Reinforcement Analysis of Toe Blocks and Anchor Cables at the Xiluodu Super-High Arch Dam

摘要

High stress concentrations near an arch dam–foundation interface may cause cracking and failure, particularly in super-high arch dams. Appropriate reinforcement measures are usually needed at the dam toe to increase the shear strength and bearing capacity of the rock mass foundation. In this paper, the criteria and procedure for reinforcement design of dam toe are first given, as priority issues in the overall safety assessment of super-high arch dams. A complete reinforcement analysis method covering the calculation of reinforcement force, effect evaluation and monitoring validation is proposed. With the Xiluodu super-high arch dam as an example, the reinforcement analysis under the numerical simulation and physical model tests performed are described in detail. The results show that the reinforcement measures adopted, such as the toe block and pre-stressed anchor cables, contribute to decrease the local high stresses at the dam toe, as well as increase the cracking initiation factor and the overall safety factor of the dam–foundation system. The reinforcement force loss of anchor cables during the subsequent construction stage has a limited effect on the dam performance. In terms of improving the stability at dam toe, the reinforcement of anchor cables is suggested to be implemented as early as possible. The reinforced dam is finally verified by field monitoring during the operation period. No anomalies in deformation, stress and seepage response near the dam are identified, and the arch dam is shown to perform as desired.