Investigation on the creep induced slip of open-pit mine with weak layers

Abstract The long-term creep-induced instability of slopes containing weak layers posed significant safety risks in open-pit mining operations. A key scientific difficulty lies in understanding the coupled mechanisms of excavation-induced stress redistribution and internal time-dependent deformation in weak-layered strata, an area that remains insufficiently studied due to limitations in replicating realistic creep properties and capturing full-field deformation evolution. This study proposes a novel similarity simulation methodology that integrates custom-formulated materials, advanced digital image correlation (DIC) technology for precise deformation tracking, and discrete element numerical simulations (PFC software) to thoroughly analyze the coupled impacts of excavation-induced stress redistribution and creep deformation on slope stability. The results reveal that slope failure transitions from localized interlayer displacements at the early creep stage to widespread, multidirectional sliding post-excavation, accompanied by significant evolution of fracture networks from isolated longitudinal cracks to interconnected multi-directional fractures. Additionally, shear stress distributions initially form localized concentrations near weak layers but subsequently develop extensive multi-regional stress concentration zones post-excavation, dramatically enhancing the slope’s susceptibility to large-scale instability. These findings offer critical insights into the progressive creep failure mechanisms of weak-layered slopes, providing essential guidance for improved slope stability assessments and engineering interventions in open-pit mining.