An index for describing the core-stone shape in weathered columnar joints

摘要: The shape of core-stones remained in the weathering basalt column is an index to classify its weathered degree. In this paper, a roundness (RI) like box dimension using fractal theory, was employed quantitatively measure core-stone various grades. rounded that seriously has smaller RI value. According value RI, five classes shown Russell–Taylor–Pettijohn chart for visually classifying grain available approximately determine grades Taiwan. A slump test preliminarily tested show difference repose angle stability slope assembled by grains similar shape. collection angular those are less (with higher value) indeed reveals greater angle.