近年來台灣極力開發綠色再生能源，由於台灣為一海島地形，具有良好的風能潛力，因此離岸風力發電成為再生能源發展之重點。而目前離岸風場常用基礎形式為單樁式基礎，其於生命週期內需抵抗風力、波浪力及地震力等反覆水平側向力之作用。因此本研究利用現地竹南砂重模相對密度為40%之乾砂與飽和砂試體，及相對密度為60%之飽和砂試體，並以模型樁進行側推試驗，再將試驗結果以回歸分析求取樁身反應，比較基樁於乾砂及飽和砂試體中側推之差別。
本研究每一種類之試體皆進行2組極限側推試驗，利用試驗結果決定反覆側推試驗之載重振幅，並進行4組不同應力準位之單向反覆側推試驗，其反覆作用週數多達10000次，求取長週數加載下之樁頭累積殘餘位移及等效勁度之變化，並以回歸分析求得此樁土系統之p-y曲線，探討樁土互制之行為。從試驗結果發現，相較於乾砂試體而言，飽和砂試體因水的介入導致有效應力下降而變得較為軟弱，使其無法提供較大之土壤反力來束制樁身變位，而地盤反力係數受反覆側推產生之衰減情形也較為明顯。

In recent years, Taiwan has tried to develop green renewable energy. Because Taiwan is an island and has good wind energy potential, offshore wind turbine has become the focus of renewable energy development. At present offshore wind turbine foundation commonly used form of monopile, in the life cycle need to resist wind, waves, earthquakes and other cyclic lateral force. Therefore, this study uses in situ Zhunan sand to remold the dry sand and saturated sand specimen, and use the model pile to carry out the lateral loading tests. The test results will use regression analysis to obtain the pile response, and compare the difference between the piles in the dry sand and the saturated sand specimen.
In this research, each type of specimen were carried out two sets of ultimate lateral pile load test. According to test results to determine the loading amplitude of one-way cyclic lateral pile load tests. Four sets of one-way cyclic lateral pile load tests will be performed with different stress level of cyclic load, the number of cycle of cyclic loading up to 10,000 times, to obtain permanent displacement and equivalent stiffness of pile under long-term cyclic lateral loading. The p-y curve of the pile-soil system is obtained by regression analysis, and the behavior of pile-soil interaction is discussed. From the test results, it is found that the saturated sand specimen is relatively weak, so that it can not provide a large soil resistance to constraint the pile displacement, and the coefficient of subgrade reaction also has a greater attenuation.

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