| 摘要 |
<p>PROBLEM TO BE SOLVED: To find the range of improved ground mass which is formed or being formed, by disposing a vibration receiver at a specified depth position in the mass, disposing vibration emitters around the ground surface above the position where the vibration receiver is disposed, emitting elastic waves from the vibration emitters, and measuring the time taken before the vibration is received with the vibration receiver. SOLUTION: Using a bore 2 in the approximate center of an improved ground mass R, a vibration receiver 1 in suspension is lowered and secured. The depth of the secured vibration receiver is calculated from graduations on a suspension cable 3 or rotation amount found with a pulse encoder attached to a sheave 5 or cable winch 6. A communication cable 4 extending from the vibration receiver 1 is connected through a n amplifier 11 to a controller-recorder 12. The bore is filled with water or muddy water. A plurality of vibration emitters 7 to 10 are disposed in a row on the ground surface centered on the position where the vibration receiver 1 is disposed, at specified intervals in the direction of the cross section to be measured. The range of the improved ground mass R is found by emitting ultrasonic pulses from the vibration emitters 7 to 10 and measuring arrival times to the vibration receiver 1.</p> |
