Abstract: Based on seismic damage survey data from 155 earth-rock dams in typical earthquakes worldwide, we analyzed the earthquake subsidence pattern of earth-rock dams and investigated key influencing factors using grey relational analysis. The results show that the upper envelope of earthquake subsidence rate increases with the increase of peak ground acceleration and earthquake magnitude, and decreases with the increase of epicenter distance. The subsidence rate is higher in the near-field range, and becomes minimal at an epicenter distance of 100–150 km. The maximum upper envelope value of earthquake subsidence rate is observed in filled earth dams, followed by core rockfill dams and face rockfill dams. The earlier the construction time, the higher the upper envelope value of earthquake subsidence rate, which reflects the differences in dam filling quality due to varying construction equipment and methods. The effects of peak acceleration, magnitude, dam type, construction year and epicenter distance on the subsidence rate decrease successively, with no single factor being absolute dominant. The prediction and control of seismic residual deformation of earth-rock dam are discussed according to the earthquake subsidence patterns and the analysis results of key influencing factors, in conjunction with the seismic code of hydraulic engineering. Control standards and design principles for seismic safety deformation of earth-rock dam are provided.

Key words: earth-rock dam, seismic damage investigation, earthquake subsidence of dam, grey relational analysis, aseismic design