弾性波速度による割れ目の定量化について

概要

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As the method of the measurement of the crack quantity in rocks, the seismic method is the most available at present. From thin point of view, the velocity through a pile of rock or glass plates was measured by the ultra-sonic pulse method under the simple conditions. Regarded such crack model is divided into a solid part and a crack part, and elastically these are element of linear spring combination, the velocity is as follows; V=V_0=√<α/α+β> in which V_0 is the velocity through the no-crack sample and α,β are respectively the thickness ratio and the Young's modurus ratio of a crack part to a solid part. Also,α may be considered to show the relative crack quantity, hence the following expression: α=V_0^2-V^2/V^2βThe result of the experiment shows the crack effect on the velocity decreases under wet conditions, large pressure, and in soft rocks.
1970-04-01