以杭州市环城北路地下通道为工程背景,对小净距上下重叠盾构隧道的施工扰动进行了研究.通过ABAQUS6.13有限元软件进行数值模拟,对比分析不同开挖顺序工况下周围土体的变形特点,地表沉降的变化,以及后建隧道对先建隧道衬砌的变形和应力影响.研究结果表明:盾构隧道的开挖会引起明显的地表沉降,约3.0cm;后建隧道的施工会引起先建隧道的内外侧应力相应地减小;不同施工顺序对这两者无显著影响,但会显著影响已建隧道的衬砌位移.先上后下工况时,后建隧道对先建隧道表现为加剧衬砌沉降,而在先下后上工况时,后建隧道对先建隧道的衬砌顶部位移有保护的作用,累计减弱下沉0.46 cm.因此推荐采用先开挖下行隧道,再开挖上行隧道的施工顺序.%The fast development of urban underground traffic has brought more construction projects of small-spacing tunnels.However,the study of the interaction of small-spacing overlapped shield tunnel is rarely seen.Therefore,based on the background of underpass of North Huancheng Road,the disturbance effected by construction order of small-spacing overlapped shield tunnel is studied.With the help of the finite element software ABAQUS 6.13,the deformation of soil mass,the change of surface subsidence,as well as the stress and deformation of the existing tunnel's upper side effected by the tunnel built later of different construction orders are compared and analyzed.The study result indicates that the excavation of tunnels will cause significant surface subsidence,approximately 3.0 centimeters;the tunnel built later will let the stress of the existing tunnel lining decreases relatively;different construction order has little influence on the change of surface subsidence and the stress of the existing tunnel's upper side,but influences the deformation of the existing tunnel's upper side significantly.When building above tunnel first,the tunnel built later aggravates the deformation of the tunnel lining,the top and base of tunnel lining increase by 1.26 cm and 1.73 cm relatively;comparatively,when building down tunnel first,the tunnel built later decreases the deformation of the tunnel lining,adding up to about 0.46 centimeters.Consequently,building the down tunnel first is better in controlling the deformation of tunnel lining.Therefore,the construction order of building the down tunnel first is recommended.
展开▼
