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The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus >
No.43 (1996/12) >

 
Title :さんご礁石灰質堆積物の透水係数(生産環境学科)
Title alternative :The coefficient of permeability of calcareous sediments in coral reefs (Department of Enviromental Sciences and Technology)
Authors :新城, 俊也
Authors alternative :Shinjo, Toshiya
Issue Date :1-Dec-1996
Abstract :さんご礁におけるさんご砂やさんご礁からなる堆積物の透水係数とそれに及ぼす間隙比,粒度,礫含有量,粒径,75μm以下粒径含有量等の影響を検討した。主な結論は次のようである。1) 透水係数(K)は間隙比(e)に支配され,ln(K)とeの間に線形関係が認められる。2) さんご砂では礫含有量の増加に伴って透水係数が増大し,礫混じりさんご砂の透水係数は礫含有量の影響が大きい。3) 一方,同じ礫含有量のさんご砂においては透水係数に及ぼす礫の粒径の大きさの影響は小さい。4) さんご砂の透水係数はシルト以下の細粒分の含有量による影響が大きい。5) さんご砂礫層の透水係数は堆積物を構成する粒子の有効径から推定できる。6) さんご砂礫層の透水係数は,粒径75μm以下の含有量が5%以上であれば(10)^<-3>cm/sのオーダの範囲にある。
Calcareous sediments consist of such bioclsatic as coral, shell and foraminifera, which have calcareous skeleton. A series of permeability tests has been performed on reconstituted calcareous sands with various grading curves to clarify the effects of grain size, content of gravelly component and fine fraction smaller than 75μm on the coefficient of permeability. Major conclusions obtained in this study are as follows. (1) There exists a liner relation in the relationship between the logarithm of the coefficent of permeability and void ratio ratio for individual grading curves. (2) The equivalent coefficient of permeability in a give void ratio increases as the content of gravelly component increases. (3) On the other hand the coefficient of permeability decreases with the increasing in the fine fraction smaller than 75μm. (4) Based on characteristics of gradation the coefficient of permeability of calcareous sediments can be estimated to be within the range of (10)^<-3>cm/s. (5) The coefficient of permeabioity of calcareous sands can be evaluated by using the effective size D_<10>.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/3730
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.43 p.73 -80
Appears in Collections:No.43 (1996/12)

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