Study on the Process and Mechanism of Slope Failure Induced by Mining under Open Pit Slope: A Case Study from Yanqianshan Iron Mine, China

Abstract

Mining under an open pit slope results in the collapse and slide of the slope. In this paper, a combination of methods including Google Earth and field investigations is applied to investigate the process of eastern slope failure induced by underground mining in the Yanqianshan Iron Mine over five years. According to the observed ground deformation features, the geomorphic zone of the eastern slope can be divided into four regions (caved rock zone, cracking zone, toppling zone, and sliding zone). Break angles and fracture initiation angles at different times are counted separately. Based on the above work, the process of initiation and development of slope failure is studied. The analysis results show that the process of slope failure could be chronologically divided into three stages. First, a collapse pit, caused by the falling of the overlying strata above the goaf, appeared on the eastern slope. Then, the rock mass around the collapse pit slid into the pit to form a small landslide. Finally, because of mining disturbances and rock creep, a large landslide occurred on the northeastern phyllite slope. The control mechanisms of each failure stage are discussed separately. Finally, the RFPA3D code is employed to simulate the slope failure process under the influence of underground mining. The results are consistent with the field observations, which provided information on deformation failure and the mechanics of the slope that could not be directly observed in the field and deepened the mechanism analysis.

Deformation and Failure Process of Slope Caused by Underground Mining: A Case Study of Pusa Collapse in Nayong County, Guizhou Province, China

“…Underground mining activities may alter the stability of slopes [15]. The surface movement characteristics induced by underground mining in mountainous areas are considerably different from those caused by slope excavation or open-pit mining [16][17][18]. The surface movements may cause subsidence, slope movements, discontinuous deformations, and variation in hydrogeological conditions [19].…”

Stability Analysis of Jointed Rock Cutting Slope Based on Discrete Element Method

“…Based on the elastoplastic constitutive model considering complex stress state, the stability of slopes with seepage ow is analyzed using FLAC [10]. According to the eld investigation and Google Earth images, Hu et al [11] analyzed the process of fracture propagation on the slope under underground mining and then investigated the failure mechanism of the slope by the numerical software RFPA3D. Taking the process of excavation of the open-pit mine as the background, Wang et al [12] analyzed the slope stability factor of the end slopes using the strength reduction method, which shows that the vertical stress and stability factor decreased with the process of excavation, while the horizontal stress initially increased and then decreased.…”

Numerical Simulation of Deformation and Failure of Drainage Boat Pond Caused by Underground Coal Mining-Induced Subsidence

“…Long et al [38] proposed a landslide model induced by the underground coal mining-trepidation triggered landslide, summarized the characteristics of this type of landslide, and distinguished its similarities and differences with the traditional mining-induced landslide. In addition, Peng et al [39], Xu et al [40], Domínguez-Cuesta [41], Nie and Ze [42], and Hu et al [43] studied the landslide deformation mechanism and proposed a treatment scheme, which provides a theoretical basis for the stability evaluation of mining-induced landslide.…”