地表开挖宽度对震波散射问题之数值研究.pdfVIP

THE 10TH CONFERENCE ON CURRENT RESEARCHES OCT.2-4 2003 IN GEOTECHNICAL ENGINEERING IN TAIWAN SANS HIA 地表開挖寬度對震波散射問題之數值研究 蔡佩勳 1 洪英州 2 黃毓棋 3 摘 要 本文利用二維頻率域邊界元素法 ，分析震波入射到基礎開挖面之散射反應。 針對震波散射影響因素，如開挖寬度、入射波型式、頻率與入射角等加以探討，並 以能量比參數來評估開挖面對震波散射之影響 。由本文之計算結果顯示，不管 P 或 S 波垂直入射，或 R 波水平入射於三種不同開挖型式，其垂直壁與開挖底面之 水平或垂直位移比皆近乎相等。若地表基礎面與 P 或 S 波震源同一側，因震波散 射之緣故，基地面上有較大振動能量。但如果地表基礎面與震源異側，因開挖面之 屏蔽作用，使開挖面後方之地表基礎承擔能量較小，致整體能量有下降之趨勢。 關鍵字：邊界元素法，散射，地表開挖 。 Numerical Analysis of Wave Scattering Effect Due to Width of Underground Excavations Pei-Hsun Tsai Yin-Chou Hung Yu-Chi Huang ABSTRACT The 2-D frequency domain boundary element method is propo sed to study the scattering problem of incident P, S or R waves to underground excavations in this paper. The influence of parameters, such as the width of excavation, frequency, and the angle of incident waves, are discussed. The numerical results with energy factor are compared in this paper, and the displacement amplitudes of excavated surface are computed as well. With P, S waves vertical incidence or R waves horizontal incidence, the displacement amplitudes of vertical excavated plane seem to be the same in all the excavated types, and the larger horizontal displacement amplitude is occurred on the ground surface foundation with partial excavation. The ground surface foundation with partial excavation and th