水下爆炸冲击荷载下碾压混凝土重力坝毁伤机理及特性研究

Because of the very serious consequences of dam failure, we should pay more attention to the safety and protection issues of high concrete dam under extreme sudden loads. To solve the antiknock safety problems of RCC dam, the split Hopkinson pressure bar (SHPB) test will be conducted to study the dynamic characteristics of concrete materials. The failure criterion of mass RCC structures subjected to impact loading will be studied and improved. At the same time, a method will be proposed to determine the parameters of RCC dynamic damage model in which the high strain rates will be considered.At the same time, our project will use the FEM/SPH coupling method to study the propagation process of explosive blast, dynamic interaction between multi-medium, and the fine modeling and efficient numerical methods of large-scale numerical simulation. Based on this theory, the proposed theories and methods of nonlinear explosive reaction analysis for concrete dam will reveal the failure mechanism and antiknock performance of concrete gravity dam subjected to underwater explosion. Moreover, the methods and antiknock measures to improve the antiknock performance of the concrete dam will be raised. Our research results will provide a theoretical basis and technical support for the antiknock performance assessment and protective design of concrete dam, which is of great theoretical significance and engineering value.

由于失事后果严重，突发极端荷载下的高混凝土坝安全及防护问题值得关注。本项目针对碾压混凝土重力坝抗爆安全问题，通过改进的分离式霍普金森压杆（SHPB）试验分析不同应变率下大坝混凝土强度及变形特性，并研究和改进冲击荷载下大体积碾压混凝土结构的失效破坏准则，建立高应变率下碾压混凝土动态损伤模型参数确定方法。同时采用FEM/SPH耦合方法研究水下爆炸冲击波的传播过程、多介质动力相互作用耦合效应以及大型数值仿真模拟的精细建模与高效数值计算方法。在此理论基础上，建立水下爆炸冲击荷载下大坝非线性爆炸反应分析理论与方法，对大坝抗爆性能开展研究，揭示水下爆炸冲击荷载下碾压混凝土重力坝毁伤机理及特性，研究改进大坝抗爆性能的设计方法和抗爆措施。研究成果可为混凝土坝抗爆性能评估和防护设计提供理论基础和技术支撑，具有重要的基础理论意义和工程价值。

将爆炸荷载作为一种极端荷载，开展大坝在爆炸冲击荷载作用下的动力破坏机理和抗爆性能研究，揭示大坝在爆炸荷载下的毁伤机理及特性，并进行防护措施研究，对提高重大水工结构物的抗爆安全性具有重要意义。本次研究通过室内试验、理论分析及数值仿真相结合的方法，对高应变率下碾压混凝土动态损伤本构模型进行改进；水下爆炸冲击波的传播过程及多介质动力相互耦合作用效应；碾压混凝土重力坝水下爆炸大型数值模拟的精细建模与高效计算方法；水下爆炸冲击荷载作用下碾压混凝土重力坝毁伤破坏机制及抗爆措施等方面进行研究。主要成果包括：(1)通过大直径SHPB试验揭示了碾压混凝土在冲击荷载作用下的毁伤特征及动态尺寸效应，修正了适用于碾压混凝土材料的HJC本构模型；(2)揭示了水下爆炸近边界面的气穴效应，阐明了水下爆炸冲击波传播的边界效应，探讨不同边界面条件下的水下爆炸冲击波传播特性机制；(3)确定了适用于大规模水工建筑物水下爆炸数值模拟的网格尺寸，提出基于FEM/SPH耦合的高效并行计算方法；(4)提出高应变率下结构非线性动态损伤的主动预测方法，建立水下爆炸冲击荷载下的碾压混凝土重力坝全耦合模型与计算体系，研究水下爆炸冲击荷载下混凝土重力坝的破坏效应及泡沫铝夹芯板的防护效果。