Abstract
This paper is concerned with the factor analysis of a boulder-fall by the theory of quantification and the presentation of a method for evaluating the possibility of the boulder-fall on a slope. Based on the considerations about the topographical, geological and mechanical conditions related to the phenomenon of boulder-fall, detailed field investigations have been carried out on many actual slopes in Yamanashi and Nagano prefectures. The statistical analysis of the data obtained from the field investigations is conducted to grasp quantitatively the degree of the influence which each of the factors gives to the phenomenon. Moreover, on the basis of the theory of quantification, the method by which the possibility of an outbreak of boulder-fall can be estimated is presented, and its applicability is examined through comparing with observations.
