Field experimental study on landslides induced by heavy rainfall in Northern Guangdong, China

Abstract Rainfall-induced landslides are widely distributed on vegetated slopes in Northern Guangdong, China. Field experiments were conducted on an exposed slope and a Chinese fir slope to investigate the impact of the root effect on slope stability. The deformation and damage processes, hydrological processes, and stress processes of landslides were compared and analyzed. Furthermore, the landslide formation mechanism was discussed. The results are as follows. For the exposed slope, after rainfall infiltration reached the maximum infiltration depth, seepage formed within the slope. Slope deformation damage began at the foot of the slope and gradually progressed upwards. For the Chinese fir slope, after the maximum infiltration depth had been reached, rain continued to infiltrate in the form of preferential flow along the root-soil gap. The root effect stabilized the slope until infiltration reached the end of the root. Once infiltration reached the end of the root, rain began to accumulate there. The slope initially deformed at the top of the slope, and it was susceptible to overall damage along the end of the root. The influence of roots on slope stability depends on whether rainfall infiltration is out of the main root zone.