高土石坝地震响应特性振动台模型试验与数值模拟

发布时间：2018-10-12 13:42

【摘要】：通过大型振动台模型试验,研究了不同幅值、不同频率和不同持时的地震动作用下高土石坝的地震响应特性,分析了高土石坝的地震破坏模式和破坏机理,并采用有限差分程序结合模型试验进行了动力数值模拟。研究结果表明:加速度响应沿坝高存在明显的顶部放大效应;坝坡加速度响应相对于同高程坝体内部呈现表层放大效应;当输入地震波的卓越频率与坝体自振频率接近时,坝体加速度响应更为强烈;坝体地震永久变形需要一定的时间累积,地震动持时对永久变形有较大影响。在振动台模型试验中,坝体破坏首先从坝顶部开始,破坏模式主要表现为坝顶部堆石松动、滚落、坍塌,甚至局部浅层滑动,其主要原因是加速度响应在坝顶部和坝坡表层存在放大效应,以及坝顶堆石围压低、抗剪强度低三个因素的叠加作用,因此,坝顶部是高土石坝抗震设计的关键部位,研究结果可为高土石坝的抗震设计提供参考。
[Abstract]:The seismic response characteristics of high earth rockfill dam under different amplitude, frequency and duration of ground motion are studied by model test of large shaking table. The earthquake failure mode and failure mechanism of high earth rockfill dam are analyzed. The dynamic numerical simulation is carried out by using finite difference program and model test. The results show that the acceleration response has obvious top amplification effect along the height of the dam, the acceleration response of the dam slope presents the surface amplification effect relative to the same height dam body, when the excellent frequency of the input seismic wave is close to the natural vibration frequency of the dam body, the acceleration response of the dam slope is similar to the natural vibration frequency of the dam body. The acceleration response of the dam is stronger, and the permanent deformation of the dam needs a certain amount of time accumulation, and the duration of ground motion has a great influence on the permanent deformation. In the shaking table model test, the dam body failure starts from the top of the dam, and the failure mode mainly shows that the top of the dam is loose, rolling, collapsing, and even local shallow sliding. The main reason is that the acceleration response is magnified in the top part of the dam and the surface layer of the dam slope, as well as the superposition of three factors: the surrounding depression of the dam top rockfill and the low shear strength. Therefore, the top of the dam is the key part of the seismic design of the high earth-rock dam. The results can be used as a reference for seismic design of high earth-rock dams.
【作者单位】：中国电建集团成都勘测设计研究院有限公司;中冶华天工程技术有限公司;
【基金】：国家重点基础研究发展计划(973计划)(2013CB036404)资助
【分类号】：P315.9;TV312;TV641

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