| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a tensioning force estimation method of an existing anchor and a ground soundness evaluation method that are superior in working efficiency.SOLUTION: Two-stage loads are loaded to a reference anchor 30, and a reference acoustic wave is generated by striking the reference anchor 30 in an anchor axial direction in each stage of this loading. A dominant frequency of a reflected wave is acquired which is derived from the reference acoustic wave, and based on the dominant frequency and the load when striking, a correlation equation of both is created. Alternatively, an estimating acoustic wave is generated by striking an existing anchor 10 becoming a target of estimation in the anchor axial direction, and the dominant frequency of a reflected wave derived from the estimating acoustic wave is acquired. The load obtained by substituting the dominant frequency in the correlation equation is estimated to be a tensioning force of the existing anchor 10, and a test in confirmation of the residual tensioning force is performed to an anchor out of a predetermined range in this estimated tensioning force to thereby evaluate the soundness of the ground G.</p> |
