Formation and Failure Characteristics of a Landslide Induced by Excavation in Western Henan, China

Engineering construction in mountainous areas is a key factor inducing slope failure, which poses severe threats to life and property safety during construction and operation. Thus, clear understanding of slope structure and potential failure mechanisms is of great importance for slope reinforcement. The Shangge landslide, located in a mountainous area of Western Henan, China, was triggered by excavation along a toll station. The slope was still unstable after a row of anti-sliding piles were constructed. To clarify the deformation characteristics and failure mechanism of this landslide and provide reinforcement guidance for slopes with similar geological conditions, a combined method of field investigation, displacement monitoring, and numerical simulation was employed. The results indicate that the natural slope comprises a dual structure of soil and rock, and that the soil, with poor permeability and high water moisture, was prone to form a potential sliding surface. Secondly, slope excavation was the direct triggering factor. Lastly, but most importantly, the preliminary investigation work failed to accurately expose the potential position of the sliding surface, and the existing anti-slide piles failed to cross the potential sliding surface, which made them unable to effectively improve slope stability. The numerical simulation verified that the recommended piles installed on the platform of level 2 could significantly improve slope stability. Therefore, when carrying out engineering slope design in similar geological environments, the slope structure and material composition should be fully identified, and the influence of groundwater on the slope stability state should be emphasized. These results can provide a reference for similar slope reinforcement designs.