ZHANG X B, WANG G D, MA Y L,et al.Stability evolution of upstream tailings dams under extreme rainfall conditions[J].Journal of Henan Polytechnic University(Natural Science) ,2025,44(6):27-35.

doi:10.16186/j.cnki.1673-9787.2025030011

Received: 2025/03/05

Revised: 2025/08/18

Published: 2025/10/14

Stability evolution of upstream tailings dams under extreme rainfall conditions

Zhang Xiaobo1,2, Wang Guodong1,2, Ma Yongli1,2, Cheng Jun1,2, Yin Cheng1,2, Li Haigang3,4

1.School of Infrastructure Engineering， Nanchang University， Nanchang  330031， Jiangxi， China；2.Jiangxi Provincial Key Laboratory of Hydraulic Geotechnical Engineering Safety， Nanchang  330031， Jiangxi， China；3.Jiangxi Academy of Emergency Management Science， Nanchang  330000， Jiangxi， China；4.Jiangxi Provincial Key Laboratory of Work Safety Risk Monitoring， Early Warning， Prevention and Control， Nanchang  330000， Jiangxi， China

Abstract: Objectives This study investigates the stability of upstream tailings dams in the Poyang Lake region under frequent heavy rainfall and prolonged rainfall conditions， focusing on the evolution of seepage fields and dam stability under different rainfall scenarios.  Methods An upstream tailings dam in the Poyang Lake region was selected as a case study. Fluid-solid coupling simulations were conducted using the Seep/W and Slope/W modules of the finite element software GeoStudio.  Results Under extreme rainfall conditions， rainfall infiltration reduced dam stability， and the rate of decrease in the safety factor was positively correlated with rainfall intensity. At rainfall intensities of 500 mm/d and 700 mm/d， the tailings dam rapidly reached saturation， with safety factors falling below the minimum allowable value at 36 h and 24 h， respectively， indicating instability. Under prolonged rainfall conditions， the safety factor gradually decreased； However， under moderate （25 mm/d） and heavy rainfall （50 mm/d）， the dam remained stable after 70 days of continuous rainfall.  Conclusions Under heavy rainfall conditions， increased water content and saturation of surface tailings in certain areas readily induced shallow sliding instability， the main cause of localized stability reduction. Under prolonged rainfall conditions，  differences in permeability across tailings layers caused localized increases in pore water pressure and unit weight within the dam， potentially triggering deep sliding instability and thereby contributing to overall stability reduction. To quantitatively characterize the rise of the seepage field， an infiltration coefficient was proposed to represent the magnitude and rate of the rise. The  findings provide a reference for stability analysis of upstream tailings dams in the Poyang Lake region under complex rainfall conditions.

Key words: tailings dam; extreme rainfall; seepage; phreatic line; stability analysis