沈降天秤法と比重計法の組合せによる泥質砂堆積物の粒度分析法

概要

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Grain-size analysis of muddy sand or sandy mud is a matter of trouble, because the sed1-ments abundantly include both sand and clay grain size which behave differently in principle.The analysis by a single method needs a very long time and/or a large labor for one specimen.The new procedure proposed here is a combination of a settling tube method for sandy fractionsand a hydrometer method for muddy fractions. The hydrometer analysis is performedaccording to an ordinary procedure. Then wash the sample on a 4.5-phi standard sieve. Drythe fractions rested on the sieve, and weigh it. After then, analyze the coarse fractions by a settlingtube method. The settling tube method is a newly-formed system which uses an electricbalance and a computer. Make the two cumulative frequency curves, and combine them by ca1-culation. Theoretically, both curves should fit at 4.0 phi of settling-size grade, on the basis ofthe detailed research of effects by 4.5-phi sieving, Both curves, however, often differ slightly at4.0 phi. Therefore, they are shifted to each other at 4.0-phi grade by changing the total weightof the used sample, namely "weight correction". This procedure takes 4 days to analyze 15samples from coarse-grained sand to clay.
堆積学研究会の論文