INFLUENCE ANALYSIS ON LONGITUDINAL DISLOCATION FOR SHIELD TUNNEL SEGMENT

A 3D discontinuous-contact computation model of shield segments and bolts is build, which has a 10mm existing dislocation on a longitudinal joint, and it simulates by the finite element software ABAQUS. The influence on the segment by dislocation has been studied, and the calculated values are compared with the measured data of experiment. The results show that the dislocation causes an additional contact pressure between the two segments which has dislocation. Because the dislocation occurs in different places in segments, the minimum increase extent of axial force is 101%, the maximum increase extent of axial force is 281%, and the minimum increase extent of bending moment is 78%, the maximum increase extent of bending moment is 275%. Influenced by the existing dislocation, the bending moments in the two sides of shield segments are less than the value in non-dislocation condition. It works out that the maximum width of a crack on a segment near dislocation is 0.21mm by the normal using limit state method. It can draw a conclusion by simulated and measured data that the dislocation of shield segments cause the increase of internal forces and breakage in local positions, and that the dislocation should make enough attention on the construction and design of a shield tunnel.