以泥砂粒徑分析探討聲波濃度計泥沙監測之可行性

泥砂淤積直接影響了水庫的供水，亦對環境產生了重大影響。傳統的水力清淤方法使用機械幫浦來提供驅動力以從水庫排出淤積之淤泥。本研究使用聲波濃度計監測清淤過程中的泥砂濃度並計算清淤量，進而已得知從水庫中清除了多少淤積物。然而，聲波濃度計在清淤監測中的應用仍需要驗證。因此，本研究之目的是了解聲波濃度計受到淤泥顆粒大小之影響以及在清淤監測中的可行性。最後，結果表明，進行濃度檢測時，於低濃度下之粒徑差異性約在±10％以內，可通過±5％的檢測誤差率標準。於中濃度時，粒徑差異性在±15％至10％之內，可通過±5％的檢測誤差率標準。於高濃度時，粒徑差異性在±10％以內，可通過±5％的檢測誤差率標準。由於聲波濃度計在清淤監測和實驗室校準過程中所碰到的情況不盡相同，因此濃度監測無法準確監測。特別是，粒徑較大的淤泥對聲波濃度計的影響較大。因此，聲波濃度計即使進行實驗室校正，但用於水庫監測水力清淤濃度的可行性仍是有難度的。

關鍵字

泥沙粒徑；聲波濃度計；泥沙監測

並列摘要

Sedimentation directly affects the water supply of the reservoir and also has a significant impact on the environment. Conventional methods of hydraulic dredging use a mechanical pump to supply the driving power to remove deposited sediment from a reservoir. In this study, a ultrasonic instrument was used to monitor the sediment concentration during hydraulic dredging and the amount of dredging was calculated so that it was possible to know how much sludge had been removed from the reservoir. However, the application of ultrasonic instrument in hydraulic dredging monitoring project still needs to be verified. Therefore, the purpose of this study was to understand the influence of the ultrasonic instrument when the sediment particle size changes and the feasibility of the ultrasonic instrument in hydraulic dredging monitoring. Finally, the results showed that when the concentration was measured, the particle size difference at a low concentration was within ±10%, and the ±5% detection error rate standard could be passed. At medium concentrations, particle size variability is within ±15% to 10%, which can pass the ±5% detection error rate.; At high concentrations, the difference in particle size is III within ±10% and can pass the ±5% detection error criterion. Because the situation encountered by the ultrasonic instrument during dredging monitoring and laboratory calibration is not the same, sediment concentration monitoring cannot be accurately monitored. In particular, sludge with a larger particle size has a greater influence on the ultrasonic instrument. Therefore, even though the ultrasonic instrument has been calibrated in the laboratory, it is still difficult to use the ultrasonic instrument to monitor the hydraulic dredging in the reservoir.