本文使用FLO-2D數值模式,模擬角埔溪土石流流動。首先至現地進行溪床泥砂採樣,將泥砂帶回實驗室進行流變試驗,經由試驗得到體積濃度與流變參數的函式。本文利用一簡易模擬渠槽,研究各種不同的體積濃度、流變參數,對土石流流動之影響。 此外,本文探討當兩土石流支流交匯的情況下,對於土石流流動之影響。研究區域內的角埔溪集水區,上游有南側與北側兩個支流,本文假設上游的兩支流同時發生土石流,並進行模擬。結果顯示,在兩支流交匯處之流動深度,和無匯流者相比差異約達7 公尺,與災後資料相比,發現考慮匯流較符合災後的情形;本研究也模擬當角埔溪土石流匯入旗山溪河道產生的影響。由FLO-2D定床模擬假設下,其結果顯示,當支流角埔溪因流量小於主流旗山溪的流量,匯入後對於旗山溪水面最大的抬升量約為30 公分左右。
This paper uses the FLO-2D numerical model to simulate debris flow in the Jiaopu River. First, a field investigation is conducted to bring silt back to the laboratory for rheological tests, in order to get through the volume concentration and function of the rheological parameters. In this paper we also use a simple channel to study various volume concentrations and the rheological parameters of debris flow. In addition, we investigate the phenomenon of two debris flow tributary confluence. Jiaopu River’s catchment within the study area has upper reaches of two tributaries to the south side and the north side. We assume that the two tributaries upstream debris flows occur at the same time. The results of simulation show that the difference in the two situations is approximately 7 meters. Compared with the post-disaster information, we find that the model which considers confluence to be more in line with post-disaster situations. This study also simulated when debris flow from the Jiaopu River flowed into the Chishan River. Under FLO-2D simulation of a fixed bed, the results show that when the tributaries Jiaopur River flow is less than the mainstream of the Chishan River, the impact to the Chishan River water surface is an uplift of about 30 centimeters.