Study on the Influence of Rainfall Patterns on the Stability of Reinforced Soil Gabion Retaining Walls

Rainfall is recognised as one of the major external factors affecting the stability of retaining walls. The magnitude of rainfall directly influences the overall stability of retaining walls, while rainfall patterns alter the infiltration process and the saturation state of the soil, thereby affecting soil shear strength and retaining wall stability. In order to investigate the effects of rainfall pattern and intensity on the stability of reinforced soil gabion retaining walls, numerical simulations were carried out to examine wall stability under two typical rainfall patterns (uniform and intermittent) and three rainfall intensities (20 mm/d, 50 mm/d, and 80 mm/d). The results indicate that: (1) under uniform rainfall conditions, the extent of the soil pore water pressure response zone is greater than that under intermittent rainfall of the same intensity, and as the uniform rainfall intensity increases from 20 mm/d to 80 mm/d, the pore water pressure response zone expands by approximately four times; (2) the rainfall pattern exerts a certain influence on the distribution characteristics of the time-history curves of lateral displacement of the retaining wall, with the horizontal displacement under intermittent rainfall exhibiting a non-uniform growth pattern associated with the rainfall pattern; (3) uniform heavy rainfall has a more pronounced effect on the horizontal displacement of reinforced soil gabion retaining walls, with the maximum absolute horizontal displacement reaching approximately 12.89 mm; and (4) rainfall pattern affects the evolution of the slope stability coefficient, which gradually decreases and eventually stabilises under uniform rainfall, whereas under intermittent rainfall it shows a continuous decreasing trend characterised by alternating rates of reduction, with a greater reduction observed under uniform rainfall conditions. These findings elucidate the influence of different rainfall patterns and intensities on the displacement behaviour and stability of reinforced soil gabion retaining walls, and provide a reference for risk assessment of reinforced soil gabion retaining walls.