“Excavation-freezing-thawing” failure and crack characteristics of open-pit slope in cold regions: a case study in Baorixile mine, Hulunbeir, China - Guanghe Li; Zihuan Hu; Yanting Wang; Dong Wang; Laigui Wang; Zhigang Tao; Xiaoxu Yang; Yongzhi Du; Zhiwei Zhou; Chunjian Ding; Kun Fang (Bulletin of Engineering Geology and the Environment, 2025)