| 摘要 |
PROBLEM TO BE SOLVED: To detect ground distortion in any direction, to execute work without a preliminary survey of distortion direction with respect to the ground for an installation field, and to execute work and detect distortion even for the ground having unpredictable distortion direction. SOLUTION: A distortion-detecting outer pipe 1 capable of being bent in any direction by distortion in the ground 2 is embedded in a depth direction in the ground 2. A distortion-detecting inner pipe 9 capable of being axially bent in any direction is disposed inside the distortion-detecting outer pipe 1. The space between the inner and outer pipes 1, 9 is filled with a filler 14 causing a bend thereof due to distortion in the ground 2. Inside the distortion- detecting inner pipe 9, there is disposed a distortion-detecting rope-shaped body 14 having a lower end fixed to a lower end of the distortion-detecting outer pipe 1 and an upper end capable of being displaced downward by a bend of the rope-shaped body 13 due to the bend of the distortion-detecting inner pipe 9. A detection means 15 is linked to an upper end of the distortion-detecting rope-shaped body 13 so that the downward displacement thereof can be detected by it.
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