Damage evaluation of gravity dams reinforced by corrugated steel–concrete slab composite structures under underwater near-field explosion

Abstract

Concrete gravity dams reinforced by corrugated steel–concrete composite structures under blast loading conditions lead to different types of damage; however, the damage evolution and damage mode characteristics of a dam body do not adequately reflect the protective effect of a composite structure, and few scholars have evaluated the damage to gravity dams. Therefore, the damage to a concrete gravity dam reinforced by a composite structure is evaluated. An ALE algorithm is used to establish a simulation model for a concrete slab undergoing an air explosion. Then, the effectiveness of this numerical method is verified. The failure mode of a dam structure reinforced by a corrugated steel–concrete slab composite structure is explored, the anti-explosion protection effect of the composite structure is evaluated, and the damage to the gravity dam is predicted and evaluated. The results show that the ALE algorithm can effectively simulate the damage to a concrete slab in an air explosion test. The degree of damage to a concrete gravity dam after adding protection is significantly lower than that of an unprotected dam under different explosion factors. Moreover, the degree of damage increases with increasing explosive equivalent and decreases with increasing explosive detonation distance (detonation depth). Therefore, adding protection and increasing the detonation distance (detonation depth) can effectively improve the anti-explosion effect of a dam. Under different initiation factors, the damage area ratio is low after a protective layer is added. Hence, the added protection scheme can significantly improve the anti-explosion performance of a dam. Nonlinear prediction formulas for the crack depth ratio and damage area ratio of a dam, which characterize the damage characteristics of a dam body, can effectively predict the degree of damage to a gravity dam under different initiation factors and provide a theoretical reference for assessing damage to high-level concrete dam structures.