To address the slope instability problem caused by the crushing of the soil arch in the framed slope and the failure of the anchorage under freeze-thaw cycles, calculation models for the interfaces between the frame beams and the soil arch, as well as between the grouted anchorage segments and the surrounding stratum, were established based on the Mohr–Coulomb theory and the shear displacement method, incorporating the effects of both free and constrained frost heave in the soil. By analyzing the evolutionary processes during the thawing construction period, frost heave period, and secondary thawing period, the frost heave period was identified as the most critical condition for designing the dimensions of frame anchors. The reliability of the theoretical approach was verified through field monitoring and numerical simulation. Case study results show that as the frost heave force increases, the geometric width of the frame beams increases significantly. With increasing frost heave force on the slope surface, the internal force of the anchors rises notably, and the anchorage length extends considerably. Compared with the thawing construction period, the elastic, elastoplastic and residual stages of anchorage all increase in length, with the elastic stage showing the most pronounced growth.