深厚覆盖层上面板堆石坝渗流敏感性分析

An Analysis of the Seepage Sensitivity Face of the Rockfill Dam with Deep Overburden

为研究防渗帷幕尺寸参数及坝基参数对大坝渗流的影响,以合理优化防渗系统的经济成本。以新疆某深厚覆盖层上面板堆石坝为例,通过自编程准三维渗流分析程序建立渗流模型;使用递进判别的敏感性分析方法,对防渗帷幕深度H、防渗帷幕厚度D、防渗帷幕渗透系数K_(a)、地基渗透系数K_(b)以及过渡区渗透系数K_(c)进行敏感性分析,确定各参数间的敏感性排序。实例分析表明,对单宽渗流量更敏感的参数为H、K_(a)、K_(b),对防渗帷幕渗透坡降更敏感的参数为H、K_(c)。定量给出参数敏感性的显著性水平,提高敏感性分析的准确性和可靠性,可为深厚覆盖层上面板堆石坝渗流分析提供依据。

In order to optimize the economic cost of anti-seepage system,this paper studies the influence of anti-seepage curtain size parameters and dam foundation parameters on dam seepage.By taking a deep overburden rockfill dam in Xinjiang as an example,the seepage model is established by self-programmed quasi-three-dimensional seepage analysis program.By using the sensitivity analysis method of progressive discrimination,a sensitivity analysis is carried out on the depth H of impervious curtain,thickness D of impervious curtain,permeability coefficient K_(a) of impervious curtain,permeability coefficient K_(b) of foundation and permeability coefficient K_(c) of transition zone,and the sensitivity order of each parameter is determined.Example analysis shows that H,K_(a),K_(b) are more sensitive to the seepage flow rate of single width,and H,K_(c) are more sensitive to the seepage gradient of anti-seepage curtain.The significance level of parameter sensitivity is given quantitatively to improve the accuracy and reliability of sensitivity analysis,which can serve as a basis for a seepage analysis of the face rockfill dam on deep overburden.