重力坝坝身管道布置形式对其抗震性能的影响

为研究重力坝坝身管道布置形式对管道抗震性能的影响,对浅埋式背管、联合承载坝内埋管和设垫层坝内埋管3种布置形式分别建立了管道与大坝整体三维有限元模型,采用时程分析法进行地震响应分析。研究表明:3种布置下钢管的动应力均较小,管道布置形式对其影响不大;管道混凝土腰部和顶部的动应力均较大,属于结构抗震薄弱环节;当管道部分露于坝体之外时,管道上弯段和斜直段动应力较大,特别是上弯段是抗震最不利之处;将管道全部埋入坝体能有效减小上述管段应力,抗震优势明显,钢管外是否设垫层影响很小。

Influence of penstock layout on seismic behavior of gravity dam

In order to study the influence of penstock layout on seismic behavior of gravity dam, the FEM models of shallow embedded penstock laid on downstream dam face, dam-embedded steel penstock and dam-embedded steel penstock with cush-ion layer were built. Time-history method was adopted to calculate the dynamic response of penstock and dam structure under earthquake. The study indicates that the dynamic stresses of penstock under all layouts are small, which were hardly influenced by the layout;the concrete stresses at the top and waist points are usually higher for each layout, so these areas are the seismic vulnerable locations of the structure;when the shallow embedded penstock laid on downstream dam face is adopted, the dynamic stresses are relatively large on the upper curved and the inclined straight segments, and especially the upper curved segment is the weakest area of earthquake resisting;the layout of fully dam-embedded one can reduce the dynamic stress efficiently and has more advantages in earthquake resisting; however the steel penstock, whether with cushion layer or not, has no influence on earthquake resisting performance.