摘要
成都地铁5号线为满足车辆调度需求,在九兴大道站小里程端采用左线盾构隧道与右线大断面浅埋暗挖隧道的双线并行布设方案,双洞净距2.9m.本文以该超小净距隧道为背景,采用数值模拟方法对隧道开挖时地表沉降规律及夹层土体应力状况进行了分析.结果表明,无论何种开挖次序,先行隧道的开挖均会导致后行洞开挖引起的地表沉降曲线向先行洞偏移并有所增大;由于左线小断面盾构隧道施工扰动理论上较小,因此先施工右线大断面浅埋暗挖隧道后再进行左线盾构隧道的施工顺序更为合理;先浅埋暗挖后盾构隧道施工造成的地表沉降值在两洞中间区域略小于先盾构后浅埋暗挖隧道施工;双线隧道通过后地表沉降槽呈现出“U”形状态,盾构隧道的通过造成地表沉降影响范围增加了约1/4;双线开挖过程中中间土体在浅埋暗挖隧道一侧受施工的影响更为明显,应重点关注.
In order to meet the demand of vehicle dispatching,the double-line layout plan is adopted in the Jiuxing Avenue Station of Chengdu Metro Line 5,which contains shield tunnel on the left line and large section shallow-buried excavation tunnel on the right line,with a 2.9 m excavation clearance.In this paper,taking the ultra-small spacing tunnel as the background,the numerical simulation method was adopted to analyze the ground settlement law and the intermediate layer soft stress state under the excavation of the tunnel.The results show that whatever the excavation sequence is,the excavation of the first-constructed tunnel will lead to the increased displacement of the ground surface subsidence caused by the excavation of the rear turmel and a deviation of the subsidence curve to the first-constructed tunnel,because the disturbance of shield tunnelling with small cross-section on the left is relatively small in theory,it is more reasonable to construct large cross-section shallow-buried tunnels on the right before the shield tunnelling on the left.The ground settlement value caused by the construction of shield tunnelling after shallow-buried excavating is slightly smaller than that of shallow-buried excavating after shield tunnelling in the middle area of two tunnels.The surface subsidence is in a "U"shape trough after the double- line tunnel passed,and the influence scope of ground subsidence caused by the shield tunnel passing is increased nearly by 1/4.In the process of the double-track excavation,the influence of intermediate soil on the side of shallow-buried tunnels is more obvious,which should be paid more attention to.
作者
王振田
Wang Zhentian(China Railway 21st Bureau Group Rail Transit Engineering Co.Ltd.,Jinan Shandong 250000,China)
出处
《铁道建筑技术》
2019年第1期82-88,共7页
Railway Construction Technology
基金
中铁二十一局集团有限公司科技研究开发计划项目(16C-9)
关键词
小净距
双线并行
盾构隧道
浅埋暗挖隧道
数值模拟
监测
small spacing
double-line parallel
shield tunnel
shallow-buried excavation tunnel
numerical simulation
monitoring
