Triggering mechanism and possible evolution process of the ancient Qingshi landslide in the Three Gorges Reservoir

Abstract

The Qingshi landslide in the Three Gorges Reservoir was selected as a case study of ancient landslides. The detailed on-site surveys and long-term monitoring data were analysed to classify the triggering mechanism and possible evolution process of the Qingshi landslide. The results show that the ancient Qingshi landslide was triggered by the water storage in 2010. The leading edge slipped first, and the trailing edge underwent large-scale deformation after losing the resistance provided by the leading edge. In early 2011, the compaction of the leading edge of the landslide provided a certain resisting force, which controlled the overall downward movement of the landslide. In 2014, the integrity of the landslide was strengthened by emergency treatment measures, which caused the stabilization of the landslide and further reduced the displacement rate of the landslide. The local strengthening of the leading edge may act as a locking segment that could provide direct support to the sections in the middle and upper parts of the landslide. However, abnormal water-level regulation and heavy rainfall may cause the landslide to collapse again. The entire evolution process of the Qingshi landslide can provide an important reference for ancient landslides located on reservoir banks.