本文旨在於研究以試驗波浪衰減與孔隙底床之物理特性（孔隙率、底床厚度）之關係。試驗內容包括四種不同孔隙率之材料、四種不同的底床孔隙材料厚度及各種波浪條件。根據試驗結果分析各種波浪條件下，孔隙斜坡底床上之底床材質物理特性對波高衰減之影響。
試驗結果發現，波高隨著波浪行進距離增加而衰減。在底床之相對厚度t/di小於0.2時，隨著厚度的增加，波浪行進於孔隙底床之波高衰減率亦快速增加。當底床之相對厚度t/di大於0.2時，隨著厚度的增加，波浪行進於孔隙底床之波高衰減率增加則趨於和緩。此一現象說明大部分波能僅在一定厚度內消耗。至於孔隙率對波高衰減的影響，試驗結果顯示當孔隙率增加，波高衰減率也會增加。
最後本文將試驗數據進行迴歸分析，建立波高衰減與無因次化行進距離、孔隙率、相對厚度之關係式，提供設計者之參考。

This paper is aimed to investigate the relationship between wave decay and the physical properties of porous bed. To achieve this, a series of experimental tests were conducted. In these tests, a total of four types of porous material and four material thickness were adopted, then wave decay over these porous beds were measured under various wave conditions.
Based on experimental results, it is observed that the wave height decreases as the dimensionless progressive distance increases. Further, the wave-decay rate increases rapidly with increasing relative thickness of the porous bed as the relative thickness is smaller than 0.2. However, if the relative thickness becomes greater than 0.2, the wave-decay rate increases only slightly with increasing relative thickness. Therefore, it is realized that waves consume more energy on the porous bed within a relative thickness of 0.2 than within the deeper part. As for the porosity, it is indicated that the wave height reduces rapidly with increasing porosity.
Finally, a regression analysis was conducted and a wave-decay formula was established relating to those factors such as dimensionless progressive distance, relative thickness, and porosity.

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