Dam foundation deformation should be paid more attention in studying foundation failure process. Key node plays an important role in dam foundation deformation analysis. In a 2D-finite element analysis of deep anti-sliding stability of dam section #12 foundation of the Xiangjiaba Project

the problem of key node selection is investigated and a key node selection method is proposed. According to the key node deformation and the distribution of the plastic zone in the foundation

the safety degree of deep anti-sliding stability of foundation of dam section #12 is evaluated on different levels based on the importance of key part which key node belongs to. The safety factor and its lower limit based on the concept of strength reserve of foundation of dam section #12 are given.