Deformation characteristics and failure mode of the Zhujiadian landslide in the Three Gorges Reservoir, China

Water impoundment of the Three Gorges Reservoir has induced more than 5,000 landslides or potential landslides. These are huge threats to the safety of the dam and the people living in the reservoir area. The deformation characteristics and failure mode of the landslides are important factors in landslide stability evaluation and reinforcement design. The work reported in this paper used the Zhujiadian landslide as an example to study the deformation characteristics and failure mode of the landslides in the Three Gorges Reservoir region. Field investigations were conducted to analyze the structure of the landslide. Then the deformations of the landslide were observed using an integrated monitoring system, including extensometer monitoring for crack development, GPS monitoring for surface displacement, and inclinometer monitoring for internal displacement. The results obtained suggest that the Zhujiadian landslide is a multi-rotational landslide containing three main rotational sub-landslides at present. The deformation and failure of this landslide have developed from front to back. The failure of the front part opens up space for the back part to slide forward into. The coupled actions of the reservoir water and rainfall have led to the failure of the Zhujiadian landslide. Finally, a risk evaluation of the water surge potentially generated by the landslide was conducted by calculating the maximum wave height at the opposite side of the river. The findings of this paper provide some useful information for the stability evaluation and reinforcement design of landslides in similar geological settings in the Three Gorges Reservoir area and in other parts of the world.