The utilization of solidified shield muck as roadbed filling material holds significant potential, which can effectively mitigate environmental pollution and generate social benefits. To explore the feasibility of using solidified cohesive soil from shield muck as roadbed fill, a finite element model of the solidified soil roadbed was established to analyze its stress-deformation characteristics under long-term traffic loading. The results indicate that traffic loads exert the greatest influence on the roadbed at and beneath the loading points, inducing the highest stress response, which decays in magnitude and rate of change with increasing depth. Under traffic loading, roadbed settlement increases with the number of load cycles, while the settlement rates of different structural layers all exhibit a decreasing trend with repeated cycles. When the internal stress state of the roadbed reaches yield, plastic zones concentrate in the base layer and extend toward deeper roadbed layers and the slope toe as the number of load cycles increases. The stress characteristics and deformation patterns under long-term traffic loads derived from the study can provide preliminary evidence for predicting the long-term stability of solidified shield muck subgrade.