Deformation characteristics and failure mechanism of the Moli landslide in Guoye Town, Zhouqu County

On February 26, 2021, the ancient Moli landslide in Guoye town, Zhouqu County, Gansu Province, China, was reactivated. The volume of the reactivated landslide was approximately 2120 x 10(4) m(3), which was classified as a remote accumulation layer landslide in a deep superlarge fault fracture zone. No casualties occurred due to timely warnings. The deformation characteristics and failure mechanisms of the landslide were systematically studied by means of field investigations and engineering mapping, field exploration, deep displacement monitoring, and high-density electrical methods. We found that the geological structure and landform of Zhouqu County are extremely complex. The sliding mass of this landslide was mainly gravelly soil with poor soil mechanical properties. The gravelly clay and phyllite clastic layers were prone to sliding. The landslide as a whole presented the comprehensive characteristics of front edge erosion traction and rear load displacement and was associated with multiple secondary landslides. The Heisongping-Sanjiaoping fault zone of the Bailong River passes through the rear edge of the landslide, and a variety of inducing factors worked together to make the landslide failure mechanism particularly complex. The monitoring and comprehensive control of this kind of landslide should be strengthened.

Automated summary

On February 26, 2021, the ancient Moli landslide in Guoye town, Zhouqu County, Gansu Province, China, was reactivated. The reactivated landslide had a volume of approximately 2120 x 10(4) m(3) and was classified as a remote accumulation layer landslide in a deep superlarge fault fracture zone. Through systematic field investigations and engineering mapping, the deformation characteristics and failure mechanisms of the landslide were studied. The complex geological structure and landform of Zhouqu County, along with multiple secondary landslides, contributed to the particularly complex failure mechanism of the landslide. Strengthened monitoring and comprehensive control measures are needed for this type of landslide.