有限弾性体中の流体で満たされたき裂に生じる振動特性の検討（き裂に生じる定常波を測定するための最適な条件の検討）

摘要

自然エネルギーの一つである地熱エネルギーを効率rn的に取り出すためには，熱水や蒸気を含んだ岩体中のrnき裂の状態を把握することが重要となる．微小地震なrnどを用いて地下き裂の状態を知る方法としては，例えrnば，複数の微小地震波形の類似性を用いて高精度に震rn源分布を推定し，その分布からき裂面を推定する方法rnなどがある．%It is examined by numerical calculation how to detect crack wave radiating from a fluid-filled crack in a finite test piece of the rock, emphasizing the application to geometrical characterization of a geothermal reservoir crack. Boundary Integral Equation Method is employed for the numerical calculation. It is revealed that resonance of the test piece and stimulation e.g., hitting by hammer to stimulate the crack, have strong effect on radiation pattern from a crack in a finite test piece. In the case of large stiffness due to contact between the asperities on the upper and lower surfaces of the crack, it is difficult to detect the crack wave. In the case of measuring crack wave on the surface of the test piece, it is better for measuring that the surface of the test piece is near the crack surface. If surface of test piece is not near the crack surface, higher modes of crack wave are veiled in resonance of the test piece and stimulation.