覆盖层厚度对面板堆石坝的动力反应的影响分析

Analysis of the influence of overburden layer thickness on dynamic response of concrete face rockfill dam

文章参考西部某拟建高面板堆石坝,利用FLAC3D软件进行完全非线性动力弹塑性分析,模拟出高面板堆石坝在地震作用下的动力反应。在整个分析过程中,针对不同覆盖层厚度的面板堆石坝,从场地的加速度放大倍数、坝体的永久位移和面板的应力分布3个方面展开分析。结果表明:可以观察到存在一个覆盖层厚度值使得场地的加速度放大倍数呈现一个极大值,将该厚度称为“临界厚度”;通过对坝体的永久位移较为严重的下游面进行变形分析,得出其永久位移所对应的“临界厚度”与场地加速度放大倍数所对应的“临界厚度”相一致;在面板的应力分析中,由于防渗墙材质的影响,面板应力极值点所对应的“临界厚度”相比于前两者有所减小。研究结果可以对在深厚覆盖层上建设的面板堆石坝提供一定的设计依据。

Referring to a proposed high-walled rockfill dam in the western China,this paper uses FLAC3D software to perform complete nonlinear dynamic elasto-plastic analysis,and simulates the dynamic response of high concrete face rockfill dam under earthquake action.Throughout the analysis process,the concrete face rockfill dams with different overburden layer thicknesses were analyzed from three aspects:the site acceleration magnification,permanent displacement of the dam,and stress distribution of the panel.The results show that there is an overburden layer thickness value that maximizes the site acceleration magnification,and this thickness is called the“critical thickness”;by analyzing the deformation of the downstream surface,it is concluded that the“critical thickness”corresponding to the permanent displacement is consistent with the“critical thickness”corresponding to the site acceleration magnification;due to the influence of the material of the anti-seepage wall,the“critical thickness”corresponding to the panel stress extreme points is reduced in the stress analysis of the panel.The conclusions may provide a reference for the design of concrete face rockfill dam on deep overburden layer.