ABSTRACT It is important to thoroughly understand the particle breakage phenomenon and to be able to comprehend quantitatively its effect with regard to engineering properties. In this paper, the particle breakage phenomenon observed during soil testing is investigated, and an attempt is made to clarify the particle breakage characteristics of granular soils by analyzing the soil test data presented by several researchers using uniformly graded soil samples. As a result, several facts have been revealed, one of which is that a certain regularity is recognized among grain size accumulation curves obtained from tests conducted under various testing conditions. Based on these findings, consideraton is given to the meaning of the “Comminution theory” that is currently used in other fields.