safety standard for slopes of ultra-high earth and rock-fill dams in china based on reliability analysis

A specific standard for stability analysis of earth and rock-fill dams with a height of more than 200 m is lacking in china. thus, the safety standard for slopes of these dams is explored on the basis of reliability analysis. the dams with a height over 200 m are divided into special classes 1 and 2 depending on the risk levels and acceptable risk standards. the concept of reliability theory-based relative ratio of safety margin is utilized to establish the relationship between annual failure probability and safety factor, thereby obtaining the reasonable safety factors for different dams. the reliability indexes and safety factors of dams under various heights and slope ratios are calculated. results show that the values of safety factors for special classes 1 and 2 are 1.70 and 1.60 under normal conditions and 1.40 and 1.35 under seismic conditions. the validity of the proposed values of safety factors are verified by carrying out stability analysis for several practical projects in china. these results can provide a reference for exploring the safety standards of dams with a height of more than 200 m.