考虑竖向荷载影响的大直径单桩承载变形特性模型试验研究

Model Test Study on Bearing and Deformation Characteristics of Monopile Considering Vertical Load

为研究近海风机大直径单桩基础在长期受水平荷载影响时的承载变形特性问题,在双层地基中完成了大直径单桩模型实验,揭示了大直径单桩承载变形随循环加载次数的变化规律。试验结果表明:竖向荷载对桩身弯矩分布规律影响不大,但对桩身最大弯矩有所影响,相同循环次数下,无竖向荷载工况的桩身最大弯矩大于有竖向荷载工况的最大弯矩;同样工况下,施加竖向荷载能加剧水平位移的发展。桩身转角在加载初期快速增加,随后趋于稳定,有竖向荷载时的累积转角均大于无竖向荷载工况。在加载初期,有竖向荷载工况的转动中心深度小于无竖向荷载工况,但在加载后期,无论是否施加竖向荷载,转动中心深度均维持在0.72 L左右。

To study the bearing and deformation characteristics of large diameter monopile of offshore wind turbine under long-term loading,monopile model tests were completed in double-layered foundation and the law of load deformation of large diameter monopile varies with the number of cyclic loading is revealed.The experimental results show that the vertical load has little effect on the distribution of pile bending moment and influences the maximum bending moment of the pile.The maximum bending moment of the pile without vertical load is larger than that with vertical load under the same number of cycles.The development of horizontal displacement can be aggravated by applying vertical load under the same conditions.The pile turning angle increases rapidly at the beginning of loading and then stabilizes.The pile cumulative turning angle with vertical load is greater than that without vertical load.The depth of center rotation with vertical load is less than that without vertical load at the beginning of loading.However,the depth of center rotation of the pile keeps at 0.72 L with or without vertical load in the later stage of loading.