深厚覆盖层高面板堆石坝长周期地震动动力响应

Long-period Seismic Dynamic Response of High Face Rockfill Dam with Deep Overburden

我国西南地区蕴藏着大量的水能资源,是当前和今后水电建设的重点区域,但大多存在深厚覆盖层、高地震烈度问题,其对高面板堆石坝正常运行的影响不可忽视。在100 m深厚覆盖层上,创建了100、200、300 m级高面板堆石坝的二维有限元模型,在长周期地震动和常规地震动作用下,采用弹塑性本构模型,研究同一深厚覆盖层上不同高度面板堆石坝的动力响应特征。结果表明,与常规地震动相比,长周期地震动对深厚覆盖层高面板堆石坝的加速度有很大影响,随着坝体高度的增加,坝体动力反应峰值加速度逐渐呈下降趋势,且在长周期地震动作用下,坝体越高,短时间内坝体的位移越大,造成的变形也越大,不利于大坝的抗震稳定。因此,在深厚覆盖层长周期地震频发地区修建面板堆石坝时,需将长周期地震动影响作为抗震稳定评价的一个关键环节。

With many hydropower resources,Southwest China is a crucial area for current and future hydropower construction.However,most southwestern regions have deep overburden problems and high seismic intensity.The impact of these problems on the regular operation of high-face rockfill dams cannot be ignored.This paper established two-dimensional finite element models of 100 m,200 m,and 300 m high-face rockfill dams on 100 m-deep overburden.Under the action of long-period ground motion and conventional ground motion,the elastic-plastic constitutive model was used to study the dynamic response characteristics of face rockfill dams with different heights on the same deep overburden.Compared with conventional ground motions,the results show that long-period ground motions significantly influence the acceleration of deep overburdened high-face rockfill dams.As the height of the dam body increases,the peak acceleration of the dynamic response of the dam body gradually decreases.Moreover,under the action of long-period ground motion,the higher the dam body is,the greater the displacement increment of the dam body in a short time.In this way,the resulting deformation is also more significant,which is not conducive to the seismic stability of the dam.Therefore,when building panel rockfill dams in areas with deep overburden and frequent long-period earthquakes,the effect of long-period ground shaking should be considered as a part of seismic stability evaluation.