含缝拱坝强震失效破坏振动台试验研究

Shaking table test on dynamic failure mechanism of arch dam with jnints

为探究强震时含缝拱坝结构的承载能力及失效路径,在振动台上开展了一系列拱坝模型强震失效破坏试验。基于弹性力-重力准则设计试验,分别进行了不分缝、只有横缝、诱导缝与横缝联合作用这三种情况的振动台模型试验,试验中考虑了材料率相关性的影响,忽略了库水-拱坝相互作用。结果表明,强震作用时由于设缝处的抗拉能力较低,导致缝位置首先发生开裂,拱向应力的传导路径遭到破坏,此后结构破坏以悬臂梁形式为主;科学合理设置缝的形式和位置,可以有效耗散地震能量,提高拱坝极限承载能力。本文研究结果可为高拱坝的抗震分缝设计和超载能力评估提供试验依据。

In order to investigate the overload capacity and failure mode of arch dam with joints during a strong earthquake,a series of failure tests for arch dam model are carried out on a shaking table.Based on the elasticity-gravity similarity law,shaking table tests are performed for three cases,including no joints,only contraction joints,and combination of induced and contraction joints.In these experiments,the influence of material rate correlation is considered,and the dam-foundation interaction is ignored.The results show that during strong earthquakes,cracks occur earlier in the joint positions due to the lower tensile capacity,and the arch-stress transmission path is damaged.After that,the structural damage occurs mainly in the form of cantilever beams.The scientific and reasonable setting of joints can effectively dissipate seismic energy and improve the overload capability of arch dams.The results reported in this work can provide experimental basis for the seismic design of joints and assessment of overload capacity for high arch dams.