考虑横缝键槽咬合的拱坝地震响应分析

基于非线性指数型动接触本构模型,对实际键槽模型进行简化处理。采用的本构模型可以考虑缝面的开合非线性以及横缝键槽的咬合作用。采用点-面接触模型模拟横缝的非线性动接触行为,精细研究了缝面开度、径向位移的变化及其对坝体应力状态的影响,并与平缝结果进行了比较。以一座拟建的混凝土重力拱坝,探讨了横缝及其诱导缝对大坝工作性态的影响,并对横缝键槽的影响进行了综合分析。研究表明,横缝的径向滑移量要远大于开度,当考虑诱导缝时,由于大坝整体性受到削弱,横缝开度变大;考虑键槽效应后,径向滑移效应大幅减小,而法向开度增大,坝踵处的主拉应力以及拱冠梁顶处的拱向拉应力的最大值均变大。

Seismic Response Analysis of Arch Dam with Key Slots Occlusion

The exponential nonlinear dynamic contact models,combined with point-to-surface contact models,are adopted for analyzing dynamic response of arch dam with key slots.Due to the complexity of the real structure of key slots,it needs to be simplified for the purpose of the research.Compared with the resuits of the flat joint models,the detailed studies of the key slot models concerns about the change law of the normal joint opening,the radial sliding and its effect on the dam stress states are carried out.A planning concrete arch dam as an instance is presented in the paper to discuss the effect of the contraction joint and induced joint on the work behavior of the dam.Additionally,the comprehensive analysis on the effect of key slot is also provided.The results show the radial slid of the arch dam with flat joints comparing to the normal opening is dominating,and the opening of contraction joints will increase with the induced joint which may weaken the stiffness and the integrity of the dam,but the induced joint have a less effect on the dam stress.Comparing with the flat joint models,the radial sliding of the key slot models will greatly decrease while the normal opening will increase;the maximum principal tension stress of the dam heel and the maximum arch stress of the crown cantilever crest will also increase.