石炭亀裂面の粗さの測定

Abstract

In this paper, the fracture surface roughness of coal samples from the four coal mines in Hokkaido was measured and analyzed. The main results obtained are summarized as follows:(1) The surface of the coal fracture is a random surface varying in some places smooth and others jagged. With a measuring length of 18 mm, it is clear that the coal fracture surface roughness varies in the range of 92 170μm. From the results of a goodness-of-fit test, it is clear that the probability density distribution of the coal fracture surface roughness fits the normal distribution.(2) The results of spectral analysis of the roughness show that the frequency content of the roughness appears widely from low to high. The significant frequency content that represents the character of the coal fracture surface can not be distinguished. The same results are also obtained by calculating the autocorrelation of the roughness.(3) From the measurement results of the coal fracture surface roughness, a relation has been obtained that the larger the largest fracture width and the standard deviation of the distribution of that fracture's surface roughness is, the greater the methane drainage ratio becomes, although the methane drainage ratio is generally affected by large number of parameters.