液化地盤樁基之靜力分析模式研究

Study on Static Modeling of Pile Foundation in Liquefied Soils

葉健輝(Chien-Hui Yeh)

指導教授 ： 張德文

淡江大學/工學院/土木工程學系碩士班/碩士(2006年)

https://doi.org/10.6846/TKU.2006.00844

摘要

本研究係以日本道路協會(JRA)與Tokimatsu建議之方法，模擬液化地盤下樁基礎受側潰流動影響之靜態反應。研究採溫氏基礎模式進行分析，並以有限差分法和矩陣技巧求解，藉Fortran程式語言開發LSPILE程式為分析工具。另利用閉迴式割線法模擬土壤與樁體之非線性行為，以了解側潰地盤下樁基礎之變形行為與破壞機制。研究結論如下：（1）JRA法所建議之土壓力模式與Tokimatsu法所建議之地盤變位模式皆可合理地估計基樁之變形與內力分佈狀況，JRA法參數選取較Tokimatsu法簡易且明確，但Tokimatsu法較為保守。（2）針對未液化底層土壤之處理模式，本研究建議將Ishihara土壓力模式納入考量，以取代傳統完全束制之模擬方式。（3）液化土層中樁基結構系統之破壞模式將同時與彎矩和剪力破壞有關，樁頂束制條件亦有影響。（4）樁體行為受液化土層和其上方非液化土層厚度影響至為明顯，故分析者須切實掌握液化潛能評估分析結果以避免分析誤差。（5）研究所得樁體最大位移量將發生於樁頂，而最大彎矩將發生於非液化與液化土層交界處；該項模擬可適用於液化所引致近地表土層流動時對樁基所產生之影響。

關鍵字

液化 ； 樁基 ； 側潰 ； LSPILE ； 破壞

並列摘要

This study following the methodology suggested by JRA and Tokimatsu, is to study the pseudo-static pile behavior under the liquefaction. It applies the programming language of Fortran to exploit the analysis of LSPILE. The research result is essentially founded on the model of wrinkler’s foundation. The difference equations and the matrix technique are used to solve the problem. With the employment of closed-form linear solution to model the nonlinear soil-foundation behavior, this study aims to examine the deformation and destruction of the pile foundation. Five research results are derived in this conclusion: First, both of the lateral earth pressure recommended by JRA and the subgrade reaction method by Tokimatsu can evaluate the deformation and distribution of the bending moment and shear force of pile foundation precisely. And that the parameters derived from the JRA method is more precise and definite than that of the Tokimatsu, but relatively JRA method is conservative for Tokimatsu method. Second, this study suggests adopting Ishihara’s theory of lateral earth pressure, in replace of the traditional fixed head, into consideration in order to access non-liquefiable and based layer. Third, the occurrence of failure type of the liquefiable layer’s pile foundation is found affected by the bending moment, shear force, and boundary condition. Four, the study shows that pile behaviors are mostly affected by thickness of the liquefiable layer as well as the non-liquefiable layer above it. Hence researcher should be make clear command on the evaluation of soil liquefaction. Five, the result of this study shows that the maximum deformation is at the pile head, while the maximum bending moment is on the border between liquefiable and non-liquefiable layers. Such simulation is applicable to study the influences on pile foundation by the floating of surface layer caused by liquefaction.

並列關鍵字

liquefaction ； pile foundation ； lateral spreading ； LSPILE ； failure

參考文獻

83.翁作新、陳正興、黃俊鴻 (2004)，“國內土壤受震液化問題之檢討” 地工技術，第100期，第63-78頁。

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