Upper bound limit analysis of slope stability is only applicable for proportional loading. In case of alternate loading and unloading

a shakedown analysis is necessary for its long term safety evaluation. Actually

besides gravity load

groundwater is also an important factor to slope stability. However

groundwater level usually changes with the rainfall or some other environmental factors

which may induce alternate wetting and drying to part of the slope. This is a disadvantage for the slope safety. In this paper

an upper bound shakedown analysis based on strong version of Koiter’s theorem is presented to analyze slope stability under such as an alternate load. Safety factor

which is defined by shear strength reduction of the materials

is adopted by a quantitative analysis to represent the influence of alternate load on slope stability. A simple example is adopted to verify the availability of this method.