Abstract
In general, the grain size analysis of conglomerate and gravel bed distributed deep underground are carried out with rock sections or boring cores. It is possible to obtain the apparent grain size distribution with these methods, however, and the key is skillfully estimate the original grain size distribution from the apparent grain size distribution.
In this paper, a cumulative probability function of apparent grain size is led theoretically in an ideal condition. Using the function, standard curves for estimating the original grain size distribution from the apparent grain size distribution are obtained. It is also evaluated that, the standard curve method is applicable to actual grains.
