Experimental investigation of corrosion effect on bending deflection of shield tunnel segment containing transverse cracks

Corrosion of the steel rebar will be generated in the cracked concrete of the shield tunnel during the operation period, which will reduce the bending performance of the tunnel segment. In this study, the effect of the rebar corrosion on the bending deflection of the shield tunnel segment that contains transverse cracks is investigated by experimental tests. The initial transverse cracks of the segment are simulated by a bending load device, and the galvanostatic method is used to simulate the corrosion of the segment rebar. The degradation of the segment bending deflection after the rebar corrosion process is measured and compared with the non-corroded segment. The results reveal that when the depth of the transverse crack does not exceed the thickness of the protective layer, the corrosion of the rebar has little effect on the bending degradation. However, when the width and depth of the transverse crack reach approximately 1.2 and 210 mm, respectively, the degradation rate of bending deflection begins to increase rapidly.