Abstract: The design methods based on reliability analysis can consider variations and uncertainties in input parameters to certain extent, while a partial factor method based on probability limit state provides a simple and effective approach in engineering practice. Based on reliability analysis and verification using a historical empirical model, the principle of the partial factor method and its coefficient calibration are investigated comprehensively in this paper. Results show the partial factors of cohesion γc and friction coefficient γf for dam materials should be 1.20 and 1.10 respectively. We suggest that the structural importance coefficient γ0 of grades I (grade 1 rockfill dams), II (grades 2 and 3 rockfill dams) and III (grades 4 and 5 rockfill dams) structures be 1.10, 1.05 and 1.00 respectively. And for super high dams, the structural coefficient γd be 1.30-1.35. These safety control indexes are verified through comparison with those of 15 rockfill dams built in China, thus helping revise the new design code.

Key words: rockfill dam, slope stability, partial factor, reliability analysis, nonlinear strength parameters