| 摘要 |
<p>PROBLEM TO BE SOLVED: To judge the support ground more accurately. SOLUTION: When a procedure is started, the measurement value of a vibration sensor is taken in while an auger rod is penetrated into the ground after an initial setting. Then, after dark vibration data are subtracted from a measurement value using the vibration sensor, the result is stored. When it is judged that the depth reaches a set stratum depth in s4, s5 is executed. The measurement values by the vibration sensor are averaged in s5 and the averaged values f(t1) to f(tn) are stored. Vibration data are subjected to Fourier transform in s6 and s7, frequency spectrum data F1 (w) to Fn(w) are stored, the maximum values for the frequency band of the spectrum data is calculated, and the average value is obtained. In s8, it is judged whether the average value of the maximum values for each frequency band greatly changes or not between the earth's surface depths or not. Then, when it is judged that the average value greatly changed, it is judged that a support ground layer exists near the area between the strata that have changed, thus completing the procedure.</p> |
