某风电塔混凝土塔筒及基础开裂对其安全性影响的研究

Effect of Cracking in the Concrete Tower and Foundation of a Wind Turbine Tower on Its Structural Safety

摘要: 为分析某风电塔项目混凝土塔筒及基础裂缝状态与结构响应特征，本研究采用现场实体检测、裂缝检测与监测、变形及频率测试、应变测试、加速度测试和沉降观测等方法，研究该风电塔混凝土塔筒及基础开裂对其安全性的影响。结果表明：基础局部混凝土抗压强度满足设计及相关规范要求；部分塔筒塔筒及基础钢筋间距、保护层厚度存在不满足设计或规范要求的情况。塔筒裂缝平均宽度均未超限，基础裂缝部分测点平均宽度超限；塔筒及基础裂缝平均深度均小于保护层厚度设计值。变形及频率测试表明，风机静止及运行工况下风电塔变形变化不大，风电塔实测基频均大于设计基频。应变与加速度测试结果表明，关键连接部位应变变化较小，运行工况下竖向振动峰值加速度满足相关标准要求。沉降观测未见陡降或突降异常。综合现有检测与监测结果，可认为该混凝土塔筒及基础裂缝在观测阶段变化不明显，整体趋于稳定，裂缝对该风电塔安全稳定运行的影响较小。

Abstract: To analyze the cracking condition and structural response characteristics of the concrete tower and foundation of a wind turbine tower project, this study employed in-situ inspection of structural members, crack detection and monitoring, deformation and natural frequency measurements, strain measurements, acceleration measurements, and settlement observation to investigate the influence of cracking in the concrete tower and foundation on structural safety. The results indicate that the local compressive strength of the foundation concrete satisfies the design and relevant code requirements, whereas the reinforcement spacing and concrete cover thickness at certain tower segments and foundation locations fail to meet the design or code requirements. The average crack width of the inspected tower did not exceed the allowable limit, while the average crack width at some measuring points on the foundation exceeded the limit; the average crack depth in both the tower and the foundation was less than the design value of the concrete cover thickness. The deformation and frequency tests show that the deformation of the wind turbine tower varied only slightly between the shutdown and operating conditions, and the measured fundamental frequencies were all higher than the design fundamental frequency. The strain and acceleration results demonstrate that strain variation at the critical connection zones was minor, and the peak vertical vibration acceleration under operating conditions complied with the requirements of the relevant standards. No abrupt or sudden drops were observed in the settlement records. Based on the available inspection and monitoring results, the cracks in the concrete tower and foundation exhibited no significant development during the observation period and tended to remain stable overall, suggesting that the cracks exert only a limited influence on the safe and stable operation of the wind turbine tower.