摘要
防渗墙作为土石坝的重要隐蔽工程,其施工质量直接影响防渗墙的功效,关乎大坝运行安全。结合工程案例,采用有限元法分析了防渗墙不同施工缺陷对大坝渗流稳定的影响,如防渗墙存在初始裂缝、材料渗透系数不足和墙体悬挂深度不够等。分析结果表明:当防渗墙潜在裂缝位于坝体土层或强风化层时,结构可能发生局部渗透破坏或整体坝坡失稳;当防渗墙渗透系数与坝体土层的防渗系数相近时,大坝抗滑安全系数小于允许值,坝体浸润线偏高将影响结构整体稳定;当防渗墙悬挂深度仅到强风化层时,坝底渗流路径缩短,渗流量增大导致大坝抗滑安全系数偏小,不满足结构整体稳定要求。因此,在实际工程中,应严控施工工艺,防止防渗墙出现质量缺陷,从而保障大坝安全运行。
As an important hidden engineering work,the construction quality of cutoff wall directly impacts on its effectiveness,and further impacts the dam safety.Taking a rock-fill dam in Jinagxi province as an example,we adopted finite element method to analyze the influence of construction defects of cutoff wall on seepage stability,such as initial cracks of the cutoff wall,insufficient permeability of the materials and depth of the wall,etc.The results show:if the outside of cutoff wall cracks is soil layer or highly weathered layer,partial seepage failure or the entire failure of the dam slope could occur;when the cutoff wall and the dam share similar coefficient of permeability,anti-sliding safety factor of the dam is smaller than the accepted value,higher phreatic line in dam could impact the stability of the entire dam;when depth of cutoff wall only reaches the level of highly weathered rock,seepage path under the dam bottom will be shortened,seepage will increase,leading to lower safety factor of anti-sliding and failing to meet the safety requirement of the entire structure.In practice,in order to avoid construction defects of cutoff wall and ensure the dam stability,construction quality control should be prioritized.
作者
周清勇
刘智
洪文浩
熊磊
ZHOU Qingyong;LIU Zhi;HONG Wenhao;XIONG Lei(Jiangxi Provincial Institute of Water Sciences,Nanchang 330029,China;Jiangxi Research Centre of Hydraulic Structure Safety Technology,Nanchang 330029,China)
出处
《水利水电快报》
2020年第5期28-32,37,共6页
Express Water Resources & Hydropower Information
基金
江西省水利厅科技项目(201921YBKT16)。
关键词
防渗墙缺陷
有限元法
初始裂缝
渗透系数
墙体悬挂深度
渗流稳定
土石坝
construction defects of cutoff wall
finite element method
initial cracks
permeability coefficient
cutoff wall depth
seepage stability
earth dam
