【摘要】 为预测近水面水下爆炸作用下拱坝结构的动态响应和损伤,基于有限元程序Abaqus/Explicit,采用声学介质描述库水,并采用拱坝-地基-库水系统有限元模型,考虑键槽作用的两种极端情况(完好和失效)及混凝土的受拉、受压损伤,假设50kg当量TNT炸药爆炸距离大坝迎水面水平距离为10m,对某133m高的薄拱坝进行了持时1s的显式动力时程分析。计算结果表明:靠近爆炸源的坝段径向加速度响应峰值大于其它坝段1倍以上,键槽失效情况下3号坝段向上游方向的位移峰值比键槽完好情况时大28%,键槽是否正常工作会影响大坝各坝段之间的动力响应传递,导致坝体损伤发展的差异;坝体损伤范围比较集中,0.3s后损伤发展基本完成,坝面不会出现大面积的宏观断裂破坏;键槽失效时,3号坝段底部下游两侧混凝土可能破坏,可考虑在拱坝横缝上配置跨缝钢筋作为键槽失效情况的安全储备。更多还原

【Abstract】 Because of invisibility and easy-feasibility of a near-surface underwater explosion,it is signifiant to predict dynamic responses and damage of an arch dam experiencing an underwater explosion shock loading.This can provide references for against-terrorism guard of the dam.An explicit 1-second-long dynamic time-historic analysis is implemented for a 133-m-high thin-arch dam using the Abaqus/Explicit code.The dam-foundation-water interaction is considered,and the water is simulated using acoustic elements.The key grooves’ extreme working behavior(work or fail) is simulated,and the tension-compression damage of concrete is also taken into account.The explosion source is supposed to be 10 meters away from the dam’s upstream face with a 50kg-TNT charge.The results show that the peak value of radial acceleration of the monolith near the explosion source is more than double that of other monoliths.The peak value of upstream displacement of the No.3 monolith increases 28 percent when the key grooves fail.The key grooves’ work performance has an influence on the transfer of dynamic responses between monoliths,which leads to a difference in damage of the dam.The local damage completes its evolution in about 0.3 second.No widespread macro-crack appears on the dam face.The concrete on both sides of the No.3 monolith’s downstream bottom may fail without the key grooves’ sound work.In this case,installation of some cross-joint reinforcing bars may potentially serve as a safety reserve.更多还原