不同位置施工冷缝对风机基础力学性能影响的研究

Research on the Influence of Construction Cold Seams at Different Positions on the Mechanical Properties of Wind Turbine Foundation

风机基础主要承担风电机组、塔筒等上部结构的荷载,风电机组基础设计规范要求基础混凝土应一次浇筑成型。风机基础的结构特点和所处环境造成其施工质量控制难度大,基础混凝土浇筑过程中极易出现施工冷缝等质量缺陷。基于非线性有限元数值分析方法,建立多种风机基础混凝土弥散裂缝模型,采用界面单元模拟水平施工冷缝,分析不同位置的水平施工冷缝对风机基础结构力学性能的影响。数值分析结果表明:施工冷缝会削减结构的受力性能,当施工冷缝位于风机基础台柱以下时,会导致正常使用极限状态下基底脱开率超过规范允许值,随着冷缝位置向基底移动,基础脱开率呈现先增大后减小的变化趋势;此外,施工冷缝会造成基础整体刚度下降、裂缝增大且超限裂缝明显增多。

Wind turbine foundation bears the weight of the tower,impeller,and engine room,as well as all the loads of the upper structure.The"Code for Design of Wind Turbine Foundations for Onshore Wind Power Projects"requires that the foundation concrete should be poured and formed in one go.The structural characteristics and construction methods of the fan foundation make it difficult to control the construction quality, and quality defects such as construction cold seams are prone to occur during the pouring process of the foundation concrete.This article establishes a dispersion crack model of fan foundation concrete based on nonlinear finite element numerical simulation method. Interface elements are used to simulate horizontal construction cold seams, and the influence of horizontal construction cold seams at different positions on the mechanical performance of fan foundation structure is analyzed.The numerical results indicate that the retention of construction cold seams can cause a reduction in the structural stress performance.When the construction cold seam is located below the column,it will cause the base detachment rate to exceed the limit under normal use limit state. When the position of the cold seam changes near the base, the detachment rate shows a trend of increasing first and then decreasing;In addition,when construction cold seams are left in the foundation,it will lead to a decrease in the overall stiffness of the structure, an increase in structural cracks, and a significant increase in exceeding limit cracks.