2024-03-28T16:21:39Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/710442022-11-17T02:08:08Zhdl_2115_20046hdl_2115_138児島湖底土の飽和透水係数に及ぼす土壌溶液pHの影響Effect of pH on Saturated Hydraulic Conductivity of Lake Kojima Sediment1000000294439石黒, 宗秀ISHIGURO, Munehide岩元, 亮一IWAMOTO, Ryouichi石田, 智之ISHIDA, Tomoyuki赤江, 剛夫AKAE, Takeoopen access© 社団法人 農業農村工学会© The Japanese Society of Irrigation, Drainage and Rural Engineering底泥pH飽和透水係数濃度CaNa分散凝集sedimentpHconcentrationsaturated hydraulic conductivityCaNadispersion flocculation519栄養塩類の供給源となる湖沼底土は, 湖沼過栄養化の一因となるため, その処理対策が検討されている. 底土を利用するためには, その利用目的に合った透水性が要求される. 一方, 土壌の透水性は, 種々の粘土鉱物や有機物の影響を受けるため, 未解明の部分が多い. 本研究では, 非膨潤性の層状粘土鉱物を含む児島湖底土を用いて, その飽和透水係数を測定し, 飽和透水特性を実験的に明らかにした. Caを吸着した土壌試料では, 浸透溶液濃度が低下しても透水係数は小さな低下に留まった. 特に, pH11のCa吸着試料では, 最も小さな変化であった. これは, 土粒子とCaの化学反応により構造が安定化したためと考えられる. 一方, Naを吸着した試料では, pH5では透水係数は小さな低下であったが, pHが上昇するに従い著しい低下を示した. この結果は, 粘土鉱物の荷電特性と拡散二重層理論により説明できた.As lake sediments are one of the cause of eutrophication, their effective use has been considered. When they are used as soil in a land, proper permeability is required. However, soil permeability has not completely been understood due to diversity of clays and organic compounds. We clarified permeability characteristics of Lake Kojima sediment, non-swelling clayey soil, by measuring saturated hydraulic conductivity (K). Decrease in K with percolation of dilute electrolyte solution was small when Ca was adsorbed by the soil. Particularly, decrease in K at pH11 was the smallest, because soil structure became stable with chemical reaction between soil particles and Ca. On the other hand, when Na was adsorbed, decrease in K was the smallest at pH5, and it became larger as soil pH increased. The obtained results could be explained qualitatively by the diffuse double layer theory.農業農村工学会2001-12jpnjournal articleVoRhttp://hdl.handle.net/2115/71044https://doi.org/10.11408/jsidre1965.2001.7710387-23351884-7234農業土木学会論文集Transactions of The Japanese Society of Irrigation, Drainage and Reclamation Engineering20012166570https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/71044/3/2001_771.pdfapplication/pdf3.26 MB2001-12