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題 名 | 樁載重之數值及成效分析=Numerical Analyses of Pile Load Testing |
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作 者 | 倪至寬; 鄭文杰; | 書刊名 | 臺北科技大學學報 |
卷 期 | 39:2 民95.09 |
頁 次 | 頁57-76 |
分類號 | 441.17 |
關鍵詞 | 基樁載重試驗; 樁底灌漿; t-z曲線; q-z曲線; p-s曲線; FLAC□; Pile loading test; Base grouting; t-z curve; q-z curve; p-s curve; |
語 文 | 中文(Chinese) |
中文摘要 | 為了瞭解基樁受力行為,本研究以台北南港某工地二支試驗樁之試樁結果來作分析,二支試驗樁分別進行壓力和拉拔力試驗,以瞭解基樁承載能力。基樁施作方式採全套管施工,壓、拉力樁樁徑分別為2 和1.5 公尺,根據地質鑽孔報告顯示,壓、拉力樁之入岩深度分別為13.7 和17 公尺。為了解試驗樁於各載重階段之樁身軸力分佈和位移, 故於試驗樁樁身埋設鋼筋計、混凝土應變計以及伸縮儀,用以量測試樁過程中樁體所受應力、應變和伸縮量,將監測數據彙整成軸力、摩擦力和平均摩擦應力分佈情形,再進一步得到樁身平均摩擦應力(t)與位移(z)曲線、樁底應力(q)與位移(z)曲線以及樁頂荷載(p)與位移(s)曲線,而後比較壓、拉力樁之樁身摩擦應力。 以FLAC3D 進行基樁受力行為之模擬,土壤和岩盤採用彈塑性Mohr-Coulomb 組成律,基樁則假設為彈性材料,而後利用基地周圍地盤之土壤三軸試驗和岩盤孔內變形試驗結果作為FLAC3D 中組合律參數輸入的依據。研究中同時考量樁—土介面和樁—岩盤介面兩種介面情況進行模擬,並且紀錄基樁受力後特定斷面(鋼筋計埋設斷面)之軸力以及位移,將數值分析結果和現地試樁結果比較。最後針對樁底灌漿壓力進行數值模擬,其基樁上浮量和現地樁底灌漿結果相互比對,進一步評估樁底灌漿成效。本研究建立了模擬基樁受力行為之方法,所得模擬結果甚佳,可作為後續類似地盤條件下基樁受力行為模擬之參考依據。 |
英文摘要 | Two bored piles with base grouting are loaded axially, the results are used to compare with numerical analyses. One compressive pile with a diameter of 2 meters is drilled through clay deposit and into bedrock 13.7 meters. One tensile pile with a diameter of 1.5 meters is drilled through the same clay deposit and into bedrock 17 meters. Both piles are installed with monitoring system such as rebar strain meters, concrete strain gauges and extensometers. The monitored data during pile loading test are used to obtain average frictional stress(t) and the displacement(z) curve, the pile tip bearing(q) and the displacement(z) curve as well as pile head load(p) and the displacement(s) curve. Finally the t-z curves of the compressive pile and the tensile pile are analyzed. FLAC3D is used to simulate the pile loading. The soil and bedrock are modeled with Mohr-Coulomb. The parameters of constitutive law are calibrated from soil triaxial test and rock bore hole deformation test. Pile is assumed as elastical body. The interface element is used to simulate the pile/soil interface and pile/rock interface. The numerical results are compared with pile loading test in terms of t-z curve, q-z curve and p-s curve. In addition, stress path analysis is attempted to understand the friction characteristics during compressive loading and tensile loading. Finally, the pile base grouting is simulated, and the uplift is analyzed. The result from this study is promising and the numerical modeling is successful. |
本系統中英文摘要資訊取自各篇刊載內容。