Deformation characteristics and reactivation mechanism of a large-scale landslide deposit with multi-level slide surfaces

Given the current research gap in understanding the deformation characteristics and geotechnical structure of landslide deposits, the understanding of these aspects of large-scale landslide deposits remains unclear. This study focuses on a particularly large-scale landslide deposit located in Toudu Town, Nanchuan District, Chongqing, China. The deformation characteristics and geotechnical structure of the Tudou Landslide Deposit (TLD) were investigated using geological surveys, drilling engineering, and data monitoring techniques. Satellite remote sensing imagery was also utilized in this research to unveil the genesis and evolutionary process of the TLD. The TLD is classified as a large-scale landslide, with an estimated area of approximately 1,210,000 m2 and a developed volume of around 92,720,000 m³. The findings indicate that the landslide material of the TLD exhibits heterogeneity, looseness, and non-uniformity, which result in greater at the rear and lesser at the front flow patterns of gullies and springs. Additionally, this unique geotechnical structure contributes to variations in the direction of surface displacement vectors. The combined effects of natural rainfall and human engineering activities have led to a reactivation of the TLD due to rising groundwater levels, with regional zonation in deformation, multi-level slide surfaces, and coordinated deformation between deep and surface level.