| 摘要 |
PURPOSE:To measure the settlement by a leveling system whose structure is simple and which scarcely causes a measurement error by obtaining an output being proportional to a water level in a transparent measuring tube by receiving a current output of a one-dimensional light position sensor. CONSTITUTION:A light beam from a light source 2 lighted by a constant-current circuit 1 is made incident on the inside of a tube from the bottom part of a transparent measuring tube 3. To the inside of the tube, water at the time of measuring the settlement of the ground is applied from an inlet/outlet 3a through a communication tube, and in accordance with its hydraulic pressure, a water level in the tube moves. To the inside surface of the transparent measuring tube 3, hydrophilic coating is applied in advance, therefore, water of a part brought into contact with the inside surface of the tube of the peripheral part of the water level swells, and the light beam from the light source 2 is refracted and emitted to the outside of the tube. As for the outside surface of the transparent measuring tube 3, the length direction is finished partially to a plane, and a refracted light is received by a one-dimensional light position sensor 4 fixed to this plane part and converted to a current value being proportional to a water level generated in the tube. The converted current value is converted to a voltage value by a current/voltage converting means and obtained as a measured value from an output side. |
