GIS and limit equilibrium in the assessment of regional slope stability and mapping of landslide susceptibility

Slope stability analysis is an enduring research topic in the engineering and academic sectors. Probability-based analysis is the most popular method for evaluating a wide range of natural slope instability risks, but the lack of landslide data limits its application. A new method of regional slope stability analysis is presented that combines spatial analysis and two-dimensional slope analysis. First, a region is divided into slope units based on terrain and hydrology analysis, and the main potential slip sections of slope units are determined. Second, the potential slip surface of each section is determined and stability factors calculated with a two-dimensional slope analysis model. Finally, regional slope stability analysis is determined from the results of slope unit segmentation and slope stability analysis. A loess gully zone in Jintai District, Baoji City, China, constitutes the study area. A topographic map is transformed into a digital elevation model and evaluation zones determined by slope unit segmentation. A 3D geological model is devised from survey, drilling and investigation data. Geological profiles are generated automatically and slope stability analysis performed immediately with the small tool developed herein. Lastly, a map of regional slope assessment is produced. The method proposed combines the two-dimensional limit equilibrium method and spatial analysis, which are the methods usually used in engineering practice. It can provide not only a distribution map of safety factors, but also the scale and location of most dangerous slip surfaces. This study provides a new way to assess the natural slope risk of large areas.