基于总应变裂缝本构的箱梁混凝土注胶修复机理研究

Research on Gluing Repair Mechanism of Box Girder Concrete Based on Total Strain Cracking Constitution

混凝土箱梁结构在长时间运营荷载和环境作用下产生的裂缝,影响着结构的整体性和耐久性,灌注式注胶是修复混凝土裂缝的有效方法.基于总应变裂缝本构模型并考虑横向约束效应的影响,通过Midas FEA建立箱梁有限元模型分析结构的应力、应变及荷载系数之间的关系,荷载系数大于0.5后箱梁各个特征节点逐渐呈现出非线性特征.在胶液渗流机理的基础上,对箱梁实体裂缝模型进行中高压灌注式注胶修复,并对修复后箱梁各个特征点进行应变量测和底板跨中挠度监测,结果表明底板跨中应变和挠度分别较修复前减小18%和25%,修复效果良好.

Cracking in concrete box girder structures caused by long-term operating loads and environmental effects affects the integrity and durability of structures. Cast-in-place glue injection is an effective method to repair concrete cracking. Based on the constitutive model of total strain cracking and considering the effect of transverse restraint, the finite element model of box girder is established by Midas FEA to analyze the relationship between stress, strain and load coefficient. When the load coefficient is greater than 0.5, the characteristic joints of box girder gradually show nonlinear characteristics. Based on the mechanism of glue seepage, the solid crack model of box girder was repaired with medium-high pressure injection glue. The strain of every characteristic point of the repaired box girder is measured and the mid-span deflection of the bottom plate is monitored. The results show that the mid-span strain and deflection of the bottom plate are reduced by 18% and 25% respectively;and the repairing effect is good.