“Excavation-freezing-thawing” failure and crack characteristics of open-pit slope in cold regions: a case study in Baorixile mine, Hulunbeir, China

Open-pit mine slopes can give rise to grave accidents that may lead to loss of life and property. In cold regions, freeze-thaw cycles can result in fractures and cracks in these slopes. It is critical to understand the failure mechanism of open-pit mine slopes in cold regions to ensure the sustainability and safety of mining operations. This study investigates a slope failure in an open-pit mine located in Baorixile, China, with emphasis on cold regions. The field investigation was carried out by employing visual monitoring techniques, Global Navigation Satellite System (GNSS), and Real-time kinematic positioning (RTK) to observe crack development and displacement changes during slope deformations. The collected data was analyzed using fractal analysis, which summarizes and demonstrates the slope’s crack characteristics. Moreover, numerical tests were conducted to gain deeper insights into the underlying causes of the slope failure. The results indicate that the fractal dimension of cracks increases rapidly in the initial stages but subsequently slows down, indicating a transition point between these stages. The root causes of the slope failure in Baorixile mine were evaluated, considering human, physical, and geological factors. An “excavation-freezing-thawing” along a weak plane is proposed for the open-pit mine slopes in cold regions. The study’s findings provide valuable insights into the factors and mechanisms influencing the instability of open-pit slopes in cold regions.