Abstract: In order to study the degradation of bending mechanical property of longitudinal joint in Shanghai Metro shield tunnel induced by reinforcement corrosion, accelerated reinforcement corrosion experiments of segment in the environment of chloride attack and fullscale tests with sagging moment are conducted based on the environmental condition and spatial distribution of metro shield tunnel. A 3D refined FEM model of longitudinal joint is established to analyze the deterioration status of longitudinal joint mechanical property under the influence of reinforcement corrosion. The results of fullscale test and numerical simulation are compared and analyzed, and the comparison results show that: (1) Under the effect of sagging moment, the deformation of longitudinal joint after reinforcement corrosion has obvious periodical characteristics; in the fullscale test, the deformation of longitudinal joint can be divided into 3 stages; and in the numerical simulation, the deformation of longitudinal joint can be divided into 7 states considering the definition of 6 feature points. (2) In the first 6 stages, the reinforcement corrosion affects the deformation of longitudinal joint little; while in the last stage, as the thickness of reinforcement corrosion increases, the bolt strain and ultimate bearing capacity reduce; the maximum bolt strain decreases greatly and ultimate bearing capacity decreases small. (3) Under the effect of sagging moment, the major failure modes of longitudinal joint after reinforcement corrosion include bolt stretch bending, end ribbed reinforcement snapped and edge concrete of outer surface stripping and crushed.

Key words: shield tunnel, reinforcement corrosion, longitudinal joint, segment, mechanical property, fullscale test, numerical simulation