不均匀胶层对CFRP-混凝土弧形界面应力状态影响

Study on effect of inhomogeneous adhesive layer on curved interface stress state of CFRP-lining concrete

受输水隧洞洞内水流冲刷的影响,衬砌混凝土表面的凹凸不平会导致胶层局部厚度发生改变。采用有限元方法研究了胶层厚度的不均匀对CFRP-衬砌混凝土界面应力状态的影响。基于“实体-弹簧-实体”三维有限元模型,在胶层单元以及衬砌混凝土单元内设置缺口以模拟凸台、凹槽以及气泡的存在;通过改变缺口的位置、深度和长度,分析了不同缺口条件下加固界面应力状态的变化规律。研究结果表明:相对于凸台和凹槽两种界面缺陷而言,气泡的存在对CFRP-衬砌混凝土界面应力状态的影响最为不利;随着气泡深度和长度的增加,界面径向应力的集中程度明显提高。故在CFRP粘贴完成后,对于CFRP的粘贴质量应进行详细检查,对于存在气泡的部位,建议采用针管注胶等方式进行处理。

Affected by the flow scouring in the water conveyance tunnel,the unevenness of surface of the lining concrete may result in a change in the local thickness of the adhesive layer.In this paper,the effect of the inhomogeneous thickness of the adhesive layer on the stress state at the interface of CFRP-lining concrete was investigated using the finite element method.Based on the solid-spring-solid 3D finite element model,notches were placed in the adhesive layer element and the lining concrete element to simulate the bumps,grooves and bubbles.By changing the position,depth and length of the notches,the stress state of the interface with different notches were analyzed.The results showed that compared with the convex and groove,the bubbles were the most disadvantageous factor to the structure.With the increasing of bubble depth and length,the concentration of radial stress at the interface increased significantly.Therefore,after the CFRP paste is completed,the paste quality of CFRP should be checked in detail,and for the parts with air bubbles,it is recommended to use syringe injection and other methods to deal with them.