联络通道施工对隧道T接结构的受力影响研究

Study on the infl uence of connecting passage construction on the stress of T-junction structure

在软弱地层施工地铁隧道联络通道会造成隧道结构局部应力集中,严重时可导致管片开裂等现象。为解决这一问题,利用ABAQUS有限元软件建立主隧道与联络通道结构模型,通过改变联络通道掘进长度与联络通道底部基床系数等因素,探究机械法联络通道T接隧道建设对主隧道结构的影响。研究发现:联络通道施工荷载使隧道发生横向扭剪变形,可导致施工过程中纵向顶推转角发生变化;随着联络通道掘进长度的增加,主隧道与联络通道管片应力不断增大;联络通道靠近主隧道上方管片受力变形大于主隧道上方(应力增加17%、变形可达4倍);随着基床系数减小,隧道结构整体受力变形呈增大趋势(应力增大44%、沉降增大34%)。研究成果可为相关工程安全建设提供参考。

When the metro tunnel connecting passage is constructed in weak strata,it will cause local stress concentration of the tunnel structure,which can seriously lead to the cracking of the segment.In this regard,the ABAQUS fi nite element software is used to establish the structural model of the main tunnel and the connecting passage.By changing the excavation length of the connecting passage and the subgrade coefficient at the bottom of the connecting passage,the influence of the construction of the T-connected tunnel of the mechanical connecting channel on the main tunnel structure is explored.It is found that the construction load of the connecting passage causes the transverse torsional shear deformation of the tunnel,which can lead to the change of the longitudinal jacking angle during the construction process.With the increase of the excavation length of the connecting passage,the stress of the main tunnel and the connecting passage segment increases continuously.The deformation of the segment near the main tunnel is greater than that above the main tunnel(the stress increases by 17%and the deformation can reach 4 times).With the decrease in subgrade coefficient,the overall deformation of the tunnel structure increases(stress increases by 44%,settlement increases by 34%).The research results can provide reference for the safe construction of related projects.