凝聚性沉滓傳輸機制之模擬應用研究

Abstract

凝聚性沉滓運移機制相當複雜，其內部凝聚力受到許多因素所影響，對於基本運移機制可由沉滓之沉降速度、淤積公式、啟動條件、沖刷公式等傳輸行為加以探討，而本研究主要採用前人實驗結果及理論公式，利用一維有限解析法動床模式加以分析探討其運移行為。 首先，本研究在既有之一維有限解析法動床模式架構上，植入可同時模擬凝聚性沉滓及非凝聚性沉滓運移行為的機制，並假設沖刷與淤積案例來驗證是否符合其物理機制，並且考慮可能影響凝聚性沉滓沖刷與淤積的因子，進行敏感度測試，以助往後模擬結果之分析，最後再以石門水庫現場案例來加以模擬應用，所得結果可供水庫排砂計畫之參考。

The mechanism of cohesive sediment transport is very complicated, with the cohesive force being influenced by many factors. The transport mechanism can be examined through the following processes: settling, deposition, initiation of movement, and erosion. This study uses 1-D finite analytic mobile-bed model to analyze the transport mechanism according to the previous investigators’ experimental results and theoretical formulas. On the basis of the existing 1-D finite analytic mobile-bed model, this study builds in the mechanisms of simultanteausly simulating the processes of cohesive and non-cohesive sediment transport. Several hypothetical erosion and deposit cases have been proposed to examine the model’s capability. In addition, sensitivity analysis is carried out on the possible influential factors of the cohesive erosion and deposit processes to assist farther analysis of the simulation results. Finally, the Shihmen Reservoir’s deposition case study is simulated and the results provide some useful information for the reservoir flushing operation in the future.