離岸風機所處的沿海風向較陸地上的風機更穩定本研究僅探討軸向力對風機結構下部之樁基礎產生作用時，基樁土間產生軸向反覆作用力之力學行為，前人對樁土行為的研究指出，土壤經過循環載重作用之後，剪力強度可能有減小以及殘餘應變產生累積的情況，此稱之為反覆退化(cyclic degradation)現象。有些情況雖然會隨循環載重作用的過程累積殘餘應變，但土壤本身的強度卻反而會有增加的可能性，若有發生，則稱其為反覆硬化現象。另外，對於基樁承受循環載重之作用，基樁的極限承載力與樁頭 位移也有類似的現象，進而對承載力產生影響。 本研究製作模型樁，並改良前人設計之模型樁之加載及紀錄系統，在飽和砂土中進行靜態極限樁載重試驗，得到模型樁之靜態極限抗壓力，並由此施加靜態極限軸向加載以及多循環軸向加載試驗，及動態加載 (dynamic 並探討前人研究下反覆軸向載重試驗與吾人之結果差異。;The offshore wind turbine is located in a more stable coastal wind direction than the land-based wind turbine. This study only investigates the mechanics of the axial forces acting on the lower pile foundation of the wind turbine structure and the axially reactive behavior of the pile soil. Previous studies on pile soil behavior point out that after the soil is cyclically loaded, the shear strength may decrease and residual strain may accumulate, which is called the cyclic degradation. In some cases, the residual strain may accumulate during the cyclic loading process, but the soil strength itself may increase. In addition, for piles subjected to cyclic loading, there is a similar phenomenon in the ultimate load carrying capacity and pile head displacement, which affects the bearing capacity. In this study, a scaled-down model pile was fabricated, and the loading and recording system of the model pile designed by the previous authors was improved to conduct a static limit loading test in saturated sandy soil to obtain the static limit resistance of the model pile. The differences between the results and those previous studies are also investigated.
