【摘要】 从模型试验和数值模拟两方面研究拱坝在地震作用下的破坏情况。在振动台上进行了高拱坝的动力模型试验,研究空库情况下整体坝的破坏过程和破坏形态。试验中采用仿真混凝土,模拟部分地基和山体。由设计加速度反应谱生成地震加速度时程,在顺河向逐级加载输入。为与模型试验互相验证,文中模拟相似的条件,对拱坝的原型进行非线性有限元分析。在宏观均质假定的基础上考虑混凝土细观分布的非均匀性,得出的破坏过程和破坏形态与模型试验结果一致。证明了模型试验设计和本文数值模型的有效性。研究表明,顶拱中部附近是拱坝抗震设防的关键部位,地震作用下易发生开裂,极端情况下坝块可能脱落,随后其两侧的混凝土相继脱落导致破坏区域扩大,应对该区域进行深入的抗震分析并采取合理的抗震措施。更多还原

【Abstract】 The failure mode of the Dagangshan arch dam under earthquakes was experimentally studied by a shaking table test and a nonlinear FEM simulation.In the test,simulation concrete was employed to model the dam material,foundation rock and topographic features,and a sequence of streamwise seismic loading of the design acceleration spectrum was generated and gradually added to the dam.Assumption of macroscopic homogeneity is adopted,but mesoscopic inhomogeneity of the concrete material was introduced.The FEM simulation conditions,except for a prototype dam,are the same as the model test.The test results are similar to the FEM analysis,which shows the validity of both methods.It is discovered that under strong earthquakes the region around the cantilever top is vulnerable,and that cracks maybe initiate there,extend further,and even result in the fell-off of concrete blocks.Thus,special seismic measures for this region are suggested.更多还原