双线不同盾构机掘进地表变形及施工参数影响分析

Analysis on Ground Surface Deformation and Influence of Construction Parameters Caused by Two Different Shield Machines in Double-tube Tunnelling

  • 摘要: 文章依托杭州地铁2号线某盾构区间段工程,对软土区双线采用不同盾构机施工引起的地表变形进行了现场实测,得到了双线盾构掘进引起的地表变形规律,并验证了修正的双线Peck公式的适用性。结果表明:软土区先、后行线盾构掘进参数不同,其影响大小也不尽相同,地表变形量在盾构机通过前后急剧变化,由于注浆的影响,在盾尾通过时会有回弹现象发生;软土区盾构刀盘扭矩可由5个计算因子组成,计算结果与实测值吻合度较高;盾构刀盘开口率越大,其平均扭矩值越大,土体损失率大的占比也就越高,引起的地表最大沉降量也越大;以刀盘扭矩T和单环排土量Q的比值作为控制参数,分析得到了其与地表沉降值存在一定的正相关关系,且刀盘开口率越小,拟合得到的结果就越精确。

     

    Abstract: Based on a shield-driven running tunnel project of Hangzhou Metro Line 2, this paper carries out field measuring of the ground surface deformation caused by two different shield machines in double-tube tunnelling in soft soil areas, obtains the laws of the surface deformation caused by shield-driven double-tube tunnelling and verifies the applicability of the modified Peck formula to double-tube tunnelling. The results show that in soft soil areas the impacts on ground surface deformation caused by different shield construction parameters in the previously and subsequently excavated tunnels are different, while the surface deformation changes sharply before and after the shield machine passing through the cutting face, and a rebound phenomenon occurs when the shield tail passes through the cutting face due to the influence of the grouting; The cutterhead torque of the shield machine in soft soil areas can be composed of five calculation factors, and the calculation results are in good agreement with the measured values. The larger the opening rate of the shield cutterhead is, the larger the average torque value will be, the higher the percentage of large ground loss rate will be, and the larger the maximum ground surface settlement will be; The ratio of cutterhead torque T to mucking volume per ring Q is used as the control parameter for analyzing the ground surface settlement, and a certain positive correlation between the ratio and the surface settlement value is determined, the smaller the cutterhead opening rate is, the more accurate the fitting results will be.

     

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