Analysis of Deformation and Ultimate Bearing Capacity of the Arch Dam of the Dagangshan Hydropower Station

The deformation and ultimate bearing capacity of a high arch dam are the key issues in the impoundment period of hydropower stations. In this paper, the ultimate bearing capacity and failure mode of the arch dam of the Dagangshan Hydropower Station are studied by means of field monitoring, theoretical analysis, and numerical simulation. The cusp catastrophe theory is innovatively applied to the study of the ultimate bearing capacity of an arch dam. The failure process and mode of the arch dam are explored from the macro and micro perspectives. The results show that: (1) the radial displacement of the arch dam reaches the maximum at the dam axis position under different water levels, and the tangential displacement reaches the maximum at the 1/4 position on the left and right sides; (2) the high stress area of the arch dam shifts from the toe to the heel when the water level decreases; and (3) the comprehensive stability safety coefficient of arch dam is 5.375–5.625 based on the comprehensive method, and which is 5–5.375 based on the cusp catastrophe model. The left and right ends of the arch dam crest elevation and the left and right sides of the dam heel are the first to crack under different comprehensive stability safety coefficients. The research results have a guiding significance for the safe operation and protection of hydropower station arch dams.