Abstract
Slope failures of forest roads often occur and are disaters to forest lands. We studied the potential of cutting and banking slope failure of forest roads using the fuzzy theory. Evaluation systems of potential slope failure risks were based on the results of research taken in Totsukawa village, Nara prefecture. We learned that slope failures often occurred in the centers of concave curves, turning points of convex curves, wider portions of forest roads, steep slopes, and cutting areas of steep slopes. Discriminant ratios with the fuzzy theory were 68.9% for cutting slopes and 70.7% for banking slopes. Those with the quantification 2 method were 67.0% for cutting slopes and 72.1% for banking slopes. The advantages of the fuzzy theory are making evaluation systems easier according to different areas. This system could also be applied to other areas by adjusting the weight of importance and potential slope failure of each factor.
