Evaluation of slope stability with topography and slope stability analysis method

In existing researches connected with landslide, natural slope was regard as a parallel slope, but it was found that many landslides were occurred on the concave and convex slopes besides parallel slopes. This study was performed to evaluate the effect of shape and length of slope and soil depth for slope stability analysis and to compare infinite slope analysis with circular failure analysis for grid by grid analysis in prediction of GIS-based landslide hazard. As grid size is increased, average slope and curvature were decreased and the decreasing tendency was prominent in mountainous areas. Comparing infinite slope analysis and circular failure analysis for various degree of slope and soil depth, safety factor by infinite slope analysis is larger than that by circular failure analysis. Result showed that the factor safety depends on the shape of slope which is composed of two continuous slopes, if grid size is small (such as 5 mx5 m). So after due consideration for soil depth and topography, proper slope stability analysis must be performed.