| 摘要 |
<p>PURPOSE:To complete the measurement of the equilibrium water level in a short period of time even in a layer wherein water is hard to permeate, obtain an accurate value, as a result, make it possible to greatly reduce working hours for the overall permeability test and to obtain high degree of accuracy in measured results. CONSTITUTION:A site permeability testing device is equipped with a packer 14 provided with a water pipe 10 passing through the central part thereof and inserted in a boring hole 12, an airtight pipe 16 connected to the water pipe, a pressure gas source 18, a selector valve 20 switching the inside of the airtight pipe to the pressure gas source side or the air side, a pressure sensor 22 detecting test section pressure and a pressure recording device 24 recording detection signals of the pressure sensor, and a cut-off valve 30 having compressible and blockable construction is provided between the lowest water level in the airtight pipe and packer 14 by means of gas pressure from the outside of a flexible tube using the inside thereof for a water passage. The cut-off valve 30 is usually opened, the cut-off valve is compressed and blocked in the case a balanced head is obtained, the movement of ground water is prohibited, and the balanced head is quickly obtained by taking advantage of pressure propagation only.</p> |
