河川沖刷對河溪生態工法安全之評析

Safety Analyzing of River Bed Scouring in Stream Ecological Engineering Methods

李世強(Shih-Chiang Lee)

指導教授 ： 林鎮洋

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00356

摘要

一般大眾對『生態工法』或『生態工程』已不陌生，政府相關單位也大幅應用此法進行各項工程，但其需求、成因與省思或學理基礎並未相對受到重視，造成只重「應用」不重「科學」的盲點。從天然環境來看，台灣地質構造脆弱、水文變化差異極大，為穩定河川狀況、減少洪水或河川流路改變，以減輕人民生命財產的損失，於河川設置大量結構物穩定河岸、河床或築堤束水以箝制河川變化、設置水庫應付水資源日增之需求等人為工程，改變了河川自然的動態平衡；然而本土河溪生態工法構造物施設，鮮少考慮此一改變之平衡，導致結構物基礎埋置深度可能不足，使構造物長期的安全與穩定產生隱憂。
　　彙整過去關於生態工法安全之研究，從「河溪生態工法參考手冊」提出安全之原則，繼之「生態工法分析模式與設計要點研究」對於五種河床沖刷機制建議不同公式，而「河溪生態工法安全評估之研究」對於安全提出定性評估因子，再由「國外經驗公式評估國內生態工法護岸安全之研究」對安全因子與沖刷公式以實際案例進行試用；呈前人之研究，深入探討常見河溪環境的沖刷問題，並檢討「生態工法分析模式與設計要點研究」所建議之沖刷公式是否合理適用。本文將常見沖刷之類型分為：一般、彎曲、束縮及落差四種，由計算結果得知各經驗公式實際使用時仍需要進一步修正，後續若需要更準確的對於台灣河川沖刷狀況進行推估，則需以台灣河川特性為背景，利用實測或實驗獲得更精確之計算公式。

關鍵字

河溪生態工法 ； 沖刷經驗公式

並列摘要

Most people in Taiwan are aware of “Ecological Engineering Method” (or “Ecological Engineering”), and most of public works have been constructed using ecological engineering method. However, attentions have not yet been paied on the fundamental theory, resaulting in the negligence of scientificfoundation. The geological structure of Taiwan is weak and hydology is changful. In order to protect life and properties of civilian from disaster, structures have been placed in the river to stablize river and to provide water resources. River morphology has been changed due to various human activies. The negligence of considering dynamic equalibrium of river has already caused instability of hydraulic structures, in most cases, the fundation depth of structure is insufficient.
According to the research results of safety of ecological engineering in the past, the “Study on Localized Aquatic Eco-technological Methods in Taiwan III” provided the design priciples, “The Development of Model and Design Guideline for Ecological Engineering Methods” has suggesed five different bed scouring formula. Furthermore the “Safety Evaluation of Stream Ecological Engineering Mehtods” generated the qualitative safety evaluation factor, and the “Evaluating the Safety Measure of Local Eco-Technology-Based Bulkhead by Foreign Empirical Equation” has tested the suitability of both safety factor and empirical equation in many real cases. This article has discussed common scouring problems in depth, reviewed the scouring formula suggested from “The Development of Model and Design Guideline for Ecological Engineering Methods” for their rationality and applicability. The author assort common type of scour including: general, bend, constraction and drop. This article compared each empirical equation and suggested that those empirical eauqtions can only be used as refercence. The author suggested that further research using local data in needed to obtain local empirical equations. Howerer, scouring equations suggested in this article can be adopted for estimeting scouring depthes in a satisfactory manner.

並列關鍵字

Stream Ecological Engineering Methods ； Scouring Experiance Formula

參考文獻

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