Seismic failure analysis of a high arch dam-foundation multiple nonlinear coupling system

In this study, a high arch dam-foundation system model with more than ten million degrees of freedom was constructed. The model innovatively incorporates multiple nonlinear couplings of the strength failure of the dam body and stability failure of dam abutment blocks for the first time. A nonlinear dynamic response analysis of the coupling system was performed at different overload coefficients. The maximum damage depth-thickness ratio and sliding area ratio are proposed as performance evaluation indices. The failure mechanism of the model under strong earthquakes was elucidated. The residual displacement of the dam crest relative to the dam bottom in the stream direction is proposed as another performance evaluation index. Sudden changes and rapid growth are suggested as evaluation criteria to assess the ultimate seismic capacity of arch dams based on proposed multi-nonlinear coupled model. The results show that the strength failure of the dam body and stability failure of the dam abutments vary dynamically with the duration and intensity of the earthquake. Earthquake energy can be fully released by only one failure mode at low seismic intensity, whereas it is gradually released by both failure modes as the seismic intensity increases. The overload coefficient corresponding to the ultimate seismic capacity of the dam is concluded to be 2.0.