2014-04-252024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/671855摘要：傳統上海床/河床底質沉積物的量測均使用現場定點底泥採樣的調查方式，以獲得底泥的物理性質，然此方法因海/水上作業不易，難以進行大範圍的水域的探測。鑑此，近年來海洋地球物理領域已快速發展聲納儀器，利用聲波於海水傳播的特性與訊號處理的技術進行地層遙測以提升探勘效率。本研究專案之目的為引進地球物理聲學遙測技術 – 變頻聲納海底地層剖面儀 (Chirp sonar sub-bottom profiler) 進行河川底泥物理性質之大範圍調查。變頻聲納海底地層剖面儀主要可提供高解析度底床淺層沉積物垂直面資訊，該資訊不僅可以直接解讀底泥厚度，經過後續資料分析，透過底泥聲學性質與物理性質間的關係式，即可估算底泥物理性質（如平均粒徑、孔隙度、滲透率、密度等），其中底泥顆粒大小與重金屬含量有密切關係，同時，這些物理性質也可提供水動力模式模擬場址的底泥分佈情形，以及因顆粒再懸浮等機制而造成的二次污染。本研究擬於基隆河與淡水河口進行變頻聲納地層剖面儀調查，並輔以現場底泥採樣。將利用測線上的聲學資料估算底泥之平均粒徑、滲透率與底泥厚度（視該區域底泥分層厚度而定）以建構底泥空間分佈，此資訊可提供整治工程估算所需移除的底泥量。比較聲學遙測與底泥採樣結果，並評估聲學遙測方法於該區域進行底泥辨識之可行性，期建立適用於臺灣河床聲學遙測分析方法，以提供未來河川底泥整治位置的優先順序之參考。<br> Abstract: Traditionally, the measurement of seabed or riverbed sediment properties is based upon the samples directly collected on site by various instruments; however, due to the constraints caused by survey operation, the method is generally limited to a small area. Recent development on sonar technology has advanced to the point that the analysis of the sediment properties may be inferred from the acoustic signals collected by various sonar systems, and as a result, the survey efficiency is highly increased. The purpose of this project is to use the chirp sub-bottom profiler sonar system (EdgeTech 216S) to probe the sediment in a river mouth area. The chirp sub-bottom profiler sonar system is capable of sending a linear frequency modulated acoustic signals penetrable to a certain depth beneath the riverbed, and the returns may then be employed to study various properties of the sediments, including sediment thickness, mean grain size, porosity, permeability, density, etc. The proposed survey area is in the river mouth of Keelung and Dansuie Rivers, and sediment samples shall be collected for comparison purpose in the analysis. The horizontal variations of mean grain size, permeability, and sediment thickness are to be estimated based upon the return signals, and the results are to be compared with the in-situ samples. The project is also served as a feasibility test of using acoustic means to study riverbed sediment properties in a large area, and should make contributions to the future development in the area of river management.地層剖面儀聲學遙測反射係數底泥平均粒徑Subbottom ProfilerAcoustic Remote SensingReflection CoefficientsSediment Mean Grain Size