Abstract:  In the fullscale compressive bending test of segmental joint, whether the joint is in a state of pure compressive bending is one of the most important factors affecting the accuracy of test results. Hence, a loading device for bending test of segmental joint with large rotation angle and in a state of pure compressive bending is designed. A series of bending tests for segmental joint under different axial forces and moments are carried out. The LVDTs and strain gauges are adopted to measure the joint deformation and bolt strain. Based on the test results, the conclusions are drawn as follows: (1) When the joint is in a state of pure compressive bending, the variation curves of vertical displacement, opening, closure, rotation angle, bolt stress with bending moment under positive and negative moments are relatively smooth. (2) The variation of the opening height of joint with bending moment under positive moment can be divided into two stages, while an obvious "platform section" appears between the abovementioned two stages under negative moment due to the influence of complex deformation contact relationship of the joint surface. (3) When the joints are connected by oblique bolt, the axial force has a greater impact on the bending performance of the joint under positive moment than that under negative moment, and the bending performance differences of the segmental joint under positive and negative moments reduce with the increase of axial force.

Key words: large crosssection shield tunnel, segmental joint, pure compressive bending, fullscale bending test, bending performance