沥青混凝土面板堆石坝防渗面板局部失效渗流特性研究

Study on local failure seepage characteristics of anti-seepage face of asphalt concrete faced rockfill dam

摘要

当沥青混凝土面板堆石坝防渗面板局部出现裂缝时，会对大坝的安全产生巨大的影响。为了掌握沥青混凝土面板防渗局部失效时对坝体渗流的影响，以甘肃某抽蓄电站上水库沥青混凝土面板堆石坝为例，建立三维有限元模型，计算面板局部失效时坝体的渗流场，分析面板不同部位局部出现裂缝及不同裂缝大小对渗流场的影响。计算结果表明，沥青混凝土面板局部失效裂缝对面板坝渗流场的影响主要集中于裂缝附近，随着缝宽的不断增大，通过坝基岩体的流量也依次变大，面板的渗透坡降变小，坝基岩体的渗透坡降基本不变。在面板裂缝周围垫层内部较小区域形成饱和区，面板防渗局部失效对渗流场的影响范围均不超过垫层区，裂缝下部垫层饱和区范围和入渗流量较大，故保证垫层料的级配和抗渗性能是极为重要的。同时发现沥青混凝土面板防渗局部失效对渗流场的影响与失效的部位、裂缝宽度等有关，相比于失效缝缝宽，失效部位对渗流的影响更大。结果可为类似工程设计、施工提供参考。

Abstract

When the local cracks appear in the anti-seepage face of asphalt concrete face rockfill dam, it will have a great impact on the safety of the dam. In order to understand the influence of local failure of asphalt concrete panel on the seepage of dam body, the asphalt concrete panel rockfill dam in the upper reservoir of a pumping and storage power station in Gansu province were taken as the example, and establishes a three-dimensional finite element model to calculate the seepage field of the dam body when the panel fails locally, and analyzes the influence of local cracks in different parts of the panel and different crack sizes on the seepage field. The result show that the influence of local failure cracks on the seepage field of the dam is mainly concentrated in the vicinity of the cracks. With the increasing of the crack width, the flow through the dam foundation rock mass increases successively, and the seepage slope of the dam foundation rock mass decreases, and the seepage slope of the dam foundation rock mass is basically unchanged. The saturation zone is formed in the small area inside the cushion around the crack of the panel, and the influence of the local failure of the panel on the seepage field does not exceed the cushion zone. The saturation zone and the infiltration flow under the crack are large, so it is extremely important to ensure the gradation and impermeability of the cushion material. At the same time, it is found that the influence of local failure on the seepage field of asphalt concrete panel is related to the failure location and crack width, and the failure location has greater influence on the seepage field than the failure seam width. The result can provide reference for similar engineering design and construction.

关键词

沥青混凝土面板堆石坝 / 局部失效 / 饱和区 / 渗流 / 三维有限元

Key words

asphalt concrete face rockfill dam / local failure / saturation region / seepage / three-dimensional finite element

Author summay

熊 珅(1996—), 男, 工程师, 硕士, 主要从事水利水电工程设计研究。E-mail: [e-mail]

基金资助

水利部重大科技项目(SKS-2022101)