Study on the Influence of Water Level on Earth Dam Reinforced by Cut-Off Wall: A Case Study in Wujing Reservoir

The construction of a cut-off wall is a common reinforcement method for earth rock dams. At present, compared with the in-depth study on homogeneous earth dams, more and more attention is being paid to the stability and deformation of earth dams strengthened by a concrete cut-off wall. In this study, aiming at the Wujing project of the earth dam strengthened by cut-off wall, the influence of the water level rise and fall on the stability of the dam slope, the deformation of the dam body, and the crack width on dam crest were analyzed by numerical calculation and in situ measurement. The analysis results show that when the reservoir encounters a sudden drawdown, the safety factor of the dam slope decreases sharply. The faster the sudden drawdown, the faster the safety factor decreases. When the reservoir water level rises, the dam's horizontal displacement shifts to the upstream direction, and the change of horizontal displacement of the downstream slope is significantly larger than that at the measuring point of the upstream slope. The water level of the reservoir rises, and the surface of the dam body rises, and the fluctuation of settlement deformation shows that the upstream side is larger than the downstream side, especially during the period of abrupt change in the reservoir water level. The longitudinal cracks on the dam crest show a tendency of shrinkage when the reservoir water level rises, and opening decreases with the decrease of deformation gradient increment and increases with the increase of gradient increment.

Automated summary

This study analyzes the influence of water level rise and fall on the stability, deformation, and crack width of a dam reinforced by a cut-off wall, using numerical calculation and in situ measurement for the Wujing project. The results show that the safety factor of the dam slope decreases sharply during sudden drawdown, and the faster the drawdown, the faster the decrease in safety factor. The horizontal displacement of the dam shifts upstream when the reservoir water level rises, with a significantly larger change in the downstream slope compared to the upstream slope. The analysis also reveals the fluctuation of settlement deformation and the tendency of shrinkage in longitudinal cracks on the dam crest as the reservoir water level rises.