Abstract
A number of primary causes, mainly topographic and geological factors, are concerned with the occurrence of rock falls and rock slope collapses. Therefore, consideration of these primary causes is important to evaluate the rock slope stability. We analyzed the primary causes aiming to propose a more accurate and practical stability evaluation method of rock slopes along railways. In the former paper, we reported the analysis by the existing stability evaluation methods
In this paper, we extract the primary causes from disaster data in the past and analyze them. In addition, we examine the results of the two analyses. By this examination, we clarify the conditions and factors which are strongly concerned with the occurrence of downfall type rock falls, separation type rock falls and rock collapses, respectively. And we can distinguish the primary causes by their characteristics, which would be classified into the three cases as follows; (1) thc cause being directly concerned with the occurrence of rock falls and rock slope collapses; (2) the one being related to an unstable progression of slope; (3) the one giving influence to railways to different degrees. So we recognize that it is important to consider the characteristics of the primary causes in evaluating the stability of rock slopes.
