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以有限元素程式Plaxis分析加勁擋土結構之力學行為（含潛變效應）
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| 作者 |
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周銘瑋 |
| 學校系所 |
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國立宜蘭大學土木工程學系碩士班 |
| 地點 |
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全臺 全部
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| 研究內容 |
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[中文摘要]
地工合成材料加勁擋土結構近年來發展相當迅速，然國內因質佳的填築土料來源較為缺乏，且基於水土保持法規挖填平衡原則，故於一般山坡地等民間工程多以現地材料為填築土料。目前現有的以及正在訂定的技術手冊或設計規範，基於上述之理由，也已儘量放寬填築土料選取之基本要求，範圍甚至可能從GW至CL。因此，本論文利用國立宜蘭大學2002年所構築的二座小型地工合成材料加勁擋土牆（稱為宜大砂土加勁擋土牆及宜大黏土加勁擋土牆），長期量測加勁材在加勁擋土牆內之應變分佈情形，以瞭解不同填築土料之加勁擋土結構應力-應變行為。並利用有限元素程式PLAXIS模擬宜大加勁擋土牆之整體穩定分析、破壞模式、彈性變形、及加勁格網受張應力之行為性質，且利用模擬分析宜大加勁擋土牆結果與實測結果加以比較探討，發現模擬結果與實測結果相符。
為能對不同材料性質的地工合成材料加勁擋土結構之互制行為，有更深入之瞭解，除了善加利用宜大砂土加勁擋土牆及宜大黏土加勁擋土牆外，本論文更以宜蘭縣境內大規模之地工合成材料加勁擋土結構進行數值模擬分析，探討其安全係數、潛在破壞面、加載荷重影響、彈性變形及加勁格網受張應力之行為性質。由分析結果顯示宜蘭縣境內大規模加勁擋土結構皆為一穩定狀態之結構物，加勁格網最大受張應力範圍為4.09至9.82 kN/m。由於宜蘭地區之土層涵蓋許多黏土，加勁擋土結構於工程之應用，常利用黏土作為加勁擋土結構之填築土料。因此，本論文亦嘗試利用軟弱土壤潛變模式，來對於加勁擋土牆之潛變行為互制關係進行研究，由結果顯示格網受張應力隨著時間增大，而格網受張應力之趨勢相同。潛變分析結果顯示，雖然加勁擋土結構存在著潛變效應，然其屬於穩態潛變階段，潛變總量相對較小，且有慢慢減緩之趨勢，不致造成潛變破壞之行為。
中文關鍵詞：加勁擋土結構、加勁擋土牆、地工合成材料、有限元素法、潛變
[英文摘要 Abstract]
In recent years, geosynthetic reinforced soil retaining structures have been increasingly constructed in Taiwan. However, because the good-quality backfilled materials are scarce and the principle of balancing cutting and filling is required to follow by the soil and water conservation legislation, the in-situ soils are used as the backfilled materials in civil engineering projects. Based on the reasons mentioned above, in the current technical manuals or design code, the basic requirement of backfilled materials has been relaxed and thus the backfilled materials in a range from GW to CL may be used. In this thesis, by utilizing two geosynthetic reinforced soil retaining walls constructed in the test site of National Ilan University in the summer of 2002, we carried out the long-term measurement of the stress and strain distributions in the geosynthetic reinforcements in order to understand the behavior of the model structures with various kinds of backfilled materials. In addition, with the aid of the finite element method program PLAXIS, we performed simulation analyses of stability, failure mode, elastic deformation, and the behavior of geogrid under tensile stress. From the comparison of the predicted results of the FEM model with the measured data of the model structures, we found that the simulation results are close to
the measurements.
In addition to the investigation of two geosynthetic reinforced soil retaining walls, we performed numerical simulations of large-scale reinforced soil retaining structures with various property materials in Ilan County to further understand the interaction of the structure. From the investigation of the safety factor, potential failure surface, effect of additional loading, elastic deformation, and behavior of the geogrid under tensile stress, we found that the geosynthetic reinforced soil retaining structures in the Ilan County are stable structures. The largest tensile stress of the geodrid is in a range from 4.09 to 9.82 kN/m. Because clayey soils cover a wide area in the Ilan County, clayey soils are often used as a backfilled material for the geosynthetic reinforced soil retaining structures. In this thesis, we also investigated the creep behavior of the reinforced soil retaining structure by using a creep model of soft soils. The results indicated that the tensile stress of the geodrid is increasing with time. Although the creep behavior exists in the reinforced soil retaining structure, the creep is in the steady-state stage, the total creep is relatively small, and the tendency of creep is gradually slowing down; therefore, the creep will not result in a failure of the structure.
Keywords：Reinforced soil retaining structure、Reinforced soil retaining wall、Geosynthetics、Finite element method、Creep |
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