林邊溪於莫拉克颱風潰堤之淤泥堆積模擬

Sediment Accumulation Simulation of Lin-Ban Creek Levee Broke by Typhoon Morakot.

張丞霄(Cheng-hsiao Chang)

指導教授 ： 葉一隆

國立屏東科技大學/工學院/土木工程系所/碩士(2014年)

https://doi.org/10.6346/NPUST.2014.00200

摘要

2009年8月7日莫拉克颱風引進強烈的西南氣流，在臺灣南部地區降下暴雨，使得位於屏東縣的林邊溪流域上游發生土石崩塌。大量泥砂隨著水流衝破林邊溪堤岸，造成下游淹水區域覆蓋淤泥。本研究之目的在應用FLO-2D模式分析莫拉克颱風事件時，林邊溪流域下游潰堤處的泥沙堆積情況。由模擬結果可得知在新埤測站之計算流量與實際流量之相對誤差為5.6 %，模擬之水位與實測水位之相對誤差為0.3 %。數值模擬結果顯示未考慮孔隙率時，在大同村的調查區域於莫拉克颱風之淤泥堆積深度為0.5 m，而實測淤泥堆積平均深度為0.6 m，依此推估現地調查之淤泥堆積的孔隙率為0.167～0.520之間。而林邊溪於莫拉克颱風期間之土砂體積濃度與流量關係曲線之率定方程式為y=0.0167x^0.4434，其中x為平均流量(cms)，y為土砂體積濃度(dimensionless)。

關鍵字

FLO-2D模式 ； 林邊溪流域 ； 淹水 ； 潰堤 ； 土石流

並列摘要

Typhoon Morakot introduced of a strong southwesterly flow on August 7, 2009 that made a strong storm in southern Taiwan. In upstream of Linbian Creek watershed, Pingtung County, occurred landslides that carried a lot of silt water and broken embankment downstream of Linbian Creek where was covered by silt flooding in the downstream area. The purpose of this study was attempted to analyze the sediment buildup located at the broken dike downstream of Linbian Creek Watershed at Typhoon Morakot event applied the FLO-2D mode. Simulation results show that the relative errors were 5.6% and 0.3% for flow rate and water level, respectively compared to the actually measured flow at Sinpi flow station. When sediment porosity was not considered the simulated accumulation depth of sediment was 0.5 m in Datong Village at Typhoon Morakot event and the average surveyed accumulated depth was 0.6 m. The estimated sediment porosity was between 0.167 and 0.520 based on the simulated and measured sediment depth. The calibration equation was y=0.0167x^0.4434 for sediment volume and flow rate during the Typhoon Morakot event for Linbian Creek. Where x is the average flow rate (cms) and y is the volume of sediment concentration (dimensionless).

並列關鍵字

FLO-2D model ； Lin-Ban river ； Inundation ； Levee Broke ； Mud Flow.

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