Abstract: This study focuses on the common problem of frost heave damage to slope protection structures of earth-rock dams in cold regions. An earth-rock dam project located in a cold climate zone is selected as the research subject. A finite element model is developed considering coupled water, heat, and stress processes based on the project characteristics. The full process of slope protection frost heave damage under the influence of reservoir water level variations and soil water migration within the dam is examined. The temperature field, moisture field, and displacement field variations in the earth-rock dam are analyzed. Finite element calculation displacement field results are compared to measured frost heave deformation data, verifying the calculation results. The findings show the frost heave impact range on the dam slope is approximately 2 meters. The dam slope temperature distribution depends mainly on freezing depth. The shallow dam slope temperature from 0-2 meters varies greatly with external air temperature. The internal temperature within the dam body exhibits smaller variation amplitude than the shallow slope, with some lag. Negative temperatures cause the shallow pore water phase in the dam slope to transform to ice, shown as decreasing unfrozen water content. Soil-rock mixture pore water phase change, fill water migration to the slope, and frozen peak movement towards the dam body are key factors in slope protection frost heave damage. Calculated dam slope frost heave volume is 20-30 cm, maximum 36 cm, consistent with measured deformation. Frost heave damage primarily results from combined effects of frost heave and ice thrust in soil-rock mixtures like sand and gravel cushion and dam fill. The research provides a basis for earth-rock dam slope protection design in cold regions.