Abstract: Shield tunnels are usually constructed by connecting lining segments with joints, typically using curved, inclined-straight, or straight bolts. However, when applied to segment joints, curved bolts tend to loosen during application, compromising the stability of the connection. Meanwhile, inclined-straight bolts cannot fully exert their mechanical properties because their performance utilization rate is relatively low, whereas the handholes of straight bolts weaken the local load-bearing performance of the segments, reducing the overall structural safety. To mitigate these shortcomings and enhance the mechanical performance and engineering applicability of lining segments in shield tunneling, the authors introduce a novel type of lining segment connector called the angular drive bolt joint. The performance of the joint is comprehensively evaluated during a full-scale experiment of two types of joint structures: single-row and double-row angular drive bolt joints. The bearing capacities and engineering applicabilities of the joints are systematically evaluated under different designs. The experimental data are analyzed and compared with those of short straight bolt joints. The results indicate (1) three deformation stages but different failure modes of both angular drive joint types under loading, (2) a considerably stronger deformation resistance of the double-row angular drive bolt than of the other two joints, and (3) easier installation of the angular drive bolt joint than of the short straight bolt joint, facilitating automatic assembly without weakening the load-bearing performance. The strong resistance of the double-row angular drive bolt joint is attributable to the strong pre-tightening force of the bolt, which increases the effective height of the joint section and reasonably distributes the tensile points, thereby enhancing the rotational stiffness of the joint.

Key words: shield tunnel, segment joints, angle drive bolts, bending test, mechanical properties