臺灣博碩士論文加值系統

　　本研究以室內模型試驗方式，模擬開挖區內側解壓後開挖底部之隆起行為，模型儀器的尺寸為74cm×50cm×43cm，模擬開挖之右半平面。試驗的方法是以不同初始含水量之泥漿準備重模土壤，以1.2kg/cm2壓密應力加壓並控制壓密時間達到3t100(主要壓密完成時間)，再將模擬開挖區之承壓鈑解壓，探討沉泥質粘土底部開挖隆起行為。
　　綜合模型試驗結果、數值分析及現場開挖破壞機制，發現試驗過程之土壤內部應力控制和模型之邊界對開挖底部之隆起行為有很大的影響，建議放大模型試驗驗儀器尺寸，側向土壓力在解壓時必須維持ko狀態，及將油壓及鋼鈑加壓系統改用氣囊加壓系統，以符合現地開挖破壞應力而達到模型試驗之成效。

　　In this study, A laboratory model test apparatus is designed in this research to study the effect of excavation induced stress release on the base stability in clay. The dimensions of soil specimen prepared from this apparatus are 74cm : 50cm : 43cm (length : width : height). It is to represent the symmetrical half of an excavation. The soil specimen is prepared from clay mud with different initial water contents and consolidated under a pressure of 1.2 kg/cm2. Three times the time needed to complete primary consolidation of a Oedometer test was adopted for the specimen consolidation. When consolidation was completed, removing the vertical load applied to the specimen surface simulated excavation process and the amount of surface up-heave was measured.
　　Based on the results of model test and numerical analysis, it has been found that the stress state within soil and the boundary restriction of soil specimen have crucial effect on the base heave behavior of an excavation. It is suggested that the size of soil specimen must be increased to allow the failure mechanism to be fully developed. The lateral earth pressure must be maintained at its Ko state also during unloading. Regarding the loading system, air bladders are more appropriate than hydraulic jacks and rigid loading plate.

1第一章　緒論
1.1研究動機與目的
1.2研究內容
2第二章　文獻回顧
2.1開挖底部隆起穩定性分析
2.1.1土壤承載力理論
2.1.2承載力破壞隆起分析
2.1.3圓弧破壞隆起分析
2.1.4強度異向性隆起穩定性分析
2.2離心機開挖模型試驗儀器
2.2.1離心機模型原理
2.2.2離心機模型試驗於開挖行為之研究
3第三章　試驗計畫、儀器設備及試驗內容
3.1研究試驗計畫
3.2儀器設備介紹
3.3試驗內容
3.3.1基本物理試驗
3.3.2試驗儀器校正
3.3.3開挖模型試驗
3.3.4三軸均向壓密不排水壓縮試驗(CIUC)
4第四章　試驗結果分析
4.1基本物理試驗
4.2開挖模型試驗
4.3三軸均向壓密結果
4.4試驗綜合討論與分析
4.4.1模型試驗結果分析
4.4.2數值分析結果
4.4.3模型試驗之改良
5第五章　結論與建議
5.1結論
5.2建議
6參考文獻

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