254 / 2023-09-30 13:17:48

Failure process of mining-induced Jianshanying landslide in China from long-term and three-dimensional motions observed by optical, LiDAR and SAR datasets

Optical remote sensing,SAR,DEM,mining-induced landslide,deformation monitoring,failure mechanism

Due to the comprehensive effects of fragile geological environment, climate change, and anthropogenic activities, landslide disasters have occurred frequently in the mountainous areas of southwest China, one of the largest karst landforms in the world, and thousands of people have lost their lives due to landslide disasters in recent decades. Therefore, revealing landslide mechanisms and failure mode is crucial for early warning of the disasters. Spaceborne and airborne remote sensing observations provide rapid and effective tools for assessing surface changes and monitoring surface deformation of such landslides. In this study, we take the Jianshanying landslide, a typical mining-induced and fast-deformed landslide, as an example, and reveal the failure mechanism of such landslide by investigating the historical surface displacement. First, the original surface of the landslide in 1975 is recovered by KeyHole (KH) digital elevation model (DEM) generated through KH-9 images, the complete evolution of the landslide surface was investigated from its original state to the overall sliding. The data include the satellite and Unmanned Aerial Vehicle (UAV) optical images, UAV three-dimensional (3-D) real scene models, high-resolution Light Detection and Ranging (LiDAR) DEM, and field survey. The results show that the head region entered the high deformation stage after 2019 due to underground mining, the maximum deformation rate was 12.3 m/yr. The landslide morphology was formed after the overall slide occurred in September 2020. Then, the pre-event 3-D surface deformation after the landslide entered the high deformation stage was recovered using Interferometric Synthetic Aperture Radar (InSAR), differential DEM, and SAR/optical offset-tracking techniques. The vertical mining-induced deformation was recovered around -78 m from 1975 to 2019. In particular, we solved the problem of unequal accuracy of SAR and optical offset-tracking observations in 3-D deformation inversion by employing Helmert variance component estimation method. The maximum deformation were 6 m and 3 m within four months in the NS and EW directions, respectively. Finally, we revealed the failure mechanism of the Jianshanying mining-induced landslide based on the disparity of horizontal and vertical deformation. That is, underground mining causes a significant subsidence of the rear part of the landslide body, resulting in different stress changes in the rear and front parts of the landslide body, which eventually led to sliding of the front part of the slope along the free surface. This work investigated and monitored the typical underground mining-induced Jianshanying landslide by using multi-sensor remote sensing approaches to trace the pre-event surface motions and to reveal its failure mechanism.