不同激振方向下动水压力对高面板坝面板动应力的影响

Effects of hydrodynamic pressure on dynamic stress of slab of high concrete faced rock fill dam under excitation of different directions

目前关于面板坝与库水动力相互作用的研究较少,而且现有的研究没有考虑库底与岸坡振动所激起的动水压力,即不能精确计算动水压力对高面板坝的影响,难以满足300 m级面板坝的安全评价要求。本文采用比例边界有限元方法计算动水压力,对坝高为300 m的面板坝进行了地震作用下三维有限元动力分析,研究了不同方向地震激励下坝面动水压力的分布规律及其对面板动应力的影响。结果表明:顺河向和坝轴向激励的动水压力最大值相差不大,而竖向激振的动水压力最大值相对较大。顺河向地震作用产生的动水压力对面板动应力有明显影响,而坝轴向地震作用下,动水压力对面板动应力有一定影响;竖向地震作用引起的动水压力对面板的动应力影响较大,不考虑动水压力时会明显低估面板的顺坡向应力最大值及高应力区范围。

There is little study on dynamic interaction of concrete face rockfill dam（CFRD） and reservoir.Existing research generally didn＇t account for the hydrodynamic pressure component which is caused by vi-bration of river valley. That means it is impossible to exactly calculate dynamic water pressure on faceslab, which go against the reasonable safety evaluation of 300m-level CFRD. In this paper, the 3D finiteelement dynamic analysis of a 300 m high CFRD is adopted to investigate the distribution rule of dynamicwater pressure and how much hydrodynamic pressure effects the stress of face slab under excitation of differ-ent directions considering hydrodynamic pressure by scaled boundary finite element method（SBFEM）. Theresearch results show that the maximum of hydrodynamic pressure caused by longitudinal and axial earth-quake has little difference, while it is relatively larger for vertical excitation. On dynamic stress of faceslab, hydrodynamic pressure has obvious influence under longitudinal earthquake, some effect under axialseismic load and a big impact under vertical vibration when neglecting dynamic water pressure can substan-tially undervalue the maximum and high amplitude region of stress along slope direction of face slabs.