大型风力机圆形扩展基础倾覆破坏机理分析

为研究以坡积土为持力层的风电基础在风荷载作用下的倾覆破坏机理,以2 MW装机容量的圆形扩展基础为研究对象,基于ABAQUS有限元软件对该基础的室内1∶10缩尺模型的地基土应力和基础沉降进行计算研究。同时利用该基础的缩尺模型试验结果验证数值模型的可靠性。研究表明:随机风荷载引起的地基土应力的扩大效应和不均匀沉降的扩大效应,是导致风力机基础出现倾覆破坏的主要原因;当受强风荷载作用时,迎风侧基础边缘的土体首先进入塑性区,发生屈服破坏,导致上覆土体隆起,基础倾覆破坏就会随之发生。建议在进行风电基础设计计算时,对风力机基础中轴线上的相对沉降验算点处的沉降乘以合适的沉降扩大系数,以保证基础结构安全稳定。

MECHANISM ANALYSIS OF OVERTURNING FAILURE OF CIRCULAR EXPANSION FOUNDATION OF LARGE WIND TURBINE

To investigate the toppling failure mechanism of wind turbine foundation with colluvial soil as the bearing layer under wind load,a 2 MW circular expansion foundation was taken as the research object. Based on the ABAQUS finite element program,the foundation soil stress and foundation settlement of the interior 1∶10 scale model is carried out. In the meanwhile,the reliability of the numerical model is verified using the scale model test results. According to the results,the effect of random ground wind load on the expansion of stress and uneven settlement of foundation soil are the main reasons for the toppling failure of wind turbine foundation.When subjected to strong wind loads,the soil on the edge of the windward side foundation first enters plastic range. As a results,the yielding damage of the overlying soil cause the overlying soil to bulge,consequently leading to overturning of foundation. It is recommended that when calculating the basic design of a wind turbine,the settlement at the relative settlement check point on the central axis of the wind turbine foundation should be multiplied by a suitable settlement enlargement factor so as to ensure the safety and stability of the infrastructure.