Selection of bolted joints and bending stiffness of shield tunnel of Z2 metro line in Tianjin Binhai New Area

Aiming at different types of bolted joints, taking into account the discontinuity of complex joints and the pre-tightening force of joints, the longitudinal joints of shield tunnel segments of Z2 metro line in Tianjin Binhai New Area are studied. The effects of straight bolts, oblique bolts and bending bolts on the mechanical properties of segment joints under different bending moments and axial forces are analyzed and compared. According to the analysis results, the applicability of the proposed three kinds of bolted joints and their values of bending stiffness under different buried depths and bending moments are given. The results show that the bolt form has little effect on the maximum stress position of the bolts. The tensile stress and joint opening of the bolts decrease with the increase of axial forces, but the bending stiffness of the joints increase. The tensile stress, dislocation and opening of the joints increase with the increase of the bending moment, but the bending stiffness of the joints decreases accordingly.