Refined failure analysis and functional evaluation of cutoff walls of rockfill dams on deep overburden
The concrete cutoff wall is the key anti-seepage structure for the foundation of rockfill dams on the over-burden.Due to the significant difference in stiffness and scale between the cutoff wall and the overburden,conven-tional numerical analysis methods struggle to ensure accuracy.Moreover,current strength-based safety evaluation methods cannot adapt to the functional evaluation requirements of the cutoff wall as an impermeable structure rather than a load-bearing structure.In this paper,a refined analysis method is proposed to describe the evaluation of an-ti-seepage performance targets after compression damage and tensile cracking and breakage by coupling the propor-tional boundary element-finite element cross-scale discretization,the plastic damage model,and the cohesion model separately,and to realize the evaluation of the performance evolution of the cutoff wall of the rockfill dams on the deep overburden.The results indicate that the hanging-type cutoff walls on the ultra-deep overburden undergo pressure damage at the bottom on both sides due to high compressive stresses approximately perpendicular to the bank slope.The in-plane bending deformation,resembling an"outstretched beam",induces high tensile stresses in the top and bottom regions near the banks of the cutoff wall,resulting in vertical cracks between adjacent sec-tions.The auxiliary cutoff walls on the upstream side is an effective measure in reducing the seepage flow after dam-age to the cutoff wall.The proposed method reveals the damage and cracking patterns of concrete cutoff walls,lo-cates weak areas of the cutoff wall,evaluates the effect of damage-induced cracking on anti-seepage performance,and quantifies the effectiveness of measures.This method bridges the gap from the traditional load-bearing capacity evaluation to the functional performance evaluation of cutoff walls,providing theoretical and technical support for the safety evaluation and design optimization of cutoff walls of rockfill dams on deep overburden.
deep overburdencutoff wallfailure analysisanti-seepage functionfunctional evaluation
万方数据
维普
