Abstract:The unstable rock body with syncline structure on the right abutment of Danjiang arch dam are analyzed under the thrust from arch dam. Firstly the seepage through the foundation and abutment as well as the thrust from arch dam are calculated by finite element method. Then the three-dimensional limit equilibrium method is used to calculate the anti-sliding safety factors under different working conditions. Finally,the number of reinforcing cables needed to meet the specification requirement of anti-sliding safety factor is evaluated;and the influence of dip direction of cables on safety factor is analyzed too. The results provide theoretical basis for the anti-sliding design of the syncline rock structure.