Abstract: To investigate the yield characteristics of expansive soils under unloaded and loaded swelling conditions, a series of unloaded and loaded swelling rate tests are conducted on intact weakly expansive soils with different initial suctions under measuring suction conditions using a consolidation apparatus for unsaturated soils. The study systematically examines the variation patterns of void ratio and suction during the swelling deformation process and explores the swelling yield characteristics of expansive soils. The results show that: under loaded swelling conditions, the void ratio decreases as suction decreases, which contrasts with the unloaded condition where the void ratio decreases as suction increases. Under one-dimensional compression conditions, a higher initial suction leads to a faster reduction rate in the void ratio of expansive soil. After compression stabilization under a net vertical stress, the void ratio decreases as the suction increases. As the net vertical stress increases, the LC yield curve shifts approximately parallel to the right, while both the one-dimensional compression yield suction and the loaded swelling yield suction decrease. The SD and SI yield curves remain nearly parallel and form an obtuse angle with the s-axis. With an increase in initial suction, the plastic region of void ratio enclosed by the LC and SD yield curves and the s- and p-axes expands, whereas the elastic domain bounded by the LC, SI, and SD yield curves and the s-axis contracts.