饱和细砂中裙式吸力基础水平单调加载模型试验——承载力及变形分析

Model tests on lateral bearing capacity and deformation of skirted suction caissons in saturated fine sand under horizontal monotonic loading

海上风电资源的开发和利用是当今世界关注的热点问题，作为其塔架的基础，主控荷载是水平荷载。裙式吸力基础具有更高的水平承载能力和控制水平位移的能力，故非常适合作为海上风电塔架的基础。通过饱和细海砂中裙式吸力基础的水平单调加载模型试验，探究基础水平承载力的影响因素及转动点位置的变化规律，并分析了地基土的变形影响范围及规律。研究发现：与传统吸力基础相比，裙式吸力基础的水平承载力提高显著，且能有效控制水平位移；水平承载力随基础的裙高、裙宽的增加而增大，随加载高度的增加而减小；在水平荷载作用下基础主要是绕某一点（即转动点）发生转动，转动点位于主桶长度的0．45～0．7倍之间；达到极限荷载时，地表隆起范围远远大于沉降范围，沿加载轴线方向，隆起范围约为2．5倍主桶直径。

Applications of offshore wind energy are increasingly attracting world attention. Horizontal loads play a predominant role in the foundation design. The skirted suction caisson, as a novel type of foundation, is capable of providing greater lateral bearing capacity and limiting the horizontal displacement, especially suitable for foundations of offshore wind turbines. A series of model tests are conducted to investigate the behaviors of skirted suction caissons under monotonic lateral loading in saturated marine natural fine sand. The test results show that the horizontal bearing capacity of the skirted suction caisson is significantly improved compared with that of the traditional suction caisson, and its horizontal displacement is effectively controlled. The bearing capacity increases with the increasing size of the skirted structure, and decreases with the increase of the loading eccentricity. The skirted suction caisson mainly rotates with a rotation center which locates approximately at a depth of 0.45-0.7 times the main structural length. When the ultimate load is reached, toward the loading direction, the range of ground surface have is approximately 2.5 times the main structural diameter away from the edge of caissons.