A simplified method for calculating the reliability of rockfill dams slope stability using nonlinear parameters

Slope Reliability analyses are widely used in geotechnical engineering. A reliability analysis of the slope stability of rockfill dams is based on the strength of the granular materials used. However, the characteristics of the shear strengths of granular materials are non-linear, so that calculating the reliability index requires significantly more iterations and partial derivatives. To optimise this iterative method, an algorithm is proposed to linearise Duncan’s non-linear strength parameters. This study expands Duncan’s non-linear model using a Taylor series, and derives a relation between the strength parameters used for Duncan’s non-linear criterion and those for the Mohr–Coulomb linear criterion. In the present study, the accuracy of the linearisation algorithm was verified for a simplified slope and the proposed linearisation algorithm is coded into a computer program, STAB. The linearisation algorithm was applied to a reliability analysis of the slope stability of the rockfill used for Shuang Jiang Kou Dam in China. Results indicate that the linearized parameters yield similar reliability indices to the nonlinear parameters, demonstrating the feasibility of the approach for reliability analysis of rockfill dams.