为了研究钢筋锈蚀劣化对隧道衬砌耐久性的影响,通过大量不同锈蚀程度钢筋混凝土试件单轴拉拔以及压弯试验,获得了不同锈蚀率下,钢筋混凝土试件的粘结强度、开裂荷载的退化规律。通过ANSYS有限元数值模拟,建立粘结力退化模型,并基于试验所获粘结力退化曲线,模拟隧道钢筋混凝土衬砌在不同腐蚀程度下结构承载力的变化,进一步研究了不同程度锈蚀量对衬砌结构内部钢筋与混凝土相对滑移量的影响。研究结果表明:混凝土保护层厚度对衬砌结构强度损失有显著影响;钢筋锈蚀率与结构残余强度呈线性相关关系;重度锈蚀条件下衬砌结构最危险的受力截面为衬砌墙角处;钢筋腐蚀与开裂荷载并非简单的线性关系。研究结论可用于评估隧道混凝土衬砌结构腐蚀程度,并为新建隧道混凝土衬砌结构的耐久性设计提供参考。
In order to investigate the effect of steel-bar corrosion on durability of tunnel lining structure, based on a large amount of pullout tests and bending-compression tests on the control specimens and corroded specimens under different corrosion conditions, the degradation rules for the bond strength and the initial crack load were obtained. By using finite element numerical simulation software ANSYS, the degradation model for the bond strength was established. Based on the degradation strength curve, the reduction of bearing capacity for reinforced concrete (RC) lining of tunnel under different corrosion conditions was simulated. The effect of corrosion degree on the relative slippage between the reinforcement bar and concrete of the lining structure was investigated. The results show that the effect of concrete cover thickness on the strength loss of lining structure is significant. There is a linear relationship between the corrosion rate and the residual strength. Lining wall corner is the most dangerous section of the lining structure under heavy corrosion. There is not a simple linear relationship between the initial crack load and the corrosion rate. This study can provide foundation for the assessment of corrosion degree of concrete tunnel lining structure and provide reference for the durability design of new concretetunnel lining structure.