近年來環保意識崛起，但由於台灣的能源短缺，必須仰賴火力、核能等非再生的發電方法，因此開發再生能源是現今的主要目標。更由於台灣四面環海，所以相當適合發展風力發電。所以如何去評估離岸風機的水平極限承載力，跟多循環載重下，估計單樁基礎的累計傾斜角度與累計水平位移，為本研究的目的。本研究將現地樁基礎進行離心縮尺，於80 g離心重力場下，進行單樁基礎受反覆側向水平力之離心模型試驗，所有側推的高程皆位於地表上34 m處。
本研究施作PP系列試驗，於飽和砂試體中對於風機模型單樁施加不同大小之單向反覆水平推力並以改變不同施力速度，藉以觀察受反覆水平力下的單樁之樁身位移、樁身旋轉角、樁身彎矩沿深度的分布狀態，並討論不同循環數與水平力大小對單樁基礎的影響，最後並透過使用最小二乘法回歸出樁身彎矩回歸曲線後與實驗量測值比較，並透過古典梁理論推求出樁之土壤反力(p)、樁身剪力(V)、樁身變位(d)以及旋轉角(θ)等方程式。
試驗結果顯示: (1) 透過將樁身所量測到之樁身殘餘變位、旋轉角便可回歸出一回歸公式，便可利用此回歸式模擬未來行為。(2)古典彈性梁理論及最小二乘法可有效反應出實驗樁身彎矩量的結果。(3)使用人機控制程式時，使用較慢加載速率(0.0015-0.0007)便可以達到較佳的控制效果。(4)最大側推力實驗中發現樁身最大彎矩位置(Z/D_p=1.6)隨側向力的增加，而逐漸下降，而當進行多循環側推時驗後，樁身最大彎矩發生於固定位置(Z/D_p=1.6)。最後利用上述所得到之參數便可對於未來風機單樁設計時作為參考之依據。

Recently, the environmental concerns is rising; due to the energy shortage in Taiwan, we must rely on some power generation methods like firepower, nuclear and other none renewable power generation methods, so the development of renewable energy is the main goal today. Because Taiwan is an island state surrounded by the sea, it's suitable for the development of wind power. Therefore, it is very important to estimate the ultimate lateral bearing capacity of monopole foundation, and to predict the inclination and permanent horizontal displacement of pile under cyclic lateral loadings.
In this study, the models were conducted in an acceleration of 80 g by using the NCU geotechnical centrifuge and the model is contained in the rigid container. The lateral load for each test was applied at the elevation of 34 m above the ground surface. PP-series tests were saturation sand models and the pile was subjected to different amplitudes of cyclic lateral load. Then use least squares method to regress moment of the pile. From the theory of beam on elastic foundation can get the formula about physical property of pile.
From the test results, the following conclusions can be drawn: (1) By use of the measurement pile head displacement and pile head rotation angle can regress the equations. These equations are useful for simulating future pile behavior; (2) the theory of beam on elastic foundation and the least squares method are useful; (3) When doing the test using slowly load speed (120-300 sec/cycle) can have best control; (4) The maximum bending moment occurred at the depth of 1.6 m under the ground surface while the lateral load was 968 kN. The place of maximum bending moment would move downward along the pile with increasing lateral loads.

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