阿尔塔什水利枢纽工程混凝土面板堆石坝抗震工程措施及静、动力有限元计算分析

Seismic engineering measures and static-dynamic finite element analysis on concrete face rockfill dam for Altash Water Control Project

鉴于强震区200 m级超高混凝土面板堆石坝所面临的变形控制难、坝体抗震等级高、砂砾石覆盖层深厚等诸多设计难点,结合阿尔塔什混凝土面板堆石坝坝体结构、坝壳料设计,借鉴已建工程经验提出抗震工程措施。通过建立坝体、覆盖层的三维有限元模型,堆石料静力本构分析采用邓肯张E-B模型,动力本构分析采用等效黏弹性模型,分析了考虑抗震工程措施的坝体抗震能力。结果表明:坝体在竣工期、正常运行期、正常运行+地震三个工况下的变形规律合理。混凝土防渗墙和面板结构中最大拉、压应力均可满足所选混凝土材料的规范要求。坝顶下游坝坡设置浆砌块石护坡后可有效减弱该区域局部动力剪切破坏和浅层滑移。坝顶上、下游边坡布置阻滑钢筋网以及适当提高填筑料的相对紧密度、孔隙率,可以有效提高大坝坝坡的抗震稳定性和坝体抗震能力。研究成果以期为今后300 m级面板堆石坝工程设计上提供借鉴。

In view of the difficulties in the design of the super-high concrete face rockfill dam with the height grade of 200 m in strong earthquake region,such as difficult control of deformation,high seismic grade of dam body,deep gravel overburden,etc.,the relevant seismic engineering measures are put forward through the reference of the experiences from the built projects concerned in combination with the design of the body structure and the shell materials of Altash Concrete Face Rockfill Dam.By means of establishing the 3-D finite element models of both the dam body and the overburden,the seismic capacity of the dam body under the consideration of the relvant seismic engineering measures are analyzed herein through adopting Duncan-Zhang E-B model for the static constitutive analysis of the rockfill materials and the equivalent viscoelastic model for the dynamic constitutive analysis.The result shows that the deformation law of the dam body is reasonable under three working conditions,i.e.completion period,normal operation period,normal operation+earthquake.The maximum tension and compression stresses in both the concrete cutoff wall and the face slab structure can meet the specification requirements of the selected concrete materials.The local dynamic shear failure and shallow slip in the downstream dam slope of the dam crest can be effectively reduced after laying masonry slope protection.The seismic stability of the dam slope and the seismic capacity of the dam body can be effectively enhanced through arranging anti-slip reinforcing bar nets on both the upstream and the downstream slopes of the dam crest as well as properly increasing the relative compactness and porosity of the filling materials.The study result is expected to provide reference for the engineering design of the concrete face rockfill dam with the height grade of 300 m in the days to come.