以淤泥實驗探討壓密、射流、擾動及水力抽砂行為之研究

Abstract

本研究目的在於探討不同自重壓密天數下的土壤特性及外力裝置對水力抽砂的影響，試圖找出最佳效率的抽泥方法。論文分成兩部分:第一部分為了解土壤特性，透過在不同壓密天數下，記錄淤泥表面得到每日壓密量、以T型貫入實驗得到剪力強度和取樣方式得到分層密度，並建立壓密理論與實驗結果進行比較；第二部分為水力抽砂實驗，過去研究顯示，水力抽砂在長天數的條件下，因為土體強度太大，效果有限，因此本論文著重於此，設計在不同壓密天數的條件下，分別配置水刀、絞刀破壞土壤結構，同時進行水力抽砂，此外，配合雷射掃描方式記錄抽泥前後的地形，結果顯示，在無外力裝置的情形下，抽砂效率會隨著天數增加而降低，然而，對於短天數而言，有無搭配外力並沒有明顯差別，但對於長天數來說，外力裝置確實發揮功用，使得水力抽砂順利進行，效果較無外力裝置大幅提升。

In order to alleviate problems caused by reservoir sedimentation, the hydrosuction is an effective way for deposition removal. To help interpret the sediment properties of different self-weight consolidation duration, we investigated the shear strength by T-bar testing, density by sampling and settlement by record. Besides, the consolidation theory is built to compare with experiment results. Moreover, compared to previous research, we conducted a series of hydrosuction experiments focused on long consolidation duration, in which hydrosuction had limitation in withdrawal. In addition to the reduced-scale hydrosuction, water jet or rotary cutter was equipped as an external force to damage sediment structure by jetting and stirring. The result shows that the efficiency of hydrosuction with no equipment gets worse as consolidation duration increases. Furthermore, the external force equipment works well in long consolidation duration yet not sufficiently in short.