As an engineering measure to reduce tensile stress of dam heel, the installation of man－ made bottom joints in upstream bottoms of arch dams has already a history of 40 years. However, the mechanism and extent of effects of bottom joints on high arch dam earthquake－ resistance performance and earthquake response when an intensive earthquake occurs have been concerned about by engineers. This paper has made a verification of the dam non－ linear fluctuation analysis and procedure developed by combining the explicit finite element－ based artificial transmission boundary fluctuation simulation method with the dynamic contact force theory after carrying out large－ scale dynamic model test on a large earthquake simulation vibration table, and then studied the earthquake response of the Xiaowan high arch dam simulation bottom joints. The study results have proved that the bottom joints have only partial effect and can not be considered as an effective earthquake－ resistant structure engineering measure to improve the earthquake－ resistance performance of the dam body.%作为减少坝踵部位拉应力的一个工程措施，在拱坝上游底部设置人工底缝已有40年的历史。然而，强震时底缝对高拱坝抗震性能和地震反应影响的机理和程度，为人们所关注。本文首先通过大型地震模拟振动台的大比尺动力模型试验，比较验证基于显式有限元结合人工透射边界的波动模拟方法与动接触力理论相结合开发的大坝非线性波动分析方法和程序;继而采用经试验验证程序，研究小湾高拱坝模拟底缝的地震反应。结果表明:底缝影响是局部的，并不能作为一个有效的抗震结构工程措施改善坝体的抗震性能。
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