| 摘要 |
PURPOSE:To measure the velocity and direction of a horizontal natural flow of ground water with high precision by charging an in-boring-hole stabilizing device consisting of a strainer, a seal lock member, and a back filter lengthwise in a boring hole where a measuring instrument body is lowered. CONSTITUTION:The in-boring-hole stabilizing device composed of the cylindrical strainer 40 having through holes 41 bored at specific intervals, >=2 seal lock member 38 with high water absorbency which are fixed at a constant interval on its lengthwise outer peripheral surface, and back filter 39 provided on the outer peripheral surface of strainer 40 between upper and lower members 38. The members 38 swells by absorbing water to be pressed against the wall surfaces and also press the back filter 39 between the members 38 to reduce the thickness; and the members are also pressed against the hole wall surfaces to stabilize the inside in the boring hole 37, and then a measurement is taken by the main measuring instrument.
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