基樁抗拉與抗壓承載力之差異為工程界尚有爭議有待解決之重要問題。本研究為一個三年期之連續性計畫，旨在詳細研究基樁抗拉與抗壓承載力之差異機制與定量關係。本研究第一年以數值程式分析探討不同樁種、樁身尺寸、不同土質、樁身包生比與平均應力場變化對抗拉與抗壓樁身受剪行為之影響。第二年規劃於土槽進行模型基樁載重試驗，比較不同土質不同長徑比下基樁抗拉與抗壓承載力之差異，並與數值模擬結果進行比對。第三年則於中央大學離心試驗機上進行模型基樁載重試驗，比較不同土質、不同長徑比下基樁抗拉與抗壓承載力之差異，並與數值模擬結果進行比對。最後綜合三年研究結果，具體提出不同土質、不同樁型、不同長徑比下，基樁抗拉承載力與抗壓承載力之定量關係，供工程界參考應用。 There has been considerable debate over the relative magnitude of pile bearing capacity in tensile (or uplift) loading, as compared with compressive loading. The problem hasn』t been solved yet, and is very important to the engineering profession. This research is a three-year project with the purpose of performing comprehensive investigation on the difference of tensile and compressive bearing capacity of piles in soils. In the first year of the study, Numerical analysis will be conducted to study the effect of pile type, pile size, soil type, poisson ratio of pile material, and the mean confining pressure change on the interface shearing behavior in tensile and compressive loading. In the second year, many model pile load tests will be planned to investigate the difference of tensile and compressive bearing capacity of piles with different slender ratio in different soils. Then, the test results will be compared with those from numerical analysis. In the third year, a number of model pile load tests will be performed in the 100 g-tons centrifuge at the National Central University to simulate the difference of tensile and compressive bearing capacity of piles with different slender ratio in different soils in the field. After that, the results of the centrifuge test will be compared again with those from numerical analysis. Finally, based on the three-year research results, we will propose a quantitative relation between the tensile and compressive bearing capacities of the piles which have different slender ratios and are installed in different soils. It is hoped the proposed relation will greatly improve the state of art of the problem. 研究期間 : 9808 ~ 9907
