利用數值地表模型估算疏濬工程土砂量體之可行性評估

Feasibility Study on Estimating of Dredging Engineering Volume by Using Digital Surface Model in Varus Creek

陳政廷(Chen Chung-Ting)

指導教授 ： 李明熹

國立屏東科技大學/工學院/水土保持系所/碩士(2021年)

https://doi.org/10.6346/NPUST202100392

摘要

本研究於屏東縣來義鄉來社溪與瓦魯斯溪匯流口之疏濬工程，於施工之前、中及後，以無人飛行載具拍攝4個時期的空拍影像，並於空拍前以VBS-RTK方式在研究區域周圍布設地面控制點，以Pix4Dmapper建立河道4個時期之正射鑲嵌影像以及DSM，本研究將量測時間分為兩個區間以地理資訊系統進行河道高程變化量以及土砂量體之估算，並與一般斷面測量方式所使用之平均斷面法分別和疏濬工程之每日採取量進行比較。其結果顯示河道經疏濬後河道高程有明顯的下降，且河道的平均堆積高度在疏濬過後有緩慢上升的趨勢，顯示疏濬後之河道斷面能長時間維持。DSM之土砂估算量較為接近真實採取量，其第一區間及第二區間之誤差百分比為18 % (高估)以及-18 % (低估)，而傳統方法之第一區間與第二區間誤差百分比分別為高估之80 %以及62 %。以無人飛行載具應用於量測疏濬工程之河道地形，能方便快速的獲取較精密的河道地形資料，估算土砂量與誤差值也較傳統方法優良，將無人飛行載具應用於土砂監測可以提升數據的收集效率以及數據的精度。

關鍵字

疏濬工程 ； 無人飛行載具 ； 數值地表模型

並列摘要

The study site selected in Laishe creek and Varus creek’s confluence, Pingtung country. To know the feasibility of Unmanned Airborne Vehicle (UAV) for terrain monitoring of dredging. Compare two methods of earth mass estimate, the average-end-area method, and the Digital Surface Model (DSM) method with the real dredging earth mass value. The Average-end-area method used the virtual base station real-time kinematic (VBS-RTK) to measure several coordinates of every dredging cross section to get the area of the section. Estimate the earth mass by using the method formula. The result shows that the error between the average-end-area method and the true value is 80% and 62%. DSM method used UAV to photograph the area of dredging river surface or 4 periods, once each before dredging and middle of dredging, twice after dredging. To make sure the elevation value of DSM’s accuracy, set 8 ground control points (GCP) by VBS-RTK around the study site before the photography. Obtained accuracies are centimeters to decimeters. Input the images and GCPs into Pixel4dMapper to processing the every period’s mosaics and DSMs. Let two periods of DSM minus each other to estimate the earth mass and calculate the riverbed variation. The result shows that the percentage error between the DSM method and the true value is 18% (overestimate) and -18% (underestimate). Elevation of riverbed is obviously decrease. Average aggradation slowly increase with the end of dredging. UAV can easily and quickly get the high resolution terrain data. Higher accuracy of earth mass estimation than the average-end-area method. According to the result application UAV into terrain monitoring of dredging can increase the efficiency and data accuracy.

並列關鍵字

Dredging Engineering ； UAV ； Digital Surface Model

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