盾构隧道管片纵缝错台的影响分析

INFLUENCE ANALYSIS ON LONGITUDINAL DISLOCATION FOR SHIELD TUNNEL SEGMENT

采用有限元软件ABAQUS建立存在10mm既有纵缝错台的盾构管片与螺栓的三维非连续-接触计算模型,分析错台对管片的影响,并与现场实测值进行对比分析。研究结果显示:管片错台使错台拼装块与邻近拼装块之间产生附加的接触压力。由于错台发生在管片环中的具体位置不同,轴力值最小增加幅度为101%,最大增加幅度为281%;弯矩值最小增加幅度为78%,最大增加幅度为275%。相对于无既有错台工况,受既有错台影响,盾构管片两侧拱腰的弯矩值均有所减小。采用正常使用极限状态方法计算得出管片在错台附近的最大裂缝宽度为0.21mm。通过模拟计算与现场实测数据可以得出:盾构管片错台会引起局部管片内力增大以及破损,在盾构施工与设计工作中应当引起足够的重视。

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.