海上风机基础大直径加翼单桩常重力模型试验数值仿真

Numerical simulation for 1g-model test of large diameter wing-monopile for offshore wind turbine

海上风机大直径单桩基础承受风、浪、流等水平荷载作用,提高其水平承载性能非常重要.针对一种通过在近地表桩体上设置稳定翼板以充分调动浅层土抗力的海上风机大直径加翼单桩基础,进行了常重力模型试验的数值仿真.数值仿真采用ABAQUS有限元软件结合Mohr-Coulomb模型,按钢管桩不同外径、壁厚、埋入深度,加载高度和加载方向,共进行9组试验.数值仿真结果与模型试验结果进行对比,均得出翼板长度或宽度的增加将引起所调动的浅层桩前土的土抗力范围增加,承载力提高,水平位移降低;翼板埋深增加,所调动的浅层土范围减少,承载力降低;这验证了数值仿真的合理性.进而借助数值仿真结果对桩、土受力特征进行了观察和分析,从数值仿真角度进一步验证了设置稳定翼能够显著提高浅层土抗力,提高单桩水平承载性能.

For the monopile of offshore wind turbine suffering horizontal loads such as wind, wave and current, its horizontal bearing capacity is one of the most important problems in foundation design. A new type of large diameter wing-monopile with a group of wings setting on the monopile near the mudline to rise the soil resistance is investigated in this study. By using ABAQUS finite element in combination with Mohr-Coulomb model, numerical simulation of 9 groups lg-model test for the wing-monopile with different shape parameters （length, width） , buried depth, height and degree of load is carried out. The mechanical characteristics of the pile and soil are shown and analyzed. The validity of the numerical simulation is proved by comparing with the model tests. It reveals that the soil resistance around the pile is mobilized fully. The horizontal bearing capacity of the monopole is increased in different grade depending on the shape parameters, the buried depth of the wings and the height and degree of the horizontal load. The numerical simulation results show that the monopile having stable wings can geatly rise subsoil resistance and remarkably improve the horizontal bearing capacity of the monopile at the same time.