盾构法隧道管片环缝面不平整对结构受力影响研究

为了解环缝面不平整导致管片产生渗漏裂缝的具体影响,对衬砌环不同错缝拼装角度、环缝面不同传力方式、环缝面不同不平整度等因素对管片纵向受力及开裂的影响进行研究。主要研究结论如下: 1)因管片制作尺寸误差不可避免,设计中必须考虑环缝面不平整对管片结构受力的影响。由环缝面不平整产生的纵向不均匀接触荷载既可能是施工荷载,也可能是使用阶段的一个可变荷载。2)因管片环缝面不平整产生的纵向荷载与衬砌环分块、拼装方式及传力方式等有关,1/3 或1/4 标准块错缝拼装角度产生的最大纵向荷载要大于1/2 标准块错缝拼装角度,凸台传力方式产生的最大纵向荷载要大于垫片传力方式。当管片分块与拼装方式相同时,凸台传力方式更容易使管片产生开裂。3)在采用最不利纵向荷载时,建议取1. 0Δ(Δ 为环宽允许偏差)作为环缝面不平整度设计值,计算所得管片纵向弯矩与管片横向内力组合后按双向偏压构件对管片进行配筋,且纵向弯矩产生的裂缝开展宽度不应大于0. 1 mm。

Influence of Uneven Annular Joint Surface of Shield Tunnel Segment on Structural Stress

The influences of different staggered joint assembly angles of lining ring, different force transmission modes of annular joint surface and different unevenness of annular joint surface on longitudinal stress and cracking of shield tunnel segment are studied. Some conclusions are drawn as follows: （1） The influence of unevenness of annular joint surface on the stress of segment structure must be considered in design due to the dimension error of segment;the longitudinal non uniform contact load caused by uneven annular joint may be either construction load or variable load in service stage.（2） The longitudinal load caused by uneven annular joint surface of segment is related to the segment of lining ring, assembling mode and transmission mode;the maximum longitudinal load produced by staggered joint assembling angle of 1/3 or 1/4 standard block is larger than that of 1/2 standard block; the maximum longitudinal load produced by convex platform transmission mode is larger than that by gasket transmission mode;when the segment is divided into blocks and assembled in the same way, the convex force transmission mode is easier to cause segment crack. （3）When the most unfavorable longitudinal load is used, it is recommended to take 1.0Δ（where Δ is the allowable error of ring width） as the design value of the ring joint surface irregularity;after the combination of the calculated longitudinal bending moment and the transverse internal force of the segment, the segment shall be reinforced according to the biaxial bias component, and the crack development width caused by the longitudinal bending moment shall not be greater than 0.1 mm.