| 摘要 |
PROBLEM TO BE SOLVED: To provide an elastic wave speed measuring method of a face in tunnel pits that can measure the elastic wave speed in a face without suspending excavation work by the face, can reduce expenses for measurement, and can automate measurement. SOLUTION: A measurement hole is excavated on a side wall at a position that is separated rearward from the face in the pit of a tunnel, a vibration sensor (seismometer) 3 is installed, and blasting vibration due to the explosion of the blasting of the face is received by the vibration sensor and is recorded by a data accumulator. This process is repeated for each face advance. Then, blasting vibration data are analyzed by a processor, and the elastic wave speed of the face Kn+1 is obtained from Vn+1=Δa/(Tn+1-Tn) from the distanceΔa between arrival time Tn, Tn+1 to the vibration sensor of blasting vibration at the faces Kn, Kn+1 in face advancing cycles n, n+1 and the faces Kn and Kn+1 at the center line of the tunnel.
|
