Formation mechanism of the Guanling landslide under the action of heavy rain in Guizhou, China

Throughout history of geology, multistage tectonic action has caused mountain folds and faults, but it is difficult to identify faults on the surface due to weathering and erosion during later periods. Under the action of rainfall, rock mass parts are prone to collapse and slide disasters controlled by fault planes. This study investigates the formation mechanism and dynamic process of the landslide by integrating field geological surveys with discrete element numerical simulations. The results highlight that the buried reverse fault in the landslide’s source area acts as a dominant infiltration zone, which significantly contributes to the instability of the slope. Rainwater seepage into the fault zone weakened the rock mass, resulting in its progressive failure. The investigation reveals that the landslide’s instability process can be divided into four key stages: fault development, rainfall infiltration, sliding surface formation, and eventual collapse. The discrete element simulation further confirmed that the rainwater infiltration along the fault zone reduced the shear resistance of the rock mass, leading to large-scale sliding and compressional fracturing. This sliding-compressional fracturing mechanism is identified as the primary cause of the Guanling landslide. The findings of this study offer new insights into the role of buried faults in landslide formation, especially under extreme weather conditions. The research conclusions contribute to the understanding of landslide behavior in fault-affected mountainous areas and provide a scientific basis for early identification, hazard prevention, and mitigation strategies in similar geologically complex regions.