以二維時間域邊界元素法分析地表幾何變化對波傳之影響

Abstract

本文主要是利用二維時間域邊界元素法來分析基礎震動波傳遞的問題，而土壤在本文中假設為彈性半無限域（elastic half-space）來處理。在處理奇異性(singularity)的過程中，我們藉由圍繞元素（enclosing element）的方法加以解決。以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。本文中對圍繞元素距離及尺寸的選擇以案例加以探討。 最後，本文藉由以上所得之結論建立分析模型，改變不同之幾何變化參數及材料性質做一系列分析，以瞭解各項變因對彈性波傳的影響。

The paper is devoted to solve the problems of wave propagation due to vibration of foundations by 2-D time-domain BEM. Soil is treated as an elastic half-space in this study. In the process of solving the singularity, ‘enclosing element’ has been developed. Using enclosing element to deal with half-space problem, the domain enclosed by the elements must be large enough in order to avoid the contamination of the reflection from the boundary. The rules of selection of enclosing element’s size and distance from loading site have been discussed in this paper. The analytic model is established according to the assumptions above. Furthermore, we will discuss the effect of varying topography and material property on wave propagation.