臺灣博碩士論文加值系統

本研究以沈泥質砂土在長1.75 m、寬1.35 m、高0.7 m的流槽內堆置一厚度0.28 m與坡角為30°的邊坡，並進行模擬降雨試驗探討邊坡在降雨中的破壞機制與土砂流出之特性。在邊坡的坡趾處、中段與頂部埋設土壤水分計，用來監測降雨時邊坡內部含水量與孔隙水壓的反應，並藉由邊坡匯流口所收集邊坡破壞後所排放出之土砂，來瞭解其排放率與混合物中體積濃度的變化情形。
實驗結果發現，邊坡破壞以坡趾液化為開始發生的起點，然後形成後退式破壞並逐漸的往邊坡上游發展。邊坡中土壤水分計有兩種反應模式，第一種為直線上升型，發生於邊坡底部。第二種為兩階段上升，發生於土層中。在邊坡中段部位的土壤含水量急遽上升時，為邊坡開始劇烈破壞的起點，因此排砂率、排水率與體積濃度開始急遽上升。邊坡的破壞與土砂排出速率隨降雨強度之增大而增大。

關鍵詞：降雨強度、含水量、排砂率、坡趾液化。

A series of artificial rainfall tests were performed on a 0.28 thick sandy slopes with a slope angle of 30°. A wooden sand box with 1.75 m long, 1.35 m wide and 0.75 m high was used inconjunction with soil moisture sensors and a data acquisition system to monitor the interior soil moisture response to the rainfall infiltration. The present study features the measurement of solid and water discharge from the slope subjected to rainfall. This substantiates the investigation into the relationship between the soil moisture response and the solid discharge (or waste) process.
Experimental evidences revealed that the liquefaction (or failure) of the slope toe triggered the retrogressive failure (or catastrophic) failure of slope , and the moment of slope toe failure seems to coincide with that for rapid increase in the moisture contents for the soil located at the soil base interface. It was also found that the rainfall intensity has a greater influence to the wasting process and soil moisture response when the rainfall intensity is 65 mm/hr.
Key word: Rainfall intensity、water content、solid discharge rate 、liquefaction of slope toe

誌 謝 I
論文摘要 II
Abstract III
目錄 IV
表目錄 VI
圖目錄 VII
第一章 緒論 1
1.1研究動機 1
1.2研究方法 1
1.3論文架構 3
第二章 文獻回顧 4
2.1邊坡破壞之形式 4
2.2邊坡破壞之原因 6
2.3降雨與邊坡破壞之研究 7
2.4 土石流體積濃度之相關研究 10
第三章 實驗儀器與律定方式之介紹 11
3.1實驗儀器介紹 11
3.1.1 實驗流槽 11
3.1.2 土壤水分計 12
3.1.3 人工降雨設備 13
3.2 律定方式 14
3.2.1 土壤水分計 14
3.2.2 降雨強度與均勻度 16
第四章 室內模型邊坡試驗 19
4.1 試驗內容 19
4.1.1 試驗土壤性質 19
4.1.2 土壤水分計儀器配置 20
4.2 試驗步驟 21
4.3 混合物之體積濃度的量測方式 24
第五章 試驗結果說明 25
5.1 降雨強度23mm/hr之試驗結果 25
5.1.1 邊坡外表與內部含水量之反應 25
5.1.2 砂土排放歷線 30
5-2 降雨強度65mm/hr之試驗結果 33
5.2.1邊坡外表與內部含水量之反應 33
5.2.2 砂土排放歷線 37
5.3 綜合結果討論 40
5.3.1降雨強度對邊坡內部含水量之影響 40
5.3.2降雨強度對邊坡排砂量之影響 41
第六章 結論 43
參考文獻 44

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