Failure process and mechanism analysis of rock slope induced by underground mining: a case study in Yanqianshan open-pit mine, China

Underground mining under the slope can induce strata movement, which in turn can induce landslides and surface subsidence. Previous studies have focused on the damage behavior of the surrounding rock mass caused by underground mining, ignoring the combined effect on the rock mass from open-pit mining to underground mining. In this paper, unmanned aerial photogrammetry (UAV) and interferometric synthetic aperture radar (InSAR) investigations were used to obtain the failure characteristics and displacement evolution of rock masses caused by underground mining. Then, based on Yanqianshan mine measurement results and combined with 3D numerical modeling, the sliding surface evolution inside the slope and the failure mechanism were analyzed. In addition, a double-sliding surface deflection (DSD) failure model for analyzing the landslide area was proposed and validated by base friction tests. The results showed that underground mining was the factor that directly led to landslide development. The failure characteristics are summarized into three phases: bottom collapse, traction landslide, and ground subsidence. The maximum deformation value reaches 193.1 cm, and vertical displacement is dominant with a maximum rate of − 115.73 cm/a. The internal movement boundary was deflected near the slope surface, and the deflection direction depended on the synthesis vector of two mining influences. These results are significant for disaster risk reduction caused by underground mining.