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。

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.

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經濟部水資源局，台灣地區地下水補注量估算，能邦科技顧問股份有限公司，2000年。