水下爆炸冲击荷载作用下重力拱坝及坝后式厂房的破坏效应

当坝身设有孔口且存在坝后式厂房时，水下爆炸冲击荷载作用下大坝的动力响应非常复杂。 针对此问题，考虑爆炸作用下混凝土的高应变率效应，采用Ｌａｇｒａｎｇｉａｎ－Ｅｕｌｅｒｉａｎ耦合方法建立水下爆炸 冲击下大坝－厂房－库水－坝基全耦合模型，利用数值模拟技术分析了水下爆炸冲击荷载作用下重力 拱坝及其坝后式厂房的动态破坏过程，得到了重力拱坝及坝后式厂房在水下爆炸冲击荷载作用下的损 伤破坏过程及损伤机理。结果表明:水下爆炸冲击荷载作用下重力拱坝的损伤破坏形式包括爆炸成坑 破坏、气穴冲切破坏、局部拉伸破坏和整体拉伸破坏；随着爆心距的增大，大坝的主要损伤破坏形式逐渐 改变，分别为爆炸成坑破坏、局部拉伸破坏和整体拉伸破坏，当爆心距进一步增大时，坝体破坏逐渐减 小；进水口和溢流表孔的存在削弱了坝体局部强度和拱效应；水下爆炸冲击荷载作用下，坝后式厂房由 于结构的整体响应发生局部拉伸破坏。

Damage Effects of Gravity Arch Dams and Powerhouse at Dam Toe Subjected to Underwater Explosion

Because of the shock load of underwater explosion ,the dynamic responses of dams with intake at dam body and powerhouse at dam toe can be very complicated .Focus on this problem ,with the consideration of the high strain rate effect of concrete by shock load ,this paper adopted a coupled Eulerian-Lagrangian method to develop a fully coupled dam-powerhouse-water-foundation model .Numerical analysis of the dynamic destruction process leads to the knowl-edge about the failure process and damage mechanism of gravity arch dams and powerhouses at dam toe .The results show that for concrete gravity arch dams the primary failure modes include crushing damage ,punching shear failure ,local ten-sile failure ,and whole tensile failure .With the increase of blasting center distance ,the main failure modes turn to the crushing damage ,local tensile failure ,and whole tensile failure .When blasting center distance continues to increase , the dam failure will diminish accordingly ,the local strength and arch effect of dam body being weaken by the impact of the intake and overflow surface bay .For powerhouse at dam toe ,the main failure mode by underwater explosion is local tensile failure due to the overall structure responses .