Integrated certainty and uncertainty evaluation approach for seepage control effectiveness of a gravity dam

摘要

The seepage problems of dam engineering with complex seepage control measures are usually investigated by numerical simulation methods such as the finite element method (FEM). In general, the material and geometrical parameters and the boundary conditions on dam seepage are regarded as definite values. The heterogeneous and uncertain changes of seepage parameters and boundary conditions, which are caused by seepage control measures and material aging, are not considered. To describe more comprehensively the seepage behavior of a gravity dam and to identify more objectively the seepage control effectiveness of a gravity dam, the conventional FEM implementing numerical analysis for dam seepage is combined with the nonprobabilistic convex set–based method. Firstly, the FEM is introduced to implement the detailed simulation of typical seepage control measures and the certain seepage field analysis. Then a nonprobabilistic convex set–based numerical simulation method, which is suitable for the description of the uncertain seepage field of a gravity dam, is presented. The influence range of seepage control measures can be determined with the proposed method without the probability distribution knowledge of uncertain parameters. Lastly, an actual gravity dam undergoing seepage reinforcement is taken as an example. The seepage control effectiveness of the gravity dam is assessed with the FEM-based calculation model of the seepage field and the analysis model of the uncertain seepage field before and after seepage control implementation. In addition, the effect of the seepage field on the stress field is considered to fulfill the further analysis for the process and mechanism of seepage control of typical measures.