盾构隧道管片施工力学性能三维数值模拟研究

摘要

研究目的:施工阶段的管片外部荷载系统和力学性能与正常使用阶段相比均表现出较大差异,大量工程经验表明,管片在施工阶段破损的概率要远远高于正常使用阶段.本文通过建立考虑环、纵向接头不连续性的三维盾构隧道有限元模型,针对注浆压力、千斤顶推力以及拼装方式三个施工要素进行研究,拟为盾构施工提供合理的意见.研究结论:分析结果表明,在施工阶段,由于管片外部荷载沿隧道纵向有差异且接头存在非连续性,管片的力学性能沿隧道纵向存在较大差异,各环变形特征也不尽相同,与传统均值连续模型相比亦存在较大差异,注浆压力、千斤顶推力对施工阶段管片力学性能有较大影响,管片在错缝、通缝拼装条件下表现的力学性能存在较大差异,综合来看,错缝拼装结构相比通缝拼装具有更好的结构整体刚度.%Research purposes: The external load system and mechanical properties of segment during construction arernbig different from the normal use. A large number of engineering experiences have shown that the damaged probability ofrnsegment during construction is much higher than that during normal use. This paper researches the key elements of therngrouting pressure, jacking force and assembling way during construction with the FEM three - dimensional model for thernshield tunnel to provide the reference to the similar works.rnResearch conclusions:The analysis results show that the segments mechanical properties along the vertical direction ofrnthe tunnel are big different, and the deformation features of each cirque are not the same and big different from thatrnobtained by the conventional mean value continuous model due to the differences of the external load of the segmentrnalong the longitudinal direction of the tunnel and the non - continuity of the joint. The grouting pressure and jackingrnforce have apparent effects on the mechanical properties of segment, and the mechanical properties of segment inrnstaggered joint are quite different from the straight joint. Moreover, the staggered joint structure is better than straightrnjoint in the overall stiffness.