hydrodynamic Isolation of Concrete Dams

这是一个由“新奇研究快速奖”(NSF 87-90)资助的项目。研究了混凝土坝抗震的动水隔震方法。大坝不是与地面运动隔离，而是通过在水库中锚定充满气体的气球、将闭孔泡沫材料附着到上游表面或连续向水库中注入气泡来隔离动态水压。因此，当水库满了或几乎满了时，大坝响应可能出现的显著增加被消除。将对所有三个方案进行潜在效益和成本评估。已有研究表明，强震是指水库满库或接近满库的大型混凝土大坝的严重荷载，导致大范围裂缝，后果不详。将混凝土坝与水动力效应隔离，可避免增加动力响应。随着水位从大坝约四分之三的高度上升到坝顶，这种增加变得非常明显。这项研究可能会对抗震不足的现有大坝的改造和新大坝的设计产生影响。

This is a project supported under the "Expedited Awards for Novel Research" (NSF 87-90). The method of hydrodynamic isolation to protect concrete dams against earthquakes is studied. A dam is isolated, not from the ground motions, but from the dynamic water pressure by means of either anchoring gas-filled balloons in the reservoir, attaching a closed-cell foam material to the upstream face, or continuously injecting bubbles into the reservoir. Thus, the significant increase in response of the dam which may occur when the reservoir is full or nearly full is eliminated. All three schemes will be evaluated for potential benefit as well as cost. It has been shown that a strong earthquake represents a severe loading of a large concrete dam with full or nearly full reservoir, causing extensive cracking with unknown consequences. Isolating a concrete dam from hydrodynamic effects avoids the increase in dynamic response. This increase becomes significant as the water level is raised from about the three-quarter height of the dam to the crest. The study has potential to impact retrofit of existing dams with seismic deficiencies and the design of new dams.