- 作者: 陳武雄
- 作者服務機構: 中國石油股份有限公司
- 中文摘要: 用因次分析將實地構造縮小成為大小恰當的實驗室模型,以利震波傳播各種特性之研究,進而判定超音瞬時脈波震測模型技術,對於亮點模擬的適用性。脈波發生器激發由直徑3毫米厚1毫米圓碟形鈦化鋇壓電結晶製成的發波器,以產生震波。震波傳播介質為由數種不同金屬薄板膠接而成,並用油質粘土消除邊角反射。受波器之構造完全和發波器相同。受波器收到的微弱震波電壓,經過前置放大器、通高頻濾波器、放大器、通低頻濾波器,而至示波器中的陰極映像管上,波形以即刻顯像紙拍攝成永久性之震測圖。 薄板震波分成對稱波和不對稱波兩種波型,由震測圖上可以明晰分辨,並用數學導引以與實驗結果相印證。震能減弱、波形變換、和反射係數對入射角之變化關係,本文亦略做探討。反射、折射、繞射、和表面波之傳播則以模型震測圖分別研討。 二度空間震測模型對於解決折射問題效果宏著,亦為解釋反射困難地區的利器,在研究和教育訓練上的功能不容忽視。若改進模擬技術,對亮點模擬的成功率仍僅為百分之五十。
- 英文摘要: Ultrasonic pulse-echo technique in 2-D seismic models made of thinplates were used to determine their usages in simulation of subsurfacestructures. The seismic source consisted of piezoelectric crystal of the bar-: m titanate on lead zirconate-titanate type was excited by rectangular-transient pulse. The wave motion was detected by another identical cry-stal.Permanent model seismograms were recorded from an oscilloscopewith a Polaroid land camera. Reflections from the plate edges can beeliminated effectively by a strip of the modeling clay attached to themodel. Various plate waves were identified on the records, and the attenuationand conversion from one wave mode to another was observed.Plate modelsmade of two or three different materials carefully glued together wereused to study reflections, refractions, and diffractions of seismic waves,and also to study the propagation of boundary waves (Rayleigh waves).
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