港口水下爆炸荷载冲击特性研究

摘要

By numerical simulation,the characteristics of underwater explosion loading in port were investigated. The numerical method was proved by comparing the results with those of the empirical formula and the experiments,then the propagation of shock wave of underwater explosion and the laws of bubble expansion were analyzed.The results show that the loading of bubble expansion in an underwater explosion in port couldn't be ignored.If the loading is scaled by impulse,the loading of bubble expansion is larger than the loading of shock wave in most area.The loading of bubble expansion and shock wave are influenced observably by the water surface,the closer to the water surface,the smaller the impulse of both.But the attenuation of the loading of bubble expansion is faster than that of shock wave,the impulse of bubble expansion even is less than the impulse of shock wave.Water bottom has less influence on the loading of bubble expansion,but has greater influence on the loading of shock wave.The acting time of shock wave would be shortened due to the influence of reflection of water bottom,thereby the impulse of shock wave would reduce rapidly.On the condition of sludge bed in existence,the reflection of shock wave on the interface between sludge bed and water is not remarkable, most of the reflection wave is from the interface between sludge bed and rock.%采用数值仿真方法研究港口水下爆炸荷载的冲击特性，并与经验公式及实验结果比较验证数值模拟方法的正确性；分析水下爆炸冲击波传播过程与气泡膨胀规律。研究表明，港口水下爆炸气泡膨胀荷载不可忽略，由比冲量知，大部分区域气泡膨胀荷载大于冲击波荷载；自由水面对冲击波荷载与气泡膨胀荷载均影响较大，越接近水面二者比冲量越小，气泡膨胀荷载衰减越快，在水面附近其冲量甚至会小于冲击波荷载。水底对气泡膨胀荷载影响不大，而对冲击波荷载影响较大。受水底反射波影响，冲击波作用时间缩短，导致比冲量迅速减小。水底有淤泥层时，冲击波在泥层与水体交界面反射不显著，水底反射冲击波主要来自泥层底部与岩石层分界面。