- 期刊
- OpenAccess
懸浮載輸運對沖積河流複式斷面底床演變之影響
The Effect of the Suspended Load Transport on Bed Evolution of Compound Channel for Alluvial Rivers
摘要
台灣河流中下游底床質常在短距離中由礫石質河床轉變成砂質河床，故探討底床演變時，應包含不平衡的懸浮載輸運。本文求解懸浮載濃度對流－擴散方程式，得到沖積河流主槽與兩側洪水平原之懸浮載輸運率，而發展複式河槽非均質底床演變數值模式，並探討懸浮載輸運對底床演變之影響。應用此數值模式模擬測試渠道及曾文溪曾文水庫下游之底床演變，由包含及不包含懸浮載輸運下演算結果之比較可得：若底床質含有可能成為懸浮載之細顆粒，則必須考慮懸浮載輸運演算，才能合理地模擬底床演變。
並列摘要
The transition from gravel river-bed to sand river-bed in Taiwanese rivers often occurs in several kilometers. Therefore, the effect on bed evolution of non-equilibrium suspended load transport should be considered. This paper develops a mathematical model of bed evolution for compound channels with heterogeneous bed material by solving convective-diffusion equations for suspended-sediment to obtain suspended load transport. Then, the effect of suspended load transport can be discussed. This model is applied to simulate the bed evolution of a hypothetical channel flow and Tsengwen River below Tsengwen Reservoir with and without suspended load transport. The comparisons of the simulated results show that it is necessary to consider suspended load transport in the simulation of bed evolution for alluvial rivers as bed material including sand and silt.