J. Jpn. Soc. Soil Phys.

No. +*2, p. 012* ,**2

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¶ 4

·*

Investigation of Leakage for a Small Earth Dam
by Underground Temperature Survey
Hiroshi YOSHISAKO** National Institute for Rural Engineering, National Agriculture and Food Research Organization,,ῌ+ῌ0 Kan-nondai, Tsukuba-shi, Ibaraki -*/ῌ20*3, Japan
Abstract
To establish a method to investigate leakage from small earth dams by measuring groundtemperature at a depth of one meter, its daily range and seasonal variation and the surface
temperature of the small earth dam body were measured at the Aoike Irrigation Pond in Kagawa
Prefecture.

The relationship between the ground temperature at a depth of one meter and theconditions of the small earth dam body surfaces, leakage paths and seepage surfaces was investigated through simulation. The results indicate that ground temperature anomalies causedby partial leakage from a low-height small earth dam can be detected by the measurement of theground temperature at a depth of one meter on the crest of the small earth dam during summer
or winter, when ground temperature di#erences are more likely to occur.

A method to set leak-age paths, seepage surfaces and ﬁxed temperature boundaries for simulation is also presented.
From the simulation of ground temperature at a depth of one meter, the width and depth ofleakage paths can be estimated by determining the conditions of leakage paths and seepage
surfaces that are concordant with the measured temperature values.
Key words : irrigation pond, small earth dam, underground temperature, leakage-./+

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74

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at a depth of + m 

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