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系統識別號 U0026-0812200912052244
論文名稱(中文) 土壤性質對非飽和土體沈陷之影響研究
論文名稱(英文) A study of impact of soil textures on consolidation of unsaturated porous media
校院名稱 成功大學
系所名稱(中) 水利及海洋工程學系碩博士班
系所名稱(英) Department of Hydraulics & Ocean Engineering
學年度 94
學期 2
出版年 95
研究生(中文) 蔡宏洋
研究生(英文) HUNG-YANG TSAI
電子信箱 n8693106@ccmail.ncku.edu.tw
學號 n8693106
學位類別 碩士
語文別 中文
論文頁數 67頁
口試委員 指導教授-詹錢登
口試委員-陳主惠
口試委員-徐國錦
指導教授-羅偉誠
中文關鍵字 土壤沈陷、非飽和土壤、孔彈性力學 
英文關鍵字 soil consolidation  poroelasticity  unsaturated soil 
學科別分類
中文摘要 飽和土壤沉陷議題的研究自從Terzaghi (1923)至今,已趨於完善並在預測許多工程現地的土壤沉陷上也顯出重要性。惟有非飽和土壤的部份,至今較少被提及。本文研究了非飽和土壤的沈陷議題,採用的方法是Tuncay and Corapcioglu (1996)年由微觀的體積平均所發展出來的理論,並假設我們研究土體的上下部份分別為自由的排水液面與不可排水的土壤底層,且由於土壤在受壓之後的側向位移通常比垂直的位移來得小,故我們將三維的情況簡化為一維(垂直)的情況。最後將得到的解析解配合由Rawls等 (1992)所列出十一種土壤的相關水文特性參數數值模擬得到四種情況分析圖形,其中分別討論無因次孔隙水壓、非潮濕性流體空氣的飽和度變化量、壓密後土壤的孔隙率和土壤的總沈陷量。由結果圖形中,我們可以發現上述四種情況與土壤滲透係數並土壤統體模數皆有直接的關係,當中砂土是最容易排出孔隙流體的土壤且隨著滲透係數的漸小(例如壤質砂土),其排出的孔隙流體也會隨之減少。而黏土是當中沈陷量最大的土壤,且隨著統體模數漸大(例如砂質壤土),沈陷量也隨著愈小。而土壤孔隙率的變化也與土壤沈陷量的趨勢相仿。無因次孔隙水壓的圖形中,我們發現當孔隙中的水愈多時,其可以承受外加壓力的能力就會愈高,因而造成無因次孔隙水壓的消散情況相對之下比較不明顯,至於空氣飽和度變化的部份,由於其同時與土壤滲透係數和土壤統體模數有關,故從圖形中,我們發現接近表面處和接近土壤底層處的趨勢分別與土壤統體模數和土壤滲透係數所造成的影響類似。




英文摘要 Since Terzaghi (1923) proposed the theory of consolidation for saturated soils, the study of the problem concerning field soil settlements has been conducted successfully and showed its importance in many engineering problems. Conversely, the research on unsaturated soils only receives limited attention. This thesis focuses on the issue of consolidation of unsaturated soils by applying the theoretical results of Tuncay and Corapcioglus (1996) from the method of microscopic volume-averaging. The soil skeleton examined here is assumed to have a free drainage surface on its top and an impervious surface on its base. Since lateral displacements are typically much smaller as compared to vertical displacements during the process of consolidation, the problem of one dimensional representation is considered in the present study. The hydraulic and elastic parameters of eleven soils listed by Rawls (1992) were used as illustrative examples. Numerical results to model dimensionless induced pore pressure, induced saturation of the air phase, porosity change, and the total settlement in response to an applied stress were presented. It is concluded that all these physical parameters have a close relation to the bulk modulus and permeability of soils. Among the eleven soils, sand is most prone to squeeze the pore fluids. The amount of fluid expelled diminishes as the permeability decreases. On the other hand, clay settles largest. When the bulk modulus becomes greater, the settlement decreases more. The porosity was found to have the same trend as the amount of the settlement. The results observed from dimensionless induced pore pressure reveal that when the pore space contains more water, it has a better ability to bear the stress which acts on the top. Accordingly, the dissipation of the dimensionless pore pressure is not obvious. In reference to the behavior of the air phase, we see that it is affected both by the bulk modulus and permeability of soils. Lastly, it is found the consolidation in the upper part of soils is closely related to the bulk modulus whereas that in the lower part is dominant by the permeability.




論文目次 中文摘要.....................................II
英文摘要.....................................III
誌謝.........................................V
目錄.........................................VI
表目錄.......................................VIII
圖目錄.......................................IX
符號說明.....................................X

第一章 緒論.................................1
1-1 研究動機..............................1
1-2 文獻回顧.................................1
1-3 研究方法.................................4
1-4 本文架構.................................5
第二章 非飽合土壤沉陷理論模式...............6
2-1 控制方程式..............................6
2-2 一維的土壤沉陷問題......................8
2-3 邊界和初始條件..........................10
2-4 一維土壤沉陷問題的解析解................12
第三章 數值模擬.............................16
3-1 土壤分類................................16
3-2 土壤和流體物質參數......................17
3-2-1 統體模數與剪力模數.....................17
3-2-2 滲透係數和固體體積分率.................18
3-3 土壤水分特性曲線........................19
3-4 水力傳導函數............................21
3-5 其它相關參數............................22
3-6 數值模擬結果............................23
第四章 結果分析與討論.......................35
4-1 非飽和土壤的無因次孔隙水壓在不同飽和度隨深度
影響之結果分析...........................35
(1) 無因次孔隙水壓變化與孔隙流體飽和度的關係.35
(2) 無因次孔隙水壓變化與土壤滲透係數的關係...35
4-2 非飽和土壤的空氣飽和度變化量在不同時間隨
深度影響之結果分析.......................38
(1) 空氣的飽和度變化與時間的關係.............38
(2) 空氣的飽和度變化與土壤滲透係數和土壤統體
模數的關係...............................38
4-3 非飽和土壤的土壤孔隙率在不同時間隨深度影響
之結果分析...............................39
(1) 土壤孔隙率變化與時間的關係...............39
(2) 土壤孔隙率與土壤滲透係數和土壤統體模數
的關係...................................39
4-4 非飽和土壤的總沈陷量在不同飽和度隨深度影響之
結果分析.................................40
第五章 討論與建議...........................42
5-1 討論....................................42
5-2 建議....................................43
參考文獻.....................................44
附錄A 體積平均理論...........................47
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