海洋环境下腐蚀后钢管桩材料性能退化研究

Degradation of Corroded Steel Pipe Pile Materials Exposed to Marine Environment

钢管桩作为钢栈桥的重要组成构件,在海洋环境下会受到严重的腐蚀威胁。研究了东海某钢栈桥经历5年海洋自然腐蚀后钢管桩的材料性能。从钢管桩的浪溅区、潮差区和全浸区共加工16个拉伸试件,分析各区域的退化力学性能,根据试验数据建立弹性模量、屈服强度、应变硬化指数和强度系数等参数与平均厚度剩余率相关的回归方程,依据三线型本构模型建立3个区域真实应力-应变曲线的拟合公式。结果表明:浪溅区受腐蚀影响最严重,各区域钢材力学性能均存在一定损失;回归方程可以较好地预测3个区域的屈服强度;通过比较各区域的平均厚度剩余率适用范围,可知三线型本构拟合公式适用于腐蚀较为严重的钢管桩。

As important components of steel trestles,steel pipe piles are under serious corrosion threats in marine environments.This study examined the material properties and characteristics of steel pipe piles from a steel trestle bridge in the East China Sea,following five years of exposure to natural marine corrosion.A total of 16 tensile specimens were extracted from the splash zone,tidal zone and immersed zone of the steel pipe piles to analyze the degradation mechanical properties of each zone.Based on the experimental data,regression equations were established to relate elastic modulus,yield strength,strain hardening index,and strength coefficient to the average thickness residual rate.The fitting formulas for the true stress-strain curves of three regions were established based on the trilinear constitutive model.The results indicate that the splash zone experiences the most severe corrosion,and there are certain losses in the steel mechanical properties of each region.The regression equation can predict the yield strength of the three regions quite effectively.By comparing the applicable range of the average thickness residual rate in each region,it can be observed that the trilinear constitutive fitting formula is suitable for predicting steel pipe piles with more severe corrosion.