Vol19 No.6: 1525-1540
【Title】Comprehensive analyses of initiation and failure mechanisms of the 2017 Xinmo catastrophic rockslide
【Author】ZHOU Jia-wen1; FAN Gang2,3*; CHEN Qin3; YANG Xing-guo1,3
【Addresses】1 State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China; 2 State Key Laboratory of Geohazard Prevention and Geoenvironment, Chengdu University of Technology, Chengdu 610059, China; 3 College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China
【Corresponding author】FAN Gang
【Citation】Zhou JW, Fan G, Chen Q, et al. (2022) Comprehensive analyses of initiation and failure mechanisms of the 2017 Xinmo catastrophic rockslide. Journal of Mountain Science 19(6). https://doi.org/10.1007/s11629-021-7209-1
【Abstract】The failure of the 2017 Xinmo catastrophic rockslide in Maoxian County, Sichuan, Southwest China was a combined effect of long-term and short-term triggering factors. Field investigation, historical data collection, laboratory tests, chemical and microstructure analysis and numerical simulations were adopted herein to reveal the initiation and failure mechanism of the Xinmo rockslide. The analytical results showed that this failure involved the coupling of several triggering factors. The initial cracks in the rock mass were induced by historical earthquakes due to the convex topography and the direction effect. Rock masses from the source area of the Xinmo rockslide contain water-sensitive minerals, i.e., albite and chamosite, and the easily oxidized chemical elementFe, resulting in obvious strength deterioration under the action of water. The scanning electron microscopy (SEM) experimental results indicated that the internal structure of the rock mass is conducive to weathering. The compressive and shear strengths of the rock mass were reduced due to freeze-thaw cycles and weathering. The antecedent rainfall further deteriorated the stability of the slope, and stress and deformation accumulated continually in the locked section. Finally, the locked section sheared out, and the slope failed. An entrainment effect was observed in the Xinmo rockslide due to the presence of old landslide deposits and the antecedent rainfall, resulting in an amplification of the catastrophic rockslide. A simplified three dimensional analysis model was established in this study to reveal the influence of the triggering factors on the failure mechanism of the Xinmo rockslide.
【Keywords】Xinmo Rockslide; Landslide; Failure mechanism; Long-term evolution; Rainfall; Entrainment effect