吉野川河口における滞積土砂の分級度について

DOI Web Site

書誌事項

タイトル別名
  • On the Degree of Sorting of Sediments in the Mouth of Yoshino River
  • ヨシノガワ カコウ ニ オケル タイセキ ドシャ ノ ブンキュウド ニ ツイテ

この論文をさがす

抄録

The authors are systematically analyzing the mechanism of sorting of sediments in the process of erosion, transportation and sedimentation in catchment areas, reservoirs, rivers and the sea. The present report concerns the analysis of the sediments in the mouth of Yoshino River; 179 samples obtained by boring were used. Mechanical analysis was made on the basis of JIS A 1204, and the degree of sorting was examined by the phi scale of Krumbein, Inman, etc.<BR>Size parameters such as Mdφ, Mφ, σφ, Qdφ, Pdφ, αdφ and βdφ were obtained from the results. The grades of σφ showing the degree of sorting were analyzed by Rominger's classification. Main interesting results are as follows:<BR>1) The degree of sorting unconformably changes at the depths of 10m, 30m and 50m; these planes of unconformity correspond to the changing planes of sediments.<BR>2) The planes of unconformity are best indicated by such size parameters as Mdφ and σdφ.<BR>3) As to the relations between phi mean diameter (Mφ) and phi deviation measure (σφ), the value of the latter increases and sorting linearly bdcomes poor for the value of the former both increasing and decreasing starting from a limit diameter (Mφ=2 to 3). The relations are shown by reflexive linear formulas (Eqs. 9 and 10).<BR>4) As to the relations between phi. mean diameter (Mφ) and phi kurtosis measure (βφ), the.value of the latter also linearly increases for the value of the former both increasing and decreasing starting from Mφ=2 to 3. These are also shown by reflexive linear formulas (Eqs. 11 and 12).<BR>5) As to the degree of sorting, the sediments are very well sorted or well sorted in the top. layer (alluvium), and are well sorted or normally sorted in the second layer (diluvial clay bed). In the third layer (diluvial gravel bed and the clay and gravel bed weathered on the ground), however, grading is poor, falling in the ranges from normally sorted to very pooly sorted. These suggest the general tendency that transported soils are well sorted and residual soils are pooly sorted.

収録刊行物

詳細情報 詳細情報について

問題の指摘

ページトップへ