摘要
大型风电机组基础顶部的巨大倾覆弯矩是其承受的主要荷载,该倾覆弯矩将转化为单桩顶部的竖向作用力。由于风的周期性,作用在风电机组群桩基础顶部的荷载具有明显的循环特性。循环荷载作用下风电机组基础将产生不均匀沉降并倾斜,因而累积沉降控制是风电机组基础设计中的关键问题之一。分析了风电机组及其群桩基础的受荷特点,计算了典型风电机组的桩顶循环荷载谱。通过桩基循环模型试验发现桩顶循环荷载比小于临界值λmin时,桩顶无累积沉降发生,因而保证风电机组循环荷载比小于该临界值则可较好地控制风电机组基础的长期不均匀沉降。根据试验结果建立了偏压条件下桩基累积沉降与循环次数的关系,用于预测风电机组基础的长期附加不均匀沉降。
Wind turbine foundations are subjected to large wind-induced overturning moinents, which transform predominantly into axial loading on piles. Such load is cyclic in nature due to the periodicity of wind and is a major load on turbine structures. The cyclic loading may cause non-uniform settlement and inclination of the turbine foundation, which is vital factor for foundation design. The behavior of the wind turbine and its pile group foundation under wind load are investigated. The typical cyclic load the spectrum of the loading on the head of single pile is also calculated. A critical value of cyclic axial loading ratio termed minimum cyclic loading ratio is identified by large-scale model tests of single pile. Below this threshold there is little settlement of the pile head even with thousands of cycles of loading. Control of the actual loading ratio for single pile may constrain the long-term non-uniform settlement of the turbine foundation within the design limit. The relationship between non-dimensional settlement and numbers of loading cycles is also proposed for prediction of the accumulated settlement of turbine foundation if the actual loading ratio is larger than the threshold.
出处
《土木工程学报》
EI
CSCD
北大核心
2010年第3期75-80,共6页
China Civil Engineering Journal
基金
国家"863"高技术研究发展计划资助项目(2007AA05Z427)
神华科技创新项目资助(SHJT-06-04)
关键词
风电机组
基础
循环荷载
累积沉降
wind turbine
foundation
cyclic loading
accumulated settlement
