本研究透過室內壓縮波速與剪力波速量測來探討夯實土壤之異向性行 為，由試驗結果得出結論與建議如下所述。
5.1 結論
1. 室內波速量測系統建立：本研究將柳儒錚(2010)之剪力波速量測系統進
行改量，製作可一併量測壓縮波速與剪力波速之 Bender-extender element 壓電感測元件，並提升資料擷取系統取樣率；改善雜訊干擾與增加感測 元件觸發能量，提高訊雜比；將僅能量測單一角度之硬體設備改良，使 之增加為多角度量測，令波速量測系統更為便利。2. 剪力波速與飽和度：在夯實曲線乾側，當飽和度(或含水量)逐漸降低時，
垂直於橫向等向面的剪力波速會有升高、降低再提升之情形，此行為與 Clariá and Rinaldi (2007)之剪力波速實驗結果相符合。而柳儒錚(2010)的 試驗資料可能因樣本不足或受試驗土壤之特性影響，在夯實曲線乾側剪 力波速並無上述之行為，因此柳儒錚(2010)提出之飽和度與剪力波速關 係式並不適合用來描述所有夯實土壤之剪力波速行為。
3. 夯實土壤異向性程度與彈性波速行為：以波速換算異向性因子來探討夯
實湖山砂土之異向性程度，可觀察到隨含水量之上升，異向性因子φ 與
ξ 之值越偏離 1，代表高含水量時夯實土壤之異相性程度較高。而異向性
因子η 變動程度則較大。另外，在具有異向性之夯實土壤中，受到傳感
器尺寸效應，剪力波的位移震盪方向不同，會導致兩震盪方向間的波速 有所差異；而壓縮波僅一種位移震盪方向，所以無此情形。5.2 建議
1. 本研究以室內實驗結果來探討夯實土壤之彈性波速行為與異向性程度，
建議可依據試驗結果合理假設土壤材料參數，以理論計算或數值模擬之 方式進行表面波震測之分析，並探討橫向等向性材料特性對表面波震測 結果之影響。
2. 依據本論文及文獻之室內試驗結果，在夯實曲線乾側，隨著飽和度逐漸 降低，剪力波速會有升高、下降再提升之行為，建議可進一步探討造成 剪力波速跳動的原因，以利未來建構可良好描述之數學模型。
3. 本研究試驗採用 Bender-extender element 來量測夯實土壤之壓縮波速與 剪力波速，在較高含水量(或飽和度)時，因震波強度降低導致收錄震動 訊號困難，尤以剪力波受含水量影響甚大，雖提升 Bender-extender element 觸發震波之能量與縮短土壤試體長度，改善效果仍有限，在含水 量約 14 %之夯實土壤試體已無法有效量測到震動訊號。為使在較高含水 量的情況下，亦能觸發與收錄良好之剪力波震動訊號，以提升收錄訊號 之品質及提高剪力波速分析之正確性，此一問題背後之原因值得進一步 探討，以期獲得改善之方法。
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