| Abstrakt: |
On March 27, 2022, a tailings dam in Jiaokou County, Shanxi Province, China, experienced a sudden breach leading to 224,000 m3 of released tailings that flowed downstream and damaged infrastructure. The tailings flow exhibited relatively slow movement according to eyewitnesses, with the complete duration of the failure process lasting 20–30 min. In order to reconstruct the slow motion of the tailings flows, we have adapted the mass flow simulation software r.avaflow to effectively simulate the slow-flow dynamic. In addition to the numerical simulation, we conducted a comprehensive investigation using satellite-based interferometric synthetic aperture radar (InSAR), optical satellite images, field surveys, unmanned aerial vehicle (UAV) photogrammetry, borehole drilling, and laboratory tests, with the aim of identifying underlying causes of this failure incident. The numerical simulation results showed a good representation of the observed impact area and reported time span, illustrating that the maximum simulated velocities during the entire flow slightly exceeded 6 m/s. InSAR analysis indicated a phase of rapid deformation that coincided with an unprecedented autumn storm in early October 2021, followed by a prolonged period of slow movements until the collapse, with an average line-of-sight (LOS) velocity of 24 mm/year. Through remote sensing surveys and field investigations, we observed the following deficiencies in design, construction, and operation of the Jiaokou TSF: (i) the TSF underwent an extra round of excessive loading from July 2021 onwards, despite being decommissioned in December 2019. and (ii) the TSF fell short of conventional design standards by the absence of drainage and seepage control measures and inappropriate dam construction methods (loess stacking). We conclude that the stability of the Jiaokou TSF was adversely affected by the extreme storm event in conjunction with deficiencies in TSF management, in particular the overloading that likely led to pore water pressure build-up and sudden strength loss. This failure incident is of significance as it draws attention to the need for more robust risk management of the thousands of existing TSFs in China. [ABSTRACT FROM AUTHOR] |
