Analysis of wedge-shaped landslide mechanism and sliding force monitoring warning in Nanfen open pit iron mine

In recent years,as the exhaustion of shallow resources and the increase of mining depth,the local slope height reaches 552 m (elevation 142-694 m). Because of the “V” shape of main pit section,the space on the bottom of pit becomes narrow and suffers the risks of rock rolling,landslides and other disasters. These are serious threats to personnel and mechanical safety. To overcome the problems above,Nanfen mine started the new phase of slope expan- sion and mining. In the last three years,landslide disasters occurred many times during the slope expansion due to the old landslide bodies. This paper uses the “Landslides 2016-1101” case to analyze the in-situ sliding force monitoring and early warning system and establish the landslide causes and failure models. Then,the Stereographic Projection Method is employed in the analysis of landslide mechanism and safety factor. Finally,a numerical modeling analysis by FLAC3D is preformed,particularly involving the Negative Poisson’s Ratio cable (NPR) model by Fish language pro- gramming. The case of “Landslide 2016-1101” is simulated by numerical calculation,and the result shows a remarka- ble consistency comparing with the in-situ data. The research may provide a theoretical and practical basis for similar engineering problems.