Abstract: The seismic safety design of an earth-rock dam usually focuses on how to prevent its structure from collapsing, which makes the issue about how to control the structural damage of an earth-rock dam within an acceptable risk level, an important topic worth researching in the field of geotechnical engineering. By applying the theory of seismic risk analysis to practice, this paper witnesses the establishment of a method of seismic risk analysis particularly designed for earth-rock dams. The method explores the seismic risk from three aspects: the seismic hazard analysis, the seismic fragility analysis and the seismic loss assessment. On the basis of the site seismic risk analysis, the ideology of performance-based seismic design is successfully realized in the seismic fragility analysis of an earth-rock dam. The seismic damage level for an earth-rock dam is classified according to the specific condition of the relative settlement of the dam crest which serves as an evaluation index. Finally, with the help of seismic economic losses analysis, a seismic risk model for earth-rock dams is established, which can be used for evaluating the seismic damage risk of an earth-rock dam in terms of technology and economy. This paper also takes a high earth-rock dam for example to analyze and predict its seismic damages and economic losses in an earthquake, using the proposed model. The conclusion of such analysis and prediction can provide a valuable reference for safety evaluations of earth-rock dams and investment decisions, especially when an earth-rock dam is located in an area endangered by possible earthquakes.

Key words: earth-rock dam, deformation, performance-based seismic design, seismic fragility, risk analysis