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坝基渗流主要受帷幕结构和防渗性能的影响,当其性态发生改变时可引起渗流场、化学场等的变化,并通过渗流量、扬压力以及溶液化学组分等反映出来。为定量研究幕后此类环境变量与帷幕性态改变之间的联系,建立了坝基渗流—溶解耦合模型反映幕后渗流场和化学场的空间分布,并通过局部和全局敏感性分析方法研究了坝基渗流量、幕后扬压力以及Ca2+浓度等环境变量受帷幕性态变化的影响。结果表明,各环境变量主要受帷幕防渗性能的影响,且该影响呈非线性,此特性也造成局部和全局敏感性分析结果略有不同。从性态参数间相互作用来看,无论对渗流场还是化学场,帷幕防渗性能与其他参数间相互作用较大,而帷幕宽度和深度与其他参数的相互作用较小。研究成果可为大坝防渗提供指导。
The seepage of dam foundation is mainly affected by curtain structure and seepage prevention performance. When its behavior changes, the seepage field, chemical field and so on will change, and it will be reflected by seepage flow, uplift pressure and solution chemical composition. In order to quantitatively study the relationship between such environmental variables and the change of curtain properties, a seepage-dissolution coupling model of the dam foundation is established to reflect the spatial distribution of seepage field and chemical field behind the curtain. The local and global sensitivity analysis methods are used to study the dam foundation seepage Environmental variables such as flow rate, back pressure and Ca2 + concentration were affected by the change of curtain behavior. The results show that the environmental variables are mainly affected by the impermeability of the curtain, and the effect is non-linear. This characteristic also causes the result of the local and global sensitivity analysis to be slightly different. From the interaction between the morphological parameters, the interaction between curtain impermeability and other parameters is larger, while the interaction between curtain width and depth and other parameters is smaller, no matter the seepage field or chemical field. The research results can provide guidance for dam seepage prevention.