暗キョ排水の機能増進に関する研究 VII. 暗キョ排水の浸出係数

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Title
暗キョ排水の機能増進に関する研究 VII. 暗キョ排水の浸出係数
Title Alternative
Studies of enlarged property of underdrainage. VII. Seepage coefficient of underdrainage
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Description

""f"", the specific yield of the soil, is often used in the theoretical analysis of the unsteady state of underdrainage. This seems to have been the cause of disagreement between the theoretical and the actual, therefore the author proposed to substitute seepage coefficient (provisional name) ""u"" for ""f"". ""u"" value is transformed along with lowering of the groundwater table. The object of this bulletin is an examination to evaluate ""u"" and the example of measureed value. The author found that equations show good agreement. The reasons are as follows: The author induced theoretical equation (14) for time and lowering of groundwater table by underdrainage. After differentiated GLOVER's equation (22) with respect to ""T"" and ""h"", in this place ""f"" is replaced by ""u"", equation (23) is given by integrating again. In the cace of d = ∞ use D = 3/2 H for equation (22) and D = H/2 + L for equation (23). Substituting ""u"" for ""f"" in WALKER'S original equation (24) we get equation (25).

暗キョ排水によって地下水面が時間的に降下する場合の理論式にはGLOVER(1950)やWALKER(1952)などの式が使われる. これらの式の中で有効間隙率(Specific yield of the soil, drainable pore space)の値をどのようにとるかが問題であって, 土壌の有効間隙率をそのまま使った場合に実際とは合致しない. KIRKHAMがおこなったGIBBS農場におけるフィルドデータによる検討(Proc. Soil Sci. Soc. Am. 16 : 86-293, 1952)においてもGLOVERの式の場合に実際より計算値の方が暗キョ間隔が大きく, またWALKERの式の場合も同様の傾向を示すことを指摘している. 著者は水位の時間的変化に伴って実有効間隙(有効間隙から一時残留水容積を差引いたときの間隙率)が変ることを考慮した浸出係数(Seepage coefficient, provisional name)を提案し, また理論式を誘導してこれらの矛盾を除去した.

Author
著者 田地野 直哉
著者(ヨミ) タジノ ナオヤ
著者(別表記) Tajino Naoya
Publication Title
香川大学農学部学術報告
Volume
30
Issue
1
Start Page
75
End Page
94
Publisher
香川大学農学部
Published Date
197809
ISSN
0368-5128
NCID
AN00038339
Resource Type
Departmental Bulletin Paper
Language
jpn
Text Version
publisher
Set
香川大学
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