Time‐dependent analysis and stability evaluation of plane rotary landslides: Insights from a case study

Abstract

Plane rotary landslides are characterized by their concealment and challenges in prevention, having caused considerable impacts in recent years. This study aims to elucidate the causative factors behind plane rotary landslides and develop a novel method for assessing their stability through a case. Our focal case, a landslide with weak interlayers, occurred on 1 April 2020, in an open‐pit limestone mine in Sichuan Province, China. The landslide demonstrated distinctive rotational behaviour deviating 45° from the expected direction, presenting a unique case of plane rotary deformation. Employing a multifaceted approach, including geological data analysis, UAV aerial photography, field investigations, laboratory experiments and displacement monitoring, we delved into the deformation and failure mechanisms. Furthermore, A three‐dimensional discrete element method was employed to examine the evolution of the landslide and its relationship with the stable rock mass barrier. The study unravelled the structural alterations of the slope due to mining activities and the degradation of physical and mechanical properties in weak interlayers, which were instrumental in triggering this geological event. The presence of the stable rock mass barrier causes the resultant forces acting on the sliding mass not to pass through its centre of gravity during deformation, thereby generating a moment that induces the rotation. The additional resistance also causes the landslide displacement to transition from being initially dominated by the leading edge to being driven by the trailing edge. This unique displacement pattern serves as a crucial reference for identifying plane rotary landslides.