混凝土坝水下爆炸损毁原型监测和理论验证

Dams are potential targets threaten by hostile forces and terrorists. Dam break caused by underwater explosion would bring serious disasters to the downstream areas and cause enormous economic losses. However, owing to the difficulties in researches on this topic, there are no clear understanding of the blast resistances and protective measures when dams are under attack. This project intends to carry out prototype tests of concrete dam subjected to underwater explosion before demolition of the dam by inner blast. The loading characteristics of shock wave, bubble oscillation and surge by single and multiple explosives as well as their different impacts and damages on structures are investigated and analyzed. Besides, the observation results in field are also used to validate results and similarity laws in centrifuge to increase accuracy and control errors of model tests. Improving the centrifugal techniques for underwater explosion, this project would provide reasonable physical modeling method for evaluation of damages in dams. Further, modules for underwater explosion and dynamic damages constitutive of concrete materials would be incorporated into mature dynamic analysis software, such as LS-DYNA and ABAQUS. After carefully validation by field and laboratory tests results, the developed method would serve as strong evidence for the protection design of concrete dams and evaluation of safe water level at war.

水库大坝是敌对势力和恐怖分子潜在的破坏目标，一旦坝体受水下爆炸作用溃决，将会给下游带来严重的洪水灾害，造成巨大的经济损失。然而限于相关研究工作难以开展，目前对坝体的抗爆性能和战时的防护措施并没有清晰明确的认识。本项目拟结合实体混凝土大坝爆破拆除工程，开展原型水下爆炸试验，研究单个及多个爆源连续水下爆炸作用下的载荷特性，分析冲击波、气泡脉动、水面涌浪等效应对混凝土坝不同的动力作用及毁伤机理。结合坝体的原型监测资料，开展离心模型试验，通过提高量测精度并合理控制误差，对离心模型试验结果及相似率进行验证，完善离心模拟水下爆炸试验技术，为坝体毁伤提供合理的物理模拟方法。本项目还将在LS-DYNA和ABAQUS等动力学分析软件基础上进行二次开发，引入水下爆炸载荷计算和混凝土损伤动力本构等模块，通过现场和模型试验资料对计算结果进行验证，为混凝土坝防护设计及战时安全蓄水位的确定提供理论支撑。

大坝是国家重要的基础设施，其防护是国防安全的重要研究课题。坝体一旦溃决，将造成极为严重的次生灾害，并产生极其恶劣的社会影响。针对目前坝体的毁伤研究主要以数值为拟为主，缺少必要的试验数据。本项目开展实体混凝土大坝原型水下爆炸试验，研究不同当量、爆距、水深条件下的水下爆炸作用。在原型试验的基础上，开展离心模型试验，研究了蓄水位高度对坝体动力响应的影响，并成功使坝体产生毁伤，对原型试验形成了有效的补充，建立了坝体水下爆炸试验数据库。基于现场与模型试验结果，研究不同爆源水下爆炸作用下的载荷特性，分析冲击波、气泡脉动等效应对混凝土坝不同的动力作用及毁伤机理，总结了坝体的毁伤模式。采用原型试验观测的水中冲击波、气泡脉动数据、坝体动力响应对离心机试验的相似性进行验证，证明了超重力场下水下爆炸相似关系的成立。分析了混凝土材料的动态力学特性，建立了动态强度准则及混凝土类材料弹塑性损伤本构模型，开发分析计算和动态仿真模块，形成混凝土坝毁伤计算方法；提出基于冲击因子的水下爆炸毁伤效应评估方法，可以综合反映爆源当量、爆距、爆深、坝体几何尺寸、蓄水位高度、边界条件对坝体水下爆炸动力响应及毁伤程度的影响，可以用于安全蓄水位的确定。