Abstract: The safety of embankment dams in the unexpected events has always been the focus of attention. The study on feature analysis of unexpected events and emergency monitoring may improve the vulnerability of embankment dams in unexpected events. In this paper, the definition of unexpected event is introduced. Combined with the statistical results of the causes of dam failure and the types of the reservoir dam unexpected events, it is considered that the unexpected events of embankment dams can be classified as flood and earthquake. On this basis, the classification standard of reservoir dam unexpected events is given. The harmful characteristics and hazards of overtopping, seepage failure, slope instability and spillway damage caused by flood as well as the cracks, seepage, landslide and structural deformation caused by earthquake are also analyzed. Based on the characteristic analysis of the unexpected events, the items and frequency requirements of emergency monitoring for embankment dams under flood and earthquake at different levels are discussed, which can provide guidance for emergency disposal.

Key words: embankment dams, unexpected events, feature analysis, emergency monitoring

摘要： 突发事件下的土石坝安全一直是人们关注的焦点。分析土石坝突发事件险情特征并开展应急监测研究，可提高土石坝应对突发事件的能力。文章引入突发事件的定义，结合国内外水库大坝溃决原因统计结果及水库大坝突发事件类别，将土石坝突发事件归纳为洪水和地震，并阐述了水库大坝突发事件的分级标准。文章还分析了土石坝洪水突发事件可能造成的漫顶、渗透破坏、边坡失稳、溢洪道破坏以及地震突发事件可能造成的坝体裂缝、渗漏、滑坡、结构变形等险情的特征和危害。基于突发事件险情特征分析结果，探讨了不同级别洪水和地震突发事件下的土石坝应急监测项目和应急监测频次要求，指导土石坝突发事件的应急处置。

关键词: 土石坝, 突发事件, 特征分析, 应急监测