Abstract Many existing earth dams have been designed and built worldwide before the establishment of a seismic code, so that it is of relevant interest to evaluate their seismic performance and post-seismic operational conditions. This requires an accurate geotechnical characterisation of the dam and foundation soils, a proper definition of the seismic scenarios at the site of the dam, the use of simplified procedures for screening-level seismic analyses and advanced non-linear dynamic analyses to study the most critical seismic scenarios. This process has been used for the evaluation of the seismic performance of a zoned earth dam located in a high seismic hazard area of Southern Italy. In this paper the available data of historical seismicity at the site of the dam and the results of a probabilistic seismic hazard analysis are first discussed and input ground motions are selected using compatibility criteria with the energy and frequency content of the expected target motion in a range of vibration period relevant for the non-linear response of the dam. Seismic performance of the dam is then evaluated through procedures based on Newmark-type computations, in which permanent displacements are related to ground motion characteristics and to the seismic resistance of the dam, the latter evaluated detecting the earthquake-induced plastic mechanisms and the corresponding critical accelerations. Also, an original improvement of the well-known Makdisi & Seed procedure, was proposed to better capture the actual influence of non-linear soil behaviour in the evaluation of horizontal acceleration and permanent displacements of the crest of the dam. The analysis results pointed out the relevant role of the earthquake-induced shear strength reduction on the dam permanent displacements.

中文翻译：

---

用于评价分区土坝抗震性能的筛选级分析

摘要 在地震规范建立之前，世界范围内已经设计和建造了许多现有土坝，因此评估其抗震性能和震后运行条件具有相关意义。这需要对大坝和地基土壤进行准确的岩土工程表征，正确定义大坝现场的地震情景，使用简化的筛选级地震分析程序和高级非线性动力分析来研究最关键的地震情景。该过程已用于评估位于意大利南部地震高危地区的分区土坝的抗震性能。在本文中，首先讨论了大坝所在地历史地震活动的可用数据和概率地震危险性分析的结果，并使用与范围内预期目标运动的能量和频率内容的兼容性标准来选择输入地震动。与大坝非线性响应相关的振动周期。然后通过基于 Newmark 型计算的程序评估大坝的抗震性能，其中永久位移与地震动特性和大坝的抗震性有关，后者评估检测地震诱发的塑性机制和相应的临界值加速度。此外，著名的 Makdisi & Seed 程序的原始改进，建议更好地捕捉非线性土壤行为在评估坝顶水平加速度和永久位移的实际影响。分析结果指出了地震引起的抗剪强度降低对大坝永久位移的相关作用。