Damage effects of caisson gravity wharf under underwater explosion
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摘要: 通过开展不同爆距下水下爆炸对沉箱重力式码头模型毁伤效应试验,对水下荷载进行了采集分析,对毁伤因素、毁伤模式和毁伤机理开展了研究,初步讨论了爆距的影响。结果表明:试验中未形成完整的气泡脉动过程,荷载超压主要出现在冲击波传播阶段,爆炸冲击波、水底反射波和侧壁反射波是主要的毁伤因素;水下爆炸对沉箱重力式码头造成的毁伤程度大、模式多、机理复杂,主要毁伤部位为迎爆面外墙、迎爆侧管沟、封仓板和面板;爆距越近码头毁伤越严重;当爆距过近时,爆炸能量被迎爆面结构变形大量吸收,迎爆面毁伤程度大幅增大,码头其他部位毁伤程度增幅放缓。Abstract: Through the experimental study on the damage effect of underwater explosion on caisson gravity wharf model under different explosion distances, data collection and analysis for underwater loads and model damage are conducted, a study on damage factors, damage modes and damage mechanisms is developed, and the impact of explosion distance is initially discussed. The results show that the complete bubble pulsation process is not formed. Load overpressure mainly occurrs during the propagation stage of shock wave; explosive shock wave, reflected bottom wave and reflected sidewall wave are main damage factors; underwater explosions causes the damage with serious damage effectiveness, multiple modes and complex mechanisms to the caisson gravity wharf, and the major damage parts are exterior wall of explsion faces, proximal pipe trenche, cabin-sealing covers and face plate; the closer the explosion distance, the more serious the structural damage; however, when the explosion distance is too close, the explosion energy is mostly absorbed by the structural distortion of the blasting surface, so the growth on the severity of the explsive-side exterior wall’s damage increases significantly and the growth on the severity of other parts’ damage slows down.
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Key words:
- underwater explosion /
- caisson gravity wharf /
- damage effect /
- explosion distance
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表 1 主要部位混凝土厚度及配筋情况
Table 1. Concrete thickness and matching bar condition of main members
位置 混凝土厚度/cm 配筋情况 保护层厚度/cm 仓格外墙 12 双层双向配筋,钢筋直径 1.2 cm,间距 18 cm 2 仓格内隔墙 8 双层双向配筋,钢筋直径 0.8 cm,间距 9 cm 1.5 沉箱底板 25 双层双向配筋,钢筋直径 2 cm,间距 18 cm 4 管沟底板 13 双层双向配筋,钢筋直径 0.6 cm,间距 15 cm 2 管沟外壁 12 双层双向配筋,钢筋直径 0.6 cm,间距 15 cm 1.5 面板 6 管沟上部面板单层双向配筋,其他部位不配筋 1.5 封仓板 6 不配筋 表 2 试验方案
Table 2. Experimental schemes
工况 爆炸类型 模型 药包编号 炸药位置 1 接触爆炸 UW2 c1 贴于迎爆面中间仓格外墙中点,水深 0.9 m 处 2 非接触爆炸 UW1 c2 正对中间仓格外墙中点,爆距 0.5 m,水深 0.9 m 处 3 非接触爆炸 UW3 c3 正对中间仓格外墙中点,爆距 1.0 m,水深 0.9 m 处 表 3 爆炸冲击波荷载验证
Table 3. Verification of explosion shock wave pressure
工况 冲击波峰值压力/MPa 冲击波比冲量/(kPa·s) 测量值 计算值 偏差% 测量值 理论计算值 偏差% 1 13.57 13.08 3.75 1.17 1.94 −39.69 2 13.58 13.27 2.34 1.00 1.96 −48.98 3 14.16 13.88 2.02 1.69 2.03 −16.75 表 4 冲击波荷载比较
Table 4. Compasion of shock wave pressure
工况 峰值压力/MPa 冲击波比冲量/(kPa·s) 爆炸冲击波 水底反射波 侧壁反射波 爆炸冲击波 水底反射波 侧壁反射波 1 13.57 6.05 7.83 1.17 0.16 0.37 2 13.58 5.73 9.58 1.00 0.15 0.36 3 14.16 8.68 6.13 1.69 0.26 0.63 表 5 沉箱码头模型主要毁伤模式
Table 5. Damage modes of caisson gravity wharf.
毁伤部位 毁伤模式 整体 1.整体滑移;2.变形;3.混凝土外表面粗骨料拔出 面板 1.弯曲变形;2.裂缝开展;3.断裂抛出;4.与其他构件交界处拉剪断裂;5.钢筋混凝土粘结破坏 迎爆面外墙 1.爆炸成坑;2.混凝土冲切破裂;3混凝土破碎失效;4.弯曲破坏;5.钢筋网架挠曲;6.裂缝开展;7.钢筋混凝土粘结破坏 侧面外墙 1.混凝土局部破碎;2.裂缝开展 管沟 1.整体倾斜;2.上面板掀飞;3.裂缝开展 封仓板 1.整体和局部弯曲;2.裂缝开展;3.断裂;4.与其他构件交界处拉剪断裂;5.钢筋混凝土粘结破坏 仓格横隔墙 1.裂缝开展;2.受弯变形;3.整体位移 仓格纵隔墙 1.裂缝开展;2.混凝土破碎、剥落;3.钢筋网架鼓曲;4.整体位移 沉箱底板 无明显毁伤出现 -
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