A Novel Method for Constructing Main‐Aftershock Sequences and Its Application in the Global Damage Accumulation Effects Analysis of Gravity Dams

Abstract

The traditional linear elastic and Drucker–Prager (DP) models cannot truly reflect the strong nonlinear characteristics of the concrete and rock foundation of the dam under earthquake. Therefore, for comprehensive evaluation of the cumulative damage of the gravity dam structure caused by aftershock, the dynamic damage of the dam body concrete is analyzed by many scholars through the plastic damage mechanics method, but there is little research on rock material at the dam foundation with the method utilized; thus, the simulation of the whole dynamic damage evolution is worthy of investigation of the dam body and dam foundation. According to the randomness of ground motion, the transcendental probability (P) is introduced to express the statistical characteristics of aftershock intensity, and a new method for constructing main-aftershock sequences of ground motion is proposed in this paper. And then, the law of the damage evolution and energy characteristics of the concrete gravity dam under the combined action of the main shock and aftershock sequences is studied. The results are shown as follows: the smaller aftershocks do not cause further damage to the dam; as the aftershock intensity increases, the energy characteristics of the dam body and foundation have shown different changing rules; when the ratio of peak aftershock acceleration to peak main shock acceleration (∇PGA) approximately equals 0.68, the aftershock will cause larger secondary damage to the dam.

Evolution law of overall damage of concrete gravity dam under near-fault ground motion

“…For example, in the seismic analysis of traditional high concrete dams, the foundation rock mass is mostly used as linear elastic materials or DP elastoplastic models are used (Ansari et al 2016;Sadeghi et al 2020;Li et al 2021). But the simulation cannot accurately reflect the nonlinear performance and stress redistribution phenomenon of rock when subjected to external loads that exceed their tensile and compressive strength (Guo et al 2020;Zhang et al 2021). In fact, the damage and failure of the dam foundation rock mass is also an important part of the overall seismic design and analysis in a gravity dam.…”