震源位置與坡地條件對被動式表面波震測分析之影響

Effect of Source Location and Slope Conditions on Passive Surface Wave Method

李瑞雅(Ruey-Yea Lee)

指導教授 ： 林志平

國立交通大學/工學院/土木工程系所/碩士(2018年)

摘要

山區複合性災害必須考慮土讓剪力波速與崩積層厚度，使用非破壞性被動式表面波震測法，可以經濟且大範圍的量測地層概況。當應用被動式表面波震測法於山區時，會因震源位置與坡地地形條件而產生與基本假設不符之處，有進行影響探討之必要。本研究利用三維數值模型搭配波譜元素法，模擬表面波在非均勻震源於水平地層、均勻震源於傾斜地層與山坡地形中的傳遞行為，並探討其對分析結果的影響，並尋求可能降低影響或避免影響之方案。
研究成果顯示，在有主要來源方向之被動震源的情況，對空間自相關分析法(SPAC)影響小，但對被動式多頻道表面波分析法(MAPS)有頻散曲線與理論解偏移的現象，建議利用主動式表面波震測法獲得某頻率段的相位速度以作為MAPS修正之參考。均勻震源於傾斜地層會造成非均勻震源，對SPAC方法影響小，對MAPS方法一樣有頻散曲線偏移的現象，且依然可利用主動式表面波震測法進行修正。中尺度山坡中，坡度與震源位置皆會影響分析結果，坡度越陡或震源與測線在山坡不同側時，頻散曲線的判釋較困難，但被動式概念-interferometry可提升表面波頻散分析在中尺度山坡的適用性。

關鍵字

被動式多頻道表面波分析法 ； 空間自相關分析法 ； 震源位置 ； 傾斜地層 ； 坡地條件

並列摘要

To prevent the disaster in mountain, we must consider the shear wave velocity of soil and the thickness of the collapse layer. Using the non-destructive passive surface wave seismic method, the formation profile can be measured economically and widely. It is different from basic assumptions, when the passive surface wave seismic method is applied to the mountainous area, so it is necessary to discuss the effect of the source location and the slope conditions. In this study, three-dimensional numerical models were utilized. The transfer behavior of surface wave is simulated by spectral element method in a horizontal stratum by non-uniform sources, in sloping stratum by uniform sources and in hilly topography, and to explore its impact on the analysis results and further reduce the impact or avoid the impact.
The research results show that in the case of passive source with main source direction, the impact on Spatial autocorrelation method(SPAC) is small, but there is offset on dispersion curve between Multichannel analysis of passive surface(MAPS) and theoretical solution. It is suggested to use active surface wave seismic method to obtain phase velocity of a certain frequency segment. Used as a reference for MAPS correction. The uniform source of the inclined layer will cause non-uniform sources, the impact on the SPAC method is not so obvious. And the dispersion curve by MAPS mothed got offset, and it can still be corrected by the active surface wave seismic method. In mesoscale slopes, the slope and source location will affect the analysis results. The steeper the slope or the source and the stations are on different sides of the hill, the interpretation of the dispersion curve is more difficult, but the passive concept-interferometry can improve the applicability of surface wave dispersion analysis in mesoscale hillsides.

並列關鍵字

MAPS ； SPAC ； Source location ； Inclined layer ； Slope conditions

參考文獻

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