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碩士論文公告區 |
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| 年度： | 95 | |
| 姓名： | 汪俊良(Jun-Liang Wang) | |
| 論文題目(中)： | 打擊式預力混凝土基樁承受軸向荷重行為 | |
| 論文題目(英)： | A Study on The Axial Loaded Behavior of Driven Prestressed Concrete Piles | |
| 摘要(中)： | ||
| 為獲得完整的打擊樁荷重-沉陷曲線，本研究同時利用砂土與粘土的組合律發展一套數值分析方法，模擬預力混凝土(PC)基樁貫入土層的過程，再分析此基樁於層狀土壤中承受軸向荷重之行為，並利用現場試驗結果來驗證數值分析之可行性。 研究結果顯示，本研究所發展的數值分析方法模擬基樁貫入土層所得之徑向位移及荷重-沉陷曲線與現場試驗結果相近。由於地下水位影響土壤的有效應力，因此當基樁位於砂土層中，地下水位於地表的基樁極限荷重小於無地下水者；對長徑比L/D=67的基樁而言，其差值可達30%。將層狀砂土簡化成單一砂土層分析所得之基樁極限荷重，其誤差小於2%；但將層狀黏土簡化成單一黏土層分析所得之基樁極限荷重，其誤差可達20%。無論是砂土層或是黏土層，當打擊式PC樁長徑比L/D大於10後，摩擦力對總荷重的貢獻超過90%，因此可將基樁視為摩擦樁。增加土壤的SPT-N值、基樁直徑與長度皆可增加基樁的承載力。於黏土中以增加直徑的效果最顯著；於砂土中則以增加樁長的效果最佳。 |
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| 摘要(英)： | ||
| To obtain complete load-settlement curves of driven piles, two constitutive equations for both sand and clay were adopted to create a numerical program. Using the developed program, the processes during piles driven were simulated, and then the axially loaded behaviors of the PC piles in layered soils were estimated. To verify the applicability of the numerical program, the results calculated by numerical program are compared with those results measured from full scale pile load tests. It was found, not only the radial displacement during a pile driven but also the load-settlement behaviors of piles calculated from the presented model are close to those measured from the field tests. Comparing with a pile driven into sandy soil without ground water, a lower ultimate load was estimated from a pile driven into sandy soil which water table lies on ground surface. The distinction between above two situations was calculated up to 30% as a pile with length to diameter ratio L/D of 67. The ultimate capacities of piles installed in a layered sandy soil are similar to those driven into a pure sandy soil. However, as the soil conditions mentioned above are changed into the claypan, error of 20% was estimated by numerical results. No matter a pile driven into which a sandy layer or driven into a claypan, the friction force always dominates 90% of ultimate load as the pile L/D is greater than 10, the pile can be categorized as a frictional pile. As the SPT blow accounts of soil, the diameter and the length of piles increased, the ultimate pile capacities also increased. Increasing pile diameter and pile length should be the best choices to increase ultimate load of piles driven into sandy soil and clayed layer, respectively. |
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| 相關連結： | http://ethesys.lib.cyut.edu.tw/ETD-db/ETD-search-c/view_etd?URN=etd-0901107-150337 | |