Investigation of the Failure Mechanisms of an Earthflow in Xiangda Village, Nangqian County, Qinghai Province, China

Exploring the failure mechanisms of slopes in seasonal frozen regions of the Qinghai‐Tibet Plateau (QTP), particularly under the influence of freeze–thaw (F–T) cycles and continuous rainfall, is highly significant for minimizing the risk of slope failure hazards and protecting engineering facilities. In 2020, an earthflow occurred in Xiangda village, Nangqian County, Qinghai Province, China, causing disruption and damage to pastures. This study aims to improve our understanding of the underlying mechanisms behind the Xiangda earthflow. Using field investigation, data analysis, and numerical simulation methods, the results reveal that water migrates from the unfrozen to the frozen zones, forming pore ice and ice lenses, which cause frost heaving during the freezing period. The interfaces of these ice lenses may serve as weak rupture surfaces, thereby contributing to slope failure during the thawing period. Meanwhile, the infiltration of rainfall raises pore water pressure, volumetric weight, and reduces shear strength during the rainy season, all of which are collectively responsible for slope failure in the seasonal frozen regions of the QTP. The findings of this study provide a comprehensive insight into how the F–T cycles and continuous precipitation affect the mechanisms of slope failure in the QTP.