| 摘要 |
PROBLEM TO BE SOLVED: To simply detect occurrence of defect of a foundation pile for supporting the foundation of a building or the like, and a position where the defect is present. SOLUTION: A drilled hole 27 is formed in the ground surface in the vicinity of a foundation 23 and a foundation pile 25, and accelerometers 29 are arranged in the hole 27 at predetermined intervals. Thereafter, the upper surface of the foundation 23 exposed from the ground surface is hit by a hammer so as to vibrate the foundation 23, and accordingly, an elastic wave induced in the foundation pile 25 and transmitted through the ground is detected by the accelerometers 29. The detection signal is processed so as to calculate a reciprocating period of the elastic wave in the foundation pile 25 and the position of a lower reflecting point. When the lower reflecting point is not at the front end of the pile, it can be determined that defect is present at the reflecting point. |
