Influence of crack characteristics on rainfall infiltration patterns and stability of clay slope

The clay slope containing cracks is subject to coupled influences of rainfall infiltration and crack development, which readily trigger landslides and other geohazards, posing serious threats to life and property. To investigate the effects of varying crack characteristics on the behavior of clay slope, this study combines laboratory unsaturated soil tests, hydraulic property measurements, physical model experiments, and numerical simulations to examine how crack location, crack depth, and crack inclination angle influence rainfall infiltration patterns and slope stability under simulated precipitation. The results show that crack location exerts a more pronounced control on changes in rainfall infiltration than either crack depth or inclination angle, whereas changes in crack depth have a stronger effect on slope stability than other crack properties. When the crack is situated mid-slope, the cumulative rainfall infiltration is maximized, and when it is located at the slope toe, the Factor of Safety (FOS) reaches its minimum. Variations in crack angles produce no significant change in additional infiltration, and the reduction in FOS remains below 1 %. Deeper crack generally led to greater rainfall infiltration, with an approximate trend of a 10% increase in infiltration volume per meter of crack depth. The FOS decreased gradually with increasing depth, and beyond a critical depth the decline became more pronounced. However, beyond a critical crack depth, the decline in FOS accelerates sharply and the potential slip surface extends from the crest to the base of the crack. These findings elucidate the mechanistic influence of distinct crack parameters on infiltration behavior and stability of clay slopes under rainfall, providing theoretical guidance for the design of protective measures in crack clay slope engineering.