二維邊界元素法研究槽溝阻隔雷利波之行為

Abstract

本次研究主要是想利用二維時間域邊界元素法來分析此類所謂的被動及主動阻隔暫態波傳之問題，土壤可假設為彈性半空間無限域來處理而雷利波視為平面波。在處理奇異性的過程中，我們藉由圍繞元素的引入加以解決。當圍繞元素處理半無限問題時，其圍繞之區域必須足夠大，以防止邊界反射之影響，藉由以上的假設分別對不同槽溝深度情形建立分析模型，透過改變不同幾何變化參數（深度、位置）再給定瞬態外力作用於基礎上當成振源後開始做一系列系統分析，預期將對各項變因對雷利波波傳衰減的行為有一深切瞭解。

This research is trying to deal with the so-called active and passive isolation of Rayleigh Wave by 2-D time-domain BEM. Soil can be assumed to be an elastic half-space medium.Numerous numerical investigations are conducted for the influence of different geometrical parameters on the effectiveness of isolation. In the process of solving the singularity in BEM, “enclosing element” has been employed and the domain enclosed by these elements must be large enough in order to avoid the contamination by the reflection waves from the fictitious boundary. The analytic model is then established according to the assumptions above. Furthermore, we will discuss how vertical displacement amplitudes be reduced for different trench depth and topography cases under a transient applied loading. Through numerical experiments, some useful conclusions will also drawn.