| 摘要 |
PROBLEM TO BE SOLVED: To specify a water leakage opening in a dam easily and accurately by a few number of people and a simple and inexpensive device without using a large-scale device such as by an elastic-wave exploration method. SOLUTION: A conducting cable 4 with electrodes 5a and 5b at both ends, a power source 3 to impress a voltage between both electrodes 5a and 5b through the conducting cable 4, and a measuring device 6 to measure the resistance value between both electrodes 5a and 5b are used. With the one electrode 5b of the conducting cable 4 arranged at the location B of a known spring water opening 40b in a dam as impressing a voltage between both electrodes 5a and 5b, the other electrode 5a is brought into contact with the foundation ground 20 (lake bottom), which is an object of detection. As changing its contact location, the resistance value between both electrodes 5a and 5b is measured every time the electrode 5a comes into contact to detect the location A at which the resistance value becomes a minimum value. By this constitution, the location A of a water leakage opening 40a in the dam can be specified.
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