「簡易土石流雨量警告器」及其警告水位設定流程之研究

The Study on the Process-setting of Warning Level of「the Economic Warning Device for Debris Flow (EWDDF)」

周瑞南(Juei-Nan Chou)

指導教授 ： 張守陽

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2005年)

https://doi.org/10.6841/NTUT.2005.00267

摘要

本研究之「土石流雨量警告器」，除可顯示總雨量外，更可反應降雨強度之累積效應。依據降雨時不飽和土層破壞機制，設定警告水位及其求算流程，以提供潛勢地區，於土石流發生前，提出適時之警告。
本研究選一特定土體，推導警告器之上升水位理論式，繼而進行實驗，求算系統水力傳導係數，並驗證其上升水位理論式，經修正後之理論式可應用實際之現場。其次，為求算合理之設計警告水位，本文結合無限邊坡理論，探討不飽和土層於降雨過程中，隨時間及不同深度，次第達飽和後之穩定性；求得在不同地文及水文條件下，其與土層破壞時間之關係，繼而繪製土層破壞臨界雨量線；再依據土石流發生之水砂厚度比關係，進而求算土石流發生之平均設計降雨強度及其降雨延時，提出警告器警告水位設定之求算流程。
最後選擇南投縣愛玉子溪及花蓮縣壽豐溪土石流發生之案例，就其地文因子及雨量記錄，進行相關參數之敏感度分析，推算現場警告器之應有警告水位，並用來提供以後設定警告水位時，設計各參數之參考。就現場安全之考慮，本文建議給予一安全係數，俾能提前發佈警告，以增長避難時間。

關鍵字

雨量警告器 ； 土石流臨界雨量線 ； 入滲效應 ； 系統效應

並列摘要

This EWDDF which has been developed, responds not only the amount of rainfall also the accumulated rainfall intensity。Following the failure mechanism of unsaturated soil under raining, to find the process to get the warning level with EWDDF to warn in time and effectively for potential debris flow area。
One kind of soil is selected to derived the rising-level formula, then go to lab.to find the system hydraulic conductivity, and to verify the formula with the experiment results。Next ,for getting a reasonable warning level ,it is to combine the stability theory of the infinite slope to get the stable situation of slope, which varied along depth as well as time, after being saturated during rain。Then a pair of regression curves can be drawn to get the relations among failure time、critical rainfall and water-sand depth ratio, that induces the process to get the warning level with EWDDF。
Finally, 3 cases of debris flow disasters are studied to apply with and to verified the derived formulas as examples。One case at AI-Yu-Tsu creek, Nan-Tou county, two cases at Shou-Feng Creek , Hwa-Lien county；the related hydro-and geo-factors are considered。Do calculation and the reasonable warning levels are found。However, a safety factor is suggested for warning earlier and getting more time to escape。

並列關鍵字

Economic Warning Device for Debris Flow(EWDDF) ； Infiltration ； critical rainfall curve for debris flow ； systematic effect

參考文獻

[8] 連惠邦,「土石流之定量判別指標」，中華水土保持學報,第二十八卷，第二期，1997。

[5] Hamblin, W. Kenneth, and Christiansen Eric H., Earth’s dynamic system(ninth edition), USA: Prentice Hall, 2001,pp. 262-283.

[7] 黃漢誠、陳主惠、譚義績，「未飽和層土壤水份遲滯效應之研究」，農業工程學報，第四十六卷，第四期，2000，第33-47頁。

[9] 游繁結，「土石流基礎研究(一)：土石流發生機制之研究」，中華水土保持學報，第十八卷，第二期，1987，第28-40頁。

[11] Brooks, R. H., and A. T. Corey, “Hydraulic properties of porous media,” Colo. State Univ. Hydrology Paper, no.3, 1964, pp.1-27.