岩石の破壊の進展に伴う弾性波伝播速度の変化
岩石の破壊の進展に伴う弾性波伝播特性に関する研究 (第1報)
1978 年 94 巻 1080 号 p. 77-83
詳細
1978 年 94 巻 1080 号 p. 77-83
A sonic method is a useful tool for inspecting the condition of a rock in-site.
In the first phase of this study, two kinds of rocks, namely “KITAGI” granite and “IZUMI” sandstone, were loaded axially by using a stiff loading machine, and the propagation velocity of longitudinal wave, AE (Acoustic Emission) count rates and the strains of test pieces were measured throughout the entire stress condition up.to the breakage.
In the second phase of this study, in order to discuss the source parameters concerning the microfracture produced in rocks, the wave analysis for the AE signals was performed by using the dislocation model.
In the third phase of this study, the change in the propagation velocity due to the progress of the breakage in rocks were analysed by using a theoretical model.
The main results obtained in these studies can be summarised as follows. The change in the propagation velocity due to the progress of the breakage in rocks has been much influenced by the shape (the aspect ratio) of microcracks produced in rocks by microfracturing. Consequently, it may be concluded that the sonic monitoring of a rock mass by watching only the propagation velocity is not enough to inspect the progress of the breakage in rocks in-situ.
