Abstract: To address the reliability analysis problems of earth slopes system, a framework was developed consisting of three major components: generation of random sample by variance-reduction techniques, minimization of slope safety factors by global optimization algorithms, and determination of system reliability of slope by Monte-Carlo method. A relatively simple method for system reliability analysis of slope stability of high earth and rockfill dams was established within the proposed framework. The sample values for input random variables were produced using the Latin hypercube sampling technique. The minimum safety factors for slip surfaces were gained using the commercial slope stability analysis software STAB. Finally, the system reliability of dam slope was calculated by reliability-index method or Monte-Carlo method. The engineering example demonstrates that variability in shear strength parameters of dam construction materials has significant effect on the location of critical slip surfaces. The system reliability of slope is less than the minimum slope reliability of single slip surface. The proposed approach can be applied to system reliability analysis of actual dam slopes.

Key words: slope stability, reliability, system reliability, earth and rockfill dams