浅埋小净距后行盾构掘进控制和变形分析

为研究小净距段后行盾构掘进引起先行隧道变形的规律,验证预先施做隔离桩对控制变形的实际效果,以某国红线轻轨盾构通过Herzl街浅埋小净距为例,详细阐述后行盾构掘进控制措施。通过对监测数据和掘进参数分析对比,得出:①小净距后行盾构掘进导致先行隧道产生不均一的水平方向位移,靠近后行隧道一侧位移远大于远离后行隧道一侧;②先行隧道位移过程中依次经历缓慢变形,急剧突变,峰值持续,明显回缩和趋势稳定5个阶段;③隧道间施做隔离桩可减小后行盾构掘进对先行隧道的影响,表现为减缓位移趋势和降低位移峰值;④后行盾构掘进合理参数选择对控制先行隧道位移至关重要。

Succeeding shield tunneling control and deformation analysis in shallow and close proximity condition

In this paper,the influence of shield tunneling on the preceding tunnel at small clear-span section is studied,and the actual effect of pre-applied isolation piles on deformation control is verified.By taking the shield of Red Line light rail in Israel passing through Herzl street with small clear-span as an example,the tunneling control measures of succeeding shield are demonstrated in detail.It concludes from comparative analysis between measuring data and tunneling data that:a)The tunneling of small clear-span succeeding shield would cause uneven horizontal displacement of preceding tunnel,and the displacement near succeeding tunnel is far larger than that away from succeeding tunnel;b)The displacement of the preceding tunnel goes through 5 phases,i.e.slow deformation,sharp raise,peak duration,obvious retraction and stable trend;c)The application of isolation piles between tunnels can reduce the influence of succeeding shield tunneling on the preceding tunnels,which presents as slowing down the displacement trend and reducing the displacement peak value;d)The reasonable parameters selection for succeeding shield is essential for controlling the displacement of the preceding tunnel.