Stability Evaluation of Tunnel Portal Rock Slope Based on Influencing Factors—Case of a Tunnel Portal Slope in Chenglan Railway

Lithology, structure and tectonic of the rock mass, excavation, vibration and geomorphologic conditions are regarded as main factors to affect stability of portal rock slope. Barton model is utilized to work out equivalent shear strength parameters of main structural plane, which are applied in stereographic projection analysis. The slope stability in condition of excavation and earthquake action is simulated with finite element and discrete element software. The stability evaluation is demonstrated with the case of tunnel portal slope in Chenglan railway. Some suggestions are presented on the tunnel portal rock slope stability evaluation based on the influencing factors.