Study on the Influence of Mainshock-aftershock Sequences on the Damage Characteristics of Gravity Dams

In order to further understand the impact of mainshock-aftershock sequences on the damage characteristics of gravity dam, this paper takes a proposed gravity dam as the research object to establish a damage simulation model. 30 artificial mainshock-aftershock sequences are fitted according to the normative response spectrum as ground motion input, and the damage energy consumption is took as the evaluation index to quantitatively analyze the impact of mainshocks and aftershocks on the damage accumulation of the upper part of the dam, the heel of the dam and the whole dam. The research shows that aftershocks increase the damage degree of the upper part of the dam by 15.8%, the damage degree of the dam heel by 6.9%, and the damage degree of the whole dam by 9.3%. Aftershocks are more likely to deepen the damage degree of the upper part of the dam. The dam has obvious secondary failure phenomenon under the action of the mainshock-aftershock, and the damage effect of the mainshock-aftershock on the structure should be emphasized in the seismic design of the dam.