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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。
In order to predict the dynamic response and damage of arch dam under near-surface underwater explosion, based on the finite element program Abaqus / Explicit, the acoustic media is used to describe the reservoir water and the arch dam-foundation-reservoir system finite element model (Intact and failure) and tension and compression damage of concrete. Assuming that the horizontal distance of 50kg equivalent TNT explosive blasting from the water level of the dam is 10m, a thin arch dam with a height of 133m is treated for 1s Explicit dynamic time history analysis. The calculation results show that the peak value of radial acceleration near dam is more than 1 times larger than that of other dam, the peak displacement of No.3 dam in upstream direction is 28% larger than the condition of key well, and the keyway is working normally Which will affect the transmission of dynamic response between the dam sections of the dam, resulting in the difference of the damage development of the dam body. The damage scope of the dam body is relatively concentrated. After 0.3s, the damage development basically completes and the dam surface does not have macroscopic macroscopic fracture failure. In the event of failure, the concrete on both sides of the bottom of No.3 dam may be damaged. It is considered that cross-seam reinforcement should be arranged on the transverse joint of the arch dam as a safety reserve for keyway failure.