栓钉在风电机组基础环式基础加固中的应用研究

APPLICATION OF STUDS IN STRENGTHENING OF EMBEDDED-RING FOUNDATION FOR WIND TURBINE TOWER

根据风电机组基础环基础常见的破坏现象,深入研究基础环基础的受力机理和损伤破坏的原因。针对基础环T型法兰的构造缺陷,提出在露出柱墩顶面的基础环内外侧焊接栓钉并施加环向预应力加强基础环与混凝土柱墩之间的连接,给出适用于风电机组基础加固的栓钉计算算法。以某风电机组基础环基础为例,通过数值分析研究加固前后基础受力状态的变化,根据相关规范对其疲劳寿命进行评估。分析结果表明,该方法可在不损伤原基础结构的前提下,通过环向预应力和焊接在基础环上的栓钉,使钢制基础环和基础混凝土变形协调,改善T型法兰和基础环侧壁受力状态,缓解基础环埋深不足导致的基础环与基础顶面脱开问题及T型法兰附近应力集中问题,提高了基础的疲劳寿命。

The mechanic mechanism and damage causes of embedded-ring foundation for wind turbine tower have been analyzed according to the common damage phenomena. To address the structural defect of the T-shaped plate for the insert ring,a strengthening method of welding studs on the outside and inside surface of the steel ring combined with the circumferential prestressed technique is proposed to strengthen the connection between the insert steel ring and the concrete foundation pier. The engineering method is proposed to calculate the contribution of welding studs on the strengthening effect. Taking an embedded-ring foundation of a wind turbine tower as an example,a series of numerical analyses are carried out to investigate the stress state change of its concrete foundation before and after strengthening. The fatigue lives of the foundation concrete and welding studs are evaluated according to the relevant design standards.The results show that this strengthening method can coordinate the deformation of the steel embedded-ring and the concrete foundation by the circumferential prestressing technique and welding studs on the premise of not destroying the original foundation structure. And then the stress states of the T-shaped flange plate and the wall of the steel embedded-ring have been improved effectively. The gaps between the steel ring and the concrete foundation caused by the insufficient embedded depth have been reduced and the stress concentration phenomena in the concrete near the T-shaped flange plate have been alleviated. So,it can be concluded that the fatigue life of the foundation concrete near the T-shaped flange has been increased.